There are two types of pyrometallurgical fluxes, one is an oxidizing flux and the other is a slag-forming flux. Commonly used oxidizing solvents are saltpeter and manganese dioxide, which function as bismuth metal (copper, lead, zinc, iron, etc.) in the charge and sulphur oxidation into oxide for slagging. Commonly used slag fluxes are borax, quartz, carbonic acid. Na and so on. Its role is to react with the oxides of base metals to form slag.