Process for smelting magnesium by microwave heating Pidgeon process

Abstract

The invention discloses a magnesium reduction process through a micro-wave heating silicothermic method; the process comprises the following steps: 1. dolomite calcinations: the dolomite is heated to 1100 DEG C to 1200 DEG C and becomes calcined dolomite; 2. the calcined dolomite, silicon nitride powder and fluorite powder are weighed, mixed, milled and then pressed into a ball which meets technological requirements; 3. the ball is put into a closed non-metal reduction tank of a micro-wave heating oven to be heated under 1000 DEG C to 1200 DEG C, so that the magnesium compound in the ball reacts with the silicon nitride powder; 4. the vacuum degree of the closed non-metal reduction tank is kept to be 13.3Pa or higher for 4h to 6h; magnesium vapor is condensed in a condenser and becomes crude magnesium; 5. the crude magnesium is heated, melted and refined by solvent, to obtain refined magnesium; 6. acid washing and the like. The method evenly and quickly heats in the principle of micro-wave heating with high heating efficiency, is easy to be controlled, saves production cost, is safe, environment protective and harmless.

Description

technical field [0001] The invention relates to a process for smelting magnesium by Pidgeon method, in particular to a process for applying microwave heating technology to smelt magnesium by Pidgeon method (also called silicothermal method). Background technique [0002] The Pidgeon method for producing magnesium metal is based on calcined dolomite as raw material, ferrosilicon as reducing agent, and fluorite as catalyst. The ingredients are measured and dosed according to the proportion and then mixed evenly. After grinding, it is pressed into balls, called pellets. Put the pellets into a reduction tank, heat to 1200°C, and evacuate the interior to 13.3Pa or higher, then generate magnesium vapor. Magnesium vapor forms crystalline magnesium, also known as crude magnesium, in the condenser at the front end of the reduction tank. Then it is refined by flux to produce commercial magnesium ingots, that is, refined magnesium. The main chemical reaction formula of Pidgeon proce...

AI Technical Summary

Problems solved by technology

[0007] The heating method of the reduction tank in the traditional process is to install a heating device outside the reduction tank, use external heating method for heating, and rely on heat conduction to heat the reduction tank and the pellet materials in it. The shortcomings are mainly reflected in the following aspects: 1. The energy consumption is large, and the thermal energy utilization rate is low, only about 24%. Usually, coal is directly used or converted into gas and used as fuel for heating. It takes about 10 tons of high-quality coal to produce 1 ton of metal magnesium. If Based on the coal consumption of 2.5kwh / kg coal power generation, it is equivalent to 25,000kwh of electricity consumption, which consumes a lot of resources

2. The cycle of magnesium smelting is long, it takes 8 to 12 hours

3. Due to the use of external heating and internal vacuuming, the existing heat-resistant metal reduction tank is easily oxidized, deformed, etc., and has a short service life. It can be used for up to 2 months

Burned out reduction tanks need to be replaced frequently, increasing costs and reducing work efficiency

4. In the smelting reduction process, a large amount of carbon dioxide and smoke dust and other harmful emissions to the environment are produced, polluting the environment

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