MINERAL COMPOSITION OF ORE OF STEBNYTSKY KOTASSIUM SALT DEPOSIT, ENRICHMENT TECHNOLOGIES, WASTES, THEIR IMPACT ON THE ENVIRONMENT AND WAYS TO SOLUTION THE PROBLEM

Abstract

The geological structure, mineral composition of potash ores of the Stebnytsky deposit, solubility of the most common minerals, main specific features of salt rocks extracted from the bowels, applied enrichment technologies, chemical composition of the enrichment residue and prospects for its use are described. It was established that the ores of the Stebnytsky deposit are characterized by heterogeneity of mineral composition, dominance of mainly kainite-langbeinite ores, relatively low content of potassium in polymineral ores (10–12% in terms of K2O), limited (poor) solubility of one of the main potassium- containing minerals (langbeinite), and a fairly significant content of clay-silt-sand fraction. All these specific features significantly complicated the applied enrichment technologies.It has been proven that the scheme implemented at the Stebnytsky Potash Plant for enrichment and processing of polymineral ores turned out to be imperfect and extremely inefficient in practice, namely, from 1 ton of potash ores, as a result of flotation enrichment, 700–800 kg of residue were formed, including almost half of potassium and magnesium. At the same time, not only an insoluble residue of clay-silt-sand composition, but also poorly dissolved langbeinite and polyhalite, as well as halite and brine with a high content of sodium chloride and potassium-magnesium salts, got into the residue. In fact, sodium chloride in the enrichment process got not only into the residue from enrichment, but in significant quantities got into the finished product “Kaliimag”, which contained an increased content of halite.The long-term operation of this technology led to the formation of significant volumes of enrichment residue, which led to the accelerated overflow of the tailings pond, which indirectly caused the accident and regional ecological disaster, as a result of the breach of its dam on September 15, 1983 and the discharge of 4.5 million m3 of highly concentrated brine into the Dniester River.The Stebnytskyi factory “Polymineral” enterprise stores significant volumes of intermediate enrichment products, in which the potassium and magnesium content is half that of primary polymineral ores, as well as the liquid phase and solid enrichment residue, which, based on the characteristics of the enrichment methods used, can be used to produce anti-iron agents, low-grade potassium- magnesium fertilizers and other applications.