Method for dephosphorization and desulphurization in process of steel production in induction furnace

Abstract

The invention provides a method for dephosphorization and desulphurization in the process of steel production in an induction furnace, which is characterized by comprising the following steps of: during the smelting period and the initial period of total meltdown of charging materials, controlling the temperature of molten steel to below 1,450 EDG C, performing dephosphorization treatment on a liquid steel by using a dephosphorizing agent consisting of lime-ferric oxide-boron anhydrous, and controlling the phosphorous content in the liquid steel to below 0.01 percent; after finishing the dephosphorization, absolutely deslagging, then rapidly raising the temperature of the liquid steel to 1, 500 to 1, 600 DEG C; and performing pre-deoxidation and alloying on the liquid steel, and then adding the desulphurizing agent consisting of lime-calcium carbide-aluminum ash, performing the desulphuration on the liquid steel, and reducing the phosphorous content in the liquid steel to below 0.08 percent. The method has the advantages of combining the smelting characteristics of the induction furnace, fully utilizing favorable thermodynamic conditions of dephosphorization and desulphurization, realizing high-efficiency dephosphorization and desulphurization by slagging and greatly improving the quality of the liquid steel; and meanwhile, the method also has the advantages of low cost, less equipment investment, simple operation, easy implementation, and obvious economic benefits and social benefits.

Description

technical field [0001] The invention belongs to the technical field of induction furnace steelmaking, and in particular relates to a dephosphorization and desulfurization method used in the induction furnace steelmaking process. Background technique [0002] For most types of steel, phosphorus and sulfur in steel are harmful elements, which will cause serious harm to the comprehensive performance of steel. Therefore, reducing the content of sulfur and phosphorus in steel as much as possible is of great significance to improve the quality of steel . Traditional induction furnace steelmaking is limited by factors such as smelting conditions and furnace lining refractory materials, so it is difficult to achieve simultaneous desulfurization and dephosphorization in the furnace. Due to the insurmountable difficulties in reductive dephosphorization in steelmaking at present, the traditional oxidation dephosphorization method is required for steelmaking dephosphorization, and ther...

AI Technical Summary

Problems solved by technology

It is precisely because the requirements of dephosphorization and desulfurization in terms of oxidation and temperature are opposite, which brings difficulties to simultaneous dephosphorization and desulfurization.

In addition, both dephosphorization and desulfurization require high-basic slag, so desulfurization and dephosphorization in the induction furnace must produce high-basic slag, which is only possible when the induction furnace lining is made of alkaline (MgO) or neutral (Al 2 o 3 ) material may be used, and the use of acid lining (SiO 2 ) induction furnace can not be desulfurized or dephosphorized in the furnace

Therefore, at present, induction furnace steelmaking generally does not carry out desulfurization or dephosphorization in the furnace, but adopts the method of processing outside the furnace, such as prior art 1 (Chinese patent authorization announcement number CN100434540C, acid induction furnace desulfurization method outside the furnace) and existing Technology 2 (Chinese Patent Application No. 200910235079.5, a kind of desulfurization agent and desulfurization method outside the induction furnace steelmaking furnace) all adopts the method of desulfurization outside the furnace, and these desulfurization methods outside the furnace can reduce the sulfur content to a lower level, but Since the molten steel has been deoxidized during desulfurization, it is a strong reducing atmosphere, so oxidative dephosphorization cannot be achieved, so it is difficult to achieve dephosphorization and desulfurization outside the furnace at the same time

Prior Art 3 (Chinese Patent Application No. 200610097440.9, method for simultaneous dephosphorization and desulfurization of chromium-containing iron water by using barium carbonate-based slag) discloses a method for simultaneous dephosphorization and desulfurization of chromium-containing iron water furnace, but the disadvantages of this invention There are two: one is to use highly toxic barium carbonate as the main dephosphorization and desulfurization agent, which will damage the health of operators and pollute the environment; the other is that the invention is equipped with high-content (<50%) iron oxide, which is difficult to realize in theory Reduce phosphorus and sulfur content to a very low level (phosphorus 0.02%, sulfur below 0.008%)

Prior art 4 (Chinese invention patent application number: 200810054730.4, the dephosphorization method of low-nickel-chromium iron solution or pig iron) also proposes to use barium carbonate, fluorite, calcium chloride, iron oxide to prepare dephosphorization agent to realize dephosphorization in the furnace. The disadvantage of this invention is also the use of toxic and harmful barium carbonate, fluorite and other substances. In addition, this invention contains iron oxide with a high content (<50%), so it is also difficult to achieve efficient desulfurization

[0005] To sum up, there is no report in the prior art that can achieve dephosphorization and desulfurization in the induction furnace steelmaking furnace, and it is difficult to achieve simultaneous dephosphorization and desulfurization by using the external treatment technology, and the external treatment will increase the process and cause temperature reduce