| Titanium belongs to the rare metal, as it has a series of excellent properties, it has been used for many fields, is named as "the twenty-first century metal". The development of titanium's industrial is so fast that the world's total output of titanium sponge had reached 166,400 tons in 2007.At present, the industrial production of sponge titanium method is based on TiCl4 raw materials for the reduction of magnesium metal-distillation (MD). Nowadays, the preparing methods of TiCl4 include boiling chlorination and molten salt chlorination. Molten chloride salt technics adapts to a wide range of the raw materials, and it can obtain good product quality, the current salt chlorination of titanium tetrachloride production in the world titanium industrial usage has been amount to 40%, the shortcomings of it are the serious waste of discharge volume and complexity of the ingredients, it contented 75%of easily dissolved metal chloride which was harm to environment. The integrated disposal of molten salt chlorination residue is one of the most important problems in the molten salt chlorination technics. Until now, the way of integrated disposal the molten chloride salt residue have not been reported.The Yunnan Metallurgical Group (CYMG) 10kt titanium sponge project which is a record's key projects in Yunnan Development and Reform Commission, they have introduced molten chloride salt technics from Ukraine as a match project, will produce 11.7kt molten salt chlorination residue each year. In this paper, the molten salt chlorination residue is provided by the CYMG. The purpose of this experiment can be summarized as follows:to clear about the composition and characteristics of the molten salt chlorination residue, find the way of integrated disposal the molten chloride salt residue, reduce the amount of waste; Treat the metal ions which concentrated into molten salt chlorination residue, make it secure and harmless; cooperate with chlor-alkali project with the realization of the recovery of chlorine, thus reducing environmental hazards.After experiment, found in water-soluble as liquid-solid ratio 2:1 and 1 times the wash water treatment, which could make the vast majority of chloride in the molten salt chlorination residue be dissolved, to be chloride solution. The chloride solution through be depurated, get NaCl saline solution which can meet the Chlor-alkali process purity requirements, for dissolved salt in production of chlor-alkali. The water insoluble residue in molten salt chlorination residue are C, SiO2, TiO2, Al2O3 mainly, there are no environmental hazards, can be stacked directly, also can be used as wear-resistant additives and used in the production of road cement.In the process of depurating the chloride dissolution will produced two types of slag. They are variety of metals insoluble precipitate, but also have some soluble materials. Take these two types of slag with water-soluble treatment, which could make the soluble material dissolved, the stripping solution can be back to dissolute molten salt chlorination residue. The iron and manganese content near 50% in pH5.2 residue, it is raw materials for high manganese slag, can be re-use. The component of pH12 residue mainly in calcium and magnesium hydroxides, can be stacked directly.Through the experiment, we have found an integrated disposal process of molten chloride salt residue, treat the easily dissolved metal chloride properly, make metal-ions to be secure, harmless and stable; Combine with disposal process of molten chloride salt residue with chlor-alkali project, achieved the recovery of 98.8%chloride, it is environmental pollution be reduced; The mass of solid residue decreased about 50%. We have found a reasonable program piling up for all residue and suggested a comprehensive utilization program for the useful parts of residue, further reduced the harm to the environment. The experiment have been achieved the purpose, with significance for environmental protection, and redound to promote the development of titanium industry. |
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