JD series seperator is high-efficiency combined raw material special powder sorting machine, which is the latest type of powder sorting equipment developed, combined with advanced powder classify technology to apply the plane eddy current theory to the cyclone type separator. Powder selection efficiency reaches 80-85%, fineness adjustment is convenient and flexible, and the performance is stable and reliable in cement plant.
The main features of the classifier are low energy consumption, large processing capacity, and flexible combination structure: it can be interchanged with the fluidized bed crushing machine to become a crushing classifier, and can be used with a rake mill, a ball mill, a roller mill, etc.
Combine and separate the ultrafine powder, which has the functions of low energy consumption and low pollution; it can be directly connected with dryers, conveyor belts, automatic packaging machines, etc., simplifying the production process and steps. Use of ultra-segmented grades that cannot be graded on common seperating equipment, especially for products that are strictly limited to the largest particles and require a narrow particle size distribution, such as heavy calcium, kaolin, talcum powder, barite powder, paint, Mica, graphite, auxin, aluminum hydroxide, etc. It can classify materials that require extremely strict grain size and meet the requirements of purity and grain shape. Typical materials: copier toner, laser printer powder, mobile phone battery powder, industrial battery powder, etc.
The classification chamber of the cyclone type separator is a cylindrical casing made of steel plate. In classification chamber, the small blades and the spreading disc are fixed together on the vertical axis. The motor is rotated by belt conveyor in the classification chamber. Strong centrifugal force is formed, and gas powder mixture entering the classification chamber is subjected to the centrifugal force.
The large or heavy particles are subjected to centrifugal force, so they are smashed to edge, no longer affected by the centrifugal force. it is collected, and then discharged as coarse powder through coarse powder tube; small or light material is less affected by centrifugal force, hovering inside the grading room, being carried to height by air flow, and moving to the next component along the pipeline It is graded or collected, and speed of the centrifugal force can be adjusted by the frequency converter to adjust speed, so as to separating the materials of the specified granularity.
In recent years, with the improvement of large-scale cloth bag dust collecting technology in China, the long bag dust collector technology used in rotary kiln tail gas treatment of cement rotary kiln with dry process method is increasing da...
Cyclone preheater is one of the core equipment in the new dry cement production process, which is responsible for many functions such as gas-solid dispersion, material heating, gas-solid separation, material transportation and some physical...
Cement separator, also called cement mill separator, is the necessary equipment in the powder classifying system of cement, chemical, mineral, and other industries. It can respectively collect the qualified fine powder and coarse powder from the airflow after they are ground by the grinding equipment to a certain extent. The utilization of cement separator prevents the fine powder from sticking to the grinding media and produces the buffering effect, so as to adjust the size composition of finished products and improve the grinding efficiency.
As a kind of cement equipment, cement separator is mainly used in the coal mill grinding system, raw mill grinding system, and cement mill grinding system of the cement production line. In order to improve the efficiency of these systems and reduce the energy consumption of products, current cement plants generally adopt the closed-circuitgrindingsystem. As an important part, the performance and quality of cement separator will directly affect the grinding system.
There are many types of cement separators, different types suitable for different materials. Besides, different models should also be selected according to the customers requirements for material fineness.
Cyclone air separator is one kind of cement separators. AGICO Cement, as a professional cement equipment supplier in China, offers different models of quality cyclone air separators for any type and size of cement plants, such as JD series cyclone air separator. It is the latest powder separator developed by our companys technicians with the plane eddy theory. Its powder selection efficiency can reach 80-85%. Besides, we also provide other types of cement separators, such as TZX series cement separator, TS series cement separator, and MX series cement separator.
The circulating air of the cement cyclone separator is generated by the air blower. During the powder classifying process, the air is sent by the air blower from the center of the separator in a tangential direction and then spirals up to the classifying chamber. After being ground in the mill, materials are fed through the top feeding port of cyclone air separator and falls onto a rotating spreading plate. Due to the action of inertial centrifugal force, the material is evenly scattered around the spreading plate and meets with the updraft. The finer particles rise to the position of blades with the airflow, among which some of the larger particles sink along the inner cone and enter the coarse powder duct. The smaller particles enter the cyclone with the updraft after passing through the blades and then collected by the centrifugal force. After being separated by the cyclone, the airflow comes out from the air duct and enters the air blower again, thus forming a closed circulation air.
AGICO is a professional cement equipment manufacturer. Cement separator is one of our hot sales products. Compared with the traditional cement separator, the separator produced by AGICO has the following outstanding advantages:
AGICO Group is an integrative enterprise group. It is a Chinese company that specialized in manufacturing and exporting cement plants and cement equipment, providing the turnkey project from project design, equipment installation and equipment commissioning to equipment maintenance.
Cement separator, also known as cement mill separator, cement classifier, is widely applied to the coal mill in cement plant, raw mill, and cement milling system. It can be usually divided into three types: separation separator, centrifugal air separator, and cyclone separator.
AGICO CEMENT combines foreign high-quality powder selecting technology, apply the theory of flat eddy current to the cyclone separator well, and develops Z type cement separator by ourselves. It has been proved that the efficiency of powder selection can reach 85%-90%, and the fineness is convenient and flexible, and the performance is stable and reliable.
The material enters from the feed pipe and is scattered into the rising airflow through the dispersion plate. The pulverized medium debris in the material overcomes the falling resistance of the rising airflow under the action of gravity and is discharged through the slag discharge outlet. The airflow carrying the powder rises to the grading section and enters the rotor through the guide vanes for grading. The guide vane can make the flow and powder particles rotate, pre-grade, and capture the coarse particles thrown out by the rotor, and also make the speed of the flow evenly distributed on the height of the whole rotor. The coarse particles trapped by the guide vane fall on the cone of coarse powder and are discharged by the outlet of the coarse powder, while the fine particles and airflow enter the middle of the rotor through the rotor blade and are sent to the collection device by the outlet of the fine powder.
Cement mill separator, or cement separator, is a type of equipment that was widely used in the cement grinding system and raw mill system of cement plants. The function of the separator is to separate the fine-sized particles from the coarse-sized particles, so as to avoid material condensation and over grinding in the mill, and improve the milling systems grinding efficiency.
Many types of separators have been developed in the past few decades, including the turbo separator, the cyclone air separator, the cage-type separator, and so on. The most advanced and efficient separators for the cement industry are the cyclone air separators with specially designed circumferential screens.
AGICO high-efficiency cement mill separators are advanced cyclone air separators developed by using the method of aerodynamics analysis on the basis of international advanced powder separation principle. They have a remarkable powder separation effect and can greatly increase the mill output.
In the working process of the cyclone air separator, the material enters the separation chamber through the feed inlet at its upper part and then falls on the distribution table through the powder pipe between the upper and lower cones of the medium-coarse powder collecting cone.
Driven by a high-speed motor and a transmission device, the distribution table rotates along the axis. Under the action of inertial centrifugal force, the materials on the table are evenly scattered around.
At this time, the separation chamber is circulated with high-speed airflow generated by fans. In the dispersed materials, the coarse particles are thrown to the inner wall of the chamber under the action of inertial centrifugal force, then slide down along the wall surface and fall into the tails cone. The rest of the material is rolled up by the airflow, and other parts of the coarse powder particles are screened under the impact of the gale blade.
Under the action of the strong and stable plane turbulence formed by the rotating rejector cage, the medium-coarse powder in the airflow is thrown to the vertical guide vane by centrifugal force and loses kinetic energy, falls into the tails cone and is discharged through the medium-coarse powder outlet.
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In this chapter an introduction of widely applied energy-efficient grinding technologies in cement grinding and description of the operating principles of the related equipments and comparisons over each other in terms of grinding efficiency, specific energy consumption, production capacity and cement quality are given. A case study performed on a typical energy-efficient Horomill grinding technology, is explained. In this context, grinding circuit is introduced and explanations related to grinding and classification performance evaluation methodology are given. Finally, performance data related to Horomill and high-efficiency TSV air classifier are presented.
Cement is an energy-intensive industry in which the grinding circuits use more than 60% of the total electrical energy consumed and account for most of the manufacturing cost . The requirements for the cement industry in the future are to reduce the use of energy in grinding and the emission of CO2 from the kilns. In recent years, the production of composite cements has been increasing for reasons concerned with process economics, energy reduction, ecology (mostly reduction of CO2 emission), conservation of resources and product quality/diversity. The most important properties of cement, such as strength and workability, are affected by its specific surface and by the fineness and width of the particle-size distribution. These can be modified to some extent by the equipment used in the grinding circuit, including its configuration and control.
Performance of grinding circuits has been improved in recent years by the development of machinery such as high-pressure grinding rolls (HPGR) (roller presses), Horomills, high-efficiency classifiers and vertical roller mills (VRM) for clinker grinding which are more energy efficient than machinery which has been in common use for many years such as tube mills. Energy-efficient equipments such as high-pressure grinding rolls, vertical roller mills, CKP pre-grinders, Cemex mills and Horomills are used at both finish grinding of cement and raw material-grinding stages due to higher energy consumption of conventional multi-compartment ball milling circuits. Multi-compartment ball mills can be classified as:Single-compartment ball millsTwo- or three-compartment ball mills
Multi-compartment ball mills and air separators have been the main process equipments in clinker grinding circuits in the last 100 years. They are used in grinding of cement raw materials (raw meal) (i.e. limestone, clay, iron ore), cement clinker and cement additive materials (i.e. limestone, slag, pozzolan) and coal. Multi-compartment ball mills are relatively inefficient at size reduction and have high specific energy consumption (kWh/t). Typical specific energy consumption is 30kWh/t in grinding of cement. Barmac-type crushers found application as a pre-grinder in cement grinding circuits operating with ball mills to reduce the specific energy consumption of ball mill-grinding stage . An overview of technical innovations to reduce the power consumption in cement plants was given by Fujimoto .
In this chapter, operating principles of high-pressure grinding rolls, Horomill, vertical roller mills, CKP pre-grinders and Cemex mills which are widely applied in finish grinding of cement are briefly explained in addition to the advantages and disadvantages over each other.
The Barmac rock-on-rock crusher has a rotor that acts as a high-velocity, dry stone pump, hurling a continuous rock stream into a stone-lined crushing chamber. Broken rock about 3050mm in diameter enters the top of the machine from a feeder set and is accelerated in the rotor to be discharged into the crushing chamber at velocities of up to 85m/s. Collision of high-speed rocks, with rocks falling in a separate stream or with a rock-lined wall, causes shattering. The product is typically gravel and sand-sized particles. Barmac crushers are available from 75 to 600kW. The product-size distribution can be controlled by the rotor speed . A schematic of a Barmac-type VSI crusher is given in Figure1 .
The material between the rolls is submitted to a very high pressure ranging from 100 to 200MPa. Special hard materials are used as protection against wear, for example, Ni-hard linings to protect the rollers. During the process, cracks are formed in the particle, and fine particles are generated. Material is fed into the gap between the rolls, and the crushed material leaves as a compacted cake. The energy consumption is 2.53.5kWh/t and about 10kWh/t when recycling of the material is used. The comminution efficiency of a HPGR is better than ball mills such that it consumes 3050% of the specific energy as compared to a ball mill. Four circuit configurations of HPGR can be used in grinding of raw materials, clinker and slag such as :Pre-grinding unit upstream of a ball millHybrid grindingSemifinish grindingFinish grinding in closed-circuit operation
Application of HPGR in cement grinding circuits and the effects of operational and design characteristics of HPGR on grinding performance were discussed by Aydoan . HPGR arrangements and semifinish-grinding options are given in Figures3 and 4.
Vertical roller mills have a lower specific energy consumption than tumbling mills and require less space per unit and capacity at lower investment costs. Vertical roller mills are developed to work as air-swept grinding mills. Roller mills are operated with throughput capacities of more than 300t/h of cement raw mix (Loesche mill, Polysius double roller mill, Pfeiffer MPS mill). Loesche roller mill and Polysius roller mills are widely applied in cement raw material grinding. Schematical view of a Pfeiffer MPS mill is given in Figure5 , and a view from inside of a vertical roller mill is given in Figure6.
A cross section of a Loesche mill with a conical rotor-type classifier is shown in Figure7. The pressure arrangement of the grinding rolls is hydraulic. The mill feed is introduced into the mill from above, falling centrally upon the grinding plate; then it is thrown by centrifugal force underneath the grinding rollers. A retention ring on the periphery of the grinding table forms the mill feed into a layer called the grinding bed. The ground material spills over the rim of the retention ring. Here an uprising airstream lifts the material to the rotor-type classifier located at the top of the mill casing where the coarse particles are separated from the fines. The coarse particles drop back into the centre of the grinding compartment for further size reduction, whereas the fines together with the mill air leave the mill and the separator. The separator controls the product sizes from 400 to 40m. The moisture of the mill feed (cement raw material) can amount to 1518%. The fineness of the mill product can be adjusted in the range between 94 and 70% passing 170 mesh. Capacities up to 400t/h of cement raw mix are recorded .
Better product quality can be achieved as compared to the ball mill product due to the better options for separate grinding. For example, in additive cement production, the blast furnace slag has to be ground to Blaine values of 5,000cm2/g. Water demand and setting times are similar to that of a ball mill cement under comparable conditions .
A mill feed arrangement conveys the raw material to the grinding bowl. Two double rollers (representing four grinding rollers) are put in motion by the revolving grinding bowl. The double rollers are independently mounted on a common shaft; they move and adjust themselves to the velocity of the grinding bowl as well as to the thickness of the grinding bed. Thus, rollers are in permanent contact with the grinding bed. A hydropneumatic arrangement transfers the grinding pressure to the rollers. The disintegrated mill feed is shifted to the grinding bowl rim from where a gas stream emerging from the nozzle ring surrounding the grinding bowl carries the material upwards to the separator. The coarses precipitated in the separator gravitate centrally back to the grinding bowl, whereas the fines are collected in the electric precipitator. A raw material moisture of up to 8% can be dried when utilizing the preheater exit gases only. If hot air from an air heater is also supplied, then a raw material moisture of up to 18% can be handled . The power requirement is 1020% lower than a ball mill, depending upon the grindability and moisture content of the raw material . Other types of roller mills such as ball race mill (Fuller-Peters mill) and Raymond bowl-type ring mill are used in coal grinding.
The CKP pre-grinder has been under development by Chichibu Cement and Kawasaki Heavy Industries since 1987. It has been commissioned by Technip under licence since 1993. The system is applied widely for clinker grinding and has also been used on raw material grinding. In operation, material is fed through the inlet chute onto the grinding table centre, spread out to the grinding path by the centrifugal force arising from the table rotation, before being compressed and ground by the rollers. The preground material drops down out of the periphery of the table to the bottom of the casing and is discharged by the scrapers through the discharge chute. Grinding principle of the CKP system is shown in Figure8. Typical CKP application is given in Figure9 .
Main advantages of the CKP pre-grinders are stated by Dupuis and Rhin  as follows:The grinding capacity can be increased up to 120% for some raw materials.Installation is very easy due to the compact design as well as the possibility of installing the CKP outdoors.The energy consumption of the total grinding plant can be reduced by 2030% for cement clinker and 3040% for other raw materials.The overall grinding circuit efficiency and stability are improved.The maintenance cost of the ball mill is reduced as the lifetime of grinding media and partition grates is extended.
F.L.Smidth has developed this cement grinding system which is a fully air-swept ring roller mill with internal conveying and grit separation. This mill is a major improvement of the cement grinding systems known today which are ball mill, roller press (HPGR)/ball mill, vertical roller mill and closed-circuit roller press for finish grinding. Views of mill interior are given in Figures10 and 11. Cemex grinds the material by compressing it between a ring and a roller. The roller rotates between dam rings fitted on the sides of the grinding ring, ensuring uniform compaction and grinding. The mill rotates at a subcritical speed, and scooping devices at both ends of the ring ensure effective internal conveying of the material being ground. The material leaves the scooping devices at various points, which ensures good distribution of the material in the airstream between the air inlets and outlets. The process air enters through two inlets at either end of the mill and leaves through an outlet at either end of the mill. The air passes the falling material and carries the finer particles to Sepax separator, in which the final classification of the product takes place. The oversize particles are returned from Sepax to Cemex for further grinding. Due to this unique combination of internal grit separation and air-swept material conveying to Sepax, no external mechanical conveyor is needed, which makes the installation very compact and simple. The airflow rate through the mill is relatively low, the only lower limitation being the need for sufficient internal grit separation and conveying of the preseparated material to the final classification in Sepax separator .
Main purposes in designing of the ring roller mill (Cemex) can be summarized as follows:To reduce the specific energy consumption of grindingTo reduce the wear on the mill elements by applying pressures on the grinding bedTo reduce the energy consumption of the mill fan by reducing the air consumption in the grinding processSimple mechanical designSimple and compact design to reduce the external mill load recirculationSimple and easy control of product quality and mill operationSimple and easy change of product type
Grinding tests by the F.L.Smidth company have shown that Cemex produces cement which meets the requirements of the standard specifications while enabling substantial savings in grinding energy consumption compared to the traditional ball mill systems. Due to the more energy-efficient grinding process, Cemex ground cement will usually have a steeper particle-size distribution curve than corresponding ball mill cements. Consequently, when ground to the same specific surface (Blaine), Cemex cement will have lower residues on a 32 or 45m sieve and tend to have a faster strength development. Grinding of cement to a lower Blaine value will reduce the specific power consumption . A comparison of typical specific energy consumption of Cemex mill with conventional multi-compartment ball mill grinding and HPGR pre-grinding closed-circuit operations is given in Table1.
Some of the advantages of Cemex mill can be summarized as follows:Up to 40% lower energy costs compared with conventional grinding installations.Low-maintenance cost.Fully air-swept mill installation.Internal conveying and grit separation.No external mechanical conveyor.Low noise level.Well-proven mill components.A third of the grinding pressure of the roller press and moderate grinding pressures.Long life of wear segments.Drying and cooling ability.Compact and simple design.High grinding capacity.Cement quality meets prevailing standards.Same or better strengths than cement from ball mill.
As it was stated in the literature, grinding tests have shown that Cemex produces cement which meets the requirements of standard specifications while enabling substantial savings in grinding energy consumption compared to the traditional ball mill systems. Due to the more energy-efficient grinding process, Cemex ground cement will usually have a steeper particle-size distribution curve than corresponding ball mill cements. Consequently, when ground to the same specific surface (Blaine), Cemex cement will have lower residues on a 32 or 45m sieve and tend to have a faster strength development. When grinding to a 28-day-strength target, Cemex cement can be ground to a lower Blaine value, which further reduces specific power consumption .
Horomill is a ring roller mill which is a joint development by the French plant manufacturer FCB Ciment and the Italian cement producer Buzzi Unicem Group . Horomill can be used in grinding of:Cement raw materials (i.e. limestone, clay, iron ore, etc.)Cement clinker and cement additive materials (i.e. limestone, slag, pozzolan, etc.)Minerals and coal
The Horomill (horizontal roller mill) consists of a horizontal shell equipped with a grinding track in which a roller exerts grinding force. The shell rotates faster than the critical speed which leads to centrifuging of the material. The main feature is the roller inside the shell which is rotated by the material freely on its shaft without a drive. Operating principle is schematically shown in Figure12. Material is fed to the mill by gravity. There are scrapers located in the upper part of the shell. Scrapers cover the entire length of the mill and scrape off the material which falls onto the adjustable panel of the material advance system. Position of the material advance system which is sloping towards the discharge end could be changed in such a way that material could advance slower or faster, and thus it determines the number of passage of material under the roller which means the adjustment of circulating load. Grinding pressures change within a range of 500800bars. Concave and convex geometries of the grinding surfaces lead to angles of nip two or three times higher than in roller presses resulted in a thicker layer of ground material .
As compared to hybrid systems, Horomilling resulted in lower energy consumptions with energy savings of 3050% for the same product quality. Noise generated is lower than conventional ball mill. They are smaller and compact units. Frictional forces in the Horomill grinding are kept at its minimum, and hence wear is due to the lack of differential speed between the material and the grinding ring. Horomill is designed for closed-circuit finish grinding when compared with an HPGR. Bed thickness is two or three times the roll press (HPGR) .
It also has the flexibility of a vertical roller mill in grinding of different materials. A larger angle of nip draws the material bed into the grinding gap and reduces wear as compared to vertical roller mills. The recirculation of material within a vertical roller mill is very high. The recycle ratios are 15 or more, but it is practically impossible to measure the recycle ratios in a mill operating on the airflow principle. Material bed passes many times through the stressing gap, and it is possible to adjust the number of stressing during operation in a Horomill. Also an internal bypass can be implemented if some of the ground material is returned from the mill outlet to the inlet. The external recycle ratio of a Horomill connected in a closed circuit lies between four and eight and is therefore lower than with a roller press (HPGR) and vertical roller mill . A comparison of the angles of nip of material is given in Figure13 . A photograph of an industrial scale Horomill  is shown in Figure14.
Typical industrial scale Horomill grinding and classification closed circuit are given in Figure15. The circuit includes an elevator, a conveyor to the TSV classifier, a finished-product recovery filter at the TSV outlet and an exhauster. The rejects from the TSV classifier are returned by gravity to the mill inlet. The main features of the plant are as follows :Horomill-installed power: 600kW at variable speedHoromill diameter: 2,200mmCircuit nominal rate in CP42.5R cement production: 25t/h at 3,200 BlaineNominal-circulating load: 140t/hTSV classifier for classification
An industrial sampling survey was carried out during CPP-30R (pozzolanic portland cement) production around the Horomill grinding and classification circuit given in Figure16. Sampling points of the circuit are shown in a simplified flowsheet (Figure16). Horomill was closed circuited with a TSV-type dynamic separator in the circuit.
Prior to sampling surveys, steady-state conditions were verified by examining the variations in the values of variables in the control room. When steady-state condition was achieved in the circuit, sampling was started, and sufficient amount of samples were collected from each point as shown in Figure16. Due to the physical limitations, dried pozzolan stream was not sampled. Samples collected after stopping the belt conveyors by stripping the material from a length between 3 and 5m is shown in Table2. The operation during sampling was closed to steady-state conditions. Important variables of the operation were recorded in every 5min in the control room. Average values of the control room data were used in the mass balance calculations. Mass balance calculations were carried out using JKSimMet computer program. Design parameters of the Horomill are presented in Table3.
A combination of sieving and laser-sizing techniques was used for the determination of the whole particle-size distributions for each sample. SYMPATEC dry laser sizer was used to determine the particle-size distribution of subsieve sample of 149m for each sample. Size distribution of +149m material was determined by dry sieving using a Ro-Tap. The entire size distribution for each sample was calculated using the sieving results obtained from the top size (50.8mm) down to 149m and laser results obtained for the subsieve sample of 149m.
Some errors are inevitable in any sampling operation. These errors result from dynamic nature of the system, physical conditions at particular point, random errors, measurement errors and human errors. Mass balancing involves statistical adjustment of the raw data to obtain the best fit estimates of flow rates. In this context, by using the particle-size distributions and the control room data, an extensive mass-balancing study was performed around Horomill#3 circuit. Tonnage flow rates (t/h) and particle sizes of the streams are calculated by JKSimMet mass balance software. The success of the mass balance was checked by plotting the experimental and calculated (mass-balanced) particle-size distributions as shown in Figure17. These results plotted in a 45 line indicate the quality of both sampling operation and laboratory studies.
According to the result of mass balance calculations, if there had been a statistically significant difference between experimental and calculated values (scattering data), the data would have been rejected and not be used for performance evaluation studies. In this research, data obtained as a result of sampling and experimental studies were found to be in a satisfactorily good fit. Mass balance model of the circuit with the calculated tonnage flow rates (t/h) in every stream and fineness as 45m% residue is shown in Figure18.
where F80 is the 80% passing size of the Horomill feed determined as 1.06mm and P80 is the 80% passing size of the Horomill discharge determined as 0.56mm. It means that the ratio of size reduction is 1.88.
Using the F80 (13.21mm) and P80 (0.024mm) size values from the mass-balanced size distributions of the fresh feed and the TSV fine, the ratio of the overall size reduction was calculated as 550.42 by Eq. (1):
Horomill motor power (2,126 kW) is the average operating mill motor power reading from the control room during the sampling survey and used in the calculation. Total fresh feed tonnage is the dry tonnage amount used in the mass balance calculations represented by the TSV fine stream tonnage flow rate which is 100.66t/h. Thus, the specific energy consumption (Ecs) can be calculated by Eq. (4):
The performance of any classifier, in terms of size separation, is represented by an efficiency (TROMP) curve. An example for a classifier is shown in Figure19. It describes the proportion of a given size of solids which reports to the coarse product. Mass-balanced particle-size distributions and tonnage flow rates around the separator were used to evaluate the performance of the separator. Percentage of any fraction in the feed pass to the coarse product (%) is defined as partition coefficient and expressed by Eq. (6):
The d50 size corresponds to 50% of the feed passing to the coarse stream. It is therefore the size which has equal probability of passing to either coarse or fine streams. When this size is decreased, the fineness of the product increases. The operational parameters that affect the cut size are rotor speed and separator air velocity. Cut size for the TSV was determined as 23.33m. The percentage of the lowest point on the tromp curve is referred as the bypass. It is the part of the feed which directly passes to the coarse stream (separator reject) without being classified. Bypass value is a function of the separator ventilation and separator feed tonnage. The bypass value of TSV was 23.29% which indicated a consistent performance for this separator. Fish-hook effect () is the portion of fines returning back into separator reject stream. When there is incomplete feed dispersion at the separator entry, or even within the classification zone, aggregates of fine particles may be classified as coarse particles and thus report to the coarse stream. Fish-hook amount of TSV was 1.58% which also indicated how effectively it is operating:
Usually, for TSV-type separator, it is between 0.55 and 0.7. When the normal range for sharpness (k) parameter is considered, it is found to be not in the normal range . When the normal range for sharpness (k) parameter is considered, it was found to be not in the normal range. The imperfection of separation is defined by Equation 8, and I was calculated as 0.47:
Typical operating conditions for the Horomill and two-compartment ball mill grinding with HPGR pre-crushing and classification circuits are compared in Table4 for the same production type. As can be seen from Table4, Horomill production configuration has resulted in energy savings of 50% as compared to HPGR/two-compartment ball milling configuration .
It was also reported that concrete workability from a portland cement with a 3,200 Blaine which is a Horomill product is equal or better than an equivalent ball mill product. Mortar and concrete strengths are always higher as shown in Figures20 and 21. The closed-circuit recirculation factor is noted as about six in Horomill grinding . A comparison between the grinding systems and conventional ball mills applied in cement grinding circuits is given in Table5. Grinding efficiencies of different systems in grinding of cement to a fineness according to a Blaine of 3,000cm2/g were compared in Table6.
The efficiency of a two-compartment ball mill is defined to be 1.0. This efficiency reflects the power consumption of the mill only and does not include any auxiliary equipment like conveyors and dust collectors nor the separator.
Comparisons between different energy-efficient grinding technologies and applications were presented for production of cement with energy savings. Industrial-scale data related to Horomill and Polysius HPGR/two-compartment ball mill circuit provided insights into the operational and size-reduction characteristics of Horomill and HPGR/two-compartment ball mill-grinding process with indications that Horomill application could produce the same type of pozzolanic portland cement at lower grinding energy requirement. The specific energy consumption figures indicated approximately 50% grinding energy savings in Horomill process.
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The cement vertical mill is a grinding equipment developed on the basis of similar grinding mills, so it has many irreplaceable advantages, such as high grinding efficiency, low power consumption (20-30% less power than ball mill), large drying capacity (simultaneously dry and grind materials with moisture up to 10%), large particle size of grinding materials, simple grinding process, small floor area, low noise and wear, long life and other advantages. This kind of machine uses a hydraulic system to make the pressure act on the material between the roller and the grinding disc, so as to achieve the purpose of grinding. AGICO, as a cement equipment manufacturer in China, supports high-quality coal vertical mill, raw material vertical mill, and thecement vertical mill.
The cement vertical mill consists of a classifier, upper housing, access door, feeding port, transmission device, roller, pull rod, balk ring, grinding table, air ducting ring, swinging arm, gearbox, hydraulic system, etc.
AGICO Group is an integrative enterprise group. It is a Chinese company that specialized in manufacturing and exporting cement plants and cement equipment, providing the turnkey project from project design, equipment installation and equipment commissioning to equipment maintenance.