Magnesium desulphurization method for molten iron pretreatment and powder used thereby

Abstract

The invention belongs to the steel metallurgic technical field and in particular relates to a hot metal pretreatment magnesium desulfurization method and the adopted powder, wherein, the powder comprises magnesium metal powder and is characterized in that the powder also comprises premelting magnesium desulfurization accelerating agent which is made from blast furnace slag and lime through production processes such as raw material selection, impurity removal and drying, mix crushing and passivating treatment; by means of the prior blowing equipment, the magnesium metal powder and the premelting magnesium desulfurization accelerating agent are mixed according to a certain proportion or are jointly injected into hot metal for desulfurization. The method is simple and feasible and the made powder can replace pure lime powder, therefore, the invention has the advantages of energy saving, high efficiency and environmental protection; moreover, the method can greatly reduce the pretreatment cost of hot metal and increases hot metal yield.

Description

technical field [0001] This application belongs to the technical field of iron and steel metallurgy, and specifically relates to a magnesium desulfurization method for pretreatment of molten iron and the powder used. Background technique [0002] As an important process link in iron and steel smelting, hot metal pretreatment has been generally recognized by the iron and steel metallurgy industry. Hot metal pretreatment includes desiliconization, dephosphorization and desulfurization, but at present, only a few enterprises in China such as Baoshan Iron and Steel Company are implementing the "three desulfurization" process, and most iron and steel enterprises use single desulfurization, and generally use powder spraying method or KR stirring Law. In the powder spraying method, the selection of powder is very important. The commonly used powders include metal magnesium powder, calcium carbide series powder, AD powder and CaO series powder, etc. Among them, the most widely use...

AI Technical Summary

Problems solved by technology

[0004] First of all, the melting point of lime powder is relatively high. Generally, the slag formed after blowing is mostly solid, and the iron beads splashed out during blowing desulfurization will be mixed in it, which cannot penetrate the solidified slag layer and return to molten iron. , so the iron loss of slag removal is relatively serious. For this reason, many metallurgists have developed a variety of thinner slag agents to reduce the viscosity of slag and reduce iron loss, but the effect is not ideal in practical applications.

[0005] Secondly, lime powder is prone to splashing when it enters molten iron

On the one hand, lime powder is very easy to absorb moisture. Once the moisture-absorbing powder reaches a certain amount and is sprayed into molten iron, the rapid evaporation of water will cause splashing. On the other hand, the raw material limestone used in the production process of lime powder is difficult to make. Until it is completely decomposed, there will always be more or less residual CaCO 3 , residual CaCO 3 After being brought into the molten iron, because of its rapid decomposition at high temperature, it will also cause the same consequences as mentioned above; the generation of splashing will not only affect the smooth flow of the process, but also cause iron loss and even personal accidents;

[0006] Third, lime is a high-energy-consuming product in its production process, and limestone is also a non-renewable resource, so it may not be the best choice for this process

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