Optimization of excess brines disposal methods at potash mining and processing plants

Abstract

The paper analyzes the positive and negative aspects of various technological solutions for the liquid brines used during the development of polymineral potash ore deposits and considers the problem of determining the choice of the optimal approach by considering geological, technical, environmental, and financial factors. The study of the issues of utilization and reduction of the liquid brines components of discharges in the production of potash fertilizers, the simultaneous reduction of valuable components loss with liquid discharges, and, due to this, increasing the production of potash fertilizers, and the usage in the technology of mine brines, are an urgent and important scientific and engineering challenge of the potash industry. Technologically, several alternative solutions can reduce the number of liquid by-products placed in sludge storage. The work used analytical methods, including statistical data processing, modeling, pre-design studies of technological solutions, and assessment of economic costs. Excess brines of potash mining and processing plants are liquid waste obtained during the production of potash fertilizers ? MOP ? SOP. The accumulation of excess brines in sludge storage facilities is estimated at millions of cubic meters per year. However, the expansion of the sludge storage facilities area and the construction of dams are only temporary solutions. They are associated with risks in the design, construction, and operation of hydraulic structures, increasing the risks of brine leakage into open and underground water basins. Therefore, it makes it necessary to use other methods of brine disposal. Depending on the nature of the processed polymineral potash ores, several methods can be combined to dispose of excess brines at once: backfilling, osmosis, injection into deep horizons, and multistage evaporation. The most optimal combination of brine reduction technologies for potassium-magnesium processing plant's raw materials is the following: 60% is disposed of by usage of vacuum evaporation units, 20 % by injecting excessive brines into deep absorbing horizons, and 10%?20% should be used for backfilling or additional products production.