National University of Science and Technology MISiS, Moscow, Russia

V. A. Ignatkina, Professor at the Department of Beneficiation and Processing of Mineral and Secondary Raw Materials, Doсtor of Technical Science, Professor, e-mail: woda@mail.ru
A. A. Kayumov, Lead Project Engineer, Candidate of Technical Science, e-mail: maliaby_92@mail.ru
N. D. Yergesheva, Postgraduate Student at the Department of Beneficiation and Processing of Mineral and Secondary Raw Materials, e-mail: nazymarzu.zharolla@mail.ru
P. A. Chernova, 5^th year Specialist Degree Student, e-mail: polina_nenay@mail.ru

This paper describes experimental data suggesting that the qualitative and quantitative composition of sulphydryl collectors (butyl xanthate, dithiophosphate and thionocarbamate), the size of molybdenum in a mixture with pyrite and the concentration of modifiers (sodium thiosulphate, sodium sulphide, hydrogen peroxide) do influence the specific rate of flotation of monomineral fractions of chalcopyrite, pyrite, molybdenum, their mixtures, as well as copper sulphides from copper pyrites. A changed ratio of dithiophosphate (xanthate) and thionocarbamate in the collector can both maintain the low flotation activity of iron sulphides and increase the collecting activity in relation to iron sulphides. The authors established a synergic action of the combination of sulphydryl collectors with an effective ratio of components. Use of modifiers in the reagent flotation of sulphides at their critical concentration of 4.4·10–3 mol/l (which corresponds to the following bulk concentrations: sodium thiosulphate — 700 mg/l, sodium sulphide — 343 mg/l and hydrogen peroxide — 150 mg/l) indicates that sulphoxide compounds bring down the flotation rate constant for all sulphides. The effect of peroxide on the floatability of pyrite is governed by the oxidation degree of the initial surface: for stale pyrite, k increases from 0.62 to 1.15 min–1; after preliminary alkaline treatment of the pyrite fraction, k, on the contrary, decreases from 0.43 to 0.36 min^–1. The flotation rate constant is shown to drop by 1.3 times – from 1.16 min^–1 (–2+0.074 mm) to 0.9 min–1 (–44+10 μm) – as the initial size of molybdenum in the mixture with pyrite is reduced, with the size distribution of pyrite and the weight of components in the sulphide mixture remaining unchanged. In the case of flotation of copper sulphides from massive copper sulphide ore, the lowest flotation performance is associated with the use of butyl xanthate (β_Cu = 10.1%; ε_Cu = 2.72%; S = 4.8 and k = 0.067 min^–1), whereas the best flotation performance was achieved when using a combination of DTP and TC (Z-200) at the effective component ratio (β_Cu = 21.8%; ε_Cu = 17.4%; S = 11.5 and k = 0.251 min^–1).
Support for this research was provided under Grant No. 22-27-00102 by the Russian Science Foundation, https://rscf.ru/project/22-27-00102/.

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