Development of technological solutions for neutralization of acidic wastewater
Abstract
The article considers the problem of neutralization of acidic wastewater generated during the regeneration of cation exchange filters at the Novo-Salavatskaya CHPP. The initial wastewater has a pH of 1.3 and a sulfate content of 11.6 g/dm³. The aim of the work is to develop a technological scheme and neutralization modes that allow obtaining two by-products: alabaster and manganese concentrate. The methods used include potentiometric pH determination, complexometric titration for calcium, and turbidimetry for sulfates. The experiment included two stages: precipitation of calcium sulfate with a 10% CaCl₂ solution and subsequent neutralization of the filtrate in a column packed with carbonate manganese ore. It was found that the optimal solution feed rate through the column is 4.57 cm³/min, at which the pH rises to 6.75 and the sulfate content decreases to 2.15 g/dm³. The CaSO₄ precipitate after calcination at 170–180 °C is converted into alabaster with a yield of 4.6 g per 1 dm³ of wastewater. The insoluble residue of the ore is enriched in MnO₂ up to 34–36% and can be used as a manganese concentrate. It is concluded that the proposed two-stage scheme makes it possible to abandon expensive alkaline reagents and obtain two marketable products.

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