Method for smelting magnesium by hot method

Abstract

The invention provides a method for smelting magnesium by a hot method. The method comprises the following steps that: (1) after dolomite and magnesite are calcined by a rotary kiln respectively at a temperature of between 1,150 and 1,200 DEG C, the dolomite and the magnesite are ground into powder with granularity less than 100 meshes, wherein the dolomite comprises the following chemical compositions in percentage by weight: 46 to 47 percent of ignition loss, 19 to 21 percent of MgO, 30 to 33 percent of CaO, and the balance of impurities; the magnesite comprises the following chemical compositions in percentage by weight: 45.2 to 47.2 percent of MgO, 0.2 to 3 percent of CaO, 0.2 to 2.0 percent of SiO2, 50.1 to 52.0 percent of ignition loss, and the balance of impurities; aluminum-silicon alloy is ground into fine powder with granularity less than 100 meshes, wherein the aluminum-silicon alloy comprises the following compositions in percentage by weight: 44 to 50 percent of Al, 45 to 55 percent of Si, and the balance of impurities; and (2) 83 to 86 percent of the calcined dolomite and 14 to 17 percent of the aluminum-silicon alloy fine powder are weighed according to weight percentage, and the mixed materials are made into pellets under the pressure of 20MPa, are filled into a reduction jar, and are reduced for 7 to 9 hours at a reducing temperature of between 1,050 and 1,160 DEG C to produce the magnesium. The method for smelting the magnesium by the hot method has low reduction temperature, small energy consumption and high production efficiency and is environment-friendly.

Description

technical field [0001] The invention relates to a metal production method, in particular to a method for smelting magnesium by thermal method. Background technique [0002] In today's industrial production, in addition to the electrolytic method of magnesium smelting, the thermal method of magnesium smelting mainly adopts the silicon thermal method, that is, calcined dolomite is used as raw material, ferrosilicon is used as reducing agent, and high temperature and high vacuum at a temperature of about 1200 ° C - 1260 ° C (1-13Pa) to carry out the reduction reaction to produce metal magnesium, which is the silicon thermal method of magnesium smelting. In the production of this method, about 1.2 tons of ferrosilicon (Si>75%) is needed to produce per ton of metal magnesium, the utilization rate of silicon in ferrosilicon is 65-70%, and the reduction efficiency of MgO is about 76%. Using this method to smelt magnesium has high reduction temperature, high energy consumption a...

AI Technical Summary

Problems solved by technology

Using this method to smelt magnesium, the reduction temperature is high, the energy consumption is large, and the production efficiency is low

In addition, for every ton of magnesium metal produced, 5.5-6 tons of industrial waste slag are produced at the same time. The main components of the slag are: CaO.SiO, MgO, SiFe, and ferrite (nCaO.mFe2O), aluminate (nCaO.mAL2O3, CaO.AL2O3.SiO2), etc., have no use value and cause industrial solid waste environmental pollution