Method for removing boron and iron from boron containing magnesium chloride saturated liquid

Abstract

The invention pertains to the technical field of inorganic salt chemical industry, and in particular relates to a method for removing boron and iron from a saturated boron-bearing magnesium chloride solution. The method is a coordinate process integrating acidification and extraction which aims at solving the deficiency of the present process for removing boron and iron from the saturated boron-bearing magnesium chloride solution in salt lakes, and the technological process includes an acidification and boron extraction section, a filtration section, an extraction section and a reverse extraction section. The saturated boron-bearing magnesium chloride solution is taken as the raw material in the method, to which hydrochloric acid or sulfuric acid is added to acidify and precipitate boric acid, the remnant boric acid in the acidizing solution is extracted and removed by a mixed alcohol, the contents of B2O3 and Fe2O3 can be reduced to be less than 25mg / l, and the recovery ratio of boric acid reaches more than 99%; owing to the adoption of the mixed alcohol extraction technology, the method not only solves the problem of great extractant loss in the extraction method effectively, but also removes iron from the saturated magnesium chloride solution, and has the advantages of short technological process, simple operation and high yield.

Description

1. Technical field [0001] The invention belongs to the technical field of inorganic salt chemical industry, and in particular relates to a method for removing boron and iron from boron-containing magnesium chloride saturated liquid. 2. Technical background [0002] Salt lakes in the Qaidam Basin are rich in salt mineral resources, and the main useful elements are potassium, sodium, magnesium, boron, lithium, etc., among which boron, magnesium, and lithium are enriched in the saturated magnesium chloride solution after potassium extraction, and can be extracted from it Extracting lithium salt, borate and high-purity magnesium salt has great utilization value. However, most high-purity magnesium salt products require very low boron and iron content. Therefore, the development of boric acid extraction from the boron-containing magnesium chloride saturated solution and the removal of the remaining boron and iron technology is the boron and magnesium resources in the brine of the...

AI Technical Summary

Problems solved by technology

There are three methods for extracting boric acid from brine. At present, the acidification method is mainly used to extract boric acid. This method is only applicable to 2 o 3 >20g / l brine, after extracting boric acid, there is still 6~7g / lB in the brine 2 o 3 Existence, the crude boric acid recovery rate after acidification is 70-75%, the recovery rate is relatively low, and this method is for B 2 o 3 Salt lake brine with content less than 10g / l is not applicable

The second method is the high-efficiency boron resin method, and the boron (in B 2 o 3 (calculated) to below 10mg / l, boron recovery > 99%, but this method has an obvious shortcoming, that is, the B in the raw material brine is required 2 o 3 2 o 3 Up to 6 ~ 10g / l salt lake brine

The third method is the extraction method, that is, a boron-alcohol complex is formed with a branched alcohol and boron in the brine, and dissolved in an organic solvent to complete the extraction process. This method can remove the boron in the brine (in B 2 o 3 (calculated) to below 20mg / l, boron recovery>99%, high boron extraction efficiency, and suitable for B-containing 2 o 3 Salt lake brine with a high salinity of 6-10g / l is an ideal method for extracting boron from salt lake brine. The extraction and dissolution loss reaches more than 1%, which greatly limits its large-scale application

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