Preparation of complex titanium-containing coagulants from large-scale mineral concentrates and their use in wastewater treatment

Abstract

Relevance. Development of new, highly effective reagents for treatment of wastewater of various origins is a complex and extremely important task. An equally pressing issue remains the development of technologies for processing large-scale mineral products, which currently have not found an economically feasible technology for their processing and have received the status of “waste”. The development of a technology for producing reagents using waste as a raw material will not only have an economic effect but will also significantly minimize the level of negative impact on the environment and take a step towards the implementation of the Zero Waste concept. Aim. Development of technology for processing large-scale titanium-containing raw materials to obtain complex titanium-containing reagents and study of their effectiveness in wastewater treatment from various industries. Methods. To study the phase composition of the samples, the X-ray diffraction method was used, and the determination of metal content in acidic solutions and wastewater was carried out by atomic emission spectroscopy. Results and conclusions. The authors have proposed the technology for production of complex titanium-containing coagulants, which includes hydrometallurgical technology for sulfuric acid processing of large-capacity mineral raw materials – titanite. Aluminum hydroxide was introduced into the resulting solutions to adjust the chemical composition and neutralize free sulfuric acid. The resulting aluminum sulfate transforms into the most stable form of 18-aqueous crystalline hydrate, absorbing moisture from the solution, realizing chemical dehydration. The study of the composition of solid samples of coagulants showed that the predominant phase in the composition of the complex coagulant is aluminum sulfate, and the content of titanium compounds ranges from 1 to 14 wt %. It was established that by varying the ratio of mineral raw materials:sulfuric acid it is possible to vary the amount of modifying additive titanium compounds in the complex reagent. It was proven that the use of complex titanium-containing coagulants in wastewater treatment allows reducing the consumption of coagulants by 25–35%, increasing the efficiency of water purification, minimizing residual concentrations of pollutants, and also significantly increasing the rate of sedimentation of coagulation sludge in comparison with traditional sulfate aluminum.