Calcium carbonate as the main component of natural rocks, such as limestone, chalk, dolomite limestone, can be used to produce lime.The main component of the natural calcium carbonate rock, calcined at appropriate temperature, the removal of the decomposition of carbon dioxide, the resulting calcium oxide (CaO) as the main component of the product that is lime, also known as quicklime.In the actual production, in order to speed up the decomposition, calcination temperature often increased to 1000 ~ 1100 C. Due to the large size of limestone raw material or the uneven distribution of temperature in the kiln, lime and lime are often contained in lime. The calcium carbonate in the lime is not completely decomposed, and the adhesive force is not used. The burnt lime structure is dense, the surface is often covered with a layer of molten material, and the curing is slow. Because the production of raw materials often contain magnesium carbonate (MgCO3), because this lime also contains minor components of Magnesium Oxide (MgO), according to the number of Magnesium Oxide content, lime into calcium lime (MgO = 5%) and magnesia lime (MgO>5%).Quicklime is white or gray block, in order to facilitate the use of bulk lime often need to be processed into quicklime powder, lime powder or lime cream. Lime powder is composed of massive pulverized quicklime obtained by fine powder, the main ingredient is CaO; lime powder is lump lime with water curing powder obtained, also called slaked lime, its main component is Ca (OH) 2; lime paste is lump lime with more water (about 3 - 4 times the volume of lime) obtained by curing paste. Also called lime slurry. Its main component is Ca (OH) 2.
The original lime production process is the limestone and fuel (wood) layered laying, firing a week. Modern machinery, semi mechanized shaft kiln and rotary kiln, boiling furnace and other equipment for production. The calcining time is shortened correspondingly, and the production of lime in rotary kiln is only 2 to 4 hours, and the production efficiency can be increased by more than 5 times. In recent years, there have been cross flow, double slope type and oil burning shaft kiln and preheater with a short rotary kiln and other energy-saving effect of significant technology and equipment, fuel is also expanded to coal, coke, heavy oil or liquefied petroleum gas, etc..
Air hardening inorganic cementitious material with calcium oxide as main component. Lime is a kind of raw material with high content of calcium carbonate, such as limestone, dolomite, chalk, shell and so on, which is calcined from 900 to 1100 DEG C. Lime is the earliest application of cementitious materials. The ancient Greeks were used in architecture in the eighth Century B. C., and China began to use lime in the middle of the seventh Century b.c.. Lime is still a wide range of building materials. Lime has quicklime and slaked lime (that is, slaked lime), according to its Magnesium Oxide content (5%), can be divided into calcium lime and lime. Because of its wide distribution of raw materials, simple production process and low cost, it is widely used in civil engineering.
