Pyro smelting of gold, do you know how to do it?

People often ask us about the refining methods of gold. Gold can be refined in a number of ways. The more common methods used in the industry include electrolytic refining, chlorination refining and pyro-oxidative refining. With the increase in the types of gold-containing waste, many manufacturers have also used chemical refining methods in recent years. In today's article, we will discuss one of the refining methods of gold, fire oxidation.
 
The basic process of the pyro-oxidative refining method is as follows. First, the gold-containing waste and the flux are mixed together, and then placed in the alchemy furnace. After the furnace temperature rises to 1200 degrees, the oxidant is added for smelting. After this process, gold crude material with higher purity can be obtained.
 
Friends often ask me what fluxes are used to mix waste. It just happened to be recorded here today that the fluxes used in the fire oxidation refining method can be basically divided into two types. One is the oxidizing flux. We usually use saltpeter and manganese dioxide. Base metals such as zinc, iron, lead, copper, etc. oxidize to form oxides. There is also a slag-making flux. Commonly used slag-forming fluxes are quartz, sodium carbonate and borax, etc. Its function, as the name suggests, is to react with the oxides generated by the oxidation of the base metals in the waste to become slag.
 
The principle of fire oxidation extraction method:
Gold's chemical properties are very stable, and it is also very resistant to oxidation. While other base metals are oxidized by oxygen at high temperatures. This method is mainly to oxidize and remove impurities in gold-containing waste, such as zinc, iron, lead, copper, tin and so on. One thing to note is that if the waste contains copper, it will be more difficult to oxidize with a general oxidant. At this time, a strong oxidant is needed for oxidation, such as sodium nitrate. If the waste contains silver, there is no way to oxidize it, and it can only be refined into a gold-silver alloy first, and then the silver needs to be separated by other methods.