Aluminium slag ball and its preparation method

Abstract

An aluminium slag ball for smelting clean or superclean steel contains aluminium, fluorspar, calcium carbonate, alumina, SiO2, small amount of water, P, S and Cu. Its advantages are simple sphericizing process, high spreadability on the surface of molten steel, excellent insulating performance, and synchronization of deoxidizing and refining.

Description

technical field [0001] The present invention relates to molten steel furnace external treatment, refining and alloying technology, in particular to a kind of pure or ultra-pure steel which is especially suitable for smelting pure or ultra-pure steel of aluminum-killed steel, and can be quickly formed to cover the surface of molten steel as an insulating agent after the initial smelting steel is added. When it is transferred to the refining furnace with the molten steel, it has a strong deoxidation effect and is synthesized into a refining agent with good performance. It can also be used for alloying molten steel surface insulation and as an additive for molten steel refining. Background technique [0002] As we all know, with the development of the national economy, the requirements for steel types and their quality are increasing day by day, and the steel smelting technology has developed from the original one-step steelmaking to the two-step steelmaking, which is divided in...

AI Technical Summary

Problems solved by technology

The second is that the molten steel comes out of the furnace without slag, and a carbonaceous thermal insulation agent (such as carbonized rice husk) with better thermal insulation performance is added to the surface of the molten steel to isolate and insulate the molten steel. extremely unfavorable

The third is to use a carbon-free protective agent based on coal fly ash. Although this protective agent avoids the carburization of molten steel, the main component of coal fly ash, Al 2 o 3 and SiO 2 On the one hand, the molten steel "returns to silicon" due to reduction during the refining period, which is very unfavorable for smelting some steel types (such as deep-drawn sheet steel) that have strict control over silicon content; on the other hand, a large amount of Al 2 o 3 It takes a lot of CaO (lime powder) to form CaAl 2 o 4 (Calcium metaaluminate) becomes slag and floats up, otherwise it will reduce the Al in steel 2 o 3 Inclusion is also bad

[0005] The deoxidation of molten steel (especially aluminum-killed steel) will eventually use metal aluminum, and the deoxidation product Al 2 o 3 Its melting point is 2050°C, and it exists in the shape of dendrites or needles in molten steel. When the molten steel condenses, it will cause dendritic or needle-like oxide inclusions in the steel, which will affect the quality of the steel.

In the prior art, on the one hand, a composite deoxidizer (such as Al-Si-Fe alloy, Al-Mn-Fe alloy) is used to form Al 2 o 3 .SiO 2 or MnO.Al 2 o 3 Low melting point eutectic, easy to form slag and float up, but this method has limited application range, because it is difficult to form silicon or manganese oxides in the presence of a large amount of metal aluminum, it is not suitable for the use of aluminum killed steel; in ferroalloy The al-calcium-iron alloy and al-barium-iron alloy researched in the field can replace al-silicon-iron alloy and al-manganese-iron alloy to solve the problem of composite slagging of deoxidized products of aluminum-killed steel, but no successful reports have been seen so far

Another aspect is the addition of calcium oxide to molten steel during refining to form CaO.Al 2 o 3 (Calcium metaaluminate) eutectic with low melting point forms slag and floats up, but this method is deoxidation first, and the compound slag of deoxidation products is behind, and the Al dispersed in the steel 2 o 3 It takes a long time to combine with CaO to form slag and float up to remove Al 2 o 3 The dynamic conditions are far from ideal