Disposal of titanium-magnesium production industrial effluents

The results of a study on the disposal of waste discharge at the iron and steel works using centrifugation and vacuum sublimation methods are presented. The object of the study was industrial effluents of titanium-magnesium production. The influence of centrifuge rotation speed, duration, temperature and fraction of solid phase on the process of industrial effluent separation into liquid (fugate) and solid (sediment) phases is studied. A complex of studies based on the multifactor experiment design was carried out to evaluate the effect of each of these factors. Optimum centrifugation parameters were established: rotor speed — 3000 rpm and duration — 30 min. The obtained solution (fugate) contained 195 mg/dm³ of suspended matter, 26500 mg/dm³ of chlorides, 39750 mg/dm³ of dry residue, which indicates its high mineralization and the need for further purification. The expediency of a thermal method of fugate demineralization using a rotary vacuum evaporator was demonstrated in laboratory conditions. Optimum process parameters were determined: temperature 70 °С, residual pressure — less than 50 mbar, duration — 30 min. Residue yield after vacuum sublimation was 6 % of the fugate weight. No suspended substances were found in the obtained condensate, and chloride content was 50 mg/dm³. The proposed technology for the disposal of industrial effluents at titanium-magnesium production will facilitate forming a closed water supply cycle at the enterprise. Residue obtained after the fugate vacuum sublimation containing mainly chlorides of alkali and alkaline earth metals can be recommended to use as an additive for the preparation of anti-ice materials, as well as drilling fluids and kill mud.

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