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 of the liquid brines use during the development of polymineral potash ore deposits, considers the problem of determining the choice of the optimal approach by taking into account 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 also 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 are possible to reduce the number of liquid by-products placed in sludge storages. A set of analytical methods was used in the work, 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 potashfertilizers - MOP ? SOP. The accumulation of excess brines in sludge storage facilities is estimated at millions of cubic meters per year. The expansion of the sludge storage facilities area and the construction of dams are only a temporary solution and associated with risks in design, construction, and operation of hydraulic structures, increasing the risks of brine leakage into open and underground water basins. This makes it necessary to use other methods of brine disposal. Depending on the nature of the processed polymineral potash ores, several methods can be used in combination for the the disposal of excess brines at once: backfiling, osmosis, injection into deep horizons, multistage evaporation. The most optimal combination of brine reduction technologies for potassium-magnesium processing plants raw materials is the following : 60% is disposed by usage of vacuum evaporation units , 20 % - by injecting excessive brines into deep absorbing horizons, 10-20% should be used for backfilling or production of additional products.