Agglomeration method The open mouth electric furnace which can be moved on the rail and the upper section of the furnace body can be detached is used, and carbon is used as the reducing agent. Fine tungsten ore, asphalt coke (or petroleum coke) and slagging agent (bauxite) composed of a mixture of charge added to the furnace in batches one after another, the metal refined in the furnace is generally viscous, with the thickness of the higher, the lower part of the gradual solidification. Furnace accumulation after stopping the furnace, pull the furnace body out, remove the upper section of the furnace body so that the lump condensation. Then take out the agglomerates for crushing and finishing; pick out the edges, with slag and unqualified parts back to the furnace for remelting. The product contains about 80% tungsten and no more than 1% carbon.
Iron extraction method is suitable for smelting ferro-tungsten containing 70% tungsten with lower melting point. Silicon and carbon are used as reductants; it is operated in three stages: reduction (also called slag depletion), refining and iron extraction. Reduction stage furnace contains a furnace to take the iron left behind after the slag containing WO3 greater than 10%, and then successively added to the tungsten concentrate charge, and then added to the silicon 75% ferrosilicon and a small amount of asphalt coke (or petroleum coke) for reduction smelting, to be slag containing WO3 down to 0.3% below the slag. Subsequently transferred to the refining stage, in this period, adding tungsten concentrate, asphalt coke mixture in batches, operated with higher voltage, at a higher temperature to remove silicon, manganese and other impurities. Sample test to determine the composition of qualified, began to take iron. During the iron extraction period, tungsten concentrate and asphalt coke are still added appropriately according to the furnace conditions. Smelting power consumption of about 3,000 kW-hr/ton, tungsten recovery rate of about 99%.
Aluminum thermal method in order to use waste tungsten carbide powder tungsten and cobalt separation of cobalt extraction of regenerated tungsten carbide, developed an aluminum thermal method of ferro-tungsten process, with regenerated tungsten carbide and iron as raw materials, aluminum as a reductant, the use of tungsten carbide in its own carbon and aluminum combustion of the heat, so that the raw material in the tungsten and iron into ferro-tungsten, can save a lot of electricity, and to reduce costs. At the same time, because the impurities in raw material tungsten carbide are much lower than those in tungsten concentrate, the quality of product is higher than that of ferrotungsten using tungsten concentrate as raw material. The recovery rate of tungsten is also higher than that of the process using tungsten concentrate as raw material.
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