Multistage continuous precipitation and concentration type salt fractionation process method

Abstract

The invention relates to a multistage continuous precipitation and concentration type salt fractionation process method. By utilizing a multistage continuous precipitation and concentration type salt fractionation process, each stage of processing unit can be continuously used, precipitable inorganic salt is removed by virtue of a chemical precipitation method, and monovalence salt and high-valence salt are fractionated by virtue of nanofiltration salt fractionation; by concentrating, the precipitation efficiency and the salt fractionation efficiency can be improved, the concentration of concentrated water can be increased, and recyclable clean water can be obtained; and by treating wastewater by virtue of a first-stage treatment unit, partial recycle water, high-purity and high-concentration monovalence salt, precipitated inorganic salt and nanofiltration concentrated water can be obtained, the nanofiltration concentrated water is mixed with raw water, and mixed water enters a second-stage treatment unit again and is subjected to precipitation, concentration and salt fractionation, so that precipitable substances can be adequately precipitated, and meanwhile, a relatively good separation effect can be achieved through nanofiltration.

Description

technical field [0001] The invention belongs to the technical field of waste water treatment, and relates to a multistage continuous precipitation, concentration and salt separation process method. Background technique [0002] With the society's increasing requirements for environmental protection technology, salt separation technology has attracted more and more attention from different industries, especially some industries that produce saline wastewater or mixed salt wastewater, such as coal chemical industry, electroplating, printing and dyeing, etc. According to the development trend of environmental protection requirements at this stage, zero discharge is an inevitable development requirement. In the middle, only through advanced and reasonable salt separation technology can the final reduction and zero discharge be efficiently completed. At the same time, some industries can also recycle There are precious metals of economic value or high-purity inorganic salts. [...

AI Technical Summary

Problems solved by technology

However, because the chemical method is affected by the solubility of salt, the concentration of the material and the relative concentration of the substances, it cannot fully remove the precipitable substances; the membrane salt separation mainly refers to the nanofiltration membrane salt separation technology, and the salt separation process is generally: the material is separated by pretreatment For clarification and filtration, the filtered material enters the nanofiltration membrane for separation. Generally, monovalent salts pass through the membrane more easily, while divalent salts are more likely to be retained by the membrane.

However, during the separation process, the separation of nanofiltration membranes is also affected by the concentration, the relative concentration of substances, and the impact of material impurities, which cannot fully remove the precipitated substances, and the efficiency is low

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