What are the characteristics of commonly

1. CaO-based calcium desulfurizer CaO-based desulfurizers used by many enterprises in China in the early stage are mainly mixed desulfurizers with lime w(CaO)=90% and fluorite w (CaF2) = 5% ~ 10%. Adding fluorite and Al to active lime can significantly improve the desulfurization effect. At present, the desulfurizer used in KR technology provided by Japan is about 5% fluorite, 10% Al and the rest is active lime. Lime is an easily available raw material, which is abundant and cheap. However, lime-based desulfurizer has a large amount of usage, a large amount of slag and a long treatment period, which also shows high desulfurization efficiency when the temperature of molten iron is high. CaC2-based desulfurizer has been used in KR desulfurization of No.2 Steelmaking Plant of WISCO for several years. Second, Mg and mg-based desulfurizer The data show that the equilibrium constant of the reaction between [Mg] and [S] is not as high as that of calcium carbide and lime desulfurization at 1350℃. However, magnesium and sulfur have very high affinity, the reaction zone has very good kinetic conditions, and the reaction is rapid and strong. The MgS produced by the reaction of magnesium and sulfur in molten iron has high melting point (2000℃), low density (2.82g/cm3) and easy slagging. However, magnesium has high activity and must be passivated as a desulfurizer. Magnesium can not only be desulfurized alone, but also can be desulfurized with magnesium-based composite desulfurizer. The magnesium powder used in the magnesium-based desulfurizer also needs passivation treatment. The magnesium powder is made by milling cutter or spraying method, with a diameter of 0.15 ~ 1.2 mm, w(Mg)=90%, and the rest is passivation coating. The fluidized calcium oxide powder is mixed with magnesium powder to ensure smooth transportation of concentrated phase. The desulfurization reaction mechanism of magnesium and lime composite desulfurizer is as follows: due to the addition of lime, calcium oxide powder is wrapped and dispersed to make it evenly distributed in molten iron, which not only expands its reaction area, but also slows down the gasification speed of magnesium and improves the utilization rate of magnesium; CaO can be used as the core of the composite to polymerize fine MGS (1 ~ 5 μ m), accelerate the floating of inclusions, continuously reduce the concentration of sulfur in the reflection area, improve the desulfurization speed, and help to achieve the requirements of rapid and deep desulfurization; Sulfur forms calcium silicate salts with high thermodynamic stability with CaO, SiO2, etc., which are fixed in slag and are not easy to recover sulfur after slag removal; And about 10% calcium oxide powder takes part in desulfurization reaction. The sulfur in the desulfurization slag is not easy to be dissolved and washed by water, which does not pollute the environment and creates conditions for the convenient treatment or development and utilization of the slag. III. NaCO3 _ 3-based sodium desulfurizer In 1950s, China adopted the method of spraying soda into the taphole of blast furnace for desulfurization. The liquid sodium oxide decomposed by soda is highly corrosive, and the volatilization of sodium oxide pollutes the environment. The slag produced by desulfurization with soda has good fluidity, which makes it difficult to remove slag. The price of soda is also relatively high. Therefore, soda as desulfurizer is very rare. Iv. CaC2-based calcium desulfurizer Calcium carbide (CaC2) has a strong desulfurization ability, and the research shows that the equilibrium constant of calcium carbide powder desulfurization reaction is the highest when the temperature of molten iron is 1350℃. Composite desulfurizers such as calcium carbide, dry coal powder, magnesium or calcium oxide are widely used in industry. For example, CaC2-based desulfurizers have been used in Panzhihua Iron and Steel Company. However, calcium carbide can easily react with the moisture in the air to generate acetylene gas, which is flammable and explosive, so the safety measures in the process of processing, transportation, storage and use of calcium carbide are very demanding, resulting in difficulties in processing. And can not meet the requirements of deep desulfurization.