INFLUENCE OF CaF2 AND CaCO3 FLUX ADDITIVES ON THE DISTRIBUTION OF GOLD AND PLATINUM BETWEEN MATTE AND SLAG DURING MELTING OF COPPER-NICKEL SULPHIDE MATERIALS

Abstract

One of the stages of extracting gold and platinum from copper-nickel sulphide materials is their melting in electric furnaces, where the melt is separated into matte and slag. Gold and platinum are concentrated in the matte, but a significant part of them ends up in the slag, which reduces the recovery of metals. The main reason for such losses is the flotation of matte droplets containing gold and platinum with gas bubbles. One of the options for reducing the loss of valuable components is to add fluxes to the initial charge before melting. The influence of calcite and fluorite on the distribution of gold and platinum over the melting products of copper-nickel sulphide materials (matte and slag) has been experimentally studied based on the above theoretical concepts of droplet flotation. When calcite was added to sulphide ore, there was a significant decrease in the sulphur content in the slag - more than 3 times. This led to a decrease in non-ferrous metals in the slag by 2-3 times, gold from 0.45 to 0.29 ppm, platinum from 2.15 to 2.06 ppm. The addition of fluorite to the mixture of copper-nickel-iron matte and model slag significantly reduced the content of sulphur, non-ferrous metals by 1.5-2.5 times, gold was not found in the slag. The decrease in the amount of sulphides in the slag is mainly due to the fact that the listed additives reduce the viscosity of the slag. This leads to acceleration of the coagulation of matte droplets and increases the rate of their settling to the slag-matte boundary