St. Petersburg State Mining University (Russia):

Zakhvatkin V. V., Associate Professor, opiopi@bk.ru

Regularities of cobalt and nickel ions precipitation from diluted solutions, similar with respect to these metals content in miningand smelting operations waste water, are considered. Commercially produced sulfhydric compounds, have been tested as reagents-precipitators: dithiocarbamates, ethyl xanthate, dithiophosphate, dithiocarbamic acid derivatives. Precipitation was conducted at medium pH values, inhibiting cobalt and nickel hydroxides formation. It was established, that metals precipitation degree depends on colligends (reagentsprecipitators) consumption, formed sublates (metalorganic compounds) solubility and duration of solution agitation with precipitator, that is, precipitate formation reaction kinetics. The latter factor, by virtue of relatively low solubility of formed cobalt and nickel compounds with all selected sulfhydric reagents, is of secondary importance for practical realization. Precipitate dispersion degree is of a high importance with regard to subsequent flotation process. Therefore, solution agitation time is determined mainly by precipitates coagulation rate. The observations showed, that with continuous mixing of solution, precipitates begin to noticeably coagulate in approx. 60–70 min, depending on metal ion and type of precipitator. It is shown, that practically complete precipitation of metals may be achieved by application of both ethyl xanthate and sodium ethyl-dithiocarbamate, consumption being 1.5–2 equivalent of stoichiometric. Hydrophobic precipitates, formed in this way, may be recovered by flotation in machines with low level of energy dissipation.

1. Rubinshtein Yu. B., Molodchik G. L. Flotatsionnaya ochistka stochnykh vod (Flotation purification of waste water), Moscow, IEITsM, 1980, 42 p.

2. Zelinskaya Ye. V. 2. Izvestiya VUZov. Gornyy Zhurnal — Isv. of Universites. Mining Journal, 2000, No. 2, pp. 51–54.

3. Zakhvatkin V. V. Obogashchenie Rud, 2012, No. 1, pp. 28–31.

4. Kireev V. A. Kurs fizicheskoy khimii (Coarse of physical chemistry), Moscow, Khimiya, 1975, 776 p.