Influence de la composition minéralogique du minerai sur les performances des procédés de broyage et de flottation ail concentrateur n° 1 de Mines Gaspé (Murdochville, Quebec)

CIM Bulletin, Vol. 77, No. 872, 1984

M.A. BÉRUBÉ, GRAAIM, Université Laval, Québec, Canada

The principal objective of this study was to verify a certain number of mineralogical hypothesis which could explain the important variations observed in the performances of the B grinding and flotation circuit of the No. 1 concentrator at Mines Gaspe. Six series of samples obtained from a sampling campaign performed in the summer of 1980 have been studied. The capacity of the grinding circuit seems mainly influenced by the variations of the mineralogical and textural properties of the ore. For instance, an increasing ratio garnet/quartz leads to a decreasing grindability. As the concentration process is concerned, the proportion of copper minerals difficult to recover by flotation, such as copper carbonates, varies within the ore deposit. This can explain, at least in part, some low copper recoveries. In spite of high variations in terms of mineralogical bulk composition and grindability of the ore, the degree of liberation of the copper sulphides in the grinding product is chiefly a function of the size distribution of the product. In an attempt to obtain a steady behaviour of the flotation process, it is strongly recommended to control this size distribution at a constant level.
Keywords: Flotation process, Grinding, Copper carbonates, Copper sulphides, Mineral liberation