How to choose a suitable lime kiln for lime production in steel plants?
The steel industry is one of the main consumer areas of lime, mainly used in key processes such as sintering, steelmaking desulfurization, and converter steelmaking. Due to the strict requirements for lime activity, purity, particle size and other indicators in steel production, it is crucial to choose a suitable lime kiln. At present, the commonly used lime kilns in steel plants mainly include vertical lime kilns (shaft kilns) and rotary kilns. Among them, vertical kilns have become the first choice for many steel enterprises due to their advantages of low investment, low energy consumption, and simple operation.
1. Quality requirements for lime in steel plants
High activity (≥ 350mL, some require ≥ 400mL)
Low sulfur and low phosphorus (to avoid affecting the purity of molten steel)
Uniform particle size (5-40mm, meeting different process requirements)
Good thermal stability (reducing pulverization rate during steelmaking process)
If the quality of lime does not meet the standard, it may lead to low desulfurization efficiency, increased steelmaking slag volume, and shortened furnace lining life. Therefore, it is necessary to choose a lime kiln with uniform calcination and precise temperature control.
2. Types of lime kilns suitable for steel plants
(1) Lime vertical kiln (energy-saving and environmentally friendly)
Lime vertical kiln (shaft kiln) is a widely used kiln type in steel plants, especially suitable for small and medium-sized steel enterprises. Its advantages include:
Strong fuel adaptability: It can use various fuels such as coke, anthracite, and gas to meet the energy conditions of different regions.
High thermal efficiency: Adopting countercurrent calcination technology, the thermal utilization rate can reach over 80%, and the energy consumption per ton of lime is 15% -20% lower than traditional kiln types.
Uniform calcination: Optimized fabric system+intelligent air distribution to ensure stable lime activity at 350-400mL.
Environmental compliance: equipped with desulfurization and dust removal devices to meet ultra-low emission requirements.
Applicable scenarios:
Small and medium-sized steel plants with an annual output of 50000 to 200000 tons
Enterprises that are sensitive to investment costs
(2) Rotary kiln (specialized for high activity lime)
Rotary kilns are suitable for large steel enterprises with extremely high requirements for lime activity (≥ 400mL), such as high-end special steel production. Its characteristics include:
More complete calcination and higher lime activity, suitable for high-end steelmaking needs.
High degree of automation, suitable for large-scale continuous production.
But with high investment and energy consumption, it is generally suitable for large steel mills with an annual output of over 300000 tons.
Applicable scenarios:
Large scale steel joint venture
Enterprises producing high-purity special steel
How to optimize lime kiln production to meet the needs of steel plants?
Precise temperature control: Adopting an intelligent combustion system to ensure stable temperature of the calcination zone at 1050-1150 ℃.
Raw material screening: Use high calcium and low silicon limestone (CaO ≥ 52%) to reduce the influence of impurities on the molten steel.
Environmental upgrade: Install SCR denitrification and bag dust removal to meet ultra-low emission standards.
For steel plants, lime vertical kilns (shaft kilns) have become the ideal choice for most enterprises due to their advantages of low investment, low energy consumption, and high activity lime; Rotary kilns are more suitable for large steel mills that have extremely high requirements for lime quality. Enterprises can choose suitable kiln types based on their own scale, fuel supply, and environmental requirements to ensure stable supply of high-quality lime and help reduce costs and increase efficiency in steel production.
