Slag adhesion preventing fluorine-free slag modifier for ladle refining, preparation method and using method

Abstract

The invention belongs to the field of steelmaking, and particularly discloses a fluorine-free slag modifier for preventing a ladle refining device from adhering slag, a preparation method and a using method. The slag modifier consists of active lime, bauxite and boric anhydride; and the slag modifier comprises the following chemical components in percentage by mass: 75 to 85 percent of CaO, 10 to20 percent of Al2O3, 5 to 15 percent of B2O3, 0 to 8 percent of MgO, and the balance of impurities, wherein SiO2 is less than 7.0 percent, H2O is less than 0.05 percent, and the total amount of sulfur and phosphor is less than 0.01 percent. During use, in order to prevent a ladle from adhering the slag, the slag modifier is fed into the ladle in the later period of discharging steel from a steelmaking furnace, and in order to prevent an RH dip pipe or a CAS-OB dip cover and the like from dipping into the ladle device to adhere slag, the slag modifier is fed at a refining station. The slag modifier can effectively control the refining device from slag adhesion and improve the service life of a fireproof material, is favorable for reducing the contents of the sulfur, oxygen and impurities in the steel, and is simple to prepare and convenient to store, transport and use.

Description

technical field [0001] The invention belongs to the field of steelmaking, and in particular relates to a fluorine-free slagging agent and a slag adjusting method for preventing ladle refining equipment from sticking to slag, which can effectively control refining equipment such as ladles, RH refining process dipping tubes and CAS-OB refining dipping covers of sticky residue. Background technique [0002] Ladles used for refining, storage and transportation of molten steel outside the furnace often reduce the diameter of the ladle due to sticky slag on the wall of the ladle, which affects the implementation of the refining process and refining effect, and a large amount of sticky slag leads to a decrease in the effective capacity of the ladle, which affects the amount of molten steel transport and is easy to It leads to overweight, which affects the safety of lifting and transportation. In addition, a large amount of slag sticks to shorten the ladle life and increases the con...

AI Technical Summary

Problems solved by technology

Such as Chinese patent CN1068282 proposes a kind of high-temperature paint of anti-sticking slag, made of Al 2 o 3 、Cr 2 o 3 , SiC, graphite and binder aluminum phosphate solution, sodium lignosulfonate solution, the number of non-stick slag furnaces can reach 7 to 10 furnaces by using this coating. The disadvantage of this patent is: the mass fraction of SiC in the coating is 55% , the mass fraction of graphite C is 5%, the coating will increase carbon and silicon in molten steel, and cannot be used to produce pure steel, low-carbon steel and low-silicon steel. In addition, the service life of the coating is 7 to 10 furnaces, and the service life is low , affecting the continuity of production

Chinese patent CN1238137C proposes a CaO coating for anti-sticking slag, using CaO and Al in slag 2 o 3 reaction to produce CA, C 12 A 7 and other low-melting-point compounds to reduce sticky slag. The invention maintains 5-7 heats for non-sticky slag, and the number of non-sticky slag is relatively low, which affects the continuity of production. When repairing and spraying between refining heats , due to the high temperature of the cladding wall or dipping tube, dipping hood, etc., it is difficult for the spray paint to adhere firmly. Therefore, the spray paint cannot be sprayed on the hot pack, that is, it cannot be used for online spraying, which affects the continuity of production

Japanese patent JP4-116117 proposes the use of 10-80% fluorite and 90-20% limestone as the main anti-slagging agent, which is sprayed on the surface of refractory materials to prevent sticking slag. The main disadvantages of this patent are two: 1. The reason is that the coating will melt at the steelmaking temperature and melt into the ladle slag. The effect of anti-sticking slag is very poor, and the number of furnaces for anti-sticking slag is lower than 5 furnaces; the second is that the coating contains a high amount of fluorite CaF 2 , not only cause fluorine pollution, but also fluoride will aggravate the erosion of refining equipment refractory materials, seriously reducing the life of refining equipment refractory materials

The main disadvantage of this invention is the higher content of fluorite, F - The mass fraction of the modifier is 4.0-8.0%. The use of this modifier at high temperature will aggravate the erosion of the refractory materials of the ladle and refining equipment, affect the service life of the ladle and refining equipment, and cause environmental pollution and damage the health of operators.

In addition, the fluxing agent fluorite in this modifier has a poor fluxing effect, and its action time is short, so the effect of anti-sticking slag is general