ENERGY REDUCTION IN BALL MILL GRINDING

COMMINUTION OF MINERALS BY BALL MILLING IS ENERGY INTENSIVE. ENERGY EFFICIENCY OF BALL MILLING RANGES FROM LESS THAN 1 PERCENT TO 10 PERCENT. BREAKAGE BY CRUSHING IS HIGHER IN EFFICIENCY BUT IS IMPRACTICAL FOR PRODUCTION OF A FINE MESHED PRODUCT. IT HAS BEEN ESTABLISHED IN LABORATORY TESTS THAT HIGH VELOCITY IMPACT BREAKAGE OF PARTICLES RESULTS IN COMPLETE BREAKAGE WHEREAS LOW VELOCITY IMPACTS OF THE SAME KINETIC ENERGY RESULT IN REDUCED OR NO BREAKAGE. SINCE SHATTERED PARTICLES FROM IMPACT BREAKAGE FLY OUT OF THE IMPACT ZONE, EXCESSIVE IMPACT ENERGY WILL BE WASTED. IN PHASE I A SERIES OF LABORATORY SINGLE PARTICLE BREAKAGE TESTS ON HARD COAL WILL EVALUATE KINETIC ENERGY REQUIRED TO BREAK PARTICLES COMPLETELY AT EACH IMPACT. BASED ON PARTICLE BREAKAGE EFFICIENCY, A COAL FEED SIZE AND MAKE UP MEDIA SIZE WILL BE CALCULATED. BATCH MILL TESTS WILL BE MADE IN A STANDARD MILL AND WITH A MODIFICATION TO THE MILL. BY MODIFYING THE MILL, A CONTROL OF IMPACT ENERGY CAN BE EFFECTED AND THE PROCESS INTENSIFIED. COMPARATIVE ENERGY CONSUMPTION VERSUS GRIND WILL DEFINE ENERGY SAVINGS AND PROVIDE DATA FOR PHASE II CONTINUOUS PILOT PLANT TESTING.