Application of Sodium Sulfite in Rare and Precious Metal Metallurgy

Sodium sulfite is a colorless crystalline substance that is insoluble in alcohols, insoluble in liquid chlorine and ammonia, and its aqueous solution is alkaline. In general, in the industrial preparation of anhydrous sodium sulfite, pure alkali and sulfur are often used as raw materials, which are obtained through a series of chemical reactions. It is worth mentioning that this is not the only production method, and sulfur dioxide or waste gas containing sulfur dioxide can also be used as raw materials. In addition, sodium sulfite can reduce corresponding substances in specific environments, providing assistance for smelting metals such as gold and silver. Its application scope in refining rare and precious metals is gradually expanding.

1、 Application in the concentration of rare and precious metals
In the actual work process, to separate and extract sulfur elements from sulfur-containing precious metal materials, physical and chemical methods can be used for specific operations. Specifically, for physical methods, flotation method, vacuum distillation method, high-pressure cleaning method, etc. can be adopted, while inorganic solvent method and organic solvent method belong to the category of chemical methods. However, it should be noted that when using inorganic and organic solvents for specific operations, suitable solvents need to be selected to meet the actual work needs. In general, the inorganic solvents used include sodium sulfide, sodium hydroxide, lime milk, etc; Xylene, kerosene, and carbon tetrachloride are organic solvents. If the treatment method and chemical solvent selection are not appropriate, it will reduce the extraction rate of sulfur elements and cause significant economic losses.
As early as the last century, there were metal smelters in China that carried out the extraction of desulfurization and silicon, mainly through the use of sodium hydroxide solution and a series of operations to achieve the goal. However, this method has to some extent improved the dispersion rate of precious metals, which is not conducive to subsequent work and has also caused huge economic losses to the smelter. Therefore, in order to effectively solve this problem, relevant technical personnel have developed the sodium sulfite desulfurization method. The main mechanism of this method is to place sodium sulfite and sulfur under appropriate conditions, and through a series of reactions to produce sodium thiosulfate. This can achieve the goal of extracting sulfur from copper nickel alloy chlorinated slag. It is worth mentioning that in this process, some links can be recycled, and for the washing water part, it can be recycled in the desulfurization process. The liquid generated in the desulfurization process can be evaporated and crystallized to produce sodium sulfate with sulfur. This not only improves work efficiency to a certain extent, but also effectively avoids unnecessary waste of resources and improves the actual recovery rate.
Related researchers have conducted in-depth experimental exploration on this method, starting from desulfurization conditions, influencing factors, and other aspects, confirming that using this method can significantly improve desulfurization efficiency and is worth promoting on a large scale. Moreover, using this method can reduce the concentration of precious metals in the desulfurization solution to a certain extent, which is conducive to ensuring the actual recovery rate and desulfurization rate of precious metals, effectively avoiding the problem of precious metal dispersion, and has profound value significance.
2、 Application in Separation of Rare and Precious Metals
1. Separation of Silver in Copper Anode Mud
In fact, using traditional methods to separate silver cannot meet the current practical needs. Not only can the separation rate of rare and precious metals not be guaranteed, but it also causes a large amount of industrial pollution,