Question

Compounds of nitrogen, phosphorus and sulphur such as ammonia, phosphoric acid and sulphuric acid are used in fertiliser industry.

Describe contact process for the manufacture of sulphuric acid?

Answer 1

The contact process is the current method of producing sulfuric acid in the high concentrations needed for industrial processes. Vanadium pentaoxide is used to be the catalyst for this reaction.

The process can be divided into five stages:

Combining of sulfur and $O_2$ to form sulfur dioxide.

Purifying the sulfur dioxide in a purification unit

• Adding an excess of $O_2$ to sulfur dioxide in the presence of the catalyst vanadium pentoxide, under temperatures of 450 °C and pressure of 1-2 atm
• The sulfur trioxide formed is added to sulfuric acid which gives rise to oleum (disulfuric acid)
• The oleum is then added to water to form sulfuric acid which is very concentrated