Solvay Process
Solvay process
Raw materials
- NaCl, salt
- CaCO3, limestone
- H2O, water
- NH3, ammonia is recycled
Useful products
- sodium carbonate. Na2CO3 – reason for process
Waste products
- CaCl2, calcium chloride
- Heat
Chemical properties of the main product (Na2CO3)
- Forms several hydrates which are used in many ways
- It is moderately alkaline, so it can neutralise strong acids
- Can precipitate many metal ions from solution as carbonates
Uses of sodium carbonate
- Glass manufacturing (most common use) o Used as a flux gas which lowers the melting point of the silicon dioxide and the calcium carbonate
- Soap and detergents o Used as a base in soap and detergents. It is also used to make sodium phosphate and sodium silicate that act as builders
- Softening hard water o The carbonate ions precipitate calcium and magnesium ions, this is why it is used in some soaps and detergents
- Baking soda production o Sodium hydrogen carbonate or bicarbonate of soda is produced as a part of the process. o The sodium carbonate is dissolved to make a concentrated solution and a stream of CO2 is passed through it so that sodium hydrogen carbonate crystals form from the solution o Sodium hydrogen carbonate = baking soda, used as rising agent in cooking
Stages of this product + Equations
1. Production and purification of brine o Brine is put in shallow ponds where the water is evaporated leaving salt o Calcium and magnesium are removed from the salt collected, calcium is precipitated by sodium carbonate and the magnesium is precipitated by sodium hydroxide o Ca2+(aq) + CO32–(aq) CaCO3(s) o Mg2+(aq) + 2OH–(aq) Mg(OH)2(s) o A flocculant is added and the precipitate removed, the brine is then concentrated so that it is saturated.
2. Hydrogen carbonate formation
i. Calcium carbonate from limestone is heated to form carbon dioxide and calcium monoxide, coke is also in the kiln. Calcium
Raw materials
- NaCl, salt
- CaCO3, limestone
- H2O, water
- NH3, ammonia is recycled
Useful products
- sodium carbonate. Na2CO3 – reason for process
Waste products
- CaCl2, calcium chloride
- Heat
Chemical properties of the main product (Na2CO3)
- Forms several hydrates which are used in many ways
- It is moderately alkaline, so it can neutralise strong acids
- Can precipitate many metal ions from solution as carbonates
Uses of sodium carbonate
- Glass manufacturing (most common use) o Used as a flux gas which lowers the melting point of the silicon dioxide and the calcium carbonate
- Soap and detergents o Used as a base in soap and detergents. It is also used to make sodium phosphate and sodium silicate that act as builders
- Softening hard water o The carbonate ions precipitate calcium and magnesium ions, this is why it is used in some soaps and detergents
- Baking soda production o Sodium hydrogen carbonate or bicarbonate of soda is produced as a part of the process. o The sodium carbonate is dissolved to make a concentrated solution and a stream of CO2 is passed through it so that sodium hydrogen carbonate crystals form from the solution o Sodium hydrogen carbonate = baking soda, used as rising agent in cooking
Stages of this product + Equations
1. Production and purification of brine o Brine is put in shallow ponds where the water is evaporated leaving salt o Calcium and magnesium are removed from the salt collected, calcium is precipitated by sodium carbonate and the magnesium is precipitated by sodium hydroxide o Ca2+(aq) + CO32–(aq) CaCO3(s) o Mg2+(aq) + 2OH–(aq) Mg(OH)2(s) o A flocculant is added and the precipitate removed, the brine is then concentrated so that it is saturated.
2. Hydrogen carbonate formation
i. Calcium carbonate from limestone is heated to form carbon dioxide and calcium monoxide, coke is also in the kiln. Calcium