Purification method of lime-flue gas brine

Abstract

The invention discloses a purification method of lime-flue gas brine, which comprises the following steps: 1) performing first-order reaction clarification: measuring concentration of Ca<2+> and Mg<2+> in raw brine, calculating required amount of lime and sodium carbonate, performing pre-feeding with the lime, feeding sodium carbonate to the raw brine and finally feeding the residual lime; 2) performing sampling and rework: testing concentration values of Ca<2+> and Mg<2+> in mixed brine liquid after a reaction, performing Step 3) if qualified, and performing further purification by utilizing caustic soda and sodium carbonate if unqualified; 3) performing primary flocculation: adding an HEC (Hydroxy Ethyl Cellulose)-maleic acid-chitosan composite flocculant to the mixed brine liquid for flocculating settling; 4) performing second-order reaction clarification: supplying carbon dioxide flue gas to liquid after the primary settling; 5) performing secondary flocculation: adding the HEC-maleic acid-chitosan composite flocculant to the brine liquid for the flocculating settling; 6) transferring liquid after the settling to a refined brine barrel of a salt manufacturing workshop. Compared with the traditional two-alkali method, the purification method has a great economic benefit; the composite flocculant is adopted, so that the purification time is short and the turbidity of the purified brine is low; the flocculant is more stable.

Description

technical field [0001] The invention relates to the technical field of salt making industry, in particular to a method for purifying lime-flue gas brine. Background technique [0002] As a necessity for human survival and one of the most basic raw materials for the chemical industry, salt plays a pivotal role in the daily life of the national economy. my country is one of the countries with the longest history of salt production in the world, and our country is rich in salt resources. Thousands of salt lakes are dotted in Qinghai, Xinjiang, Tibet and other provinces and autonomous regions. In Sichuan, Yunnan, Jiangsu, Shandong, Henan There are abundant mineral salt underground in Huai'an and other provinces, and Huai'an City has the largest salt mine in the world. [0003] Most of the brines of sulfate-type salt mines in my country contain Mg after water mining 2+ , Ca 2+ , SO 4 2- Due to the calcium and magnesium impurities contained in the brine, it is easy to precipit...

AI Technical Summary

Problems solved by technology

[0006] The application and research of the two-alkali method in the deionization of salt-making brine is relatively mature. However, with the continuous rise of the market price of the two-alkali, the consumption of NaOH in the two-alkali method is large, the cost is high, and the caustic soda is highly corrosive. The loss is large, which also increases the production cost from another aspect

In addition, flocculants play a key role in the purification of brine. The existing flocculants cannot completely remove the suspended particles generated during the brine purification process, causing some suspended particles to enter the next process with the brine, and finally enter the salt products and nitrate products. The purity of the product is not high, or the qualified rate is reduced, and the annual loss is relatively large

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