Synthesis of sodium polysulphide for copper ore processing

摘要

Sodium polysulphide consists of yellow-brown, yellow-green crystals. Its chemical formulas are Na_2S_2, Na_2S_3, Na_2S_4. Currently there are several known methods for the production of sodium sulfide: chemical reduction of sodium sulphate by solid carbonaceous material; reduction of sodium sulfate by gaseous reductant; absorption of hydrogen sulphide with sodium hydroxide; electrolytic (amalgam) method; exchange decomposition of barium sulfide with sulfate, carbonate and sodium hydroxide. In addition to the known methods for the preparation of sodium polysulphide, there are electrochemical methods for the preparation of polysulphides that have been discovered in a long time and have received potentities: an electrochemical method for producing sodium polysulphide, an electrochemical method for producing alkali metal polysulphides.We examined the main standard methods for the preparation of sodium polysulphide, using mechanochemical activation.The mineralogical composition of the ore was analyzed, which allows us to conclude that it is possible to use mechanochemical sulphiding. Synthesis of the sulfidizer was carried out using elemental sulfur, caustic soda and sulphonic acid, in a planetary centrifugal mill mark "Pulverizette 6 classic line". Several modifications of sodium polysulphide have been developed, differing in the ratios of the reacting substances that have been tested in the flotation enrichment of the Irtysh deposit. During the testing of various modifications of polysulphides, the best result was revealed which showed an increased copper recovery into the concentrate by 8.98%. To determine the significance of the influence of polysulphide constituents and their consumption on flotation, as well as on the selectivity index, graphical data were presented on the dependence of the change in copper, zinc and selectivity on the ratio of the content in polysulfide: sulfur and caustic sodium, sulfur and sulfonic acid, sodium and sulfonic acid. Based on the data on the approbation of sodium polysulfide in flotation experiments, as well as graphical data, a correlation analysis was performed that showed the best ratio of polysulphide components that would allow higher copper recovery and higher selectivity.