Refining process of crude selenium

Abstract

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<3> 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.

Description

technical field [0001] The invention relates to the technical field of extraction and refining of rare and precious metals, in particular to a process for refining crude selenium or extracting and refining selenium-containing materials. Background technique [0002] The crude selenium produced during the sulphating and roasting process of copper anode slime generally contains more than 90% selenium and contains impurities such as copper, lead, and silicon dioxide. The current purification methods usually include rectification and chemical methods. [0003] The basic principle of the rectification method is to use the different volatility of selenium and impurities to control a certain rectification temperature to separate selenium from impurities. The process is to put crude selenium in a rectification tank and heat it to a temperature of 700-750°C for rectification. After the selenium volatilizes, it enters the condensation tank and condenses into solid crude selenium, so a...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problems that the existing crude selenium refining process is complex, consumes a lot of chemical reagents, high cost, and produces a large amount of toxic and harmful gases at the same time, and provides a simple process that can realize the separation of crude selenium and metal impurities. Refining process, the present invention can obtain selenium ingots with a purity of 99.99%, low cost, energy saving, emission reduction, environmental protection, and good economic and social benefits

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