Comprehensive utilization method for separating, concentrating and purifying manganese sulfate, magnesium sulfate and calcium sulfate in high-salt waste water

Abstract

The invention relates to a comprehensive utilization method for separating, concentrating and purifying manganese sulfate, magnesium sulfate and calcium sulfate in high-salt waste water. The method is characterized by comprising the following steps of maintaining the temperature of mother liquor of waste water at 50DEG C to 60DEG C, utilizing ammonia water or liquid ammonia to adjust the pH value of the waste water to 10 to 1.5, collecting separating manganese ions and magnesium ions in the waste water in a form of manganese hydroxide and magnesium hydroxide, adding sulfuric acid into the separated manganese hydroxide and magnesium hydroxide to prepare a manganese sulfate solution and a magnesium sulfate solution, and adopting a segmented evaporation crystallization method to realize the separation to produce manganese sulfate monohydrate and magnesium sulfate hexahydrate; adding lime milk into the waste water after the manganese hydroxide and magnesium hydroxide are separated to adjust the pH value, crystallizing calcium sulfate, precipitating the calcium sulfate, and press filtering the calcium sulfate to produce calcium sulphate dehydrate. After being treated by utilizing the method, the waste water can reach the emission standard and can be externally discharged or recycled by the enterprise, and solid wastes in the waste water can be completely recycled. The investment is low, and the annual net investment return rate is more than 15 percent.

Description

technical field [0001] The invention belongs to the chemical industry fields such as manganese chemical industry and vanadium chemical industry and the field of waste water treatment and production in heavy metal extraction in metallurgical industry, and specifically relates to the step-by-step process of manganese sulfate, magnesium sulfate and calcium sulfate in high-salt waste water containing manganese sulfate, magnesium sulfate and calcium sulfate Separation, concentration crystallization, purification and wastewater recycling methods. Background technique [0002] In the process of preparing qualified manganese sulfate electrolyte in electrolytic manganese enterprises, and in the process of calcification and roasting in vanadium chemical enterprises to produce vanadium oxide, most of them will produce high-salt wastewater containing manganese sulfate, magnesium sulfate and calcium sulfate, of which Mn 2+ The content is 10-20g / L, Mg 2+ Content in 1-3g / L, Ca 2+ The con...

AI Technical Summary

Problems solved by technology

For the separation of manganese sulfate, magnesium sulfate, and calcium sulfate, the treatment method of most enterprises at present is to first use milk of lime to precipitate manganese sulfate, magnesium sulfate, and calcium sulfate together, and then discharge the waste water or try to reuse it. Manganese sulfate, magnesium sulfate, and calcium sulfate cannot be separated, which not only wastes resources, but also makes it difficult for the treated wastewater to meet the discharge standards

Some companies have also proposed the method of manganese sulfate electrolysis after calcium removal, but due to the high content of magnesium sulfate in wastewater, the power consumption of electrolysis is greatly increased, and the concentration of manganese sulfate is too low, which is far from meeting the concentration requirements of qualified electrolyte. There is also a large amount of calcium ions, so it is impossible to pass through, and the cost is high, and the gain outweighs the gain

There are also some manganese sulfate production enterprises. Although calcium and magnesium are removed from manganese sulfate, a considerable part of manganese sulfate is lost, and the separated calcium and magnesium are also wasted.

With the implementation of new standards for environmental protection and energy conservation, and the intensification of supervision, it is difficult to discharge this type of wastewater up to standard, especially because resources cannot be comprehensively utilized

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