Hydrated Limes
What is Hydrated Limes?
Calcium hydroxide is an inorganic compound with the formula Ca(OH)2. It is a colourless
crystal or white powder. It is also known as hydrated lime or slaked lime. It has a
boiling point of more than 1000oC and dissolves sparingly in water to give a highly
alkaline solution of pH 12 to 13.
Specifications
| IUPAC Name | Calcium Dihydroxide |
|---|---|
| CAS Number | 1305-62-0 |
| HS Code | 28259040 |
| Formula | Ca(OH)2 |
| Appearance | White Powder |
| Common Names | Slaked Lime, Hydrated Lime, Calcium(II) Hydroxide |
| Packaging | 25 kg PP Bag |
Applications
Paper Industry
Hydrated lime is used to recover sodium hydroxide for reuse in the Kraft process of paper
manufacturing. After converting wood into wood pulp, spent liquor is obtained. The spent
liquor undergoes recovery process to recover sodium sulphide and sodium carbonate solution,
which is diluted and treated with hydrated lime. The sodium carbonate is causticised into
sodium hydroxide for use. It is sometimes used to produce calcium hypochlorite used to bleach
paper. It also acts as a coagulant aid to clarify plant process water. It is used to make
precipitated calcium carbonate as filler in papers by bubbling carbon dioxide through lime.
Water Treatment Industry
Hydrated lime is used as a flocculant to treat sewage water which causes the waste materials
in the water to form colloids that can then be removed. The pH of water can also be increased
by using hydrated lime which prevent corrosion of water pipes due to acidic water.
Other Applications
Hydrated lime is used to treat animal hides and stabilise roads. It can also be used to
remove acidic gases by injecting it into the flue gas. It is used in the steel industry as a
flux, in gold mining and also in fertilizer industry.