Refining process of crude selenium

The invention relates to the technical field of extracting and refining of rare precious metals and especially discloses a refining process of crude selenium. The refining process of crude selenium comprises the following steps: washing the crude selenium raw material by water for 2-3 times, wherein the ratio between the crude selenium raw material and the water is 1:1; adding 3-8m sodium sulfite solution into per ton of the filtered filter residue, wherein the concentration of the sodium sulfite solution is 150-300g/L; heating the solution to 95-100 DEG C and reacting for 2-3 hours; then adding ammonium sulfide into the solution until no sediment emerges; filtering the solution and removing the filter residue; cooling the filtrate at normal temperature for 48 hour, so that the refined selenium is separated from the sodium sulfite solution; adding 15-20Kg of washed filter residue into per cubic meter of the solution after the separation out of the refined selenium, so that circulating leaching is continued; washing the separated refined selenium until the pH of the eluate is 7.0-7.5; drying the refined selenium and casting the refined selenium into selenium ingot whose grade is 99.99%; and adding concentrated sulfuric acid into the sodium sulfite solution after 5-7 times of recycling use in the technological process to perform acid hydrolysis, so that the sodium sulfite solution can be recycled after acid hydrolysis and cyclically used. The refining process of crude selenium is simple in technical process, small in raw material consumption, low in production cost, friendly to the environment, high in raw material applicability and very good in economic and social benefits.