The steps that make up the Contact Process are:Heating sulphur or sulphide ores produces sulphur dioxide. For example, iron pyrites have been exposed to an excess of air.Then, using V2O5 as a catalyst, sulphur dioxide is oxidised with ambient oxygen to produce sulphur trioxide.The sulphur trioxide is then broken down into 98 percent sulfuric acid to produce oleum. Pyrosulfuric acid is another name for oleum. The oleum is then diluted with water to achieve the necessary sulfuric acid concentration.