Technological studies of the use of modifiers in the flotation of calcium-containing minerals

Abstract

Using samples of skarn scheelite-sulfide ore from the Vostok-2 deposit, studies were carried out to model combinations of increased dose of inorganic modifiers (sodium carbonate, water glass, sodium sulfide) based on publications by foreign researchers on the achieved positive result in increasing the contrast of the mineral surfaces of scheelite and calcite and their floatability. Testing was carried out according to the standard flowsheet on tap and recycled water. Oxyhydryl collector was sodium oleate of technical acid B-115, dose 250 + 50 g/t. The order of feeding modifiers (sequential supply and combination of a mixture of sodium carbonate (bicarbonate) + water glass), the effect of the temperature of the pulp upon contact, the dose of modifiers and the ratio of components in the mixture were studied. The dose of water glass varied from 350 to 1450 g/t, sodium carbonate (bicarbonate) varied from 0 to 11.5 kg/t, sodium sulfide up to 4.9 kg / t. With increased dose of inorganic modifiers, it was not possible to achieve selective depression of calcite and apatite while maintaining effective scheelite flotation. The use of sodium bicarbonate in comparison with sodium carbonate, at the same flow rates, creates a less alkaline pH in the flotation pulp, which leads to an increase in the concentration of hardness ions [Са2+, Mg2+] and overdose of the collector. Using combinations of reagents: sodium carbonate (bicarbonate) + water glass, sodium sulfide + sodium hydroxide + water glass, even with a slight increase in the dose of water glass in the mixture, after heat treatment, concentrates of lower quality were obtained, with increased losses of scheelite compared to the factory mode according to the Petrov method.