Chemical equation for the industrial process of ammonium sulfate:

In the first step, sulfur dioxide is prepared by calcining pyrite (mainly ferrous sulfide) at high temperature (reaction conditions are omitted, the same below):

4FeS2+1102=2Fe2O3+8SO2.

In the second step, under the action of high temperature and catalyst, oxygen is injected into sulfur dioxide to produce sulfuric anhydride (sulfur trioxide, SO3):

2SO2+O2<=> 2SO3 (reversible reaction).

In the third step, sulfuric acid was prepared by absorbing sulfuric anhydride with concentrated sulfuric acid (more than 98%).

SO3+H2O=H2SO4.

The above is the industrial preparation of concentrated sulfuric acid, diluted to dilute sulfuric acid.

In the fourth step, ammonia is prepared from nitrogen and hydrogen at high temperature and pressure.

N2 + 3H2 <==> 2NH3. This is also a reversible reaction.

Finally, ammonia gas is injected into dilute sulfuric acid solution to prepare ammonium sulfate solution.

H2SO4+2NH3=(NH4)2SO4

Ammonium sulfate was obtained by evaporation, crystallization and drying of ammonium sulfate solution.