The grate-discharge type of Ball Mill has a grate at the outlet of the shell and causes less excessive grinding, compared to the overflow type. Therefore, generally, it is best suited to grind materials up to the particle sizes ranging from 60 to 100 mesh.

For overflow ball mills, the charge should not exceed 45% of the mill volume . For grate discharge mills, the charge should occupy about 50% of the mill volume . Bond developed a relationship that can be used to determine the percent charge by volume as a function of the vertical height above the charge, He, and the radius of the mill, R, i.e.,

For overflow ball mills, the charge should not exceed 45% of the mill volume . For grate discharge mills, the charge should occupy about 50% of the mill volume . Bond developed a relationship that can be used to determine the percent charge by volume as a function of the vertical height above the charge, He, and the radius of the mill, R, i.e.,

Overflow VS Grate Discharge Ball or Mill Why Retrofit. 24/06/2015 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 In the past, I had worked with +10% as an expected increase created by the conversion How much capacity you gain by using grate …

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. This is different to an overflow mill which holds the slurry and balls inside until ...

Grate Discharge Ball Mill: This type of mill usually works with a high circulating load and thus produces very little extreme fines. The specific power consumption is therefore less than for an Overflow Mill. A Grate Discharge Mill will also have 15—25 % higher capacity per volume unit as compared with an Overflow Mill.

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.. Its basic structure and grinding process are basically the same as the overflow type ball mill, but the structure of the ore discharge part is different.

Compared with the overflow type ball mill, the ore discharge of grid type ball mill is low-level forced discharge. The pulp surface of the ore discharge port is low, the fine ore particles can be discharged in time, and the heavy mineral will not be concentrated in the ball mill, which greatly reducing the over-grinding phenomenon.

It is better to choose a grate discharge ball mill when the required discharge size is in the range of 0.2 to 0.3 mm. Grate discharge ball mill is usually applied in the first grinding system because it can discharge the qualified product immediately. Overflow discharge ball mill

(1) Rao Latchireddi, (1) Raj K Rajamani and (2)Sanjeeva Latchireddi. (1) University of Utah, (2) EE-Mill Solution LLC, USA.

This reduced impact energy results in a reduced rate of breakage across all size fractions inside an overflow mill compared with a grate discharge mill. If the slurry pool is removed, the balls fall without cushioning and the breakage rates increase.

The discharge end of the Grate Discharge Ball Mill has at least ten times the discharge opening area, through the grate slots, compared to the common trunnion overflow type mill. The discharge grates are designed to run clean and free of any blinding or choking. The pulp level in the mill may be varied by merely changing the pulp dilution.

Overflow Versus Grate Discharge Ball Mills: An Experimental Investigation It has been widely accepted to go for grate discharge ball milling when a coarse product is preferred or to avoid production of extreme fines, but overflow discharge mills are preferred for their simplicity of design and production of finer product.

Discharge of pebbles, finer rock, ball scats and slurry from mills and its flow through trommels, and into other processing operations has strong impacts on overflow ball mill performance.

The discharge end of the overflow type ball mill (usually used for wet operation) is not equipped with a discharge grate plate, but on the inner surface of the hollow shaft bushing at the discharge end, a screw with a spiral direction opposite to the rotation direction of …

A set of experimental test work has been carried out in a continuous pilot ball mill of 0.41m X 0.56 m (diameter X length) at different mill speeds, percent solids and discharge mechanism. The results of study on material flow through a grate discharge tumbling mill verses an overflow tumbling mill are presented to emphasize the effect of ...

Ball Mill Trunnion and Mill Grate Discharge The overflow type is more commonly used as it is lower in first cost. These mills have large trunnion openings which allow high circulating loads to be carried if desired.

The cost of a ball mill conversion from overflow to grate discharge is 'fairly' affordable at $65,000 for a 13′ x 15′ mill. This is only for the discharge head, grates and pulp filters (rubber). A comparison in laboratory …

The overflow mills use much simpler trunnion bearings to support the mill, whereas grate-only discharge mill would require a tire gear around the shell which is expensive and involves complex manufacturing process as the grate has to withstand the pressure exerted by the steel ball charge and allow slurry to discharge effectively."

Grate Discharge Ball Mill For Fluorite High Speed. Types Of Mostly Used Ball Mill In Grinding Line Fote. Nov 02, 2019 the discharge of overflow type ball mill is caused by the pulp itself overrunning the lower edge of the bushing of the hollow shaft neck. generally speaking, due to the forced discharge mode, the grate discharge ball mill has higher production capacity than …