Electrochemistry of flotation of sulphide minerals / Электрохимия флотации сульфидных минералов

Sulphide minerals are the important resources of nonferrous metals, which are widely used in many fields such as electronics, chemical engineering, aviation, transportation, construction and metallurgy etc. Flotation technology is the most important method to beneficiate sulphide ores to obtain concentrate containing nonferrous metals since it has been used in industry at the end of the 19th century. As early as in the 1930s-1950s, considerable amount of fundamental research had been conducted on the flotation of sulphide minerals based on wettability, electrokinetics and chemical interactions. The "chemical reaction" hypothesis based on the solubility product of metal-collector salts involved and competitive adsorption based on the interaction of thio-collectors and hydroxide ions with sulphides were proposed to explain the flotation mechanism of sulphide minerals. A mixed potential model has been established, in which there existed a potential at which an anodic reaction of xanthate to form metal xanthate or dithiolate and the cathodic reduction of oxygen proceed at finite rates, underlying the basis of the researches on the interaction mechanism between thio collectors and sulphide minerals in 1950s. Since then, it was realized that the electrochemistry was very important in flotation of sulphide minerals as it determined the oxidation and dissolution of mineral particles in the pulp, the electrochemical equilibria of reagents, electrochemical interactions among reagents with both soluble and surface species of minerals and the galvanic interactions among grinding media, mineral and reagents. The efficiency of flotation and separation of sulphide minerals and consumption of reagents are thus controlled by the electrochemistry of the pulp. The potential controlled flotation technology has been developed and used in industry recently to obtain higher efficiency of flotation separation in many copper, lead, zinc sulphide mines in China. <...>