Dec 09, 2017 Ball mills give a controlled final grind and produce flotation feed of a uniform size. Ball mills tumble iron or steel balls with the ore. The balls are initially 5–10 cm diameter but gradually wear away as grinding of the ore proceeds. The feed to ball mills (dry
Jan 31, 2015 If the powder is feed for milling then smaller ball size is preferred for homogeneous mixing and milling by avoiding local impact between the
Get PriceJul 05, 2020 The balls which could be of different diameter occupy 30 – 50 % of the mill volume and its size depends on the feed and mill size. The large balls tend to break down the coarse feed materials and the smaller balls help to form fine product by reducing void spaces between the balls. Ball mills grind material by impact and attrition
Get PriceMar 31, 2021 However, if you are dealing with coarse feed between 1-3 mm, then it will drop to 1.5). The true density of balls are around 7.5. Then, the optimal mass ratio of ball to powder in ball mill is 7.5
Get PriceNov 26, 2019 And because the ball mill feed grain size is larger, ball mill feeding groove must have a larger slope and height, so that feed smooth. Bearing. Since the power of the autogenous tumbling mill is relatively small, it is appropriate to choose dynamic and static pressure bearing. The ball bearing liner is made of lead-based bearing alloy, and the
Get PriceAbout thirty percent of ball filling of the mill was found to be the optimum. This was explained by an analysis of the motion of the balls and the measurement of the contact force. It was found that the grinding limit is greatly dependent on ball size. An experi mental equation expressing the relationship between the finest average size of the
Get PriceAug 30, 2019 1 Calculation of ball mill capacity. The production capacity of the ball mill is determined by the amount of material required to be ground, and it must have a certain margin when designing and selecting. There are many factors affecting the production capacity of the ball mill, in addition to the nature of the material (grain size, hardness, density, temperature and humidity), the degree of
Get Priceprogram. At the time of this research, mill ball charged, feed rate, and average moisture were 7 tons (ball size was 100 mm) per week, 720 t/h and 5%, respectively. Then, ball abrasion rate was calculated by Equations 4, 5 and 6. Total mill feed per week = 720*24*7*0.95= 114912 tons (4) Total ball charge per week = 7*106 g (5)
Get PriceF80 is the milling circuit feed 80% passing size, m, fSAG is a calibration parameter for pebble crushing and/or fine feed (typically 1.0 for 80% passing six inch mill feed and when no pebble crusher is present). WiBM is the Bond ball mill work index, unitless CFnet is an empirical adjustment to a ball mill circuit [CFnet = 2.35 - 0.29 ln(P80)]
Get PriceEquation 2. The approach requires the feed size to the SAG, the SAG mill product size (transfer size) and the final product size. The prediction of the SAG mill transfer size used in the formula is made by comparison with pilotplant data and operating plant data for similar ore types (Barratt, 1989). The
Get Priceadditional grinding in the ball mill, or “Corrected Ball Mill Feed.” T2’ is the 80% passing dimension of the Corrected Ball Mill Feed. Figure 1. Comparison of the Particle Size Distribution Slopes Figure 2. Relationship Between the Transfer Size Distribution Slope and T 80 or AWi0/BWi Figure 3. Typical Circuit and Shortcut Taken by the
Get PriceGrinding tests were performed with two mono size fractions 53+38 and -38+25 microns and natural feed 100 microns using various pin tip velocities, ball densities and within the normal stirred ball milling operating range. relationship between the ball diameter and the particle was explained by the angle of nip theory which applied for
Get Pricedrawn by ball, semi-autogenous and fully autogenous mills have been developed by Morrell and by Austin. (Morrell, S. Power draw of wet tumbling mills and its relationship to charge dynamics - Part 2: An empirical approach to modeling of mill power draw. Trans. Instn. Mining. Metall. (Sect C:Mineral Processing Extr Metall.) 105, January-April
Get PriceThere is a relationship. The following equation is used by Moly-Cop, I believe: d (optimal) = 6.06 * (F80)^ (0.263) * (ps*Wi)^ (0.4) / (ND)^ (0.25) Where: d (optimal) is the ideal ball size (mm) F80 - 80% passing size of feed (micrometre) ps - density of ore (tonne/m^3) Wi - Bond's Work Index of the ore, kWh/tonne
Get PriceJun 01, 2018 For this coarser feed the 50 + 20+10 mm ball diameter mix breaks the material at a faster rate compared to the other ball matches. The availability of a ball size for a particular feed size ensures breakage occurs at a faster rate. The 10 mm ball size is unable to nip the large particle size hence the breakage rate is slower
Get Pricethan the small ball diameters, but the performance for this ball size had decreased for the -2 mm +1.4 mm mono-size feed compared to the bigger -4 mm +2.8 mm mono-size feed. This therefore shows that should the material feed size continue to decrease, the smaller balls will perform better than the larger balls during milling, as was mentioned
Get PriceBall mills tumble iron or steel balls with the ore. The balls are initially 5–10 cm diameter but gradually wear away as grinding of the ore proceeds. The feed to ball mills (dry basis) is typically 75 vol.-% ore and 25% steel. The ball mill is operated in closed circuit with a particle-size measurement device and size-control cyclones
Get PriceJun 19, 2015 A wet grinding ball mill in closed circuit is to be fed 100 TPH of a material with a work index of 15 and a size distribution of 80% passing inch (6350 microns). The required product size distribution is to be 80% passing 100 mesh (149 microns). In order to determine the power requirement, the steps are as follows:
Get PriceJan 31, 2015 If the powder is feed for milling then smaller ball size is preferred for homogeneous mixing and milling by avoiding local impact between the
Get PriceMay 15, 2015 A) 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). B) Overflow Discharge Mills operating at low ball fillings – slurry may accumulate on top of the ball charge; causing, the Total Charge Filling Level to be
Get PriceFeb 13, 2017 A ball mill efficiently operated performs a wide variety of services. In small milling plants, where simplicity is most essential, it is not economical to use more than single stage crushing, because the Steel-Head Ball or Rod Mill will take up to 2″ feed and grind it to the desired fineness. In larger plants where several stages of coarse and fine crushing are used, it is customary to crush from 1/2″ to as
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