3. Chemical Process Industries

In 2018, the global production of sulfuric acid was 270 million ton (in 1997, it was 156 million ton), with India’s share of 6%. Currently, there are more than 65 sulfuric acid plants spread across India. The major raw materials used in the manufacture of sulfuric acid include elemental sulfur, hydrogen sulfide, pyrites, etc. Nearly all factories in India rely heavily on elemental sulfur as the major source of raw material.

There have been evolutions in the methods for the production of sulfuric acid, however, there are two major processes for its commercial production. There is the lead chamber process (no production after 1960s), and the contact process. Irrespective of the difference in the processes, the manufacture of sulfuric acid is generally based on the following principles:

• The extraction of pure elemental sulfur from its ore.

• The conversion of elemental sulfur into sulfur dioxide in the presence of oxygen.

• The conversion of sulfur dioxide into sulfur trioxide.

• The conversion of sulfur trioxide into sulfuric acid.