The influence of lime kiln calcination process on lime activity
The activity of lime is a key indicator for measuring its reaction rate with water, which directly affects its application effect in fields such as steel smelting and environmental protection. The calcination process of lime kiln is the core factor affecting the activity of lime, mainly involving calcination temperature, time, raw material quality, and kiln type selection.
The calcination temperature is a key factor. Research has shown that the optimal calcination temperature is 900-1100 ℃, at which point limestone decomposes fully, resulting in a loose CaO crystal structure, a large specific surface area, and high activity. Low temperature can lead to incomplete decomposition and reduced activity of residual CaCO3; If the temperature is too high, CaO crystals will sinter and become denser, resulting in a decrease in specific surface area and activity.
The calcination time needs to be precisely controlled. The complete decomposition of limestone takes a certain amount of time, but if it is too long, it can lead to excessive growth of CaO crystals and a decrease in activity. In addition, the quality of raw materials cannot be ignored. High purity limestone (CaCO3 ≥ 95%) has high activity after calcination, while low-grade limestone is prone to form low melting point compounds, leading to CaO sintering and a decrease in activity. The selection of kiln type is equally important. Rotary kilns have uniform calcination and high activity, while vertical kilns have moderate activity but lower energy consumption.
