Based on his work, this formula can be derived for ball diameter sizing and selection: Dm <= 6 (log dk) * d^ where D m = the diameter of the singlesized balls in = the diameter of the largest chunks of ore in the mill feed in mm.
WhatsApp: +86 18203695377The minimal magnitude of ball size is calculated in millimeters from the equation: where is the maximum size of feed (mm); σ is compression strength (MPa); E is modulus of elasticity (MPa); ρb is density of material of balls (kg/m 3 ); D is inner diameter of the mill body (m).
WhatsApp: +86 18203695377Erdem, Ş.L. Ergün, Benzer 222 () KW b D V p fC s C S s s ⎟+ ⎠ ⎞ ⎜ ⎝ ⎛ = × × − × × − 9−10 2 3 1 (1) where Kwb Kilowatts per metric ton of balls D Mill diameter inside liners in meters Vp Fraction of mill volume loaded with balls fCs Fraction of critical speed Ss Ball size factor To determine the power that a dry grinding ...
WhatsApp: +86 18203695377The SAG Mill has a "small" circulation load of oversize given be the 3/8″ trommel screen and the 1/2″ x 1 1/4″ discharge grates. The load of 4″ balls in this SAG is "good" but unmeasured. SAG Ball consumption is "average" at 400 g/t while Ball Mill grinding media (3″ balls) usage in 550 g/t. Yet, you add steel and nothing ...
WhatsApp: +86 18203695377The basic parameters used in ball mill design (power calculations), rod mill or any tumbling mill sizing are; material to be ground, characteristics, Bond Work Index, bulk density, specific density, desired mill tonnage capacity DTPH, operating % solids or pulp density, feed size as F80 and maximum 'chunk size', product size as P80 and maximum a...
WhatsApp: +86 18203695377grind size. For any process, including ball mill circuits, we can say that output equals input multiplied by efficiency*. Output = Input x Efficiency In a ball mill circuit, the "output" can be defined as the production rate of fines of the circuit. As for any output, ball mill circuit output is a function of both its inputs and efficiencies.
WhatsApp: +86 18203695377particles under gravity. In a ball mill most of the size reduction is done by impact. The energy expanded in lifting the grinding units are utilizes in reducing the size of the particles. Ball mill can accept a feed size of 12mm or less and deliver a product size in the range of 50µm. The speed of ball mill varies between 6070 RPM. As the ...
WhatsApp: +86 18203695377The starting point for ball mill media and solids charging generally starts as follows: 50% media charge. Assuming 26% void space between spherical balls (nonspherical, irregularly shaped and mixedsize media will increase or decrease the free space) 50% x 26% = 13% free space. Add to this another 10%15% above the ball charge for total of 23% ...
WhatsApp: +86 18203695377size ball mill was used with ball media of sizes 10 mm, 20 mm and 30 mm respectively. Quartz was the material used to perform the experiment and was arranged into 3 monosizes namely 8 mm + mm, 4 mm + mm and2 mm + mm for the experiment. A mill run having a mixture of the 3 ball diameter sizes was also conducted. It was
WhatsApp: +86 18203695377The original ball load in the mill was 6614 lb. (3000 kg.) and the load at the end of the 694 hr. was 6338 lb. ( kg.). During this time, 590 lb. ( kg.) of balls less than 3 in. ( mm.) in diameter were discarded from the mill. The screen analysis of the ball charge at the end of the operation is shown in Table 20.
WhatsApp: +86 18203695377The basic parameters used in ball mill design (power calculations), rod mill or any tumbling mill sizing are; material to be ground, characteristics, Bond Work Index, bulk density,...
WhatsApp: +86 18203695377For overflow ball mills, the charge should not exceed 45% of the mill volume . ... Ball wear is directly proportional to surface area per unit mass and thus inversely proportional to ball diameter. ... Calculate the mill size required to handle the desired throughput: Solution: W = 10*(1/√100 1/√100 0) kWt/t = kWh/t ...
WhatsApp: +86 18203695377Example: A mill in closed circuit with a classifier receives 300 dry tons of crude ore per day, and the percentages of solid are respectively 25, 50, and 84% in the classifier overflow, feed to classifier, and sand, equivalent to L: S ratios of,, and Then the circulating load ratio equals
WhatsApp: +86 1820369537721 CONCLUSIONS Continued In the present work, equations were also derived, giving: zthe ballmill power drawP as a function of its dimensions: internal mill diameter D and length L, zthe ballmill power drawP as a function of the feed D f (mm) and the product size d (mm), the Bond work index w i (kWh/short ton) and the mill throughput T (short ton/h), zthe ballmill dimensions (D and L), when ...
WhatsApp: +86 18203695377The use of ball mills for reducing crusher product to 85 per cent,: below 200mesh in two stages, as practised at the United Eastern, Tom Reed, and Montana mines, in Arizona, is a distinct advance in fine crushing. The simplicity, small floor space and large capacity of these installations are especially notable.
WhatsApp: +86 18203695377Ball charges: This calculator gives the surface and the average weight of the ball charges. It gives also a rough interpretation of the ball charge efficiency: Ball top size (bond formula): calculation of the top size grinding media (balls or cylpebs):
WhatsApp: +86 18203695377For example, for an 36′ × 17′ SAG Mill, with a power consumption of MW, operating at 73% solids, % balls charge and at 76% of the critical speed, with 50% of the feed in the size class −6″ +1″; it could be possible to increment in 2% the balls charge (to %), reducing the % −6″ +1″ to %, with no changes in the ...
WhatsApp: +86 18203695377An alternative mill ball charge is proposed that closely approximates Bond's original total ball mass, number of balls and ball surface area. Results of 30 Bond Work index tests of six pure materials (calcite, magnesite, labradorite (feldspar), quartz, andalusite and glass) using closing screen apertures (P 1 ) values of 500, 250, 125, 90 and ...
WhatsApp: +86 18203695377EF5 Fine Grinding in ball mills to product sizes finer than 80% passing 200 mesh (75 micrometers). EF6 High or low ratio of reduction rod milling. EF7 Low Ratio of reduction ball milling. EF8 Rod Milling. Example Rod Mill Design Calculations. Rod Mills. F = 18,000 micrometers. P = 1,200 micrometers. Wf =
WhatsApp: +86 18203695377Ball Roller Power Calculation Model #1. A wet grinding ball mill in closed circuit is to be detective 100 TPH of a substance with a work index of 15 and a size distributor of 80% passing ¼ inch (6350 microns). ... TUNGSTEN = weight of charge ... only should be aware that mill manufacturers do nope observe a size convention. Ball Mill Power ...
WhatsApp: +86 18203695377For the ball mill grindability test, the work index is calculated from the following revised equation (in short tons): where: Pi = sieve size tested (microns) Gpb = ball mill grind ability Wi, P F have the same meanings as in the top equation. Equipment required: Laboratory ball mill, cm x cm with following ball charge: Agitator ...
WhatsApp: +86 18203695377grams per revolution (Gbp) is the ball mill grindability. The ball mill work index, Wi (kWh/short ... Place the FC Bond Ball charge in the mill. 7. ... Perform a screen analysis on the material and weigh each size fraction. Calculate the weight of the under size (( 106 microns (140 mesh screen) or the size fraction being reduced to in ...
WhatsApp: +86 18203695377Ball Mills Guidelines for sample amount and ball charge As a rule of thumb, the grinding balls should be approximately 3 x larger than the largest sample particle. In addition to the instrument settings and the ball size, the filling level of the jar is also of crucial importance for a successful grinding process in ball mills.
WhatsApp: +86 18203695377A) Total Apparent Volumetric Charge Filling including balls and excess slurry on top of the ball charge, plus the interstitial voids in between the balls expressed as a percentage of the net internal mill volume (inside liners).
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