Method for Al-Si-Fe alloy preparation and magnesium reduction in Pidgeon-process magnesium reduction process

Abstract

The invention discloses a method for Al-Si-Fe alloy preparation and magnesium reduction in a Pidgeon-process magnesium reduction process. The method comprises the following steps: (1) mixing calcined dolomite, powdered aluminium, silicon iron and calcium fluoride, pressing the mixture into balls to obtain mixed balls, then filling a magnesium reduction tank with the mixed balls, and enabling heating reaction; and (2) performing cooling after finish of reaction, performing vacuum breaking, and collecting volatilized magnesium in the format of elemental magnesium, wherein the mass percents of calcined dolomite, powdered aluminium, silicon iron and calcium fluoride in the mixed balls in the step (1) are 80-85%, 1-12%, 4-15% and 1-3%; and the reaction temperature in the step (1) is 1,000-1,300 DEG C, and the heat preservation reaction time is 1-12 h. According to the method, in the Pidgeon-process magnesium reduction process, aluminum and silicon iron react to produce Al-Si-Fe alloy, and the Al-Si-Fe alloy serves as a reductant in the traditional Pidgeon-process magnesium smelting process to reduce magnesium oxide in calcined dolomite; and the cost caused by using the Al-Si-Fe alloy in the magnesium reduction process is lowered.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for producing aluminum silicon ferrosilicon in vacuum and for reducing magnesium. Background technique [0002] The traditional process of smelting magnesium by Pidgeon method is to calcinate dolomite, and the material obtained after calcining is usually called calcined white. In the calcined white, a certain amount of ferrosilicon and calcium fluoride are added according to the reduction ratio requirements and then heated at 1200 ° C. Heating under vacuum for about 12 hours reduces the magnesium in it. Due to reasons such as reduction process, charge ratio, heating conditions, etc., the reduction rate of magnesium is generally about 75% when reducing magnesium by Pidgeon method. The slag obtained after reduction is called magnesium slag. According to the factory practice results, the magnesium oxide content in the slag is generally between 5% and 12%. Th...

AI Technical Summary

Problems solved by technology

Another method of smelting aluminum silicon ferrosilicon is to use aluminum-containing minerals such as kaolin, industrial alumina and silicon-containing minerals, etc., to mix aluminum-containing minerals with bituminous coal and petroleum coke, etc., and then use pulp as a binder for kneading The kneaded block is smelted in an electric arc furnace after drying to obtain ferrosilicon alloy. The cost of smelting ferrosilicon alloy by these two methods is relatively high. The cost of ferrosilicon alloy as a reducing agent in the Pidgeon process of magnesium smelting Compared with ferrosilicon as the reducing agent, the cost is much higher, which leads to the fact that AlSi-Fe alloy cannot be used in the Pidgeon process of magnesium smelting, and it is impossible to use Al-Si-Fe alloy to reduce the magnesium reduction temperature, shorten the reduction time and increase the reduction rate of magnesium during the magnesium reduction process. The advantages

Therefore, ferrosilicon is still the main reducing agent for magnesium smelting in the Pidgeon process at present. When using ferrosilicon as reducing agent, the energy consumption is high, and the problem of high magnesium oxide content in magnesium slag is still insurmountable.

[0005] From the above analysis, it can be known that aluminum powder, aluminum-silicon alloy and aluminum-silicon-iron alloy have higher efficiency and lower energy consumption than ferrosilicon in reducing magnesium; from the perspective of reduction temperature, aluminum-silicon-iron alloy can greatly reduce the reduction temperature of magnesium (1000 ° C), If the production cost of aluminum silicon ferroalloy can be reduced, it is expected to become a more promising magnesium reducing agent, which reduces the energy consumption of magnesium reduction and improves the reduction efficiency of magnesium; but in terms of cost, the above three new reducing agents There is a problem of high cost in replacing ferrosilicon, and it is difficult to realize large-scale industrial application at this stage