Wilson Miola*
Abstract
The decision to include homogenization stockpiles in ore processing circuits, especially before concentration stages, has always been a matter of debate, often ending with the decision not to include homogenization because there has not been unequivocal data on the trade-offs of implementing this.
Data showing these trade-offs are scarce because the costs of performing tests, either on bench or pilot scale, are high and it is a challenge to select ore samples that properly represent the variability of the ore sources.
There is a widespread view in the industry that says that “the recovery of the average of two different grades of ore is the average of their recoveries”. This statement is only valid if either the process recovery curve is a straight line, which is rarely the case, or if the two materials are treated separately. In summary, there is a general lack of literature and understanding of the advantages of the homogenization of stockpiles.
The results from two experiments are presented which indicate increased metal recovery in a copper and in a gold flotation process, solely due to homogenization and the convex shape of the homogenized stockpile process curve. On the other hand, if the process curve is concave, the result of homogenization maybe detrimental, compared to not homogenizing.
The copper ore experiment allows comparison of the results of processing with and without homogenization in a full-scale plant operation that allowed for homogenization of stockpiles before both the grinding and the flotation processes.
The gold ore experiment uses recovery results from flotation bench tests on ore samples with variable grades and compares these with the recoveries of different homogenized blends.
The experiment with nickel ore, upgrade by scrubbing silica, shows that homogenization is detrimental to the upgrade factor
because the process curve is concave.
See full arthicle below
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*Wilson Miola
CEO at Miola & Miola Ltda
