How does a lime kiln work
Lime, an important building material, began its journey of birth with a passionate transformation in a lime kiln. How does a lime kiln work? The core principle is to convert limestone, mainly composed of calcium carbonate (CaCO3), into quicklime (CaO) through high-temperature calcination.
The entire process can be clearly divided into three stages:
Firstly, the loading. The workers will layer and load the selected block shaped limestone and an appropriate amount of fuel (such as coal and coke) into the kiln through the feeding port on the top of the kiln. Modern large-scale kilns use automated continuous feeding to ensure stable production.
Next is the core calcination stage. The blower at the bottom of the kiln sends air to assist combustion and ignite the fuel. As the temperature steadily rises to 900 ℃ to 1200 ℃, a wonderful chemical reaction occurs inside the kiln - calcium carbonate decomposes at high temperatures, releasing carbon dioxide gas and leaving behind solid calcium oxide, namely quicklime. This endothermic reaction needs to last for several hours and requires precise temperature control. If it is too high, it will cause the product to agglomerate, while if it is too low, the reaction will be incomplete.
Finally, there is cooling and discharging. After calcination is completed, stop heating and allow the material to cool naturally in the kiln or cool down through a controlled cooling system. After the temperature drops to a safe range, the discharge port at the bottom of the kiln can be opened to remove the white or gray white block shaped quicklime.
From then on, the hard limestone completed its magnificent transformation under the quenching of flames, and was widely used as quicklime in many fields such as construction, metallurgy, environmental protection, and chemical engineering, continuing to write its chapter of serving human civilization.
