Are you are looking for grinding efficiency or grinding costs?
Grinding efficiency: as a first estimate, I would tend to say no major difference if you ad the same ball sizes (to control mill power draw).
Grinding costs: very much depends on the milling conditions. Main parameters are corrosion (ie iron ore), impact (ie grate discharge ball mills) and abrasion (ie sand milling industry).
One approach is to take a sample at the outlet of the mill (to analyze for corrosion and abrasivity) and to go into the mill (to evaluate impact conditions such as liner design, filling degree, OF/GD, mill revolution speed). Then do a “marked steel ball test” with different alloys and check which ones gives you the best results.
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