This product is an important part for ball mill and its call "feed end liners for ball mill' its main function is to protect the end cover of ball mill. The high wear-resistance head liner provided by our company have improved the wear condition of the feed end liners for ball mill, that make the end liners have good wear-resistance and effectively increase the service life. We can also make customized products according to client design.
As a liner, the lift bar is used to protect ball mill head from direct impact and friction by grinding medium and material. This kind of Mill Lifter Liner is widely used in all kinds of working condition to increase grinding efficiency and production and reduce consumption of metal. We are able to provide customise this lifter bar conforming to customers' requirements & by using combination of liner and lifter user can rotate the ball mill both clockwise & anti clockwise easily.
Established in 1973, MJ TSR has been growing to become a global company based on assimilated technologies with world class quality for the past 50 years. MJ TSR has been contributing to the development of the industrial plants by manufacturing special industrialized rubber products and rubber linings.
SAKAR Rub-Tech Pvt. Ltd. is Indias leading Ball Mill Rubber Liner / Rubber Mill Liner supplier for the mineral beneficiation, mining and bulk solids handling industries , Established in 2016, with a very humble start but with a vision to grow into one of the most trusted and reliable company of the country. SAKAR has grown from strength to strength since then and today have own comprehensive designing and manufacturing facilities.
Founder (Mr Manish Pajapati & Mr.Babubhai Pajapati ) of SAKAR Rub-Tech is having 15 years experience of rubber parts production. SAKAR Rub-Tech provides excellent grinding solution through Ball Mill Rubber Liner / Rod Mill Rubber Liner / Rubber Mill Liner for all over mineral beneficiation, mining and bulk solids handling industry.SAKAR Rub-Tech takes care of Ball Mill or Rod Mill with wear & tear and abrasion resistance Rubber Mill Liner. SAKAR strictly follow the principal of Always deal with quality product only. Quality remains our top priority and equal attention is given even to the smallest of the product leaving factory. No wonder then repeat clientele remains our consistent growth engine, as they say Quality Pays!
Ball Mill Rubber Liners are used to protect the inner shell of cylinder from being impacted and worn directly by material and grind-ball. At the same time we can use different forms of the mill liners ...
SAKAR RUB-TECH PVT. LTD. is Indias Leading Manufacturer, Supplier and Exporter of Ball Mill Rubber Liners, Rod Mill Rubber Liners, Wear Resistant Rubber Liners, Mill Lining Solution, Shell Plates, Lifter Bar, Head End Plates, Rubber Screen Panel in India.
There are basically two groups of Grinding Mill Liners. Ones with a HIGH PROFILE and those with a LOW PROFILE. The high profile liner is designed to give the media the higher lift. This type will be used in mills that are designed for primary grinding and as a result require the impact of the higher cascade. Ball mills working as the secondary portion of a grinding circuit will utilize the lower profile liners. The reason is as lift decreases, friction increases. To function effectively they need this type of grinding action to obtain the maximum contact of their high surface area. There are two other factors that the liner design must accommodate other than the degree of lift. The TYPE of grinding media and the SIZE of the media. To do this, there have been developed different liner profiles, RIPPLE LINERS, WAVE LINERS, SINGLE STEP LINERS, DOUBLE STEP LINERS, SHIPLAP LINERS and LIFTER BARS. These are also known as a KICKER BAR LINERS. The important measurements being the WIDTH of the valleys, the HEIGHT of the lifting portion of the liner and the overall THICKNESS of the liner.
(A liner takes up space and will reduce the tonnage accordingly.) When a mill is being designed, the type of liner that will be used is very important. The wrong liner design will increase power and steel consumption, as well as reduce the grind and throughput of the mill.
Liners not only come in different designs, they are available constructed from different materials. Liners may he built from MANGANESE STEEL for rod mills and ball mills that use bigger than two inch balls. Or they may be what is known as CHILLED CAST IRON LINERS. This type of liner have their own content formulas and are cast in their own manner as well. An example of such a liner is the NIHARD LINERS. In the last few years RUBBER LINERS for secondary grinds have also been used with some success.
For an operator the biggest effect that the liners will have on his job will be the result of wear.As the liners wear out the lifting portion of the liner will be reduced until the liner has a lower profile.
This means that the cascade of the media will become flatter as the as the leading edge of the lifter wears away. The amount of unground material will slowly increase until the mill can no longer grind the bigger ore. When this happens the liners will have to be changed.
If you ever have to start up a mill that has had a complete liner change I would suggest starting at a reduced tonnage and slowly bring the tonnage up to its maximum. This is because the new liners may have too much lift and literally throw the media across the mill spoiling the cascade action. Once the LEADING- EDGE of the liner has worn off a bit you will be able to increase the tonnage again. You will notice that the grind will continue to improve due to the liners slowly wearing away providing a longer retention time for the ore to be processed in. This of course has a limit, once the liners wear past a critical size the efficiency of the mill will slowly deteriorate until the liners are completely worn out requiring replacement.
This system combined rubber plates with cast manganese lifter bars which assures that the major portion of the surface of the mill will be protected with an abrasion -resistant resilient surface under compression and that the remaining portion of the lining will be capable of sustaining the lifting load, will maintain a uniform lift and will resist abrasion .
Todays rubber mill liners have built up from these origins and rubber liner manufacturers have worked closely with the mill operators to develop better compounds and better designs to provide the best liner system for each application.
Abrasion Resistance: Todays rubber compounds are specifically designed to resist wear by abrasion. The success has been well documented in regrind mill applications where rubber has outlasted cast metal liners and given better cost effectiveness.
Impact Resistance: This feature is more important in the larger grinding mills. Rubber liners absorb the impact of the larger grinding media and thus protecting the mill structure and prolonging its life.
Weight: Rubber weighs about 15% of an equivalent volume of steel. This means that a rubber liner system reduces the load on the mill structure and also reduces the basic power draw. Another benefit is that liner components are lighter, easier and safer to handle. A major factor in todays milling operation where fewer people are available for liner changeouts.
Tight Seal: Because rubber liners can be produced to relatively close tolerances and rubber is deformable, a rubber liner system is designed as a tight liner. This protects the structure of the mill from any abrasive or corrosive wear. Another very important side benefit for gold operations is that the amount of free gold trapped between or underneath the liners is significantly reduced.
Flexibility: This feature of rubber is particularly significant in the use of rubber for grate discharge mills. The natural flexibility of rubber reduces the potential of blinding the grates. This will be discussed in greater detail later in this paper.
The design of rubber mill liners is very specific to the grinding application and will not be covered in this paper. Instead, three design concepts based on rubber as a lining material will be discussed. These are combination liners, rubber grates and rubber covered pulp lifters.
Long ago, it was recognized that there were grinding applications where rubber alone was not effective. The patent for the combination liner was issued for a design that extended the use of rubber into those applications. Although rubber technology has improved, there are still applications today where rubber alone is not effective and the combination liner is successfully used. These applications include semi autogenous mills and primary single stage ball mills.
The revised and updated design of a combination liner is a rubber plate with a separate metal lifter bar. Most of the volume of the liner is rubber so that the features and benefits of a rubber liner are retained. This plate can be either a plain contoured slab liner plate as shown or it may have a molded intermediate rubber lifter if required due to the chordal spacing, the size of the grinding media and feed.
The rubber plate is held in place by the metal lifter bars. A metal spacer sits between the rubber slabs and lifters to keep the liner from shifting. This spacer is usually made of low cost mild steel and is a one time item as it does not experience any wear and does not need replacing. This results in significant cost reduction of the liner system.
The metal lifter bar design is generally a function of the grinding application and mill size. The cross section however must retain two critical dimensions. The first is that the lips or edges of the lifter that extend over the rubber plates must be kept at a minimum of 25 mm to provide adequate clamping of the liner plates by the lifter.
The second critical dimension is the depth of the base. This should also be a minimum of 25 mm to prevent any lateral displacement. The base of the metal lifter must also be a flat smooth surface in order to properly seat on top of the metal spacer. The lifter bar is bolted through the shell with oval head taper grade 5 forged bolts.
This design has several important benefits. First, the amount of scrap loss in metal lifter bars at change out is kept to a minimum through the use of the mild steel spacer. The spacer also provides a solid base for the lifter so that the liner bolts can be properly torqued down. The second benefit of this design is that there is no metal in the rubber plates, as the lifter is supported by the permanent metal spacer. This simplifies the manufacturing of the rubber liners, and makes the plates lighter and easier to handle on installation.
The metallurgy of the lifter bars must be carefully matched to the grinding application. In mills with high impact such as large SAG mills, a high impact resistant Cr-Mo steel is required. In applications of low impact, the more abrasion resistant, castings such as Nihard are utilized to achieve maximum life through high abrasion resistance.
Liner design has a significant effect on mill performance and mill liner life. The process of getting it right is an evolutionary process over the life of the project. Usually this is a joint continuous improvement process by the Plant Superintendent and the Mill Liner Supplier. Excess liner wear results in high liner material costs, increased downtime and impacts on plant throughput. Improved liner design can result in improved mill grinding performance and the best economic balance between liner life and cost.
The history of liner design development fell under the maintenance department where longer life was the main consideration to reduce cost. Over the last twenty years new cost engineering approaches and mill modeling has highlighted the mill performance issues with the development of liner profiles and improved materials.
The other change that has occurred is the advent of large diameter SAG mills. It became apparent to the operators that the liner/lifter profile and mill speed had a significant impact on mill performance. The gains from good liner design and selection also became more important because of the change from multiple mill lines to single train large mills.
These were developed in South Africa and are suited to higher critical speed mills and are very economic for highly abrasive ores. They are light weight and the balls infill the liners and provide an effective wear material. They are manufactured in manganese steel which often spreads (metal flow) and makes removal difficult. Safety inside the mill from dropping balls is also an issue if personnel enter the mill.
These are commonly used and convenient but the correct wave angle needs to be specified for a particular mill. This is a difficult profile to get right first up. Some modifications normally required as the plant progresses from initial commissioning stages to fully operational and changing ore characteristics through the mine life.
These are economical and convenient as the original high lifter becomes a low and by alternating is later changed out to be a high lifter. The mill wears to give a good lift profile. These are used in the primary SAG mill at Casposo, Argentina to good effect. This is applicable to mills where ore packing is not an issue.
This is used for grid liners and work hardens with use and can withstand extreme impact without breakage. Its biggest disadvantage is the difficulty of removal after many months of use because it spreads.
These are 550 BN hardness and were used in rod mills and ball mills where impact is low for this brittle material. It is extremely wear resistant but has been superceded by the chrome moly irons and chrome moly white iron.
Rubber is commonly used in ball mills because of its long wear life, lower cost and easy change out. It can be used in primary mills as rubber steel composites (Polymet). Rubber steel composites are gaining in popularity because of much better economical outcomes. The bolts and fittings are much lighter than for steel liners. Rubber alone is not suitable for primary mills. (Powell, 2012)
The lining system consists of permanent magnets embedded in rubber mouldings. These are more expensive than rubber liners but can give years of trouble free operation with minimal wear. They are more applicable where wear is a primary consideration.
Liner design is an evolutionary process where small improvements are made over time resulting in positive outcomes. Heavy reliance is made on the mill Vendor and the liner supplier. Guarantee for performance and liner life is very hard to extract because of the inherent risks and difficulty in quantifying unknowns. There is also no guarantee that the operators will follow the liner suppliers advice to prevent damage. Most suppliers work on a trial and error approach with iterations of improvement based on findings. Whilst this appears to be slow and a ramp up approach with a loss of potential production the industry has not developed a better way. (Connelly, 2011)
It has been established in the field that a higher lifter height will increase throughput but result in excessive wear over a lower height. Monitoring the wear on the liner is also relative to the height of the lifter bar in use. Monitoring liner height and undertaking mill profiles with a piano rod profiler or a measuring instrument. Monitoring the profile during life allows calculating charge trajectories.
Optimising design is about maximizing impact grinding in AG/SAG mills, ensuring cascade action for regrind mills and avoiding impact on the mill shell, minimizing ball breakage, maximizing mill throughput and balancing wear life with throughput and liner cost.
Modern computer aided finite stress analysis (FEA) can highlight the impact of normal stress on a liner and shear stress which can be many times more severe. This results in changes to the liner which overcomes high stress points.
The Bond Abrasion test is a good predictor of liner wear. Tests using liner panels have been notoriously misleading because they dont represent a full mill condition. Plant trials using parallel trials for multiple lines can yield meaningful results. Ore changes from variability in the pit can influence the service life of liners under test.Historical records can be used but the ore must be similar and operating conditions should be similar.
The bolt hold drilling is determined by the mill manufacturer. Mills drilled for rubber cannot accommodate steel liners without changes to the hole configuration. A far wider spacing of holes is required on larger mills.
A distinctly noisy or mill that rattles suggests grinding media is impacting on the liners and causing unnecessary wear and possibly damage. Incorrect speed, poor feed blending and incorrect liner profile can contribute to this. Other negatives are ball breakage and liner cracking. Reduced mill efficiency is a direct result. The liner bolts may also loosen because of the incessant pounding they receive with resultant leaking around the bolt holes.
Mill liner bolts are consumables. Usually a forged head into a cast liner so some bedding in is inevitable. Broken bolts are a sure sign of quality issues but it can also be caused by a multitude of other problems. Loose bolts are bad and can lead to shearing of the bolt.
Bolts becoming loose after a liner change are not uncommon. And a scheduled rattle (torque multiplier) gun tightening 24 hours after a liner change is recommended. With large SAG mills the discharge end may require two intervals of tightening. The bolts should not loosen after that unless over worn in which case the liner speed needs to be carefully checked.
Regrind mills require a motion to maximize abrasion not high energy impact. Densities and viscosity are also more of an issue to be taken into account. Minimising circulating load and minimizing over grinding is more of an issue.
It is not uncommon for liner wear to impact on mill throughput and efficiency. Mill throughput drops markedly when new liners are installed .At Bougainville the single stage ball mills gave best performance at or near the end of the liner life. Bedding in or poor performance after a liner change out is not uncommon. Design changes should be made to overcome this.
Liner wear measurement was the responsibility of the maintenance personnel but now is the responsibility of the Metallurgist because of the demand to increase mill throughput and efficiency. It is possible to represent the wear graphically using a piano rod measuring device or a mill mapper (electronic gauge).
With mill liner inspections these should be on a regular basis rather than as the opportunity arises. Some of the things to look for are broken balls, loose bolts, broken lifters or cracking, damage around the bolt hole, the shape of the balls, excess grate wear and pegging of the grate with balls or rock as well as any tramp metal present. Excessive metal flow from peening causing the gaps between liners to lessen and increase the internal stress in the liners (especially for chrome/moly steel material).
MillTraj by Liner Design Services can produce visual plots of mill trajectory (Figure 5). This is a very useful tool for SAG mills and prediction accuracy depends on the ore type, viscosity and ore properties. One can evaluate the space height ratio and wider lifter bar spacing.
Utilising charge trajectory predictions is not straight forward and lifter bar face angles can if not taken into account lead to erroneous predictions if not taken into account. Liner bar heights are easy to predict but high low lifter profiles under new and worn profiles become more difficult to predict accurately.
Mill speed affects the trajectory and the liner profile should be selected to suit the mill operating speed. The final liner selection can be based around the desired operating window. For large SAG mills the new lifter speed may be 73% critical but with worn lifters the mill may be running at 80% critical some 6 months later.
This is a particularly nonstandard operating period and care should be taken not to run empty or noisy mills during feed ramp up. There are cases where a set of liners have been damaged under such conditions.
Usually for a SAG mill at start up a much lower ball charge should be used and built up over time. The mill should be operated at low speeds and the feed blend should be neither too soft nor too hard. A new mill and soft oxide ore is an extremely high risk scenario for liner damage. The outcome can be catastrophic. High volumetric fillings are recommended and not relying on instruments such as load cells but stopping to visually check the mill load is essential.
Mill throughput and efficiency gains through iterative liner lifter configurations are common over time based mainly on trial and error. Substantial gains can be achieved in the design, selection of liners based on mill trajectory modeling, supplier selection of lifter bar heights, angles, and spacing.
The height of the lifter bar is critical and should be determined by the ball size, desired wear life balanced against mill throughput. Face angles can be determined by simulation to give impact at the toe of the charge. Field trials are the acid test and comparing predictions with actual data in use. Sensible and controlled changes in consultation with the operator and liner supplier over time results in an optimized outcome. This results in the liner profile and material to be optimized with respect to mill performance, liner cost and liner life.
The raw materials are imported, such as butyl rubber (USA EXXON MOBIL 1066, Japan JSR 268), natural rubber (Vietnam SVR 3L), chloroprene rubber (Japan DENKA M40). According to differences of compounds, the rubber lining has the following types: HNR, SNR, IIR and CR. According to the vulcanization methods, the rubber lining can be divided into press vulcanization, atmospheric pressure vulcanization and prevulcanization type. Seawater resistant, sodium hypochlorite resistant or low calcium and magnesium specialty rubber linings are also available.
Tega Mill Linings provide optimal grinding solutions in major mineral processing plants all over the world. Tega rubber lining system is the preferred lining system for secondary ball mills; regrind mills, rod mills and scrubbers.
Fastening System : Tega reinforced lifters have an integrated aluminium track to accommodate the fixing clamp. Non-reinforced Tega Lifter Bars are installed with detachable steel clamps which can slide inside the groove on the lifter base and be bolted to the mill shell. Tega Lining bolt attachment systems are compatible with conventional attachment for rubber linings used in grinding mills. The latter are available with different grades of steel as well, if required for very high or low pH-values.
Crushers & Equipment International Limited can supply newBall Millsor Rod Mills to specific request. From 4 (1 metre)diameterto 18 (5.5 metre) diameter. These can be overflow or grate discharge,suppliedwith the followingliners:
We supply over 2000 tonnes of various mill liners into themarket. Materials as specified above can be used in Ball, Rod, Sag and FAG mills. The mills areAllis Chalmertype,steel headsand usually supplied with white metal bearings, howeverroller bearingsare available on request. Larger mills can be supplied withgear boxes, or direct synchronous motor drive, and variable speedcan be an option.
We can supply liners from existing drawings anddesignsor as per request can design new liners tooptimisewear life and improve grind. We also assist the mine in planning replacement sets, to ensure stock is always on hand.
A lot of mining operations do not place a lot of interest in millliningsas they have used a product for years, have a historical life, and assume that is the best they can get. However we can do design changes to the liners (at no extra cost) that can change the grind in the mill,increase throughput, and reduce wear points on the shell and ends. In some instances we have achieved more than double the life of mill liners by altering the design, or material used.
We also supply trunnion liners, bolts, girth gears and pinions, and many other spares that are required formilling. These can be supplied per drawing, and if no drawings are available, we have qualified staff that can travel to site to measure up, produce working drawings and supply.
Poly-Teks seals are made out of high-quality natural rubber designed to handle the most difficult environment. Poly-Tek manufactures a variety of rubber seals for the mining and aggregate industry. This includes seals used for preventing seepage from a mill liner used grinding mills such as ball mills and rod mills. The Lister bolt and fastening system has been a ubiquitous presence in the mining industry for over a century. The system includes a liner bolt that fastens a liner to a mill shell. The threaded portion of the bolt extends through the shell and is fastened using a hex nut. Between the hex nut and the mill shell is a cup washer and a rubber seal that can extend through the mill shell. Poly-Tek manufacturers replacement rubber seals for Lister Liner Bolts and other liner bolts used to prevent leaks and seepage.
There are different types of seals used in a mill liner fastening system. As bolt holes age, the hole may begin to enlarge from the wear. For enlarged or elongated bolt holes, there are cone repair seals in diameters of 1 through to 2. A repair seal includes a cone that extends through the grinding mill shell, whereas a regular seal does not have a cone. The cone can vary in length. For example, the repair seal cones come in lengths of 2 inches, 2 inches, and 3 inches. The length and diameter of the cone will depend upon the size of the bolt and the surrounding metal cup washer. The seals are available in a variety durometers and base polymers, for example, natural rubber durometer, EPDM rubber, or silicon for use in corrosive or high temperature applications.
Poly-Tek is a rubber manufacturing company, so you are dealing directly with the people who know rubber best. Poly-Teks mill liner rubber seals will last longer and eliminate seepage from the bolt holes. Contact us today at [emailprotected] or (510) 895-6001.