Study of the possibilities of technology of complex extraction of useful components from coastal-sea placers of Primorye with application of methods of pyro-hydrometallurgy

Abstract

Intensive exploitation of placer gold deposits in Primorye led to the depletion of their geological reserves, which was reflected in a sharp decrease in the production of precious metals. An alternative source of precious metals is the never before exploited placer deposits of the Primorsky shelf, which have concentrated a significant amount of gold and titanomagnetite. The importance of gold as the basis of the economic security of our country can hardly be overestimated. Titanomagnetites are solid solutions of titanium dioxide in magnetite containing a rich gamut of impurities V, Cr, Zr and other alloying elements. Russia has gained vast experience in processing gold-bearing ores, but the problem of developing gold-titanomagnetite coastal-marine placers has not yet been solved. The objectives of our research included assessing the possibilities of industrial processing of metal-bearing sands of the Rudnev Bay of the Sea of Japan using pyro-hydrometallurgy and fluoride opening methods. For this, a four-stage scheme for the extraction of useful components was developed. In the first of them, the initial sands underwent gravitational enrichment, followed by separation by electromagnetic separation into magnetic and non-magnetic fractions. In the second stage, the magnetic material represented by titanomagnetite underwent fine grinding, reduction firing in hydrogen, and sintering of the powder material. In the third stage, non-magnetic components, which include the bulk of gold and zircon, served as the feedstock for exposure to a thiocarbamide-thiocinate solution. In the fourth stage, the insoluble cake concentrating zircon was fluorinated with ammonium bifluoride. The use of this scheme for processing metal-bearing sands made it possible to extract native gold, zirconium concentrate and iron powders of various fineness.