Potassium ore contains readily sludgable water-insoluble silicate–carbonate impurities which actively adsorb cation collectors (primary alkylamines) used in sylvine flotation. This fact determines inclusion of multistage de-sludging flowsheets, with rougher and cleaning flotation of sludge in the processing technology. A prerequisite for flotation de-sludging of ore is pre-flocculation of sludge. Flotation of sludge in mechanical flotation machines is carried out with intensive mechanical stirring of the suspension, which impairs the selective separation of sludge into the flotation froth and leads to the partial destruction of sludge floccules, which causes an increased consumption of the flocculant. In column machines, flotation is carried out in a laminar-upward flow of finely dispersed air bubbles ejected into the suspension in the lower part of the column, and is characterized by the minimal hydromechanical effect on the mineral particle–air bubble attachment. An important feature of flotation in column machines is the adjustability of the foam layer height in a wide range of values (up to 0.5 m and more) and its washability, which makes it possible to increase the recovery selectivity of the floated material into the foam product. The design of column machines for enrichment of potash ores, which are water-soluble and floatable in rich salt solutions, should ensure elimination of crystallization of the aeration system for supplying air to the column machine. The tests of column flotation of sludge produced from potash ores of the Upper Kama deposit with different contents of water-insoluble impurities were carried out on the experimental installation of ERIEZ Flotation Division. The results of the comparison of flotation efficiency and selectivity in mechanical and column flotation machines are presented. The possibility of de-sludge flotation of potash ores with different contents of water-insoluble impurities (1.5–4%) with the significant improvement of flotation selectivity at the lower consumption of reagents is shown. The use of column flotation creates conditions for simplifying the instrumental and technological flowsheet of flotation.
Column flotation monitoring based on electrical capacitance volume tomography: A preliminary study
