Three Methods of Producing Magnesium Metal by Silicothermic Method？
The basic principle of silicon thermal magnesium smelting is to mix ferrosilicate with calcined dolomite ore, press it into small pieces, and put them into a steel distillation flask. Under certain temperature and corresponding vacuum conditions, silicon reduces magnesium oxide to produce magnesium vapor, and then condenses to crystallize magnesium.
There are three main ways to produce magnesium by silicothermal process:
(1) Pijiang method: first, the dolomite is calcined and mixed with ferric silicon and fluorite into pellets, and then heated in a vacuum furnace at 1100℃ for reduction to generate magnesium vapor and other substances, and then the magnesium vapor is condensed and recycled into magnesium ingots. The production of magnesium metal by this method is high energy consumption and heavy operation.
(2) Magnetherm method (Magnetherm): the method is in a sealed arc furnace with carbon graphite lining and equipped with a fixed graphite electrode, calcined dolomite with ferrosilicate reduction group, and add bauxite or alumina as flux to produce magnesium metal. This method has the advantages of low raw material consumption, high yield and less environmental pollution. Disadvantages are poor product quality, high silicon content, long non-production time.
(3) Bolgnao method: calcined dolomite and ferrosilicate are put into the internal thermal vacuum reduction furnace through compaction, and then heated by electric heating (reduction temperature is generally 1250℃). Magnesium metal vapor is condensed externally to make magnesium metal. In addition to the above methods, there are horizontal vacuum graphite resistance reduction furnace silicon heat and so on.
