Continuous Desulfurization System for Blast Furnace Iron
With the rapid development of Chinas steel industry and the rising demand for steel consumption in the world, the comprehensive utilization of resources, environmental protection of ultra-low emission and energy saving and consumption reduction have become the main directions of steel production and emission reduction. Continuous desulfurization (CDS) for blast furnace iron is an advanced technology for the smelting and reduction of iron ore. It combines the process of iron pre-reduction, iron smelting and secondary desulfurization with smelting reduction slag. This technology is not only energy efficient, but also takes into account the requirements of resources, environment and efficiency. It has become an important measure to seize the initiative in international competition and meet the needs of sustainable development.
Continuous desulfurization process of blast furnace iron consists of two parts: iron pre-reduction and secondary desulfurization. In the part of iron pre-reduction, ore is first smelted in a blast furnace and then pre-reduced in a pre-reduction plant. The pre-reduction of the ore is mainly composed of the reducer (carbon gas), the oxidant (oxygen) and the coating material (flux). The reducer can be anthracite, natural gas or liquid coke; the oxidant is usually air or oxygen-enriched air. The pre-reduced ore is generated at high temperature and becomes ignition, which is suitable for the efficient smelting in the blast furnace.
In the second stage of secondary desulfurization, the hot metal from the blast furnace contains relatively high sulfur content. After entering the continuous desulfurization device, the hot metal first passes through the heating furnace and desulfurization furnace under the condition of reducing atmosphere and reducing agent, and then to the common runner. The molten iron is cooled and solidified, then desulfurized and cleaned. The reductive agent used in the device includes carbon, coke breeze, coke and coal mesh. The carbon monoxide generated by the oxidized reducer can effectively react with sulfur, thus desulfurizing the molten iron. At the same time, the slag generated during the desulfurization process can effectively adsorb the iron oxide and other impurities, which can be tapped after desulfurization.
The use of continuous desulfurization technology of blast furnace iron is more efficient and economical than intermediate desulfurization. Its desulfurization rate is as high as 89.6%, and the desulfurized iron can meet the requirements of ultra-low emission. In addition, the CDS process can reduce the consumption of sintering ore and reduce the reduction temperature of iron ore, which can save a lot of energy for the smelting process. At the same time, the slag produced by secondary desulfurization has a certain activity and can be used for the production of cement and slag sand.
In conclusion, the use of continuous desulfurization technology for blast furnace iron has great advantages and has become an important measure for the safe, efficient and sustainable development of Chinas steel industry. In the future, this technology will receive more and more attention and play an important role in the future green development of Chinas steel industry.
