Sources of sulfur
The element of sulfur is found in underground sulfur beds in the USA, Mexico, and Poland.
Natural gas and petroleum contain sulfur compounds. These have to be removed and are an important source of sulfur.
Metal sulfides occur as ores, for example zinc blende.
Uses of sulfur dioxide
The major uses of sulfur dioxide is in the contact process for the manufacture of sulfuric acid. It is also used in bleach in the manufacture of paper from wood pulp, and as a preservative for food by killing bacteria.
Contact process
The process of making sulfuric acid is called the contact process.
Sulfur is burnt in air to form sulfur dioxide
This is mixed with oxygen to form sulfur trioxide.
Note: The forward reaction is exothermic.
The reaction between sulfur trioxide and water produces sulfuric acid. The reaction would be written as follows:
Unfortunately, this reaction is too violet to carry out directly.
Instead of adding sulfur trioxide directly to water, sulfur trioxide is dissolved in concentrated sulfuric acid first to produce oleum.
Water is then added to oleum to form sulfuric acid.
The conditions required for the contact process is as follows:
- 400-450 degrees Celsius
- 1-2 atmospheres
- Vanadium (V) Oxide catalyst
Properties and uses of sulfuric acid
Dilute sulfuric acid
Properties
- Typical strong acid
Uses
- Making fertilizers
- Treat metals and remove oxidation before painting
- Laboratory reagent
- Acid in car batteries
- Dye, fiber, and paint manufacture
Concentrated sulfuric acid
Properties
- Strong acid
- Powerful dehydrating agent
- Powerful oxidizing agent
Uses
- Making detergents
- Catalyst
- Dehydrating agent