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INFLUENCE OF THE PRECIPTATOR ION ON THE EFFICIENCY OF NON-FERROUS METAL IONS EXTRACTION FROM AQUEOUS SOLUTIONS THROUGH ELECTROFLOTATION

V. А. Brodskiy

Abstract

The research studied the effects of solubility, disperse features (Z-average diameter dav, and charge (?-potential) of the particles of non ferrous-metal slightly soluble compounds of different natures exemplified by hydrates, carbonates, phosphates and sulfides of cuprum(II) and nickel(II) related to efficiency of their extraction from aqueous solutions through electroflotation. The research showed that minimum solubility of the dispersed-phase? particles of cuprum(II) and nickel (II) cannot be used to predict their electroflotation behavior. The empirical tests proved that the dispersive capacity and charge of particles are the key factors influencing the kinetics of electroflotation, which, in turn, depend on the nature of a precipitator ion. The research showed that the efficiency of electroflotation treatment of aqueous solutions from cuprum (II) compounds in the presence of ??- ? CO32 ions serving as precipitators reaches 96% expressed as metal ions in 10 minutes after the beginning of treatment. Identical efficiency of the electroflotation process for cuprum (II) hydrates and carbonates may be determined by significant coincidence of their dispersive features (dav = 50 ? 55 ?m) and charges (? = -13 ? -16 mV). The level of extraction of slightly soluble copper compounds in the solution with phosphate ions does not exceed 77%. This may be caused by complexities related to extraction of significant amounts of a finely dispersed phase (dav = 37 ?m) with the negative charge(-44 mV). Extra low efficiency of electroflotation extraction of cupric sulfide particles (? ? 5%) from aqueous solutions is likely related with high negative charge of particles (-51 mV), which may prevent their coagulation (dav < 1?m). The data obtained for slightly soluble Ni compounds differ a bit. The research showed that the particle charges of slightly soluble nickel compounds with ??-, CO32-, PO43- and S2- ion -1, -7, -25 and -41 mV respectively. Notwithstanding significant differences of Zav of the particles (dav = 34 ? 50 ?m), these compounds are characterized by the sufficiently high level of extraction. In 10 minutes after the beginning of the electroflotation process, ? reaches 76 ? 80 %. At the same time, the extraction dynamics of the dispersed phase? particles in the presence of carbonate ions decreases significantly (the level of extraction does not exceed 25 %). This is likely determined by the lower particle size (dav = 27 ?m), as well as their high negative charge ( ? = -33 mV). The obtained data are important for understanding how the nature of precipitator ions effects the physical and chemical properties of the dispersed phase of slightly soluble metal compounds and efficiency of the electroflotation process in general.

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