Sep 01, 1986 A model for the effect of flowrate and viscosity of slurry on the hold-up of slurry in a grate-discharge grinding mill has been developed. Given detailed specifications of the grate design (such as the area in the grate within which the holes are situated, the number of holes per m 2 and the hole size) and the flowrate and viscosity of the slurry flowing through the mill, the model provides ...
crusher, Table 3. The interior of the mill is illustrated in Figure 1, showing the length and filling of the mill, and low lifters on top of standard AMS grid type liners. The detail shows sections of the discharge grate (18mm round holes extending to near the centre of the grate), and pebble ports (75mm round holes).
Transport of slurry through the mill is described by a function which relates the hold-up of slurry, grate design, grate open area and mill speed to the volumetric discharge rate through the grate. The model reflects feed size changes by changing the load size distribution and hence rock grinding media size.
Transport of slurry through the mill is described by a function which relates the hold-up of slurry, grate design, grate open area and mill speed to the volumetric discharge rate through the grate (Morrell and Stephenson, 1996) Jp k Q0.5 g-1.25 A-0.5 f0.67 D-0.25 (7) where. Jp fractional slurry hold-up. D mill diameter (m)
The discharge grates of the SAG mill were identified as a key component in the SABC circuit, and their design is a crucial factor in the mills performance 17,18,19,20,21. The initial design of the grate section caused a serious accumulation of pebbles within the SAG mill which contributed to a decreased grinding efficiency.
Jun 01, 2006 The performance analyses of conventional design of pulp lifter have shown that a large amount of slurry flows back from pulp lifter into the mill. The degree of slow-back depends on the size and design of the pulp lifters. The ideal slurry flow in a typical grate discharge mill
Jun 23, 2020 Converting a mill from an overflow to a grate discharge arrangement leads to an increased power draw. This happens because the installation of the grate discharge arrangement enables the mill to run with a lower level of slurry due to it being no longer necessary for the slurry to build up inside the mill until it overflows from the mill discharge.
Jan 01, 2007 The discharge rate of the product material depends on how efficiently the discharge pump (grate and pulp lifters) is operating. Similar to the impeller design affecting the pump capacity, the pulp lifter design affects the discharge capacity (or mill throughput) of the SAG/AG grinding mills.
Mill Pulp Trommel Free Flow by Free SAG Plant Diameter, feet Diameter, feet Long, feet Flow, m 3/h Area, m 2 Area, m 2 Area, m 3/m 2/h C.M.D.I. Collahuasi 32 14,4 13,6 935 57,0 15,4 61 Minera Los Pelambres 36 15,9 16,4 2.063 75,9 19,7 105
and Closed Circuit AG/SAG Mills S Morrell1 ABSTRACT The aspect ratio (mill diameter/mill length) of autogenous and semi autogenous mills varies widely and can be as high as three or as low as 0.5. The literature on the subject of what effect aspect ratio has on grinding mill performance or energy efficiency is almost non-existent.
AG/SAG-Ball mill experimental flow sheet with sampling points 2.3. AG to SAG Conversion Mill Design During the industrial experiments two discharge grate apertures 15x30 mm and 30x42 mm have been tested. In addition, an appropriate rubber liner and lifters (Figure 2) and steel balls 100 mm in diameter (8% ball charge volume) were provided.
Feb 01, 2019 The impact of the shape representation used for rock particles in a DEM model of a SAG mill on charge dynamics and energy utilisation is investigated. A 1.8-m diameter pilot scale SAG mill which includes realistic end walls and a discharge grate is used. This size of mill is used for scale-up and design processes for industrial SAG mills so understanding the effect of approximating the ...
Jan 01, 2015 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 discharge flow mechanism. The experimental results are analyzed to study the influence of operating variables on specific energy, product size, hold-up and residence time distribution in ...
mill performance could become worse or better by putting in a new shell liner. Data from pilot plant test work illustrates the influence of the shell lifting effect on the grind for a primary grinding duty. Figure 5 shows the evolution of the mill discharge product size in relation to the lifting effect of the liners.
The literature exposed a clear lack of previous research on the influence and performance of grate/pulp lifter design in AG/SAG mill discharge. The current understanding from literature lacks knowledge of mill content size distribution and its effect on discharge through
mm (8 in.) and water enter the feed end of a SAG mill through a feed chute the ore is milled in the shell and milled product exits through grates and pulp lifters at the discharge end (Fig. 1). The discharge is screened and the undersize, typically less than 12 mm (0.5 in.), provides ball mill feed and the oversize is returned for further milling.
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 ...
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 discharge trunnion, their performance depends on their design as well as that of the grate and ...
Jul 01, 2003 Effect of grate open area on hold-upIn rotating tumbling mills, initially the resistance to the flow of slurry is exerted by the charge (grinding media). The discharge grate offers further resistance to flow of slurry in grate discharge mills, the most important factors being open
Mar 21, 2007 The discharge rate depends on how efficiently the discharge pump (grate and pulp lifters) operates. Similar to the impeller design affecting pump capacity, the pulp lifter design affects the discharge capacity (or mill throughput) of AG and SAG grinding mills.
SAG mill throughput as a function of grate open area As shown in Figure 2 the grate open area has a strong effect on Sossego SAG mill throughput. The nominal capacity of the circuit should be achieved with a combination of 13.5% ball charge and 10.8% open area with 3 and 3.5 inch apertures.
which relates the hold-up of slurry, grate design, grate open area and mill speed to the volumetric discharge rate through the grate (Morrell and Stephenson, 1996) J - k 0.5 -1.25-0.50.6710.25 P- Q Y where J, fractional slurry hold-up D mill diameter
Mar 02, 2010 As a result, mines have shifted their emphasis in optimization from ball mills to SAG mills. The rock load in the mill essentially depends on ore characteristics and the discharge rate of broken particles through the discharge end. The discharge rate depends on how efficiently the discharge pump (grate and pulp lifters) operates.
Modeling and Simulations two parallel primary grinding lines. Each line consists of a variable 4. Validation speed SAG mill measuring 28 feet in diameter by 11 ft long. The mill 5. Implementation motors are rated at 5,500 HP. At the discharge of each SAG mill is a pair of vibrating screens.
Grate discharge Dry Grate discharge Wet Overflow discharge Wet Figure 8.5 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 8.4
Mar 08, 2021 Overflow discharge ball mill can grind ores into the size under 0.2 mm, so it is very suitable for the second grinding system. The capacity of it is about 15% lower than grate discharge ball mill in the same specification, and the loaded grinding medium is also less than that one. Rod mill Fote rod mill It can be divided into three types of rod ...
Sep 20, 2018 A Discrete Elements Method (DEM) study of load movement within a SAG mill 12,192 7620 (40 25) in normal operating conditions is performed. The purpose is to determine how the geometry of the lifters affects the kinetics of the load inside the mill. Specifically, the changes produced by the incorporation of inclined lifters and spiral or helicoidal pulp lifters to the kinetics are ...
Furthermore, the spider and discharge cone are segmented and removable. Together these solutions minimize the time and cost associated with mill relining and discharge-end servicing. Optimized discharge-end serviceability is particularly important for an open-ended mill as the grate design is the primary mechanism to control the slurry pool level.
from 344 stph to 421 stph was realized. A 35% decrease in the SAG mill power draw from 3,908 HP to 2,526 HP (2,915 kW to 1,884 kW) was recorded.
- Poly Met Outer Grate for Sag Mill 9144 mm x 4880 mm. ... I elaborate works in the Mill Lining area I developed Poly Met projects to Sag Mill and Ball Mill. Actually, I take wear profile of Poly Met and Steel Liners. ... - Poly Met Discharge System for Sag Mill 40 x 25. - Bambas Mining - Poly Met Heads Liners for Ball Mill 26 x 40 ...
SAG MILL DISCHARGE SCREENS-TROMMEL vs. VIBRATING ... the mill from the grates in the slot between the grates and the head. The oversize falls into a bucket wheel on the discharge end of the trommel, gets picked up as the trommel ... screen area, for roughly 30,000 tons a day or 1,300 tons an hour. These trommels were
The discharge grates of the SAG mill were identified as a key component in the SABC circuit, and their design is a crucial factor in the mills performance 17,18,19,20,21. The initial design of the grate section caused a serious accumulation of pebbles within the SAG mill
discharge mode does vary substantially between hol-low discharge trunnions to screen plates (grates) that can be either placed at the periphery of the cylinder or radially to the trunnion. The mill shell is internally protected by means of steel liners. Todays extensive use of AG/SAG mills is credited to the combination of relative high ...
SAG Mill Circuit Example Gold Processing SAG mill circuit example for gold processing image (135-6-3) AG/SAG Mill. AG/SAG mills are normally used to grind run-off-mine ore or primary crusher product. Wet grinding in an AG/SAG mill is accomplished in a slurry of 50 to 80 percent solids. 2D and 3D simulations of particles in a SAG Mill
A SAG Mill trommel screen lets you control the true discharge size of your SAG mill or the transfer size to the downstream Ball Mill circuit. A well sized trommel should not let rocks pass to the Ball Mill if they are to be more than say 5/8 or 16mm In the image case below, strangely enough, is the mill shell liner and discharge grate ...
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