A method for recycling miscellaneous salt produced in industrial wastewater treatment

Abstract

The invention provides a method for recycling impurity salts generated in industrial wastewater treatment. The method comprises the following steps: (1) calcining impurity salts generated in an industrial wastewater treatment process, cooling, dissolving in pure water, and obtaining a high-concentration sodium chloride solution; (2) performing solid-liquid separation, and removing residual organisms in the solution; (3) successively removing sulfate radicals and calcium ions, adjusting the pH of the solution to neutral, and obtaining a high-purity sodium chloride solution; and (4) crystallizing the high-purity sodium chloride solution obtained in step (3), obtaining a sodium chloride crystal product, and washing to obtain the high-purity sodium chloride crystal product. By adopting the method, the effective treatment and recycling of impurity salts generated in the industrial wastewater zero emission process of electric power, petroleum chemistry, coal chemistry and the like; moreover, the method is simple in treatment process and moderate in operation conditions, and is a high-efficiency and stable impurity salt recycling method; and a final product sodium chloride is high in recycling rate and purity.

Description

technical field [0001] The invention relates to the fields of wastewater treatment technology and refining of industrial miscellaneous salts, in particular to a method for recycling miscellaneous salts produced in industrial wastewater treatment. Background technique [0002] In recent years, with the rapid development of electric power, petrochemical, coal chemical and other industries, the treatment and utilization of miscellaneous salts generated in the process of wastewater treatment has gradually been paid attention to and has become an important part of environmental protection. In the process of wastewater treatment and reuse in these industries, the salt and other impurities in the natural water body, and the soluble salts added and left in the water treatment process are continuously concentrated in the water, and the final miscellaneous salts are mostly complex in composition and contain certain organic matter. It cannot be directly applied in the field of salt che...

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Problems solved by technology

However, the method described in this patent cannot remove impurities such as organic matter and heavy metals in the high-concentration salt concentrate, and the organic matter and other impurities will be distributed in the obtained sodium chloride and sodium sulfate products, which will affect the subsequent utilization of the products; Most of the miscellaneous salts produced in the water treatment process of coal and chemical industries are sodium chloride, and the content of sodium sulfate is low. The process setting and actual operation continuity of the method described in this patent are affected by the change of salt content in incoming water. bigger

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