Resource technology and system for separating salt from high-salinity wastewater

Abstract

The invention discloses a zero-drainage technology for recycling crystallizing salt from high-salinity wastewater and a treatment system thereof. The treatment system comprises a tubular microfiltration system, a weak acid resin hardness removal system, a nanofiltration membrane salt separating system, a nanofiltration concentrated water oxidizing system, a nanofiltration concentrated water sodiumsulfate evaporating and crystallizing system, a sodium sulfate freezing and crystallizing system and the like. The zero-drainage technology has the advantages that the pretreated wastewater is subject to nanofiltration primary salt separating, the salt component in the produced water is mainly sodium chloride, the sodium chloride with purity no lower than 98.5% is obtained by membrane concentration, evaporating and crystallizing, and the sodium sulfate with purity 99.1% or more is produced by MVR (mechanical vapor recompression) crystallizing after concentrated water oxidizing; a mother liquid after evaporating and crystallizing of sodium sulfate and a mother liquid after nanofiltration evaporating and crystallizing are mixed and frozen, so as to obtain mirabilite, and the mirabilite is converted into anhydrous sodium sulfate after sodium sulfate evaporating and crystallizing; at the premises of ensuring quality, the whole recycling rate of salt reaches 90% or above; finally, a smallamount of mother liquid is sprayed, dried and cured, and the zero-drainage effect of wastewater is realized.

Description

technical field [0001] The invention relates to a high-salt waste water separation and resource utilization technology. Specifically, the invention relates to a zero-discharge process for recovering salt from high-salt waste water and the system used. Background technique [0002] The shortage of water resources and insufficient capacity of water environment are important bottlenecks restricting the development of modern coal chemical industry in some areas. Among them, the treatment and discharge of high-concentration brine is one of the main challenges facing industrial development. Taking the Yellow River Basin as an example, the salt concentration in the western section of the Yellow River in Mengxi has reached 700-800 mg / L, and the sulfate content is close to the limit value of the environmental quality standard for surface water. Therefore, controlling salt in wastewater discharge has become an urgent problem to be solved. The "zero discharge" solution for wastewater ...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problems in the existing high-salt industrial wastewater "zero discharge" technology that the recovery rate of crystallized salt is low, the amount of impurity salt is large, and the target of reducing solid waste cannot be achieved by separating salt and recovering salt

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