Sulphuric acid is manufactured by the contact process. Which step is not involved in the process?

How is sulphuric acid manufacture by contact process ?

Sulphuric acid is manufactured by Contact process : Give all the main reactions of this process.

Sulphuric acid is manufactured by Contact process : Why H_2SO_4 is not obtained by directly reacting SO_3 with water ?

Which step is not involved in hydrometallurgical process?

Which step is not involved in hydrometallurgical process?

Which step is not involved in hydrometallurgical process ?