Study On The Crystallization Order And Separation Ways Of Potash For Marine Deep Brines Which Enrich In Potash And Bron

Brine (salt lake brine , oilfield and gasfield water brine) is very rich in high-value minerals, the marine deep brine of Pinlopa Well 4 is a oversize liquid treasures first been found in the word which have multi-element and enrich in potash and bron . According to the assessment of mineral resources of Sichuan province , the total reserves of this marine brine is more than 250 billion cubic meter , 20 billion tons of potassium chloride and 5 billion tons of boric acid can be produce by it. In addition, this brine containing much of bromine , iodine, lithium and other elements , the total value of this marine brine is about million billion yuan. This brine comes from about 4600 meters underground , because of its depth storage , it is not have been development and utilization beforetime , the utilization technology of it has not been reported on the known domestic and foreign literature. The research of its utilization technology have important significance for the alleviation of the current resources shortage in China. The laws of the enrichment of various elements and the crystallization order of the salts in 30℃was found in this article first time , the sequence of salt precipitation at 30℃is : rock salt→mixed salt of the sodium , potassium and boron→mixed salt of the sodium, potassium, boron, calcium and magnesium. The results of this experimental showed that the key and the difficult points of the comprehensive utilization of this brine is the separation of the boron and potassium. The study found that the sequence of salt precipitation in forced evaporation is similar with the isothermal evaporation , the different was in the end stages of the evaporation : the calcium , magnesium and boron have a similar concentration law in the liquid phase , their density has declined and likely to precipitation by the form of complex salts , which is different from other brine systems , this discovery have guiding significance for the utilization of this brine. This study have confirmed that separation of the sylvinite by thermally dissolved - cold crystallization could have better result , and can obtain pure products of sodium chloride and potassium chloride. According to this brine's different composition and special properties , this study gave the comprehensive utilization program is: extracting iodine by ion-exchange method , extracting bromine by the air air blowing process , extracting boron by solvent extraction , and separation of the potassium salt by thermally dissolved - cold crystallization method .