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ABSTRACT
Calcium polysulfide is a promising reagent for concentration of oxidized ores of non-ferrous metals.
We have determined physical-chemical regularities of calcium polysulfide synthesis from elementary sulfur obtained from oil-processing wastes and calcium hydroxide solutions. Experiments confirm positive influence of polysulfides on synthesis process.
Interaction of sulfur with calcium hydroxide solutions was studied using probabilistic-deterministic experiment design.
Dependence of sulfur dissolution on temperature, interaction duration and polysulfide-ion concentration was determined. Based on partial dependence the mathematical model was designed in the form of generalized multi-factor equation:
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Adequacy of the model is confirmed by results significantly correlating with experimental data (R = 0,96, tR= 52).
Using the mathematical model optimal parameters of calcium polysulfide synthesis were determined: ratio CaO:S:H2O=1:2:7; temperature 90°C; duration 60 min; initial concentration of calcium polysulfide 12,5 g/l by S2-. Sulfiding agent based on elementary sulfur with polysulfide degree 4,4 was obtained under above parameters.
Sulfur dissolution kinetics was studied using described mathematical model. Temperature dependencies of sulfur interaction with calcium hydroxide were obtained. It was found that activation energy of sulfur dissolution is 171,1 kJ/mole and the process occurs in kinetic mode.
Mechanism of calcium polysulfide formation is proposed together with structure model in the form of polysulfide systems.
Based on obtained data on thermodynamic properties of polysulfide systems we have determined the following parameters: ΔfH0298,15, S0298,15, ΔfG0298,15, Ср0298,15 of eight polysulfides: CaS2, CaS3, CaS4, CaS5, CaS6, CaS7, CaS8 и CaS9.
Keywords: oxidized copper ore, sulfidizing, sulfination agent, flotation, copper concentrate, calcium polysulfide. polysulfide.
(ProQuest: ... denotes formulae omitted.)
Calcium polysulfide is a promising sulfination agent for concentration of oxidized non-ferrous metal ores.
We have determined physical-chemical regularities of sulfination agent synthesis from calcium hydroxide solution and elementary sulfur obtained from oil processing wastes. Results of experiments confirm positive influence of polysulfides on synthesis process.
Production of sulfination agent...