Passive Treatment of Wastewater Generated During the Enrichment of Potash Ores

Abstract

Large amount of solid and liquid waste is a serious issue associated with potash mining and processing. Potash ore enrichment generates solid halite waste, clay-salt slurry, and industrial wastewater with a high content of water-soluble salts. The «environmentally friendly» storage of such waste is a difficult technological issue. Highly mineralised water is stored on the surface and discharged into slurry storage, while some of the effluent is recycled during the production process. Over the long period of slurry storage operation at the Verknekamskoe Potash Deposit, water filtration through the dam and the slurry storage base has created a stable flow of highly mineralised water into the surface water and groundwater. The slurry storage facilities that are currently in use cannot completely fulfil the protective environmental functions. This study provides scientific rationale for the potential use of slurry reservoirs as wastewater treatment facilities. The findings show that there are fewer suspended solids in clarified water: purification efficiency is greater than 99.9%. In the clarified circulating brine, the content of mineral impurities is reduced: the content of chloride ions decreases by 46%, and the content of dry residue decreases by 45.6%. Based on the findings, the study provides recommendations for the construction and new design of a slurry storage that can be used as a treatment facility on the territory of the Verkhnekamskoe Potash Deposit in order to reduce the negative environmental impact.