Energy Use of Fine Grinding in Mineral Processing,
Dec 18, 2013· The smallest ball size typically charged into ball mills and tower mills is ½ inch (12.5 mm), although media diameters as small as 6 mm have been used industrially in Vertimills. In a laboratory study by Nesset et al .,[ 7 ] a GIS mill charged with 5-mm steel shot, and with other operating conditions similarly optimized, achieved high energy,Energy and Cost Comparisons of HPGR-based Circuits | E & MJ,At a grind of 80% passing 160 μm, the HPGR-ball mill circuit shows significant cost advantage over the SABC circuit with a NPV of $33 million and an IRR of 22% (See Table 4). At a product size of 80% passing 75 μm, both options have costs advantages over the SABC option, although the HPGR-ball mill circuit had lower overall costs than the two,TECHNICAL AND COMMERCIAL BENEFITS OF GEARLESS,general, the bigger the mill diameter, the lower are the mill operating and critical speeds. Thus, for larger mills the number of poles will increase. As a result, the number of poles can vary from 48 to 72 poles (Fig. 3.) with typical mill speed requirements of about 10 rpm for larger SAG mills and about 15 rpm for smaller ball mills. Figure 3.