A Basic Research On Preparation Of Ti-rich Material Process Intensification By Reduction Corrosion Method From Ilmenite

With the gradual depletion of rutile resource, inexpensive ilmenite has been applied in titanium industry as the main raw materials. But its grade is rather low, and so that it generally needs to be made into Ti-rich material with high grade. As an effective way to produce Ti-rich material from ilmenite, reduction corrosion method has been applied industrially, but it still has a number of problems in terms of difficult reduction, long time corrosion, low efficiency, etc. The basic research which is done to strengthen the producing Ti-rich material with the reduction corrosion method in view of the above questions has great significance in accelerating its application and promotion in producing Ti-rich material industrially.In this paper, the effects of additives and different corrosion systems on the ilmenite reduction corrosion method in producing Ti-rich material have been systematically researched, using Panxi ilmenite as raw materials and applying the principle of metallurgy kinetics and electrochemistry, as well as by the modern micro analyses technologies such as X-ray diffraction, optical microscope, scanning electron microscope and so on. On this basis, strength measures for rust reaction rate of reduced ilmenite and the relationship between Ti-Fe separation and phase control of iron byproduct are also systematically studied. The conclusions were obtained as follows:(1) Adding additive in ilmenite, which is the main reason for effects of additive on the reduction corrosion method, has obvious effects on the metallization rate of reduced ilmenite by adding additive in ilmenite, but not significant on the separation of non-ferrous impurity in corrosion separation process. The results reveal that the suitable additive is Na2CO3+ Na2B4O7·10H2O and the appropriate additive amount:Na2CO3 1.5% and Na2B4O7·10H2O 1.5%.(2)The selection research about corrosion system of reduced ilmenite shows that the systems of ammonium acid fluoride+ hydrochloric acid and ammonia chloride+ hydrochloric acid both tend to make rust reaction of reduced ilmenite transfer to infusion reaction. The best corrosion system is ammonia chloride solution and the main control factors are liquid-to-solid ratio, ventilation rate and reaction temperature.(3)Flowing oxygen is the effective action to promote the intensification of rust reaction rate of reduced ilmenite in the corrosion system of ammonium chloride. The result of kinetics displays that the corrosion process of metallic iron in reduced ilmenite is controlled by the internal diffusion and the apparent activation energy of corrosion process of metallic iron decreased from 13.28 KJ·mol-1 to 8.12 KJ·mol-1 when air is instead by oxygen, namely that oxygen accelerates the internal diffusion process and promotes the negative pole reaction of metallic iron of reduced ilmenite.(4)Ti-Fe separation efficiency is affected by the iron byproduct phase of corrosion product from reduced ilmenite. The research result shows that Ti-Fe separation efficiency is the best when the goethite is forming with the TiO2 grade of ilmenite concentrate 77.81%, recovery 90%, as well as the granule of product is uniform and the main mineral phase is anosovite which is acidsoluble, and the product is the high-quality raw material in producing titanium dioxide rutile by sulfuric acid process.The research results in this dissertation provide theoretical direction and technical support for increase of production efficiency in producing Ti-rich material by reduction corrosion method form ilmenite, with positive effect on the technical progress in producing Ti-rich Material industry.