Zero-emission resource recycling method of high-salt sodium sulfate wastewater

Abstract

The invention discloses a zero-emission resource recycling method of high-salt sodium sulfate wastewater. The method comprises the following steps: 1) removing noncondensable gas from a gas phase space, gasifying water in sodium sulfate wastewater through pressure difference, enabling the gasified water to flow to the surface of lithium bromide solution through a gas phase channel, and evaporating, cooling, concentrating and crystallizing the high-salt sodium sulfate wastewater; 2) separating mirabilite and mother liquid from crystal mush, carrying out heat exchange and concentration on the mother liquid to obtain concentrated mother liquid and fresh water; feeding the concentrated mother liquid and new sodium sulfate wastewater together into a crystallizer and then repeating the steps 1) and 2); and 3) pumping the diluted lithium bromide solution into an evaporator, heating for evaporating to form concentrated lithium bromide solution, and returning the concentrated lithium bromide solution back into an absorber. According to the method disclosed by the invention, evaporation and crystallization are completed at a low temperature, no low-temperature clod source or septate heat exchange equipment, and therefore the energy consumption is lowered. By the method, mirabilite which is the crystallization product and fresh water can be recycled; furthermore, the aim of zero-emission resource recycling of high-salt sodium sulfate wastewater is achieved and the whole process is easy to operate.

Description

Technical field [0001] The invention relates to a method for wastewater treatment and resource utilization, in particular to a technology for zero discharge and resource utilization of sodium sulfate and high-salt wastewater, belonging to the technical field of wastewater treatment. Background technique [0002] Wastewater discharged from chemical, electric power, metallurgy and other industries contains a lot of salt, especially in water treatment, because water softening process will introduce a lot of SO 4 2- Plasma makes the effluent wastewater contain a lot of sodium sulfate. If these high-salt wastewater are discharged directly, it will cause sudden salinization and damage the ecological environment. Therefore, it is of far-reaching significance to treat such high-salt wastewater to achieve zero discharge and turn it into treasure for resource utilization. [0003] For the treatment of this kind of sodium sulfate and high-salt wastewater, thermal treatment process and membra...

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Problems solved by technology

[0006] In view of the shortcomings of high energy consumption, large thermal resistance, and wall attachment of crystallization on the refrigerant partition wall existing in the existing treatment of high-salt wastewater contain...

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