Blast furnace production generates several byproducts, including slag, blast furnace gas, and dust (also known as gas dust). These byproducts have diverse applications that contribute to both industrial processes and environmental sustainability. Here’s a detailed overview of each byproduct and its uses:
1. Blast Furnace Slag and Its Applications
Blast furnace slag is a versatile byproduct with a variety of uses across different industries:
- Cement Production: Liquid slag can be rapidly cooled with water to form granulated slag, which is a key ingredient in producing high-quality cement.
- Insulation Materials: When liquid slag is blown with high-pressure steam or air, it forms a slag wool, which is commonly used as an excellent heat insulation material.
- Lightweight Concrete: Rapid cooling of liquid slag with pressurized water onto a rotating drum results in expanded slag, also known as “puffed slag.” This material is widely used as an insulating material and as a lightweight aggregate in concrete.
- Road Construction: Slag can also be used to manufacture slag bricks or dry slag blocks, which are suitable for road paving and construction materials.
2. Blast Furnace Gas and Its Applications
Blast furnace gas, a key byproduct of the blast furnace process, typically contains over 20% carbon monoxide, along with small amounts of hydrogen and methane. With a calorific value of 2900-3800 kJ/m³, blast furnace gas is an efficient fuel source. Its applications include:
- Fuel for Heating: It is primarily used to fuel hot blast stoves that support the furnace operation.
- Fuel for Other Industrial Processes: Blast furnace gas is also utilized in coke ovens, heating furnaces, and steam boilers for energy generation and heating purposes.
3. Blast Furnace Dust (Gas Dust) and Its Uses
Blast furnace dust, or gas dust, consists of fine particles of furnace materials carried away by the rising blast furnace gases. These dust particles typically contain 30% to 50% iron and 10% to 20% carbon. After being collected by gas dust recovery systems, blast furnace dust can be repurposed as a valuable material in the following ways:
- Sintering Material: The dust can be recycled as a raw material in the production of sintered ore, which is essential for the ironmaking process.
Conclusion
The byproducts of blast furnace production—slag, blast furnace gas, and dust—serve as valuable resources for various applications. Their reuse not only enhances industrial efficiency but also contributes to reducing environmental impact, promoting sustainability in the steel and iron industries. By making the most of these byproducts, industries can optimize their operations while minimizing waste.
*(Excerpt adapted from “高炉生产知识问答” (第2版), 冶金工业出版社, 2005, ISBN 7-5024-3380-5)
