Method for purifying crude selenium through anhydrous ethanol

Abstract

The invention discloses a method for purifying crude selenium through anhydrous ethanol, and belongs to the technical field of wet metallurgical engineering. The method comprises the steps that a sodium sulfite solution is used for leaching the crude selenium (containing 90%-99% of selenium), wherein the leaching temperature is 50-150 DEG C, the leaching time is 0.5-3 h, and the stirring speed is100-350 r / min; and after leaching, filtering is conducted to obtain a sodium selenosulphate leaching solution, the obtained sodium selenosulphate leaching solution and the excess anhydrous ethanol aremixed and stirred to obtain selenium precipitate, and finally the selenium precipitate is washed, filtered and dried to obtain fine selenium with the purity being 99.99%-99.999%. Metal impurities such as tellurium, lead, copper, silver and gold in leaching slag are further enriched. The anhydrous ethanol is adopted to precipitate the selenium from the sodium selenosulphate solution, thus efficient extraction and purification of the selenium are achieved, and no exhaust gases or waste residues are generated in the whole process.

Description

technical field [0001] The invention relates to a method for purifying crude selenium with absolute ethanol, and belongs to the technical field of hydrometallurgical engineering. technical background [0002] Selenium is a scattered metal, and its important position in the national economy and human health is becoming more and more prominent. Selenium has a wide range of applications, mainly used in electronic industries such as photoelectric cells, solar cells, and pigment industries. In terms of human health, selenium is one of the essential trace elements for the human body. Selenium-enriched foods have also received widespread attention, and they also play a key role in the synthesis of human anticancer drugs. The production of high-purity selenium has also been highly valued; for a long time, the selenium produced in my country is mainly industrial-grade products with a purity of more than 98%, which severely limits the development of high-tech new materials. Selenium ...

AI Technical Summary

Problems solved by technology

Vacuum distillation can effectively separate impurities with high melting point and low saturated vapor pressure such as copper, silver, and gold, but it is difficult to remove impurities such as Te, Pb, and S to a low level; zone smelting is an effective method for purifying metals. But the production cycle is long, not suitable for mass production

Chemical methods include crude selenium oxidation and volatilization-sulfur dioxide reduction method, hydrogen selenide thermal decomposition method, sodium sulfite method, solvent extraction and ion exchange method, etc.; oxygen volatilization-sulfur dioxide reduction method requires high test conditions, complicated process and poor working conditions , pollute the environment; highly toxic gas hydrogen selenide will be produced in the process of purifying selenium by thermal decomposition of hydrogen selenide, so this method can only produce high-purity selenium in a small amount

The sodium sulfite method can effectively remove impurities that are difficult to remove by vacuum distillation. This method utilizes that selenium is soluble in hot sodium sulfite solution but impurities are insoluble. Disadvantages such as long time and extremely low recovery rate

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