Comprehensive process method for salt production by seawater desalination

Abstract

The invention provides a comprehensive process method for salt production by seawater desalination and belongs to the technical field of seawater treatment. The process method comprises the followingsteps: enabling pre-treated seawater to be subjected to reverse osmosis treatment, entering a nano-filtration device after reverse osmosis concentrated water is subjected to bromine extraction and pHregulation and is added with a reducing agent, performing salt production with nano-filtration concentrated water, and enabling concentrated water obtained by the treatment of nano-filtration producedwater with a high-pressure reverse osmosis device to enter an electrodialysis device so as to obtain strong brine and performing salt production with the strong brine through a mechanical steam recompression device. By utilizing a series of technologies such as nano-filtration, high-pressure reverse osmosis, electrodialysis, a mechanical steam recompression technology, a closed circulating loop is formed through dosage, concentration and graded reuse, and further, salt production, bromine extraction, magnesium extraction, mirabilite production and the like are performed, so that the comprehensive utilization of the seawater is realized.

Description

technical field [0001] The invention relates to the technical field of seawater treatment, in particular to a comprehensive process for seawater desalination and salt production. Background technique [0002] my country's water resources are in serious shortage, with low per capita fresh water and uneven temporal and spatial distribution. Desalination of seawater can provide fresh water resources stably without restriction. In recent years, with the advancement of technology, the cost of water production has been greatly reduced, and desalination of seawater in my country has developed rapidly. [0003] With the expansion of the scale of seawater desalination industry, the discharge of by-product concentrated seawater is an urgent problem to be solved in seawater desalination technology. At present, the commonly used concentrated brine treatment methods can be divided into two categories: the first category is direct discharge, such as discharge into the ocean, surface wate...

AI Technical Summary

Problems solved by technology

Direct discharge of concentrated seawater will have a certain impact on marine organisms and the marine environment, pollute surface water and groundwater, and increase the processing burden of sewage treatment plants

In terms of reuse, the method of tanning in salt fields is mainly used now, but with the economic development of coastal areas, the area of ​​brine making in salt fields is gradually shrinking, which limits its application range

[0004] For the salt industry, due to the development of emerging industries, land resources are urgently needed, and the low-yield salt fields have become the primary reduction target. On the other hand, the underground brine resources are exhausted, and the concentration and stock are declining. The production capacity is gradually shrinking. In addition, the substantial increase in the production and labor costs of the salt industry also promotes the transformation and development of the salt industry

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