Two main types of reactions occur in the smelting process of non-ferrous metals: oxidation of sulfide ore and reduction of oxide ore or oxide material.
The main reactions that occur in the smelting of sulfide ores are:
Where Me represents the metal to be extracted, FeS represents the sulfide or metal melt, and SO2 represents the oxide slag solubles. The oxide MeO in the slag, in fact, acts as a transfer of oxygen from the gas phase. It can be seen that the process of obtaining metal from sulfide ore smelting is an oxidation process from the beginning to the end. When the concentration of oxygen in the melting blast is larger, the partial pressure of oxygen in the furnace is higher, and the diffusion rate of oxygen is faster, and the oxidation rate of sulfide increases.
Oxidized ore or oxide material reduction smelting (including slag smelting) mostly use solid carbon fuel as a heating agent and reducing agent, fuel combustion to provide the reduction reaction and the heat required for the melting of the charge and CO reductant. The main reactions are:
When using oxygen-rich blast, the theoretical maximum temperature of fuel combustion increases with the increase of oxygen content in the blast, the combustion rate is accelerated, the partial pressure of carbon monoxide in the gas phase and the temperature in the furnace increases, thus accelerating the reduction reaction and the melting of the furnace charge.