Active lime rotary kiln

Introduction

Active lime is widely used in the steel, aluminum oxide, magnesium metal, calcium carbide and power plant desulfurization and papermaking industries. Active lime is an important auxiliary raw material for steelmaking. Using active lime can improve the quality of molten steel, increase production, and reduce steelmaking consumption and costs, stable operation and other characteristics. Practice has proved that all enterprises that use activated lime for steelmaking have achieved significant economic benefits. In recent years, China's steelmaking lime production has increased by 40%, but high-grade lime with an activity of more than 300ml accounts for the total steelmaking lime from 27% increased to 29.5%, an increase of only 2.5%. Jiangsu Pengfei Group Active Lime Rotary Kiln, on the basis of introducing and digesting advanced foreign technology, has formed a series of products with a daily output of 1,000 tons, which are exported to Vietnam, Russia, Central Africa and so on.
 

Technical parameters

1. Steelmaking practice has proved that activated lime can improve the desulfurization and dephosphorization efficiency by 80%, and shorten the smelting time. The reaction with acid in molten steel can be completed within 3-5 minutes, and the reaction time of shaft kiln lime should be at least 6-10 minutes. In addition, the furnace range is increased by more than 40%. The consumption of the charge is also reduced by 5-8Kg / t steel. Based on 10 million tons, the annual saving is about 15 million, and the production efficiency is significant.
2. The efficiency of desulfurization and dephosphorization of activated lime is significantly improved. The average desulfurization rate of steelmaking is 34.5%, especially for high-sulfur molten iron (S≥0.06%). The consumption of desulfurization agent can be reduced by about 45%.
3. Activated lime is used for steelmaking compared to non-activated lime, steel consumption can be reduced by 5-15Kg / t steel, and molten steel splashing, sticky oxygen gun, sticking furnace mouth and sticking flue can be reduced. 4. The unit consumption of lime decreases: the unit consumption of activated lime for steelmaking can be reduced by 20 ~ 25Kg / t steel compared to non-activated lime, while the use of non-activated lime, the consumption per ton of steel is not less than 65 ~ 70Kg, and the active lime is 40 ~ 41.5Kg / t steel.
5. Activated lime produces slag quickly during steelmaking, with significant desulfurization and dephosphorization capabilities, and production efficiency can be increased by 5% ~ 10%.

Advantages of calcining active lime in rotary kiln

1. The high output of rotary kiln is very suitable for large-scale activated lime production line. Lime rotary kilns with a daily output of 2200 tons have been put into production in the world. Many lime rotary kilns with a daily output of 150-300 tons have been built at home and abroad. They are in good operating conditions and are also suitable for the application of small and medium-sized lime enterprises.
2. The rotary kiln is open calcination, the structure of the kiln body is simple, the gas is smooth, the sulfur-containing flue gas can be discharged in time, the sulfur in the fuel is not easy to adhere, so the product has low sulfur content and meets the steelmaking requirements. At the same time, the materials roll forward evenly in the kiln, the heat is uniform, the product quality is stable, the raw and over-burning rate is very low, and high-activity lime for steelmaking can be calcined. Under the same conditions, the activity of lime produced by rotary kiln is higher than that of gas-fired kiln, the average height is more than 30ml, and the activity is generally 340-380ml, even as high as 400ml.
3. The rotary kiln can directly calcine 10-50mm fine-grained limestone. Generally, the mine product 0-30mm fine-grained limestone accounts for about 30-40% of the total output. This type of limestone cannot be used for other kiln types. And with the "concentration" of steel raw materials, sintering gradually replaces limestone with quicklime, and fine-grained limestone cannot be comprehensively utilized. The construction of a rotary kiln production line can not only make full use of high-quality limestone mine resources, but also meet the sustainable development guidelines of the lime industry.
4. The vertical preheater at the kiln tail can make full use of the high temperature flue gas generated by the calcination in the rotary kiln to preheat the limestone from normal temperature to the initial decomposition state. This can not only greatly increase the output of the rotary kiln, but also fully reduce the heat consumption per unit of product.
5. The vertical cooler at the kiln head can not only quench the high temperature lime, improve product activity, but also facilitate transportation and storage. At the same time, higher temperature secondary air into the kiln can be obtained. It can effectively increase the firing temperature in the kiln and reduce fuel consumption.
6. The temperature of the flue gas discharged through the vertical preheater at the kiln tail is low, between 280-350 ℃, and the dust content is low, about 20g / Nm3, which makes the subsequent flue gas treatment configuration simple and effective, and meets the requirements of environmental protection.
7. Stable lime quality of rotary kiln is its biggest advantage. The active lime production equipment is suitable for the comprehensive development of mine resources and has very good development prospects.