Composite desiliconization and dephosphorization agent for molten iron pretreatment and preparation method thereof

Abstract

The invention provides a hot metal pretreatment composite desiliconization and dephosphorization agent. The composite desiliconization and dephosphorization agent comprises extracted vanadium tailingsand active lime which are mixed uniformly, and the extracted vanadium tailings account for 60%-90% of the composite desiliconization and dephosphorization agent by weight; and the active lime accounts for 10%-40% of the composite desiliconization and dephosphorization agent by weight. Not only are the extracted vanadium tailings utilized effectively, but also the silicon and phosphorus contents in hot metal can be reduced effectively; and high quality hot metal is provided for steelmaking, and meanwhile the recovery of iron resources in the composite desiliconization and dephosphorization agent can be achieved in the hot metal pretreatment process. The invention further provides a preparation method of the hot metal pretreatment composite desiliconization and dephosphorization agent, andthe preparation method comprises the steps of drying the extracted vanadium tailings and the active lime, and then uniformly mixing the dried extracted vanadium tailings and the dried active lime according to the amounts of the extracted vanadium tailings and the active lime in the composite desiliconization and dephosphorization agent, so that the composite desiliconization and dephosphorizationagent is obtained. The proportioning and preparation are simple, and the cost is low.

Description

technical field [0001] The invention belongs to the technical field of molten iron pretreatment in the iron and steel metallurgy industry, and in particular relates to a composite desiliconization and dephosphorization agent for molten iron pretreatment and a preparation method thereof. Background technique [0002] In the iron and steel metallurgical industry, in order to improve the quality of steel, hot metal pretreatment is an essential process in the steelmaking process. The molten iron pretreatment process is mainly to provide molten iron with stable composition and low silicon and phosphorus content for the steelmaking process, so as to facilitate the operation and control of steelmaking. Two important tasks in hot metal pretreatment are hot metal pretreatment desiliconization and hot metal pretreatment dephosphorization. [0003] Desiliconization of hot metal pretreatment is mainly to use oxidant to oxidize Si in hot metal to SiO 2 into the slag for removal: [00...

AI Technical Summary

Problems solved by technology

The cost of soda-based desiliconization and dephosphorization agents is high, the temperature drop of molten iron is relatively large during the treatment process, and it is easy to cause environmental pollution and corrosion of refractory materials and equipment, so it is generally not used

At present, lime-based desiliconization and dephosphorization agents composed of fluorite, iron oxide scale and lime are widely used, but the existence of fluoride will cause serious environmental pollution

[0008] Chinese patent CN200410013065.6 discloses a molten iron pretreatment agent and its preparation method, specifically, red mud and Fe 2 o 3 , CaO, Na 2 CO 3 , MnO 2 , CaCl 2 , SiO 2 Or other metallurgical wastes containing these components are mixed and ground to obtain the molten iron pretreatment agent, which ensures the high oxidation, strong alkalinity and good melting performance of the molten iron pretreatment agent, but there are many types of ingredients and complex process ratios. The utilization of red mud is small, only accounting for 15-30% of the ratio of molten iron pretreatment agent

Chinese patent CN201110117960.2 discloses a molten iron pretreatment dephosphorization agent containing magnesium slag, specifically, magnesium slag, barium carbonate, converter sludge, iron oxide scale, fluorite, B 2 o 3 Mixed and formulated as a dephosphorization agent, the dephosphorization effect is good, but the fluorite contains a large amount of fluoride, which will bring a series of environmental pollution problems

Such a precious and abundant secondary resource, due to its low utilization rate, most of it can only be piled up in the open environment, which not only wastes resources, but also produces a large amount of dust and toxic V 5+ 、Cr 6+ cause great harm to the environment and human health

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