Lime is one of the most widely used and cheapest alkalizing agents employed worldwide. Limestone is a naturally occurring and abundant sedimentary rock consisting of high levels of calcium carbonate (CaCO3) in the form of the mineral calcite. Limestone is also a very important industrial mineral. Its chemical properties make it a valuable mineral for a wide range of industrial/manufacturing uses. Limestone is also one of the vital raw materials used in production of iron and steel.
The main uses of limestone in iron and steel industry are as a fluxing material, and other usage which consists of desulfurizing agent, coating of molds of pig casting machine, neutralizing of acidic water, water treatment, waste water(effluent) treatment, flue gas treatment, and sludge and sewage treatment. It is also a component of synthetic slag. Limestone is normally used in three forms. These are raw limestone which is also the natural form of limestone, calcined limestone or quicklime, or simply lime, and as hydrated lime. When limestone is used as a fluxing material then it is used as either raw limestone or as calcined limestone. Hydrated lime is generally produced from high calcium quicklime and contains 72 % to 74 % calcium oxide with 23 % to 24 % chemically combined water.
It is often applied in chemical processes in a slaked or calcium hydroxide or slurry form. The term “calcinations of limestone” refers to the process of thermal decomposition into quick lime and carbon dioxide. It is frequently referred to as “calcinations.” Decomposition of limestone is characterized by very simple chemical reactions.
| Element | Unit | Value | SCHEME |
|---|---|---|---|
| SiO2 | % | 0.88 | WR-01 |
| Al2O3 | % | 0.39 | WR-01 |
| BaO | % | <0.01 | WR-01 |
| CaO | % | 92.16 | WR-01 |
| Fe2O3 | % | 0.31 | WR-01 |
| K2O | % | 0.05 | WR-01 |
| MgO | % | 2.81 | WR-01 |
| MnO | % | 0.01 | WR-01 |
| Na2O | % | 0.13 | WR-01 |
| P2O5 | % | 0.02 | WR-01 |
| SO3 | % | <0.05 | WR-01 |
| TiO2 | % | 0.02 | WR-01 |
| Cr2O3 | % | <0.01 | WR-01 |
| Cu | % | 0.22 | WR-01 |
| Pb | % | <0.01 | WR-01 |
| Zn | % | <0.01 | WR-01 |
| LOI | % | 3 | WR-01 |