Comparison of energy efficiency between ball mills and stirred mills .
WEBJun 1, 2009 · Ball mills may be used for primary, secondary, tertiary and regrind appliions. In the 1950s and 1960s ball mills dominated primary grinding, however they were supplanted in the 1970s by AG and SAG mill – which also replaced two stages of crushing. ... Currently the separator operates at the same speed as the grinding disks .