Desulfurization reaction of reduced iron powder

The desulfurization reaction

In the secondary reduction process, the H2 in the reduction atmosphere and the sulfur contained in the sponge iron powder (exists in the form of FeS) react as follows: 

FeS+H2=Fe+H2S

Thus, the sulfur content of iron powder can be greatly reduced. For example, the sulfur content of sponge iron powder can be reduced to less than 0.02% in the secondary reduction of hydrogen by ammonia decomposition.The sulfur content of sponge iron can be reduced to 0.015 by secondary reduction in wet converted natural gas.