The essential condition for using the rotary kiln to calcine the active lime is on the selection and use of the raw materials. To determine the calcinations equipment and the method by the property of the limestone is an important guarantee for obtaining the qualified products. 

The raw material for producing active lime is mainly carbonate rocks with the main element of CaCO3, which is referred to the limestone by us.

There are many kinds of limestone, commonly are: granular crystalline limestone, dense limestone, porous limestone, earthy limestone, marly limestone, chalk, dolomite, shell, calcareous gravel and so on.

In the main chemical compositions of active lime, the content of CaO (CAO) is required to above of 90% while the lower and lower content of S (sulfur), P (Phosphorus) will be better. Therefore, there is a specific requirement for the quality of limestone which is used for the production of active lime.

In the selection of lime raw material, the limestone with the content of CaO calcium oxide more than 54%, low content of silicon dioxide (SiO2), S (sulfur), P (phosphorus) and MgO (magnesium oxide), hematite (Fe2O3), Al2O3 (aluminum oxide) is usually chose from various types of limestone. Because it is a primary guarantee to gain the physical and chemical properties of the active lime product.

In order to meet the needs of the lime properties, dense limestone (ordinary limestone) is usually chose as the main raw material for production of metallurgical lime or active lime for a long time. The dense limestone has the features such as the fine grain structure and the low hardness of the material texture, which makes it the ideal raw material of the active lime calcinations.