The invention discloses a method for preparing high-purity
selenium through wet-process purification of crude
selenium. The method comprises the following steps: a, slowly adding crude
selenium into a
sodium hydroxide solution at a uniform speed, wherein a liquid-
solid mass ratio is 3-5: 1, reaction time is 1.5 to 2 h and complete dissolving and leaching of crude selenium are ensured; b, adjusting a pH value to 6.5 to 7.0 by using
hydrochloric acid, adding
sodium sulfide, then carrying out uniform mixing under stirring and carrying out standing to remove impurities; c, adjusting the pH value of an alkaline leaching solution obtained in the previous step to 1.0 to 1.5, carrying out
ageing for 2.5 to 3 h and then carrying out
solid-liquid separation after complete
precipitation of selenium; d, oxidizing leached fine selenium by using a
sodium sulfite solution, carrying out sufficient stirring and then successively carrying out standing and filtering so as to obtain a selenium-rich solution; and e, slowly adding
sulfuric acid into the selenium-rich solution, and successively carrying out acidification and reduction, filtering, washing and
drying so as to prepare high-purity selenium. The method provided by the invention realizes preparation of high-purity selenium through two-step leaching and wet-process purification of crude selenium, shortens the purification flow of selenium, improves
recovery rate, reduces production cost and mitigates limitation of large-scale production.