D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia:

E. N. Kuzin, Associate Professor at the Department of Industrial Ecology, Candidate of Technical Sciences, e-mail: e.n.kuzin@muctr.ru
N. E. Kruchinina, Dean of the Faculty of Biotechnology and Industrial Ecology, Deputy Head of the Department of Industrial Ecology, Professor, Doctor of Technical Sciences, e-mail: krutch@muctr.ru

A series of experiments has been conducted and samples of complex coagulants have been obtained from the by-products of apatite-nepheline ore flotation (nepheline concentrate) and from refractory production waste — i. e. synthetic brucite. It was established that aqueous solutions of titanium tetrachloride can be used as an acid leaching reagent. The authors examined the process of recovering the principal active components with aqueous solutions of titanium tetrachloride and identified the priority mechanism behind leaching of metallic components with highly diluted aqueous solutions of titanium tetrachloride. The quantitative and qualitative composition of the obtained solutions of complex coagulants was analyzed. Modified magnesium coagulants were found to demonstrate high efficiency at high pH values of the treated water. At neutral pH values, complex aluminiumbearing reagents proved to be significantly more efficient than the conventional coagulants (i.e. aluminium sulphates and aluminium (oxy)chlorides). The obtained reagents were analyzed for their coagulation ability. Run-off and waste waters generated by an off gas purification unit in use at a non-ferrous metal casting site were used for the analysis. The analysis showed that, with the same dosage used, the modified aluminium coagulant is 30–35% more efficient than the conventional reagents. Experiments aimed at analyzing the water treatment efficiency in the case of water with high pH values (e.g. wastewater generated by a cement plant) showed that due to the use of inoculants in magnesium coagulants the water treatment efficiency can be increased by more than 20%. It was proved that the introduction of titanium compound hydrolysis products helps to significantly increase the water treatment efficiency irrespective of the principal component of the coagulant (aluminium or magnesium salt).
This research was carried out as part of the funding programme aimed to support young research and teaching staff of D. Mendeleev University of Chemical Technology of Russia (Application: З-2020-013.).

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