Conventional wisdom' believes that fine particles have low flotation recoveries. Plant size - recovery graphs often have the classic hill' shape - high recovery in the mid sizes and low recovery at the fine and coarse ends. Yet if mineral liberation is poor, low fines recovery may be because you don't grind fine enough! This apparent paradox is explained by the old concept of sand/slimes' circuits, which recognises the different flotation needs of fine and coarse particles. This concept is overlooked in the push for simpler circuits and larger equipment. Most plants now treat all particles together in a wide size-distribution. Reagent conditions are set for the dominant coarser particles, so fines are starved of collector. Worse still if there are significant midsized composites - often these have to be rejected in cleaning to achieve target concentrate grade. But the conditions which reject mid-size composites - collector starvation and high depressants - also reject fine liberated particles. In fact, fines flotation can be excellent when flotation chemistry is tailored to fines._x000D_
FORMAL CITATION:Pease, J D, Young, M F, Curry, D and Johnson, N W, 2004._x000D_
Improving fines recovery by grinding finer, in Proceedings Metallurgical Plant Design and Operating Strategies 2004, pp 65-78 (The Australasian Institute of Mining and Metallurgy: Melbourne).