Method for recovering germanium from flyash by wet process

Abstract

The invention relates to a method for recovering germanium from flyash by a wet process, belonging to the technical field of wet-process metallurgy. The method comprises the following steps of: (1) crushing flyash to more than 200 meshes by a wet process; (2) carrying out oxidizing leaching twice on wet flyash by using a sulfuric acid solution, sodium chlorate and ammonium fluoride; (3) crushing the flyash to 200-400 meshes for a second time; (4) leaching 3 or 4 times by using the same condition as that of the first leaching; (5) regulating the pH value of the first leached liquid to 2-2.5 by using ammonia water, and then precipitating and leaching out germanium in the liquid by using tannin with a weight percentage content of 80-99 percent; (6) drying and roasting the germanium precipitate to prepare a germanium concentrate; distilling the germanium concentrate with hydrochloric acid by using a conventional method to obtain germanium tetrachloride; and redistilling, rectifying, purifying and hydrolyzing to obtain high-purity germanium dioxide. The invention is used for flyash after recovering germanium by a fire process, sufficiently utilizes rare germanium metal, reduces the pollution of tailings to the environment, and has the advantages of low cost and high recovery rate.

Description

technical field [0001] The invention relates to a method for recovering germanium by wet method, in particular to a method for secondary recovery of germanium by wet method from fly ash after extracting germanium by fire method, and belongs to the technical field of hydrometallurgy. Background technique [0002] Germanium metal is a relatively scarce strategic resource, which is widely used in optical fiber communication, infrared optics, chemical catalysts, photovoltaic industry, aerospace, military industry, medical and health products and other fields. Most germanium elements are associated in lignite mines, and the fire method is generally used to extract germanium from lignite. When germanium is extracted by lignite fire method, the recovery rate of germanium is generally 70-85%, and the recovery rate is related to the recovery method adopted. Some lignite mining areas in my country have used different fire methods to extract germanium for many years, and the fly ash a...

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Problems solved by technology

At the same time, the content of silicon in these tailings is relatively high, and magnesium also occupies a large proportion, but the increase of magnesium due to the addition of lime is not large, and the proportion of magnesium oxide only increases from less than 1% to less than 4%. , and the content of calcium varies greatly depending on whether lime is added when extracting germanium, GW in the table 1 , GW 3 The group is the fly ash after using the method of extracting germanium without adding lime, and GW 2 , GW 4 The first group is the use of fly ash after the method of adding lime to extract germanium. For many years, these tailings have not been reused. First, the long-term storage of radioactive fly ash has caused environmental pollution. The waste of resources, the third is that it also takes up a lot of land for stockpiling tailings

[0008] At present, there is no method for recovering germanium from fly ash by wet method, and there is only a method for recovering germanium from fly ash by fire method twice, but the recovery cost is too high, the recovery rate is low, the environment is polluted seriously, and germanium cannot be extracted. Thoroughly wait for the question

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