| Approximately2.5million tons blast furnace slag containing TiO222-25%is produced every year after being smelt from the vanadium-titanium magnetite in Panzhihua-Xichang region of our country. A large amount of slag not only wastes the resources, but also pollutes the environment. There are a lot of researches about separating the titanium from the blast furnace slag, but a feasible method has not been found to solve its larger yield and lower resource utilization.This comprehensive utilization of titania are focused in this paper. The blast furnace slag containing TiO217.91%from Xichang area is selected as the research object. The technology combining smelting and mineral concentration had been determined based on the process mineralogy. The systematic research about the technological parameters during modifying and mineral concentration has been carried out. It laid the foundation for recycling the titanium from blast furnace slag. The main content and results of this study are showed as follows:(1) The main phase of Xichang blast furnace slag containing titanium was obtained by phase analysis. The result shows that the main components of the slag are perovskite, titanium pyroxene, Ti-rich diopside, spinel, titanium carbide, etc. The composition about the slag is very complex.(2) CaF2was selected as the additive in the process of modification and oxidation. Influence factors including the amount of the additives and cooling rate on the precipitation and growing of perovskite has been investigated. The optimization reaction condition was confirmed, which the additive content is5%, cooling rate is0.5℃/min. The average particle diameter of the perovskite reaches48.46μm, the maximum particle diameter is74.28μm, and the volume fraction is24.19%at the optimization condition.(3) The sample of oxidative modification is used in flotation. According to the degree of dissociation studies, it is relatively higher when the grind size is in less than74μm, the degree of dissociation is up to72.52%. The influence of collector, inhibitors, frother additive content and the pretreatment time of pulp to the flotation of modified slag are investigated. The gravity separation combined with flotation was used to further improve the concentrate grade and recovery.The optimization technology is gravity separation and three times of flotation. When the salicylic hydroxamate is800g/t, pH is11, the additive of sodium silicate is200g/t, the sodium hexametaphosphate is800g/t, the additive content of2-oil is80g/t, and the pretreatment time of pulp is3h, the grade of concentrate is48.96%, the grade of tailings is7.54%, and the recovery of concentrate is43.88%.(4) The flotation concentrate is calcined into rutile by adding a certain amount of phosphorus pentoxide. Rutile is separated through acid leaching and alkaline leaching, phosphoric acid solution can be recycled. The influence factors are investigated which includes acid leaching temperature, acid leaching time, acid extract concentration, alkali leaching temperature, alkali leaching time and alkali extract concentration on the separation of rutile phase. The optimization reaction condition is that the acid leaching temperature is90℃, the phosphoric acid concentration is20%, acid leaching time is4h, alkali leaching temperature is90℃, NaOH concentration is50g/L, alkali leaching time is4h. At the optimization reaction condition, titania grade in the products is81.9%. After acid cleaning by20%HCl, the TiO2grade is up to92.47%. |
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