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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 revolves and falls into the stationary rock box. A water jet then squirts that oversize back into the mill through the conical discharge tube.
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Grate Discharge Ball Mills have shown 25% to 45% more tonnage ground and a substantial reduction in power consumed per ton of material compared size for size with overflow mills. To illustrate the characteristics of various type mills we have shown the types of discharge for rod mills and ball mills.
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Finally, the quantity of flow through grates into the pulp lifter is still lacking. Plants often increase open area of grates with the hope of increasing mill throughput. However, the back flow from the pulp lifter increases simultaneously thus nul-lifying the anticipated increase in throughput. DEM could be used to simulate slurry discharge
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This allows, in principle, the prediction of the breakage and transport of coarser material and the transport of the finer material within the grinding and pulp chambers of a SAG mill including...
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It is clear that the effect of pebble removal depends on the amount of pebbles taken out of the SAG mill and that this amount depends on how many pebble ports are opened in the discharge grates. The best result is achieved by maximizing the number of pebble ports which at the same time maximizes the pebble flow rate.
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The model output variables are: power-draw, load level, ball load, mineral discharge rate and size distribution, water discharge rate, ball throughput, bearing pressure, pebble throughput, and toe and shoulder angles of the internal load. 2.1 SAG mill model The particles fed to the mill are ground in the milling chamber and subsequently
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the grate area available. In order to not over design and result in an excessively deep pulp lifter (which would result in excess loss of mill length), simulations of the mill operating without a pool were performed. This allowed estimation of charge volume and shape so that approximate flow area through the grates could be determined and used.
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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 ...
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Abstract. Fine grinding in an air swept and a grate discharge ball mill working in closed circuit with a forced vortex air classifier has been investigated in continuous laboratory scale. Minerals with different physical properties were ground down to 40, 20, and 10 micron top size. The shape of the product particle size distribution curve was ...
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As the pebbles flow down and slide across the grate slots, they get an equal chance to go back into the mill. Similar to slurry pool formation, pebbles flow-back would increase the quantity of critical size material in the mill. The amount of pebbles passing through the grate increases with the angle of the grate.
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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 ...
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This causes a decrease in the cataracting intensity which is more than balanced by the increasing shear within the bulk of the charge. It is commonly reported that mill performance improves as...
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Effect Of Grate Discharge Area Of Sag Mill. sag mill grates Grinding Mill China. the effects of changes to SAG mill grate and screen apertures are shown in Table 2 The CEET program maintains the average tph at the specified level of 906 and the average P80 at 210 microns at all apertur The major effect of increasing 187; Learn More. Get price
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H&G Casting had success to use ASTM 2074/L2B alloy steel to manufacture AG/SAG mill liners. Under this material, our mill liners span life can be obviously improved. Our Australia customers had ordered more than 10,000 tons per year of this material mill liners. As a casting foundry, H&G Casting also has own SAG Semi-Autogenous Grinding Mill ...
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In cases such as autogenous mills at the Empire Mine, all the pulp discharges through ports, approximately 3″ square, with no slots in the "grates." It is important that autogenous mills have a "low level" discharge in order for the grinding charge to run as "dry" as possible.
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A vibrating screen was used to provide a mill discharge product separation at 19 mm (¾ in.). The minus 76 trail (-3 in.) plus 19 mm (+¾ in.) screen oversize product, which are the "pebbles", were then crushed to essentially 100% minus 19 mm (-¾ in.) in a crushing circuit. This product was returned to the feed end of the mill.
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The separating tank accepts the mill discharge in a tangential fashion to provide a coarse classification effect. ... 98 • Brasil Indústria e Comércio Ltda. Av. Independência, 2500 Éden, 18087-101 Sorocaba-SP - Brazil, Phone: +55 15 2102 1300 • Perú S.A. Calle 5 Nro. 144, Urb. ... (AG/SAG) Mills Brochure. 3 Pages. ...
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A 2 x 8500hp dual pinion drive system. the plant was designed to process 1585 h mtpof sag feed. from startup, the mill struggled to meet the required production rates. over time, a major initiative that involved blasting and fragmentation, optimization of the sag mill in terms of discharge grates, ball size and slurry.
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DOI: 10.1016/0301-7516(95)00060-7 Corpus ID: 96624199; Slurry discharge capacity of autogenous and semi-autogenous mills and the effect of grate design @article{Morrell1996SlurryDC, title={Slurry discharge capacity of autogenous and semi-autogenous mills and the effect of grate design}, author={Stephen Morrell and Ian Stephenson}, journal={International Journal of Mineral Processing}, year ...
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Under orifice conditions, the grate area controls the capacity. The capacity of a grate inlet operating under orifice flow is computed equation: where: Q o = orifice capacity of grate (cfs) C o = orifice flow coefficient = 0.67 A = clear opening area (ft 2) of the grate (the total area available for flow) g = acceleration due to gravity (32.2 ...
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Improved Relationships for Discharge in SAG/AG Mills. 2019-10-9 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 the grate at various aperture sizes and radial positions. It also indicates that in
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Product Description SAG Mill Liner from H&G use Cr-Mo materials (AS2074 Standard), SAG Mill Liner provides superior impact and wear resistance in all ... lifter spacing and angle, grate open area and aperture size, and pulp lifter design and capacity must be considered. Each of these topics has had a considerable amount of research, and ...
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Since the 2014 year, H&G Machinery has had become one of the largest AG/SAG mill liner manufacturers from China. No matter which material you want, manganese steel or Ni-hard steel or Cr-Mo steel or alloy steel; No matter which type of your mill liners need. wave shape or raised edge shape or stepped shape; H&G Machinery is your first choice.
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Evidently, as the mill diameter and particle sizes increase particle collisions not including grinding media could reach an energetic level in which autogenous breakage becomes possible and even...
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What A Grate Discharge In A Ball Mill. What A Grate Discharge In A Ball Mill Overflow VS Grate Discharge Ball or Mill Why Retrofit 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
Get priceA 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 ...
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A grate inlet in a sag operates first as a weir having a crest length roughly equal to the outside perimeter (P) along which the flow enters. Bars are disregarded and the side against the curb is not included in computing P. Weir operation continues to a depth (d) of about 0.4 feet above the top of grate and the discharge intercepted by the ...
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This begins with the motion of the charge (rocks and balls) in SAG mills, which creates a field of breakage. If the ore is sufficiently ground, the slurry leaves through the slots in the grate. Next, the pulp lifter transports the slurry into the trunnion discharge.
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that are believed to take place in AG/SAG mills. 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 ret1ects feed size changes by
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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 mill's 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.
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Unlike a concentrator with multiple grinding lines, conducting SAG mill maintenance shuts down an entire concentrator, so there is a tremendous focus on minimizing required maintenance time; the reline timeline often represents the critical path of a shutdown (but typically does not dominate a shutdown in terms of total maintenance effort).
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SAG lifter and end cone geometry - can change SAG mill performance more than 20%-50% depending on P80 transfer size and Axb, some of which is published and some will be published at SAG 2015. SAG mill wear rates and performance changes with wear morphology, grate details, mill speed changes and optimization with speed control Ball feed size SAG ...
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Mineral movement simulation through the grates and pulp lifter in a SAG mill and evaluation for a new grate design using DEM ... slots and a total evacuation area of 5.84 m2. The discharge transport ducts have been included in detail ... This fracturing effect takes place inside the mill's chamber, with the material reaching the grates with ...
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Optimum Critical Speed For Grate Discharge Mills The role of SAG mill grate open area and aperture was evaluated in detail The SAG mill discharges onto two 12 x 24 horizontal vibrating screens whose and grate pebble port sizing resulted in a best overall performance of the circuit 30 Speed critical Up to 82 Product P 80 mm 25 Specific power
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It is also possible to use the À1 00 fraction that shows a positive effect on the SAG mill throughput (the power consumption decreases, but the specific energy decreases more) because the mineral...
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The Bradken Vortex® Discharge System: Provides superior discharge performance for SAG and AG mills. Is ideally suited to high throughput, high solids discharge mills. Increases ore throughputs. Increases pulp lifter wear life. Our one-piece Super Vortex® Grates cover the full depth of the charge to maximize grate open area and mill throughput ...
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Cleary (2006) examined the axial transport and discharge of coarse rock in a ball mill using a very simple permeable wall to represent the effect of a grate. Coarse particle flow through the grate of a dry SAG mill into the pulp chamber was simulated by Cleary (2004) and slurry discharge by Cleary and Morrison (2012).
Get priceSAG mill geometry and operating conditions. To explore three dimensional slurry flow in a SAG mill, including discharge through the grates and flow in the pulp chamber, we use a pilot scale Hardinge 6 ft (D) × 2 ft (L) (1.8 m × 0.6 m) mill. The model contains the complete mill geometry including the feed end, the main/belly/circumferential ...
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A generalized SAG mill power draw equation developed by Austin, is given by: where the parameters used in the model are defined as: mp= net mill power (kW) K = a constant (kW/ton m0.5) D = mill internal diameter (m) L = mill length (m) J = fractional volume of mill filled by total charge. εB = effective porosity of the total charge.
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The dry ball mill machine adopts grate plate mill tail discharge and straight barrel outlet discharge. The discharge is smooth without swelling grinding. ... The discharge port of the dry ball mill machine is straight cylinder, and it is also equipped with an induced draft device and a dust discharge system, which is environmentally friendly ...
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