REDUCTION OF THE VOLUME OF PUMPING OF LIQUID WASTE FROM THE PRODUCTION OF APATITE CONCENTRATE DUE TO THE TECHNOLOGY OF PARTIALLY CLOSED WATER CIRCULATION

"The use of recycled water supply technology in mineral dressing plants solves current environmental and economic problems for the mining and processing industry. Usually, water treatment takes a long time and requires constructing large-volume tailing dumps. The paper proposes a technology of a partially closed water circulation with the purification of watered production waste from suspended particles and water-soluble impurities that negatively affect the flotation process, based on the regularities describing the interaction of flocculants with the phases of a heterogeneous system of process waters. The authors have determined the most effective reagents providing optimal indicators of recycled water. The proposed technology is implemented in hardware in a radial thickener and eliminates the discharge of process water into an external tailings dumps facility, which will reduce the area occupied by production waste. Based on the particle size distribution data for various preliminary treatment options, differential and integral particle size distribution curves have been obtained. Analytical expressions of the obtained curves have been used to create discrete functions of volume fractions of particles with different sizes when constructing a model of the initial feed. The hydrodynamic processes of highly diluted suspension flows in the thickener’s body were studied using computational experiments on a model developed in the ANSYS Fluent software package, which is based on the real 3D geometry of a radial thickener. To build the geometry, the authors used a standard module GAMBIT. A computational experiment on cleaning the apatite concentrate discharge was performed on a virtual stand. The distributions of the concentrations of volume fractions of particles and the velocities of their movement in the thickener’s volume were obtained. The results of laboratory studies and computer simulation data allow the authors to tell about the prospect implementation of the technology of intra-plant water circulation, which will reduce by 10% the amount of wastewater discharged into the tailing dump. The use of the most efficient reagents will provide optimal water parameters for the content of suspended particles and hardness cations and, ultimately, will increase the technological and environmental performance of the Khibiny apatite-nepheline ores processing."