RECOVERY MECHANISMS FOR PENTLANDITE, AND MGO-BEARING GANGUE MINERALS IN NICKEL ORES FROM WESTERN-AUSTRALIA

The flotation behaviour of a Western Australian nickel ore was charact erised by size-by-size flotation rate tests to extract rate constant i nformation. The aim was to identify the effect of surface interactions on the flotation of the nickel sulphide mineral, pentlandite, with ma gnesium-silicate bearing minerals (predominantly serpentines). Flotati on tests were carried out using collector (amyl xanthate), both with a nd without the other standard reagents for this ore. In this study the latter were carboxy-methyl cellulose (CMC) and soda ash. The addition of soda ash and CMC was shown to improve pentlandite flotation rate a nd recovery. Soda ash addition was found to be essential for improving flotation performance, as without it nickel recovery was unacceptably low. It is proposed that carbonate ions, derived from soda ash additi on, enhance dispersion in the pulp and that CMC may assist removal of adhering slime particles from pentlandite surfaces. Drawing on the lit erature in this area, a number of mechanisms are proposed to explain t he observed flotation behaviour of gangue magnesium-silicate bearing m inerals. (C) 1997 Elsevier Science Ltd.