Research On The Green Synthesis Technology Of Alkyl Xanthate Collectors

Abstract:Sulfide ores are main mineral resource of non-ferrous metals, and the development of high efficiency collectors is the key to comprehensive utilization of sulfide ores. Xanthate collectors are the most widely used as flotation reagents, the maximum consumption of collectors and the most economical sulfide ores collectors. However, the traditional technology of xanthate is high inefficiency and pollution. Therefore, it is necessary to improve production technology of xanthate and the quality of production.In this paper, xanthates were synthesized with solvent method, which began from CS2. Through the research on the synthesis process conditions, sodium xanthates were prepared, starting from C2-Cg alkyl alcohols, NaOH and CS2. Synthesis technologies of C2-C8alkyl xanthates were studied systematically by experimental research, and optimal conditions were acheieved. Take isobutyl xanthate as an example: molar ratio of (CH3)2CHCH2OH, NaOH and CS2was1:1:3.6, isobutyl xanthate was synthesized under25℃for3.5h. The purity and yield of xanthate prepared by this solvent method was increased by3.47%,3.69%respectively. There were7xanthates which were prepared:ethyl xanthate, isopropyl xanthate, n-butyl xanthate, isobutyl xanthate, isoamyl xanthate, methyl isobutyl methyl xanthate, sec-octyl xanthate, the purity and yield of them are all bove90%and82%. Elemental analysis, infrared spectrum and UV spectroscopy were adopted to characterize their structures and properties.Isoamyl-isobutyl mixed xanthate, methyl isobutyl methyl-isobutyl mixed xanthate and sec-isobutyl mixed xanthate were synthesized by using CS2as solvent, and optimized the synthesis conditions. Infrared spectrum was adopted to characterize their structures.Flotation properties of xanthate for monominerals of sulfide ore were investigated systematically. The C2～C8sodium xanthates showed excellent collecting ability for chalcopyrite, and the order of their collecting ability for chalcopyrite was as follows:sec-octyl xanthate> methyl isobutyl methyl xanthate> isoamyl xanthate> isobutyl xanthate> n-butyl xanthate> isopropyl xanthate> ethyl xanthate. The isobutyl xanthate performed better than the n-butyl xanthate. For copper sulfide ore from Dahongshan copper mine, the copper recovery improved with the increases of the xanthates’chain length through one roughing flotation, and mixed xanthates performed better than single xanthate.The interaction mechanism of xanthate with sulfide ores was discussed by ultraviolet spectrum and infrared spectrum. The intensity of interactions between the different chain length of xanthate and Cu2+, Fe3+was examined by ultraviolet spectrum. The results showed that xanthates could coordinate Cu2+and Fe3+. Chalcpyite before and after adsorbing xanthates were characterized by infrared spectrum, the results indicated that the adsorption of xanthate on chalcopyrite surface was chemical adsorption.