ball mill in korba

ball mills, sand mill, pug mixer, high speed disperser, mumbai, india

Raymer Engineering Most Trusted Manufacturer, Supplier and Exporters of Ball Mills in Mumbai-India. You're Source for Ball Mill Come to us. Bead Mills For the production of Dyestuffs, paints, pigments, Fertilizer, Insecticides & pesticide. Our Ball Mills complies with international standards. In this product range, we also offer shrouded ball mills that are extensively used in various industrial sectors for dispersion of enamels & primers, powder distempers and cement paints. Industrial ball mills made available by us are fabricated using quality-approved mild steel & stainless steel, and are used to grind materials into extremely fine powder. Owing to the quality and efficiency of our equipment, these find widespread demand for processing mineral dressing, paints, pyrotechnics and ceramics, among others. Our ball mills are perfect for dispersion of enamels and primers in the range of 25 kg to 5000 kg batch in both pebble and steel, with or without water cooling. Furthermore, the shrouded ball mills are especially designed & developed for powder distempers and cement paints.

Uses / Applications Pigment colors Minerals & ores Chemicals Technical products Dyestuffs Fertilizer Insecticides & pesticide The equipment offered in this range are also used for dispersion of enamels and primers in the size range of 25 kg to 5000 kg batch. Features Long functional life Hassle-free operations Corrosion & abrasion resistance Easy installation Sturdy construction Facilitates easy loading and unloading of material Construction Material Mild steel MS or SS coating SS Jacketed

We Manufacturer, Supplier and Exporters of Ball Mills to the following locations across the world : India Ambaji, Ayodhya, Abids, Agra, Ahmedabad, Ahmednagar, Alappuzha, Allahabad, Alwar, Akola, Alibag, Almora, Amlapuram, Amravati, Amritsar, Anand, Anandpur Sahib, Angul, Anna Salai, Arambagh, Asansol, Ajmer, Amreli, Aizawl, Agartala, Aligarh, Auli, Aurangabad, Azamgarh, Aurangabad, Baran, Bettiah, Badaun, Badrinath, Balasore, Banaswara, Bankura, Ballia, Bardhaman, Baripada, Barrackpore, Barnala, Barwani, Beed, Beawar, Bellary, Belgaum, Bhadohi, Bhadrak, Bharuch, Bhilai, Bhilwara, Bhiwani, Bidar, Bilaspur, Bangalore, Bhind, Bhagalpur, Bharatpur, Bhavnagar, Bhopal, Bhubaneshwar, Bhuj, Bilimora, Bijapur, Bikaner, Bodh Gaya, Bokaro, Bundi, Barasat, Bareilly, Basti, Bijnor, Burhanpur, Buxur, Calangute, Chandigarh, Chamba, Chandausi, Chandauli, Chandrapur, Chhapra, Chidambaram, Chiplun, Chhindwara, Chitradurga, Chittoor, Cooch Behar, Chennai, Chittaurgarh, Churu, Coimbatore, Cuddapah, Cuttack, Dahod, Dalhousie, Davangere, Dehri, Dewas, Dwarka, Dehradun, Delhi, Deoria, Dhanbad, Dharamshala, Dispur, Dholpur, Diu Island, Durgapur, Didwana, Ernakulam, Etah, Etawah, Erode, Faridabad, Ferozpur, Faizabad, Gandhinagar, Gangapur, Garia, Gaya, Ghaziabad, Goa, Godhra, Gokul, Gonda, Gorakhpur, Greater Mumbai, Gulbarga, Guna, Guntur, Gurugram, Greater Noida, Gulmarg, Hanumangarh, Haflong, Haldia, Haridwar, Hajipur, Haldwani, Hampi, Hapur, Hubli, Hardoi, Hyderabad, Guwahati, Gangtok, Gwalior, Imphal, Indore, Itanagar, Itarsi, Jabalpur, Jagadhri, Jalna, Jamalpur, Jhajjar, Jhalawar, Jaipur, Jaisalmer, Jalandhar, Jammu, Jamshedpur, Jhansi, Jaunpur, Jodhpur, Junagadh, Jalore, Kishanganj, Katihar, Kanpur, Kangra, Kasauli, Kapurthala, Kanchipuram, Karnal, Karaikudi, Kanyakumari, Katni, Khajuraho, Khandala, Khandwa, khargone, Kishangarh, Kochi, Kodaikanal, Kohima, Kolhapur, Kolkata, Kollam, Korba, Kota, Kottayam, Kovalam, Kozhikode, Kumbakonam, Kumarakom, Kurnool, Kurukshetra, Lalitpur, Latur, Lucknow, Ludhiana, Lavasa, Leh, Laxmangarh, Madikeri, Madurai, Mahabaleshwar, Mahabalipuram, Mahbubnagar, Manali, Mandu Fort, Mangalore, Malegaon, Manipal, Margoa, Mathura, Meerut, Mirzapur, Mohali, Morena, Motihari, Moradabad, Mount Abu, Mumbai, Munger, Munnar, Mussoorie, Mysore, Muzaffarnagar, Mokokchung, Muktsar, Nagpur, Nagaon, Nagercoil, Naharlagun, Naihati, Nainital, Nalgonda, Namakkal, Nanded, Narnaul, Nasik, Nathdwara, Navsari, Neemuch, Noida, Ooty, Orchha, Palakkad, Palanpur, Pali, Palwal, Panaji, Panipat, Panvel, Pathanamthitta, Pandharpur, Patna Sahib, Panchkula, Patna, Periyar, Phagwara, Pilibhit, Pinjaur, Pollachi, Pondicherry, Ponnani, Porbandar, Port Blair, Porur, Pudukkottai, Punalur, Pune, Puri, Purnia, Pushkar, Patiala, Raxual, Rajkot, Rameswaram, Rajahmundry, Ranchi, Ratlam, Raipur, Rewa, Rewari, Rishikesh, Rourkela, Sitamrahi, Sagar, Sangareddy, Saharanpur, Salem, Salt Lake, Samastipur, Sambalpur, Sambhal, Sanchi, Sangli, Sarnath, Sasaram, Satara, Satna, Secunderabad, Sehore, Serampore, Sangrur, Sirhind, Shillong, Shimla, Shimoga, Shirdi, ShivaGanga, Shivpuri, Silvassa, Singrauli, Sirsa, Sikar, Siwan, Somnath, Sonipat, Sopore, Srikakulam, Srirangapattna, Srinagar, Sultanpur, Surat, Surendranagar, Suri, Tawang, Tezpur, Thane, Thrippunithura, Thrissur, Tiruchchirappalli, Tirumala, Tirunelveli, Thiruvannamalai, Tirur, Thalassery, Thanjavur, Thekkady, Theni, Thiruvananthpuram, Thiruvannamalai, Tirupati, Trichy, Trippur, Tumkur, Tuni, Udaipur, Udhampur, Udupi, Ujjain, Unnao, Ujjain Fort, Vidisha, Vadodra, Valsad, Vapi, Varanasi, Varkala, Vasco da Gama, Vellore, Visakhapatnam, Vijayawada, Vizianagaram, Vrindavan, Warangal, Washim, Yamunanagar, Yelahanka African Countries South Africa, Nigeria, Kenya, Ghana, Ethiopia, Tanzania, Johannesburg, Algeria, Angola, Benin, Botswana, Burkina Faso, Burundi, Cabo Verde, Cameroon, Central African Republic (CAR), Chad, Comoros, Democratic Republic of the Congo, Cote d'Ivoire, Djibouti, Egypt, Equatorial Guinea, Eritrea, Gabon, Gambia, Guinea, Guinea-Bissau, Lesotho, Liberia, Libya, Madagascar, Malawi, Mali, Mauritania, Mauritius, Morocco, Mozambique, Namibia, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, Somalia, South Sudan, Sudan, Swaziland, Togo, Tunisia, Uganda, Zambia, Zimbabwe. Gulf and Other Countries Oman, Qatar, Kuwait, Saudi Arabia, Dubai, Bahrain, Iran, United Arab Emirates, Australia, Sydney, Queensland, Melbourne, Perth, Adelaide, New Zealand, Auckland, Wellington, Hamilton. Asian Countries Afghanistan, Armenia, Azerbaijan, Bahrain, Bangladesh, Bhutan, Brunei, Cambodia, China, Cyprus, Georgia, India, Indonesia, Iran, Iraq, Israel, Japan, Jordan, Kazakhstan, Kuwait, Kyrgyzstan, Laos, Lebanon, Malaysia, Maldives, Mongolia, Myanmar (Burma), Nepal, North Korea, Oman, Pakistan, Palestine, Philippines, Qatar, Russia, Saudi Arabia, Singapore, South Korea, Sri Lanka, Syria, Taiwan, Tajikistan, Thailand, Timor-Leste, Turkey, Turkmenistan, Uzbekistan, Vietnam, Yemen

ball mills - an overview | sciencedirect topics

A ball mill is a type of grinder used to grind and blend bulk material into QDs/nanosize using different sized balls. The working principle is simple; impact and attrition size reduction take place as the ball drops from near the top of a rotating hollow cylindrical shell. The nanostructure size can be varied by varying the number and size of balls, the material used for the balls, the material used for the surface of the cylinder, the rotation speed, and the choice of material to be milled. Ball mills are commonly used for crushing and grinding the materials into an extremely fine form. The ball mill contains a hollow cylindrical shell that rotates about its axis. This cylinder is filled with balls that are made of stainless steel or rubber to the material contained in it. Ball mills are classified as attritor, horizontal, planetary, high energy, or shaker.

Grinding elements in ball mills travel at different velocities. Therefore, collision force, direction and kinetic energy between two or more elements vary greatly within the ball charge. Frictional wear or rubbing forces act on the particles, as well as collision energy. These forces are derived from the rotational motion of the balls and movement of particles within the mill and contact zones of colliding balls.

By rotation of the mill body, due to friction between mill wall and balls, the latter rise in the direction of rotation till a helix angle does not exceed the angle of repose, whereupon, the balls roll down. Increasing of rotation rate leads to growth of the centrifugal force and the helix angle increases, correspondingly, till the component of weight strength of balls become larger than the centrifugal force. From this moment the balls are beginning to fall down, describing during falling certain parabolic curves (Figure 2.7). With the further increase of rotation rate, the centrifugal force may become so large that balls will turn together with the mill body without falling down. The critical speed n (rpm) when the balls are attached to the wall due to centrifugation:

where Dm is the mill diameter in meters. The optimum rotational speed is usually set at 6580% of the critical speed. These data are approximate and may not be valid for metal particles that tend to agglomerate by welding.

The degree of filling the mill with balls also influences productivity of the mill and milling efficiency. With excessive filling, the rising balls collide with falling ones. Generally, filling the mill by balls must not exceed 3035% of its volume.

The mill productivity also depends on many other factors: physical-chemical properties of feed material, filling of the mill by balls and their sizes, armor surface shape, speed of rotation, milling fineness and timely moving off of ground product.

where b.ap is the apparent density of the balls; l is the degree of filling of the mill by balls; n is revolutions per minute; 1, and 2 are coefficients of efficiency of electric engine and drive, respectively.

A feature of ball mills is their high specific energy consumption; a mill filled with balls, working idle, consumes approximately as much energy as at full-scale capacity, i.e. during grinding of material. Therefore, it is most disadvantageous to use a ball mill at less than full capacity.

Grinding elements in ball mills travel at different velocities. Therefore, collision force, direction, and kinetic energy between two or more elements vary greatly within the ball charge. Frictional wear or rubbing forces act on the particles as well as collision energy. These forces are derived from the rotational motion of the balls and the movement of particles within the mill and contact zones of colliding balls.

By the rotation of the mill body, due to friction between the mill wall and balls, the latter rise in the direction of rotation until a helix angle does not exceed the angle of repose, whereupon the balls roll down. Increasing the rotation rate leads to the growth of the centrifugal force and the helix angle increases, correspondingly, until the component of the weight strength of balls becomes larger than the centrifugal force. From this moment, the balls are beginning to fall down, describing certain parabolic curves during the fall (Fig. 2.10).

With the further increase of rotation rate, the centrifugal force may become so large that balls will turn together with the mill body without falling down. The critical speed n (rpm) when the balls remain attached to the wall with the aid of centrifugal force is:

where Dm is the mill diameter in meters. The optimum rotational speed is usually set at 65%80% of the critical speed. These data are approximate and may not be valid for metal particles that tend to agglomerate by welding.

where db.max is the maximum size of the feed (mm), is the compression strength (MPa), E is the modulus of elasticity (MPa), b is the density of material of balls (kg/m3), and D is the inner diameter of the mill body (m).

The degree of filling the mill with balls also influences the productivity of the mill and milling efficiency. With excessive filling, the rising balls collide with falling ones. Generally, filling the mill by balls must not exceed 30%35% of its volume.

The productivity of ball mills depends on the drum diameter and the relation of drum diameter and length. The optimum ratio between length L and diameter D, L:D, is usually accepted in the range 1.561.64. The mill productivity also depends on many other factors, including the physical-chemical properties of the feed material, the filling of the mill by balls and their sizes, the armor surface shape, the speed of rotation, the milling fineness, and the timely moving off of the ground product.

where D is the drum diameter, L is the drum length, b.ap is the apparent density of the balls, is the degree of filling of the mill by balls, n is the revolutions per minute, and 1, and 2 are coefficients of efficiency of electric engine and drive, respectively.

A feature of ball mills is their high specific energy consumption. A mill filled with balls, working idle, consumes approximately as much energy as at full-scale capacity, that is, during the grinding of material. Therefore, it is most disadvantageous to use a ball mill at less than full capacity.

Milling time in tumbler mills is longer to accomplish the same level of blending achieved in the attrition or vibratory mill, but the overall productivity is substantially greater. Tumbler mills usually are used to pulverize or flake metals, using a grinding aid or lubricant to prevent cold welding agglomeration and to minimize oxidation [23].

Cylindrical Ball Mills differ usually in steel drum design (Fig. 2.11), which is lined inside by armor slabs that have dissimilar sizes and form a rough inside surface. Due to such juts, the impact force of falling balls is strengthened. The initial material is fed into the mill by a screw feeder located in a hollow trunnion; the ground product is discharged through the opposite hollow trunnion.

Cylindrical screen ball mills have a drum with spiral curved plates with longitudinal slits between them. The ground product passes into these slits and then through a cylindrical sieve and is discharged via the unloading funnel of the mill body.

Conical Ball Mills differ in mill body construction, which is composed of two cones and a short cylindrical part located between them (Fig. 2.12). Such a ball mill body is expedient because efficiency is appreciably increased. Peripheral velocity along the conical drum scales down in the direction from the cylindrical part to the discharge outlet; the helix angle of balls is decreased and, consequently, so is their kinetic energy. The size of the disintegrated particles also decreases as the discharge outlet is approached and the energy used decreases. In a conical mill, most big balls take up a position in the deeper, cylindrical part of the body; thus, the size of the balls scales down in the direction of the discharge outlet.

For emptying, the conical mill is installed with a slope from bearing to one. In wet grinding, emptying is realized by the decantation principle, that is, by means of unloading through one of two trunnions.

With dry grinding, these mills often work in a closed cycle. A scheme of the conical ball mill supplied with an air separator is shown in Fig. 2.13. Air is fed to the mill by means of a fan. Carried off by air currents, the product arrives at the air separator, from which the coarse particles are returned by gravity via a tube into the mill. The finished product is trapped in a cyclone while the air is returned in the fan.

The ball mill is a tumbling mill that uses steel balls as the grinding media. The length of the cylindrical shell is usually 11.5 times the shell diameter (Figure 8.11). The feed can be dry, with less than 3% moisture to minimize ball coating, or slurry containing 2040% water by weight. Ball mills are employed in either primary or secondary grinding applications. In primary applications, they receive their feed from crushers, and in secondary applications, they receive their feed from rod mills, AG mills, or SAG mills.

Ball mills are filled up to 40% with steel balls (with 3080mm diameter), which effectively grind the ore. The material that is to be ground fills the voids between the balls. The tumbling balls capture the particles in ball/ball or ball/liner events and load them to the point of fracture.

When hard pebbles rather than steel balls are used for the grinding media, the mills are known as pebble mills. As mentioned earlier, pebble mills are widely used in the North American taconite iron ore operations. Since the weight of pebbles per unit volume is 3555% of that of steel balls, and as the power input is directly proportional to the volume weight of the grinding medium, the power input and capacity of pebble mills are correspondingly lower. Thus, in a given grinding circuit, for a certain feed rate, a pebble mill would be much larger than a ball mill, with correspondingly a higher capital cost. However, the increase in capital cost is justified economically by a reduction in operating cost attributed to the elimination of steel grinding media.

In general, ball mills can be operated either wet or dry and are capable of producing products in the order of 100m. This represents reduction ratios of as great as 100. Very large tonnages can be ground with these ball mills because they are very effective material handling devices. Ball mills are rated by power rather than capacity. Today, the largest ball mill in operation is 8.53m diameter and 13.41m long with a corresponding motor power of 22MW (Toromocho, private communications).

Modern ball mills consist of two chambers separated by a diaphragm. In the first chamber the steel-alloy balls (also described as charge balls or media) are about 90mm diameter. The mill liners are designed to lift the media as the mill rotates, so the comminution process in the first chamber is dominated by crushing. In the second chamber the ball diameters are of smaller diameter, between 60 and 15mm. In this chamber the lining is typically a classifying lining which sorts the media so that ball size reduces towards the discharge end of the mill. Here, comminution takes place in the rolling point-contact zone between each charge ball. An example of a two chamber ball mill is illustrated in Fig. 2.22.15

Much of the energy consumed by a ball mill generates heat. Water is injected into the second chamber of the mill to provide evaporative cooling. Air flow through the mill is one medium for cement transport but also removes water vapour and makes some contribution to cooling.

Grinding is an energy intensive process and grinding more finely than necessary wastes energy. Cement consists of clinker, gypsum and other components mostly more easily ground than clinker. To minimise over-grinding modern ball mills are fitted with dynamic separators (otherwise described as classifiers or more simply as separators). The working principle is that cement is removed from the mill before over-grinding has taken place. The cement is then separated into a fine fraction, which meets finished product requirements, and a coarse fraction which is returned to mill inlet. Recirculation factor, that is, the ratio of mill throughput to fresh feed is up to three. Beyond this, efficiency gains are minimal.

For more than 50years vertical mills have been the mill of choice for grinding raw materials into raw meal. More recently they have become widely used for cement production. They have lower specific energy consumption than ball mills and the separator, as in raw mills, is integral with the mill body.

In the Loesche mill, Fig. 2.23,16 two pairs of rollers are used. In each pair the first, smaller diameter, roller stabilises the bed prior to grinding which takes place under the larger roller. Manufacturers use different technologies for bed stabilisation.

Comminution in ball mills and vertical mills differs fundamentally. In a ball mill, size reduction takes place by impact and attrition. In a vertical mill the bed of material is subject to such a high pressure that individual particles within the bed are fractured, even though the particles are very much smaller than the bed thickness.

Early issues with vertical mills, such as narrower PSD and modified cement hydration characteristics compared with ball mills, have been resolved. One modification has been to install a hot gas generator so the gas temperature is high enough to partially dehydrate the gypsum.

For many decades the two-compartment ball mill in closed circuit with a high-efficiency separator has been the mill of choice. In the last decade vertical mills have taken an increasing share of the cement milling market, not least because the specific power consumption of vertical mills is about 30% less than that of ball mills and for finely ground cement less still. The vertical mill has a proven track record in grinding blastfurnace slag, where it has the additional advantage of being a much more effective drier of wet feedstock than a ball mill.

The vertical mill is more complex but its installation is more compact. The relative installed capital costs tend to be site specific. Historically the installed cost has tended to be slightly higher for the vertical mill.

Special graph paper is used with lglg(1/R(x)) on the abscissa and lg(x) on the ordinate axes. The higher the value of n, the narrower the particle size distribution. The position parameter is the particle size with the highest mass density distribution, the peak of the mass density distribution curve.

Vertical mills tend to produce cement with a higher value of n. Values of n normally lie between 0.8 and 1.2, dependent particularly on cement fineness. The position parameter is, of course, lower for more finely ground cements.

Separator efficiency is defined as specific power consumption reduction of the mill open-to-closed-circuit with the actual separator, compared with specific power consumption reduction of the mill open-to-closed-circuit with an ideal separator.

As shown in Fig. 2.24, circulating factor is defined as mill mass flow, that is, fresh feed plus separator returns. The maximum power reduction arising from use of an ideal separator increases non-linearly with circulation factor and is dependent on Rf, normally based on residues in the interval 3245m. The value of the comminution index, W, is also a function of Rf. The finer the cement, the lower Rf and the greater the maximum power reduction. At C = 2 most of maximum power reduction is achieved, but beyond C = 3 there is very little further reduction.

Separator particle separation performance is assessed using the Tromp curve, a graph of percentage separator feed to rejects against particle size range. An example is shown in Fig. 2.25. Data required is the PSD of separator feed material and of rejects and finished product streams. The bypass and slope provide a measure of separator performance.

The particle size is plotted on a logarithmic scale on the ordinate axis. The percentage is plotted on the abscissa either on a linear (as shown here) or on a Gaussian scale. The advantage of using the Gaussian scale is that the two parts of the graph can be approximated by two straight lines.

The measurement of PSD of a sample of cement is carried out using laser-based methodologies. It requires a skilled operator to achieve consistent results. Agglomeration will vary dependent on whether grinding aid is used. Different laser analysis methods may not give the same results, so for comparative purposes the same method must be used.

The ball mill is a cylindrical drum (or cylindrical conical) turning around its horizontal axis. It is partially filled with grinding bodies: cast iron or steel balls, or even flint (silica) or porcelain bearings. Spaces between balls or bearings are occupied by the load to be milled.

Following drum rotation, balls or bearings rise by rolling along the cylindrical wall and descending again in a cascade or cataract from a certain height. The output is then milled between two grinding bodies.

Ball mills could operate dry or even process a water suspension (almost always for ores). Dry, it is fed through a chute or a screw through the units opening. In a wet path, a system of scoops that turn with the mill is used and it plunges into a stationary tank.

Mechanochemical synthesis involves high-energy milling techniques and is generally carried out under controlled atmospheres. Nanocomposite powders of oxide, nonoxide, and mixed oxide/nonoxide materials can be prepared using this method. The major drawbacks of this synthesis method are: (1) discrete nanoparticles in the finest size range cannot be prepared; and (2) contamination of the product by the milling media.

More or less any ceramic composite powder can be synthesized by mechanical mixing of the constituent phases. The main factors that determine the properties of the resultant nanocomposite products are the type of raw materials, purity, the particle size, size distribution, and degree of agglomeration. Maintaining purity of the powders is essential for avoiding the formation of a secondary phase during sintering. Wet ball or attrition milling techniques can be used for the synthesis of homogeneous powder mixture. Al2O3/SiC composites are widely prepared by this conventional powder mixing route by using ball milling [70]. However, the disadvantage in the milling step is that it may induce certain pollution derived from the milling media.

In this mechanical method of production of nanomaterials, which works on the principle of impact, the size reduction is achieved through the impact caused when the balls drop from the top of the chamber containing the source material.

A ball mill consists of a hollow cylindrical chamber (Fig. 6.2) which rotates about a horizontal axis, and the chamber is partially filled with small balls made of steel, tungsten carbide, zirconia, agate, alumina, or silicon nitride having diameter generally 10mm. The inner surface area of the chamber is lined with an abrasion-resistant material like manganese, steel, or rubber. The magnet, placed outside the chamber, provides the pulling force to the grinding material, and by changing the magnetic force, the milling energy can be varied as desired. The ball milling process is carried out for approximately 100150h to obtain uniform-sized fine powder. In high-energy ball milling, vacuum or a specific gaseous atmosphere is maintained inside the chamber. High-energy mills are classified into attrition ball mills, planetary ball mills, vibrating ball mills, and low-energy tumbling mills. In high-energy ball milling, formation of ceramic nano-reinforcement by in situ reaction is possible.

It is an inexpensive and easy process which enables industrial scale productivity. As grinding is done in a closed chamber, dust, or contamination from the surroundings is avoided. This technique can be used to prepare dry as well as wet nanopowders. Composition of the grinding material can be varied as desired. Even though this method has several advantages, there are some disadvantages. The major disadvantage is that the shape of the produced nanoparticles is not regular. Moreover, energy consumption is relatively high, which reduces the production efficiency. This technique is suitable for the fabrication of several nanocomposites, which include Co- and Cu-based nanomaterials, Ni-NiO nanocomposites, and nanocomposites of Ti,C [71].

Planetary ball mill was used to synthesize iron nanoparticles. The synthesized nanoparticles were subjected to the characterization studies by X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques using a SIEMENS-D5000 diffractometer and Hitachi S-4800. For the synthesis of iron nanoparticles, commercial iron powder having particles size of 10m was used. The iron powder was subjected to planetary ball milling for various period of time. The optimum time period for the synthesis of nanoparticles was observed to be 10h because after that time period, chances of contamination inclined and the particles size became almost constant so the powder was ball milled for 10h to synthesize nanoparticles [11]. Fig. 12 shows the SEM image of the iron nanoparticles.

The vibratory ball mill is another kind of high-energy ball mill that is used mainly for preparing amorphous alloys. The vials capacities in the vibratory mills are smaller (about 10 ml in volume) compared to the previous types of mills. In this mill, the charge of the powder and milling tools are agitated in three perpendicular directions (Fig. 1.6) at very high speed, as high as 1200 rpm.

Another type of the vibratory ball mill, which is used at the van der Waals-Zeeman Laboratory, consists of a stainless steel vial with a hardened steel bottom, and a single hardened steel ball of 6 cm in diameter (Fig. 1.7).

The mill is evacuated during milling to a pressure of 106 Torr, in order to avoid reactions with a gas atmosphere.[44] Subsequently, this mill is suitable for mechanical alloying of some special systems that are highly reactive with the surrounding atmosphere, such as rare earth elements.

In spite of the traditional approaches used for gas-solid reaction at relatively high temperature, Calka etal.[58] and El-Eskandarany etal.[59] proposed a solid-state approach, the so-called reactive ball milling (RBM), used for preparations different families of meal nitrides and hydrides at ambient temperature. This mechanically induced gas-solid reaction can be successfully achieved, using either high- or low-energy ball-milling methods, as shown in Fig.9.5. However, high-energy ball mill is an efficient process for synthesizing nanocrystalline MgH2 powders using RBM technique, it may be difficult to scale up for matching the mass production required by industrial sector. Therefore, from a practical point of view, high-capacity low-energy milling, which can be easily scaled-up to produce large amount of MgH2 fine powders, may be more suitable for industrial mass production.

In both approaches but with different scale of time and milling efficiency, the starting Mg metal powders milled under hydrogen gas atmosphere are practicing to dramatic lattice imperfections such as twinning and dislocations. These defects are caused by plastics deformation coupled with shear and impact forces generated by the ball-milling media.[60] The powders are, therefore, disintegrated into smaller particles with large surface area, where very clean or fresh oxygen-free active surfaces of the powders are created. Moreover, these defects, which are intensively located at the grain boundaries, lead to separate micro-scaled Mg grains into finer grains capable to getter hydrogen by the first atomically clean surfaces to form MgH2 nanopowders.

Fig.9.5 illustrates common lab scale procedure for preparing MgH2 powders, starting from pure Mg powders, using RBM via (1) high-energy and (2) low-energy ball milling. The starting material can be Mg-rods, in which they are processed via sever plastic deformation,[61] using for example cold-rolling approach,[62] as illustrated in Fig.9.5. The heavily deformed Mg-rods obtained after certain cold rolling passes can be snipped into small chips and then ball-milled under hydrogen gas to produce MgH2 powders.[8]

Planetary ball mills are the most popular mills used in scientific research for synthesizing MgH2 nanopowders. In this type of mill, the ball-milling media have considerably high energy, because milling stock and balls come off the inner wall of the vial and the effective centrifugal force reaches up to 20 times gravitational acceleration. The centrifugal forces caused by the rotation of the supporting disc and autonomous turning of the vial act on the milling charge (balls and powders). Since the turning directions of the supporting disc and the vial are opposite, the centrifugal forces alternately are synchronized and opposite. Therefore, the milling media and the charged powders alternatively roll on the inner wall of the vial, and are lifted and thrown off across the bowl at high speed.

In the typical experimental procedure, a certain amount of the Mg (usually in the range between 3 and 10g based on the vials volume) is balanced inside an inert gas atmosphere (argon or helium) in a glove box and sealed together with certain number of balls (e.g., 2050 hardened steel balls) into a hardened steel vial (Fig.9.5A and B), using, for example, a gas-temperature-monitoring system (GST). With the GST system, it becomes possible to monitor the progress of the gas-solid reaction taking place during the RBM process, as shown in Fig.9.5C and D. The temperature and pressure changes in the system during milling can be also used to realize the completion of the reaction and the expected end product during the different stages of milling (Fig.9.5D). The ball-to-powder weight ratio is usually selected to be in the range between 10:1 and 50:1. The vial is then evacuated to the level of 103bar before introducing H2 gas to fill the vial with a pressure of 550bar (Fig.9.5B). The milling process is started by mounting the vial on a high-energy ball mill operated at ambient temperature (Fig.9.5C).

Tumbling mill is cylindrical shell (Fig.9.6AC) that rotates about a horizontal axis (Fig.9.6D). Hydrogen gas is pressurized into the vial (Fig.9.6C) together with Mg powders and ball-milling media, using ball-to-powder weight ratio in the range between 30:1 and 100:1. Mg powder particles meet the abrasive and impacting force (Fig.9.6E), which reduce the particle size and create fresh-powder surfaces (Fig.9.6F) ready to react with hydrogen milling atmosphere.

Figure 9.6. Photographs taken from KISR-EBRC/NAM Lab, Kuwait, show (A) the vial and milling media (balls) and (B) the setup performed to charge the vial with 50bar of hydrogen gas. The photograph in (C) presents the complete setup of GST (supplied by Evico-magnetic, Germany) system prior to start the RBM experiment for preparing of MgH2 powders, using Planetary Ball Mill P400 (provided by Retsch, Germany). GST system allows us to monitor the progress of RBM process, as indexed by temperature and pressure versus milling time (D).

The useful kinetic energy in tumbling mill can be applied to the Mg powder particles (Fig.9.7E) by the following means: (1) collision between the balls and the powders; (2) pressure loading of powders pinned between milling media or between the milling media and the liner; (3) impact of the falling milling media; (4) shear and abrasion caused by dragging of particles between moving milling media; and (5) shock-wave transmitted through crop load by falling milling media. One advantage of this type of mill is that large amount of the powders (100500g or more based on the mill capacity) can be fabricated for each milling run. Thus, it is suitable for pilot and/or industrial scale of MgH2 production. In addition, low-energy ball mill produces homogeneous and uniform powders when compared with the high-energy ball mill. Furthermore, such tumbling mills are cheaper than high-energy mills and operated simply with low-maintenance requirements. However, this kind of low-energy mill requires long-term milling time (more than 300h) to complete the gas-solid reaction and to obtain nanocrystalline MgH2 powders.

Figure 9.7. Photos taken from KISR-EBRC/NAM Lab, Kuwait, display setup of a lab-scale roller mill (1000m in volume) showing (A) the milling tools including the balls (milling media and vial), (B) charging Mg powders in the vial inside inert gas atmosphere glove box, (C) evacuation setup and pressurizing hydrogen gas in the vial, and (D) ball milling processed, using a roller mill. Schematic presentations show the ball positions and movement inside the vial of a tumbler mall mill at a dynamic mode is shown in (E), where a typical ball-powder-ball collusion for a low energy tumbling ball mill is presented in (F).

what's the difference between sag mill and ball mill - jxsc machine

A mill is a grinder used to grind and blend solid or hard materials into smaller pieces by means of shear, impact and compression methods. Grinding mill machine is an essential part of many industrial processes, there are mainly five types of mills to cover more than 90% materials size-reduction applications.

Do you the difference between the ball mill, rod mills, SAG mill, tube mill, pebble mill? In the previous article, I made a comparison of ball mill and rod mill. Today, we will learn about the difference between SAG mill vs ball mill.

AG/SAG is short for autogenous mill and semi-autogenous mill, it combines with two functions of crushing and grinding, uses the ground material itself as the grinding media, through the mutual impact and grinding action to gradually reduce the material size. SAG mill is usually used to grind large pieces into small pieces, especially for the pre-processing of grinding circuits, thus also known as primary stage grinding machine. Based on the high throughput and coarse grind, AG mills produce coarse grinds often classify mill discharge with screens and trommel. SAG mills grinding media includes some large and hard rocks, filled rate of 9% 20%. SAG mill grind ores through impact, attrition, abrasion forces. In practice, for a given ore and equal processing conditions, the AG milling has a finer grind than SAG mills.

The working principle of the self-grinding machine is basically the same as the ball mill, the biggest difference is that the sag grinding machine uses the crushed material inside the cylinder as the grinding medium, the material constantly impacts and grinding to gradually pulverize. Sometimes, in order to improve the processing capacity of the mill, a small amount of steel balls be added appropriately, usually occupying 2-3% of the volume of the mill (that is semi-autogenous grinding).

High capacity Ability to grind multiple types of ore in various circuit configurations, reduces the complexity of maintenance and coordination. Compared with the traditional tumbling mill, the autogenous mill reduces the consumption of lining plates and grinding media, thus have a lower operation cost. The self-grinding machine can grind the material to 0.074mm in one time, and its content accounts for 20% ~ 50% of the total amount of the product. Grinding ratio can reach 4000 ~ 5000, more than ten times higher than ball, rod mill.

Ball mills are fine grinders, have horizontal ball mill and vertical ball mill, their cylinders are partially filled with steel balls, manganese balls, or ceramic balls. The material is ground to the required fineness by rotating the cylinder causing friction and impact. The internal machinery of the ball mill grinds the material into powder and continues to rotate if extremely high precision and precision is required.

The ball mill can be applied in the cement production plants, mineral processing plants and where the fine grinding of raw material is required. From the volume, the ball mill divide into industrial ball mill and laboratory use the small ball mill, sample grinding test. In addition, these mills also play an important role in cold welding, alloy production, and thermal power plant power production.

The biggest characteristic of the sag mill is that the crushing ratio is large. The particle size of the materials to be ground is 300 ~ 400mm, sometimes even larger, and the minimum particle size of the materials to be discharged can reach 0.1 mm. The calculation shows that the crushing ratio can reach 3000 ~ 4000, while the ball mills crushing ratio is smaller. The feed size is usually between 20-30mm and the product size is 0-3mm.

Both the autogenous grinding mill and the ball mill feed parts are welded with groove and embedded inner wear-resistant lining plate. As the sag mill does not contain grinding medium, the abrasion and impact on the equipment are relatively small.

The feed of the ball mill contains grinding balls. In order to effectively reduce the direct impact of materials on the ball mill feed bushing and improve the service life of the ball mill feed bushing, the feeding point of the groove in the feeding part of the ball mill must be as close to the side of the mill barrel as possible. And because the ball mill feed grain size is larger, ball mill feeding groove must have a larger slope and height, so that feed smooth.

Since the power of the autogenous tumbling mill is relatively small, it is appropriate to choose dynamic and static pressure bearing. The ball bearing liner is made of lead-based bearing alloy, and the back of the bearing is formed with a waist drum to form a contact centering structure, with the advantages of flexible movement. The bearing housing is lubricated by high pressure during start-up and stop-up, and the oil film is formed by static pressure. The journal is lifted up to prevent dry friction on the sliding surface, and the starting energy moment is reduced. The bearing lining is provided with a snake-shaped cooling water pipe, which can supply cooling water when necessary to reduce the temperature of the bearing bush. The cooling water pipe is made of red copper which has certain corrosion resistance.

Ball mill power is relatively large, the appropriate choice of hydrostatic sliding bearing. The main bearing bush is lined with babbitt alloy bush, each bush has two high-pressure oil chambers, high-pressure oil has been supplied to the oil chamber before and during the operation of the mill, the high-pressure oil enters the oil chamber through the shunting motor, and the static pressure oil film is compensated automatically to ensure the same oil film thickness To provide a continuous static pressure oil film for mill operation, to ensure that the journal and the bearing Bush are completely out of contact, thus greatly reducing the mill start-up load, and can reduce the impact on the mill transmission part, but also can avoid the abrasion of the bearing Bush, the service life of the bearing Bush is prolonged. The pressure indication of the high pressure oil circuit can be used to reflect the load of the mill indirectly. When the mill stops running, the high pressure oil will float the Journal, and the Journal will stop gradually in the bush, so that the Bush will not be abraded. Each main bearing is equipped with two temperature probe, dynamic monitoring of the bearing Bush temperature, when the temperature is greater than the specified temperature value, it can automatically alarm and stop grinding. In order to compensate for the change of the mill length due to temperature, there is a gap between the hollow journal at the feeding end and the bearing Bush width, which allows the journal to move axially on the bearing Bush. The two ends of the main bearing are sealed in an annular way and filled with grease through the lubricating oil pipe to prevent the leakage of the lubricating oil and the entry of dust.

The end cover of the autogenous mill is made of steel plate and welded into one body; the structure is simple, but the rigidity and strength are low; the liner of the autogenous mill is made of high manganese steel.

The end cover and the hollow shaft can be made into an integral or split type according to the actual situation of the project. No matter the integral or split type structure, the end cover and the hollow shaft are all made of Casting After rough machining, the key parts are detected by ultrasonic, and after finishing, the surface is detected by magnetic particle. The surface of the hollow shaft journal is Polished after machining. The end cover and the cylinder body are all connected by high-strength bolts. Strict process measures to control the machining accuracy of the joint surface stop, to ensure reliable connection and the concentricity of the two end journal after final assembly. According to the actual situation of the project, the cylinder can be made as a whole or divided, with a flanged connection and stop positioning. All welds are penetration welds, and all welds are inspected by ultrasonic nondestructive testing After welding, the whole Shell is returned to the furnace for tempering stress relief treatment, and after heat treatment, the shell surface is shot-peened. The lining plate of the ball mill is usually made of alloy material.

The transmission part comprises a gear and a gear, a gear housing, a gear housing and an accessory thereof. The big gear of the transmission part of the self-grinding machine fits on the hollow shaft of the discharge material, which is smaller in size, but the seal of the gear cover is not good, and the ore slurry easily enters the hollow shaft of the discharge material, causing the hollow shaft to wear.

The big gear of the ball mill fits on the mill shell, the size is bigger, the big gear is divided into half structure, the radial and axial run-out of the big gear are controlled within the national standard, the aging treatment is up to the standard, and the stress and deformation after processing are prevented. The big gear seal adopts the radial seal and the reinforced big gear shield. It is welded and manufactured in the workshop. The geometric size is controlled, the deformation is prevented and the sealing effect is ensured. The small gear transmission device adopts the cast iron base, the bearing base and the bearing cap are processed at the same time to reduce the vibration in operation. Large and small gear lubrication: The use of spray lubrication device timing quantitative forced spray lubrication, automatic control, no manual operation. The gear cover is welded by profile steel and high-quality steel plate. In order to enhance the stiffness of the gear cover, the finite element analysis is carried out, and the supporting structure is added in the weak part according to the analysis results.

The self-mill adopts the self-return device to realize the discharge of the mill. The self-returning device is located in the revolving part of the mill, and the material forms a self-circulation in the revolving part of the mill through the self-returning device, discharging the qualified material from the mill, leading the unqualified material back into the revolving part to participate in the grinding operation.

The ball mill adopts a discharge screen similar to the ball mill, and the function of blocking the internal medium of the overflow ball mill is accomplished inside the rotary part of the ball mill. The discharge screen is only responsible for forcing out a small amount of the medium that overflows into the discharge screen through the internal welding reverse spiral, to achieve forced discharge mill.

The slow drive consists of a brake motor, a coupling, a planetary reducer and a claw-type clutch. The device is connected to a pinion shaft and is used for mill maintenance and replacement of liners. In addition, after the mill is shut down for a long time, the slow-speed transmission device before starting the main motor can eliminate the eccentric load of the steel ball, loosen the consolidation of the steel ball and materials, ensure safe start, avoid overloading of the air clutch, and play a protective role. The slow-speed transmission device can realize the point-to-point reverse in the electronic control design. When connecting the main motor drive, the claw-type Clutch automatically disengages, the maintenance personnel should pay attention to the safety.

The slow drive device of the ball mill is provided with a rack and pinion structure, and the operating handle is moved to the side away from the cylinder body The utility model not only reduces the labor intensity but also ensures the safety of the operators.

ball mill, ball grinding mill - all industrial manufacturers - videos

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... LN2 feeding systems, jar and ball sizes, adapter racks, materials low LN2-consumption clearly structured user interface, memory for 9 SOPs programmable cooling and grinding cycles (10 ...

The XRD-Mill McCrone was specially developed for the preparation of samples for subsequent X-ray diffraction (XRD). The mill is used for applications in geology, chemistry, mineralogy and materials science, ...

The Planetary Ball Mill PM 200, engineered by Retsch, is a milling device best suited for mixing and size reduction processes and is also capable of meeting the necessary requirements for colloidal grinding ...

... Micro Mill PULVERISETTE 0 is the ideal laboratory mill for fine comminution of medium-hard, brittle, moist or temperature-sensitive samples dry or in suspension as well as for homogenising of emulsions ...

... , fast, effective. WORKING PRINCIPLE Impact and friction The FRITSCH Mini-Mill PULVERISETTE 23 grinds the sample through impact and friction between grinding balls and the inside wall of the grinding ...

... grinding mills includes being safe throughout. When the mills are quoted we make sure to include any and all safety components needed. Long life and minimum maintenance To help you get the most of your ...

Annular gap and agitator bead mills are used for processing suspensions and highly viscous products in chemicals and cosmetics as well as in the food sector. Studies have shown that annular gap bead ...

... Pneumatic extraction from the surface of the agitated media bed Wet grinding: Separation of suspension from the agitated media by ball retaining device Flexibility Through careful selection of the size and quantity ...

... details; Agitating power: 0,37 kW Total Power Consumption : 1.44 kW Total Weight : 100 kg Metal Ball Size : 6.35 mm Metal Ball Amount : 7 kg Cold water consumption : 10 liters / hour ...

Cement Ball Mill Processing ability: - 200 t/h Max feeding size: - 25 mm Product Fineness: - 0.074-0.89mm Range of application: - limestone, calcium carbonate, clay, dolomite and other minerals ...

... grinds and classifies a product. Vilitek MBL-NK-80 mill is specially designed for grinding valuable materials, which, when grinding, the re-milled fractions are not a commodity product. In particular, this mill ...

Dimensions: Height: 1530 mm Width: 650 mm Length : 1025 mm Description: Ball mills are capable of rapidly producing chocolate, nut pastes (for gianduia), and spreadable creams. It has been ...

small ball mills for sale

Our small-scale miners Ball Mills use horizontal rotating cylinders that contain the grinding media and the particles to be broken. The mass moves up the wall of the cylinder as it rotates and falls back into the toe of the mill when the force of gravity exceeds friction and centrifugal forces. Particles are broken in the toe of the mill when caught in the collisions between the grinding media themselves and the grinding media and the mill wall. In ball mills, the grinding media and particles acquire potential energy that becomes kinetic energy as the mass falls from the rotating shell. Ball mills are customarily divided into categories that are mainly defined by the size of the feed particles and the type of grinding media.

Intermediate and fine size reduction by grinding is frequently achieved in a ball mill in which the length of the cylindrical shell is usually 1 to 1.5 times the shell diameter. Ball mills of greater length are termed tube mills, and when hard pebbles rather than steel balls are used for the grinding media, the mills are known as pebble mills. In general, ball mills can be operated either wet or dry and are capable of producing products on the order of 100 um. This duty represents reduction ratios as great as 100.

The ball mill, an intermediate and fine-grinding device, is a tumbling drum with a 40% to 50% filling of balls. The material that is to be ground fills the voids between the balls. The tumbling balls capture the particles in ball/ball or ball/liner events and load them to the point of fracture. Very large tonnages can be ground with these devices because they are very effective material handling devices. The feed can be dry, with less than 3% moisture to minimize ball coating, or a slurry can be used containing 20% to 40% water by weight. Ball mills are employed in either primary or secondary grinding applications. In primary applications, they receive their feed from crushers, and in secondary applications, they receive their feed from rod mills, autogenous mills, or semi-autogenous mills. Regrind mills in mineral processing operations are usually ball mills, because the feed for these applications is typically quite fine. Ball mills are sometimes used in single-stage grinding, receiving crusher product. The circuits of these mills are often closed with classifiers at high-circulating loads.

All ball mills operate on the same principles. One of these principles is that the total weight of the charge in the mill-the sum of the weight of the grinding media, the weight of the material to be ground, and any water in the millis a function of the percentage of the volume of the mill it occupies.

The power the mill draws is a function of the weight of the charge in the mill, the %of volumetric loading of the mill, the %of critical speed, which is the speed in RPM at which the outer layer of the charge in the mill will centrifuge.

For closed grinding circuits producing typical ball mill products, indirect and direct on-line measurements of the product size are available. The indirect means are those which assume that the product size is relatively constant when the feed condition to the classifying unit and the operating conditions in the classifying unit are constant. One example is maintaining a constant mass flow, pulp density and pressure in the feed to the cyclone classifier.

By using math modeling, it is possible to calculate the product size from measured cyclone classifier feed conditions and circuit operating data, thus establishing the effect on the particle size distribution in the product for changes in the variables.

Direct on-line means to measure either particle size or surface area are available for typical ball mill circuit products. These require the means to obtain representative or at least consistent samples from the grinding circuit product stream. These direct means and the calculated product particle size distributions can be used to:

Small variations in the feed size to ball mill circuits generally is not critical to the calculation of operating work index because they make a very small change in the 10F factor. Thus, a computer program can be developed to calculate operating work indices from on-line data with the feed size a constant and with the program designed to permit manually changing this value, as required to take into account changes in feed size resulting from such things as drawing down feed bins, crusher maintenance, work screen surfaces in the crushing plant, etc. which are generally known in advance, or can be established quickly. Developments underway for on-line measurement of particle size in coarser material which when completed will permit measuring the feed size used to calculate operating work indices.

recorded by a data logger, gives continuous means to report comminution circuit performance and evaluate in-plant testing. Changes in Wio indicated on data loggers alert operating and supervisory personnel that a change has occurred in either the ore or in circuit performance. If sufficient instrumentation is available, the cause for a problem can often be located from other recorded or logged data covering circuit and equipment operation, however, generally the problem calls for operator attention to be corrected.

Wio can be used to determine the efficiency of power utilization for the entire comminution section of a mill, and for the individual circuits making up the comminution section. The efficiency of a comminution circuit is determined by the following equation.

Wi is obtained by running the appropriate laboratory tests on a composite sample of circuit feed. Wio is calculated from plant operating data covering the period when the feed sample was taken. Since Wi from laboratory tests refers to specific conditions for accurate efficiency determinations, it is necessary to apply correction factors as discussed in The Tools of Power Power to Wio to put the laboratory and operating data on the same basis.

To-date, there is no known way to obtain standard work index data from on-line tests. Continuous measurement of comminution circuit efficiency is not possible and thus efficiency is not available for circuit control. Using laboratory data and operating data, efficiency can be determined for overall section and individual circuit for evaluation and reporting. Just monitoring Wio and correcting operating problems as they occur will improve the utilization of the power delivered to the comminution circuits.

Samples taken from the chips around blast hole drillings and from broken ore in the pit or mine for laboratory work index and other ore characteristic determinations before the ore is delivered to the mill, can be used to predict in advance comminution circuit performance. Test results can also be used for ore blending to obtain a more uniform feed, particularly to primary autogenous and semi-autogenous circuits.

We sell Small Ball Mills from 2 to 6 (600 mm X 1800 mm) in diameter and as long as 10 (3000 mm) in length. The mills are manufactured using a flanged mild steel shell, cast heads, overflow discharge, removable man door, spur type ring gear, pinion gear assembly with spherical roller bearings, replaceable roller bronze trunnion bearings, oil lubrication, replaceable trunnion liners with internal spirals, rubber liners and lifters, feed spout with wash port, discharge trommel with internal spiral, motor and gear reducer drive, direct coupled to pinion gear, gear guard and modular steel support frame. All ball mills always come withOSHA-type gear guard.

A PULP level sufficiently high to interpose a bed of pulp, partly to cushion the impact of the balls, permits a maximum crushing effect with a minimum wear of steel. The pulp level of theseSmall Ball Millscan be varied from discharging at the periphery to discharging at a point about halfway between the trunnion and the periphery.The mill shell is of welded plate steel with integral end flanges turned for perfect alignment, and the heads are semi-steel, with hand holes in the discharge end through which the diaphragm regulation is arranged with plugs.The trunnion bearings are babbitted, spherical, cast iron, and of ample size to insure low bearing pressure; while the shell and saddle are machined to gauge so that the shells are interchangeable.

Data based on:Wet grinding, single stage, closed circuit operation: feed:( one way dimension); Class III ore. All mills:free discharge, grated type, rapid pulp flow. N. B.for overflow type mills: capacity 80%power 83%. Dimensions :diameters inside shell without linerslengths working length shell between end liners.

The CIW is a Small Ball Mill thats belt driven, rigid bearing, wet grinding, trunnion or grate discharge type mill with friction clutch pulley and welded steel shell. The 7 and 8 foot diameter mills are of flange ring construction with cut gears while all other sizes have cast tooth gears. All these mills are standard with white iron bar wave type shell liners except the 8 foot diameter mill which is equipped with manganese steel liners. The horsepowers shown in the table are under running conditions so that high torque or wound rotor (slip ring) motors must be used. Manganese or alloy steel shell or head liners and grates can be supplied with all sizes of mills if required. Alloy steel shell liners are recommended where 4 or larger balls are used and particularly for the larger sized mills.

Small (Muleback Type) Ball Mill is built for muleback transportation in 30 and 3 diameters (inside liners). A 4 (Muleback Type) Ball Mill is of special design and will be carefully considered upon request. Mankinds search for valuable minerals often leads him far away from modern transportation facilities. The potential sources of gold, silver and strategic minerals are often found by the prospector, not close by our modern highways, but far back in the mountains and deserts all over the world. The Equipment Company has realized this fact, and therefore has designed a Ball Mill that can be transported to these faraway and relatively inaccessible properties, either by the age old muleback transportation system, or by the modern airplane. As a result these properties may now obtain a well-designed ball mill with the heaviest individual piece weighing only 350 pounds.

The prime factor considered in this design was to furnish equipment having a maximum strength with a minimum weight. For this reason, these mills are made of steel, giving a high tensile strength and light weight to the mills. The muleback design consists of the sturdy cast iron head construction on the 30 size and cast steel head construction on the larger sizes. The flanges on the heads are arranged to bolt to the rolled steel shell provided with flanged rings. When required, the total length of the shell may consist of several shell lengths flanged together to provide the desired mill length. Liners, bearings, gears and drives are similar to those standard on all Ball Mills.

This (Convertible) and Small Ball Mill is unique in design and is particularly adapted to small milling plants. The shell is cast in one piece with a flange for bolting to the head. In converting the mill from a 30x 18 to a 30x 36 unit with double the capacity, it is only necessary to secure a second cast shell (a duplicate of the first) and bolt it to the original section.

30 Convertible Ball Mills are furnished with scoop feeders with replaceable lips. Standard mills are furnished with liners to avoid replacement of the shell; however, themill can be obtained less liners. This ball mill is oftendriven by belts placed around the center, although gear drive units with cast gears can be furnished. A Spiral Screen can be attached to the discharge.

This mill may be used for batch or intermittent grinding, or mixing of dry or wet materials in the ore dressing industry, metallurgical, chemical, ceramic, or paint industries. The material is ground and mixed in one operation by rotating it together with balls, or pebbles in a hermetically sealed cylinder.

The cast iron shell which is bolted to the heads is made with an extra thick wall to give long wearing life. Two grate cleanout doors are provided on opposite sides of the shell by means of which the mill can be either gradually discharged and washed, while running, or easily and rapidly emptied and flushedout while shut down. Wash-water is introduced into the interior of the mill through a tapped opening in the trunnion. The mill may be lined with rubber, silex (buhrstone) or wood if desired.

The Hardinge Conical Ball Mill has been widely used with outstanding success in grinding many materials in a wide variety of fields. The conical mill operates on the principle of an ordinary ball mill with a certain amount of classification within the mill itself, due to its shape.

Sizes of conical mills are given in diameter of the cylindrical section in feet and the length of the cylindrical section in inches. Liners can be had of hard iron, manganese steel or Belgian Silex. Forged steel balls or Danish Flint Pebbles are used for the grinding media, depending upon the material being milled.

The Steel Head Ball-Rod Mill gives the ore dressing engineer a wide choice in grinding design so that he can easily secure a Ball-Rod Mill suited to his particular problem. The successful operation of any grinding unit is largely dependent on the method of removing the ground pulp. The Ball-Rod Mill is available with five types of discharge trunnions, each type obtainable in small, medium or large diameters. The types of discharge trunnions are:

The superiority of the Steel Head Ball-Rod Mill is due to the all steel construction. The trunnions are an integral part of the cast steel heads and are machined with the axis of the mill. The mill heads are assured against breakage due to the high tensile strength of cast steel as compared to that of the cast iron head found on the ordinary ball mill. Trunnion Bearings are made of high- grade nickel babbitt.

Steel Head Ball-Rod Mills can be converted intolarger capacity mills by bolting an additional shell lengthonto the flange of the original shell. This is possible because all Steel Head Ball or Rod Mills have bearings suitable for mills with length twice the diameter.

Head and shell liners for Steel Head Ball-Rod Mills are available in Decolloy (a chrome-nickel alloy), hard iron, electric steel, molychrome steel, and manganese steel. Drive gears are furnished either in cast tooth spur gear and pinion or cut tooth spur gear and pinion. The gears are furnished as standard on the discharge end of the mill, out of the way of the classifier return feed, but can be furnished at the mill feed end by request. Drives may be obtained according to the customers specifications.

Thats one characteristic of Traylor Ball Millsliked by ownersthey are built not only to do a first class job at low cost but to keep on doing it, year after year. Of course, that means we do not build as many mills as if they wore out quicklyor would we? but much as welike order, we value more the fine reputationTraylor Ball Mills have had for nearly threedecades.

Thats one characteristic of Traylor Ball Mills We dont aim to write specifications into thisliked by ownersthey are built not only to do advertisementlet it suffice to say that theresa first class job at low cost but to keep on do- a Traylor Ball Mills that will exactly fit anyanything it, year after year. Of course, that means requirement that anyone may have.

If this is true, there is significance in the factthat international Nicked and Climax Molybdenum, theworlds largest producers of two important steel alloys, areboth users of MARCY Mills exclusively. With international interest centered on increasingproduction of gold, it is even more significant that MARCYMills are the predominant choice of operators in everyimportants gold mining camp in the world.

Ball Mill. Intermediate and fine size reduction by grinding is frequently achieved in a ball mill in which the length of the cylindrical shell is usually 1 to 1.5 times the shell diameter. Ball mills of greater length are termed tube mills, and when hard pebbles rather than steel balls are used for the grinding media, the mills are known as pebble mills. In general, ball mills can be operated either wet or dry and are capable of producing products on the order of 100 pm. This duty represents reduction ratios as great as 100.

The ball mill, an intermediate and fine-grinding device, is a tumbling drum with a 40% to 50% filling of balls (usually steel or steel alloys). The material that is to be ground fills the voids between the balls. The tumbling balls capture the particles in ball/ball or ball/liner events and load them to the point of fracture. Very large tonnages can be ground with these devices because they are very effective material handling devices. The feed can be dry, with less than 3% moisture to minimize ball coating, or a slurry can be used containing 20% to 40% water by weight. Ball mills are employed in either primary or secondary grinding applications. In primary applications, they receive their feed from crushers, and in secondary applications, they receive their feed from rod mills, autogenous mills, or semiautogenous mills. Regrind mills in mineral processing operations are usually ball mills, because the feed for these applications is typically quite fine. Ball mills are sometimes used in single-stage grinding, receiving crusher product. The circuits of these mills are often closed with classifiers at high-circulating loads.

These loads maximize throughput at a desired product size. The characteristics of ball mills are summarized in the Table, which lists typical feed and product sizes. The size of the mill required to achieve a given task-that is, the diameter (D) inside the liners-can be calculated from the design relationships given. The design parameters must be specified.

The liner- and ball-wear equations are typically written in terms of an abrasion index (Bond 1963). The calculated liner and ball wear is expressed in kilograms per kilowatt-hour (kg/kWh), and when multiplied by the specific power (kWh/t), the wear rates are given in kilograms per ton of feed. The wear in dry ball mills is approximately one-tenth of that in wet ball mills because of the inhibition of corrosion. The efficiency of ball mills as measured relative to single-particle slow-compression loading is about 5%. Abrasion indices for five materials are also listed in the Table.

The L/D ratios of ball mills range from slightly less than 1:1 to something greater than 2:1. The tube and compartment ball mills commonly used in the cement industry have L/D ratios 2.75:1 or more. The fraction of critical speed that the mill turns depends on the application, and most mills operate at around 75% of critical speed. Increased speed generally means increased power, but as the simulations presented in Figure 3.26 show, it can also produce more wasted ball impacts on the liners above the toe. causing more wear and less breakage.

There are three principal forms of discharge mechanism. In the overflow ball mill, the ground product overflows through the discharge end trunnion. A diaphragm ball mill has a grate at thedischarge end. The product flows through the slots in the grate. Pulp lifters may be used to discharge the product through the trunnion, or peripheral ports may be used to discharge the product.

The majority of grinding balls are forged carbon or alloy steels. Generally, they are spherical, but other shapes have been used. The choice of the top (or recharge) ball size can be made using empirical equations developed by Bond or Azzaroni or by using special batch-grinding tests interpreted in the content of population balance models. The effect of changes in ball size on specific selection functions has been found to be different for different materials. A ball size-correction method can be used along with the specific selection function scale-up method to determine the best ball size. To do this, a set of ball size tests are performed in a batch mill from which the specific selection function dependence on ball size can be determined. Then, the mill capacities used to produce desired product size can be predicted by simulation using the kinetic parameter corresponding to the different ball sizes.

The mill liners used are constructed from cast alloy steels, wear-resistant cast irons, or polymer (rubber) and polymer metal combinations. The mill liner shapes often recommended in new mills are double-wave liners when balls less than 2.5 in. are used and single-wave liners when larger balls are used. Replaceable metal lifter bars are sometimes used. End liners are usually ribbed or employ replaceable lifters.

The typical mill-motor coupling is a pinion and gear. On larger mills two motors may be used, and in that arrangement two pinions drive one gear on the mill. Synchronous motors are well suited to the ball mill, because the power draw is almost constant. Induction, squirrel cage, and slip ring motors are also used. A high-speed motor running 600 to 1,000 rpm requires a speed reducer between the motor and pinion shaft. The gearless drive has been installed at a number of locations around the world.

ball mill - eastman rock crusher

Ball mill is a type of grinder machine which uses steel ball as grinding medium, can crush and grind the materials to 35 mesh or finer, adopted in open or close circuit. The feed materials can be dry or wet, they are broken by the force of impact and attrition that created by the different sized balls.Types of ball milldry grinding ball mill and wet grinding ball mill; grate discharge ball mill and overflow ball mill.Applicationsmining, chemical, glass, ceramics, etc.Suitable MaterialsCement, silicate products, new building materials, refractory materials, fertilizers, mineral processing and glass ceramics.

Ball mill is a horizontal machine, contains a hollow cylindrical shell that rotates around its axis, Inside the cylinder, there are many different sized stainless steel balls. As the the cylinder rotates, the mill balls lifts and then drops, strikes the materials, that is the impact and attrition take place.The cylinder chamber which turning around the horizontal axis is partially filled with grinding mediums: mostly are steel balls, cast iron or porcelain balls. Filling rate best at 40%, steel balls diameter with 30 to 80mm.These grinding balls are initially 3-10 cm in diameter, but gradually became smaller as grinding progressed. So we usually just refill the big balls.The chamber is lined with a wear resistant material, such as manganese-steel or high quality rubber, to extend the service time.Thanks to the closed grinding chamber, the dust and pollution generated in the grinding process are avoided to emit to air.

Eastman provides you with complete rock crushers and full list of replacement parts, original ball mill parts, form and function are a perfect fit.If your equipment breaks down, the productivity of the whole factory will be threatened. Critical wear parts are shipped with the goods to ensure they are available when you need them and to reduce maintenance time.

Eastman is a crushing manufacturer with more than 30 years of experience, produces hammer crusher used for a variety of applications.We not only can provide you with various types of rock crusher, but also can design reasonable crushing process for you free.

Factors of ball mill product sizeWithin the rotating chamber the grinding balls rub and strike against each other.The final discharge size can be changed by changing the number and size of the steel balls, the material of the ball, rotate speed, and the what material to be ground. Besides, the ball mill production rate is directly proportional to the drum rotation speed. Check the ball mill critical rotation speed which indicated in the manufacturers technical specifications.