Effect of High-Power Nanosecond Electromagnetic Pulses on the Microhardness, Physicochemical and Flotation Properties of Rare Metal Minerals

Abstract

One of the actual problems in flotation of complex niobium-tantalum ores is to develop the advanced methods to improve rare metals mineral processing efficiency by enhancing the contrast of the structural-chemical (phase) surface state and technological properties of ore and rock-forming minerals. In the recent years, various types of energy impacts have been used to enhance the contrast of the physicochemical and technological properties of minerals, and the techniques used are the radiation, ultrasound, electrochemical, laser, plasma, microwave, electromagnetic pulse, high-voltage electric pulse, and other effective methods of energy impact. In this paper, we report the results of experimental studies on the directional modification of the surface morphology (SEM–EDX), microhardness (Vickers), physicochemical (electrokinetic and electrochemical potentials, surface hydrophobicity, sorption activity) and flotation properties of columbite, tantalite, zircon, feldspar, and quartz as a result of the nonthermal effect by high-power nanosecond electromagnetic pulses. The rational pretreatment with nanosecond pulses (ttreat = 100 s is the treatment minerals time, f = 100 Hz is the pulse repetition rate, and UA ≅ 25 kV is the amplitude of pulses) of rare metal minerals provided higher selectivity of columbite and zircon flotation separation, without any appreciable boost in flotation activity of rock-forming minerals (feldspar and quartz).KeywordsRare metal mineralsHigh-power nanosecond electromagnetic pulsesScanning electron microscopySurface morphologyMicrohardnessElectrode potentialSorptionFlotation