Aluminium-calcareous premelted refining slag for low-cost steel-making and method for preparing same

Abstract

The invention relates to aluminium-calcareous premelted refining slag for low-cost steel-making and a method for preparing the same. The refining slag mainly uses industrial waste rich in calcium oxide and alumina as raw materials of production. The method comprises powdering the industrial waste, mixing the powder according to a certain proportion, putting the mixed powder into a high-temperature kiln to smelt at a temperature of 1600 to 1750 DEG C, cooling crystallization after smelting and tapping, and crushing to prepare the blocky premelted refining slag which has a low melting point and a granularity of 0 to 70 mm, and is rich in CaO and Al2O3. The refining slag is low in melting point and quick in melting rate, and can be added during the steel-making process to promote slagging and shorten smelting time. Meanwhile, the refining slag is high in sulfur capacity and can be used for refining desulphurization of molten steel during the process of tapping or the process of refining the molten steel by an LF furnace. Moreover, the refining slag is prepared from high temperature smelting and thus has advantages of stable performance and low fluorine, and is without deterioration, pulverization and water-absorption, thereby not only facilitating storage and transport but also benefiting environmental protection and pollution reduction. In addition, the refining slag uses industrial waste as raw materials and the used amount of the refining slag is fewer than that of other types of refining slag, and thus the cost of production of the steel can be reduced.

Description

technical field [0001] The invention belongs to the technical field of steelmaking production, and particularly relates to an aluminum-calcium premelted refining slag for steelmaking and a preparation method thereof. The refining slag is especially suitable for desulfurization. Background technique [0002] At present, the methods for refining molten steel mainly include: one is to add lime into the molten steel tank and add part of fluorite at the same time. This refining and desulfurization method is relatively simple, but fluorite will pollute the environment and affect the furnace body or molten steel. The service life of tank lining refractories; Another method is to add lime to the molten steel tank and add part of bauxite. This refining desulfurization method is also relatively simple, and there is no fluorite pollution, and it is very easy to corrode the refractories. Small, but the lime is not easy to melt, and the desulfurization effect is not good; there is anothe...

AI Technical Summary

Problems solved by technology

At present, the slag system of pre-melted slag is still CaO-Al 2 o 3 base and CaO-CaF 2 Base slag system, and CaO-CaF 2 The base slag is mainly based on CaO-CaF 2 The desulfurization effect of the base slag system is not bad, but it has a greater impact on the erosion of refractory materials

[0004] Chinese patent CN97121984.2 discloses a formula of low-silicon-content aluminum-calcium slag and its manufacturing method. The high content of S and Si in raw coke leads to a decrease in its sulfur capacity coefficient, which limits its desulfurization effect and is not conducive to deep desulfurization of molten steel

[0005] Chinese patent CN02120744.5 discloses a pre-melted low-melting calcium aluminate composite desulfurizer and its preparation method. Since the composite desulfurizer must be passivated first and then melted in the production process, the process is cumbersome and the cost is high

[0006] Chinese patent CN200710023020.0 discloses a desulfurizer for pre-melting vacuum smelting and its preparation method. The desulfurizer adopts the method of pre-melting first and then mixing ingredients. The components are prone to unevenness and unstable effect, and The process is more cumbersome and the cost is higher

[0007] Chinese patent CN200310103105.1 discloses a pre-melted refining purifier and its production process. Although the pre-melted molten steel cleaner has achieved a certain desulfurization effect, the erosion of refractory materials caused by the high fluorite content is not only Seriously affects the service life of furnace lining or molten steel tank lining, and is not conducive to environmental protection, so the application is greatly restricted