Dmitry Mendeleev University of Chemical Technology of Russia (Moscow, Russia):

Kuzin E. N., Associate Professor, Candidate of Engineering Sciences, e.n.kuzin@mail.ru
Kruchinina N. E., Dean, Doctor of Engineering Sciences, Professor, krutch@muctr.ru

Complex coagulants ensure significantly higher treatment rates for industrial and natural water with the removal of iron compounds, petroleum products and suspended solids. The most promising are those coagulants that contain metals with oxidation state IV, such as silicon or titanium. The issue of obtaining complex silicon-containing coagulants has been widely covered in numerous papers, while titanium-containing reagents are only beginning to draw the attention of researchers. It had been previously established that hydrolysis products of titanium compounds demonstrate increased coagulation efficiency as compared with traditional aluminum and iron-containing reagents when used in wastewater treatment. Despite this, there is currently no industrial technology for producing titanium-containing complex reagents. For their synthesis, the solutions obtained in sulfuric acid liberation of titanium-containing minerals contained in ilmenite and sphene concentrates were modified and converted to the solid form by chemical dehydration. This ensured the formation of complex reagents based on aluminum sulfate and titanium compounds. Depending on the feed type and solution dehydration conditions, the mass fraction of titanium in the complex coagulant varied from 4 to 20 %, the mass fraction of water-soluble aluminum compounds was 50 to 90 %, and the mass fraction of the insoluble part ranged from 3.5 to 28 %. Trial treatment of surface runoffs from a water supply source in Moscow (Skhodnensky diversion channel) and wastewater from one of the engineering enterprises of the Moscow region using a complex titanium-containing coagulant demonstrated its increased efficiency as compared with traditional reagents (aluminum sulfate) in reducing the indicators of suspended solids content, color, residual content of iron compounds and petroleum products.

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