Abstract. The lack of constraints in ball mill capacity in the published ball mill models may result in unrealistic predictions of mill throughput. This paper presents an overfilling indicator for wet overflow discharge ball mills. The overfilling indicator is based on the slurry residence time in a given mill and given operational conditions.
Pulp lifters, also known, as pan lifters are an integral part of the majority of autogenous (AG), semiautogenous (SAG) and grate discharge ball mills. The performance of the pulp lifters in conjunction with grate design determines the ultimate flow capacity of these mills. Although the function of the pulp lifters is simply to transport the slurry passed through the discharge grate into the ...
Ball mills are usually either of the grate ( diaphragm) or overflow type. Ball Mill Components Ball mills consist of the following components: Inlet crushed ore is fed to the ball mill through the inlet. A scoop ensures the feed to the mill is constant. Discharge reduced feed exits the mill through the discharge. Ball Mill Components
Discharge grates play an important role in determining the performance of autogenous, semiautogenous and grate discharge ball mills. The flow capacity (grinding capacity) of these mills is strongly influenced by the discharge grate designopen area and position of apertures, as well as the performance of the pulp lifters.
A grate discharge may give beneficial results on certain ores especially where an excess of fine sizes is detrimental. Rod Mill Capacity Table Small Ball Mill Capacity and Sizing Ball VS Rod Mill Conversion
model and ball mill model, to integrate the overall mill system model within 10 years as ... design of discharge grate and pulp lifter on power draft of the mill by isolating the effect that one has on another . The second subobjective is to conduct plant surveys at
Furthermore, it should be observed that a grate discharge ball mill converts about 20% more energy than an overflow discharge mill with the same shell dimensions. Ball mill shells are often furnished with two manholes. Ball mills with small balls or cylpebs can produce the finest product of all tumbling mills. 80% minus 74 microns is a ...
Unlike the grate ball mill, the overflow type ball mill has a simple structure, and the discharge method is based on the gravity flow of the slurry to discharge the ore. The product size of the overflow discharge ball mill is generally less than, which is suitable for concentrate regrinding operation and can be used as onestage grinding ...
Converting a ball mill from overflow to grate discharge involves installing a grate inside the mill at the discharge end. The grate holds the balls inside the mill but allows the slurry to pass through, and it is then pumped out of the mill by the pulp lifters.
(1) Rao Latchireddi, (1) Raj K Rajamani and (2)Sanjeeva Latchireddi. (1) University of Utah, (2) EEMill Solution LLC, USA.
Discharge grates play an important role in determining the performance of autogenous, semiautogenous and grate discharge ball mills. The flow capacity (grinding capacity) of these mills is strongly influenced by the discharge grate designopen area and position of apertures, as well as the performance of the pulp lifters.
Analyze ball trajectories so that mill speeds can be chosen to avoid "destructive contact between balls and exposed shell liners". ... Historically the grate discharge has been a design option in grinding mills. With the introduction of wet autogenous and semiautogenous mills, this type design is used exclusively. ...
Reducing the ball charge will reduce the grinding capacity, and the comment on installing a grate discharge is a good one as it will let ore out sooner, thus minimizing overgrinding, which will occur if the mill is (temporally) too big, or one chamber is too big in a multi chamber mill. ... Ball mill liner efficiency based on liner geometry and ...
Please be aware that adding a grate to your ball mill will reduce your EGL by around 500 600mm (the depth of the pulp lifters and grate plate / liner thickness, plus it will also increase your mill motor power draw by anything from 1020% for the same throughput.
Grate ball mill ( grate discharge ball mill) is a ball milling machine used to grind various ores and other materials. Grate type ball mill is a traditional ball milling equipment for forced ore discharge by ore discharge grate.
Ball mills can be classified into two type Based on different Ore discharging types: grate ball mill and overflow ball mills. In this article, we will compare the two types to help you choose the ...
Trelleborg has been providing mill lining systems since 1920. The focus is on working with our customers to provide incremental improvement to enhance mill availability, increasing efficiency and reducing energy consumption. Full lining kits are designed and supplied including Lifter bars, shell plates, pulp lifters, fasteners and discharge grates.
Six Sino Iron SS AG mills (~1200 t/h), CiticHIC, 40x33 ft (EGL), 28 MW each CONCLUSIONS Scrubber and AG mills are modelled in a similar way as to how overflow ball mills and grate discharge ball ...
In South Africa wet grate discharge mills having a nominal ratio of length to diameter slightly larger than 1 (16/12 = 1. 33 and 14/12 = ... Where in conventional rod and ball mill plants there are usually 3 to 4 stages of crushing followed by 1 to 3 stages of grinding, depending on ore fineness and hardness, primary autogenous plants ...
In grate ball mill work there are no discharge head liners. The discharge grates and grate assembly replace these parts. Mill LINER BOLTS. Where cast liners are used shell liner bolts and head liner bolts are made of forged steel with an oval head to prevent turning and loosening within the liners. These are held in place with two hex nuts and ...
Grate ball mill discharge side cover liner inner sleeve shaft liner liner bars key. Different of feeding device of grate ball mill. 1. The feeders of ball mill are: drum type, worm type and combined type, and their structures are shown as (a), (b) and (c) in the figure.
A ball mill is a type of grinder used to grind or blend materials for use in mineral dressing processes, paints ... wet or dry. There are two kinds of ball mills according to their ways of discharging material: grate type, and overfall type. Many types of grinding media are suitable for use in a ball mill, each material having its own specific ...
In this video, a fullscale SAG mill was modeled using the recently released fully coupled embedded SPH (Smoothed Particle Hydrodynamic) and Discrete Element...
Summary and conclusions. The slurry transportation in AG/SAG mills is a twostage process consisting of flow through the grate and the discharge of slurry by pulp lifters into the discharge trunnion. The grateonly discharge condition provides the ideal relation between slurry holdup and flowrate.
Reasonable Solutions For Common Faults. Regularly check the wear of cylinder lining plate and timely adjust the proportion of steel balls. Regularly check the installation position of the main bearing to ensure that it meets the specified requirements. Regularly check the contact between the hollow shaft journal and the bearing bush to ensure ...
Grate discharge ball mill: the ore is discharged through the grate plate. The grating part can strictly control the minerals' discharge size that meets the demand, it has a good effect on fine particle grinding. 3. Peripheral type: discharge ore through the periphery of the cylinder.
The role of the pulp lifters is to lift the slurry which passes through the grate into the discharge trunnion. They are incorporated in both flat and conicalended mills (Fig. 1) and are normally either radial or spiral in design (Fig. 2). Of the above two designs, the radial or straight type is most commonly used in industry.
Grate discharge Dry Grate discharge Wet Overflow discharge Wet Figure Effect of mill filling on power draft for ball mills. The data is taken from Rexnord Process Machinery Reference Manual, Rexnord Process Machinery Division, Milwaukee, 1976 The effect of varying mill speed on the power drawn by the mill is shown graphically in Figure
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