CLEANING OF WATER BY COAGULANTS RECEIVED FROM WASTE ALUMINUM MANUFACTURING

Abstract

To date, the unresolved part of the scientific problem is the utilization of sludge - waste of alumina plants, for example, the Mykolaiv Alumina Plant, which contains iron oxides and aluminum in its composition.The article reviews the coagulants obtained from waste aluminum production, the composition of which consists of aluminum and iron compounds, the effect of sulfuric acid (KH-1 coagulant) and hydrochloric acid (KH-2 coagulant), that is, the determination of the doses of the reagents that contribute effective illumination and discoloration of water when purified by settling and filtration. As a comparison, aluminum sulfate and Polwak were used. Polwak is a coagulant produced in Ukraine, it contains 2/3 and 1/3 aluminum hydroxychlorides.In these studies, model solutions of bentonite and humate of sodium were used in Artesian water of the city of Mykolaiv. To reduce the turbidity of the model suspension of bentonite and to reduce the color of the suspension of sodium humate to a sample of 200 cm3 water, an estimated dose of coagulant was added, the water was stirred vigorously for 2 to 3 minutes, after which it was advocated for 2 hours, and then determined turbidity and color. The settled water was filtered through a paper filter red tape. After that, in the selected sample, the residual turbidity, the color of the filtrate, the residual concentrations of aluminum and iron were determined. Turbidity, expressed in mg SiO2 per 1 dm3 of water, was determined by the photocolorimetric method, chroma-cobalt scale chromatography, residual concentrations of aluminum and iron were determined by the same method.When processing a model solution of bentonite with KH-2 coagulants, it was much more effective than all other used reagents after precipitating. At a dose of 20 mg/dm3 (for Al2O3, Fe2O3), the KH-2 coagulant provides a degree of illumination of the suspension at 97.8%. The effectiveness of the coagulant KH-1 was slightly worse compared to KH-2, but better compared to known coagulants.With the discoloration of the model solution of sodium humate, also the most effective was the coagulant KH-2. He reduced the color from 278 to 47 deg. CCS with an increase in the dose of coagulant from 2.5 to 40 mg/dm3. The results were even better at refining water by settling and filtering. In this case, the KH-1 coagulant was not inferior to the effectiveness of sulfuric acid aluminum and the Polwak coagulant. The most effective was a coagulant KH-2, at doses of 15 - 40 mg/dm3, it provided a reduction of color to 0.0 - 20.0 deg. CCS - it meets the requirements for drinking water quality. In all experiments presented in the light and discoloration of water, residual concentrations of aluminum and iron did not exceed 0.2 mg/dm3.