Precipitation And Separation Of Rutile Phase In Ti-bearing Blast Furnace Slag

50% of the titanium in Vanadium-titanium magnetite entered into iron concentrate after the mineral processing. This part of the titanium enters into the blast furnace slag after blast furnace smelting process thus the Ti-bearing blast furnace slag was formed. At present, the comprehensive utilization of Ti-bearing blast furnace slag has not yet been resolved, thus the enrichment of titanium in Ti-bearing slag is fully of theoretical significance and application value.Based on the distribution characteristics of titanium in the Ti-bearing slag, a method which is a combination of "high temperature modification-shaker sorting-hydrometallurgy" was proposed in this paper, titanium component in the slag was enriched in the rutile phase and then separated by shaker sorting and hydrometallurgy method.The factors including oxidation process, melting temperature, addtion amount of additive and crystal seed, and oxygen flow which can affect the precipitation and coarsening process of rutile in the molten slag were studied. The best parameters of the high-temperature modification were obtained. The behavior and settlement process of metallic iron in the molten slag were studied, the relationship between oxidation time and iron content of the metallic iron and in the molten slag was fixed, the settlement metallic iron was recovered. The precipitation and coarsening kinetics of rutile under isothermal and cooling conditions were discussed. The vilume fraction of rutile during the cooling process can be approximately described by JMAK equation: the average grain size of rutile can be described by the following equation:When it was in the isothermal process, the average radius of the rutile changed with time can be given by the following equation:The shaker sorting process of modified slag was also been discussed, it came to the best parameters of the shaker sorting process:the stroke was 12mm, the vibration frequency was 360 times/min. The results of single particle size shaker sorting experiments indelicate that the finer particle size, the higher TiO2 content and lower yield of the concentrate, the higher yield of the middles and the tailings as well as the higher TiO2 content of the tailings, the recovery rate was reduced when the size of the slag was smaller. One concentration and scavenging experiment which laid the foundation for the expand experiment was done when the size of the slag were 74-150μm and 48-74μm.The hydrochloric acid leaching for removal of impurities was studied, the appropriate conditions were:25% HCl solution, reacting at 373K, reaction for 5h, liquid-solid being 6ml/g, particle size of the slag was 48～74μm. Under the above optimum conditions, high-grade synthetic rutile preparation and circulation leaching experimental were done, the leaching time of the high-grade synthetic rutile preparation experiment were 5h,2h, and 2h, the total content of CaO and MgO in the rutile was 1.45%, the rutile can be applied in the titanium in industry as high-quality raw materials. The leaching solution can be continue used for leaching after supplementary joining of HCl, the ions in the solution can be removed by adjusting the pH of filtrate after several cycle times.The expand experiment of the high-temperature modification and shaker sorting were also studied, the average size of rutile crystal in 60kg and 300kg experiment were relatively 82.02μm and 95.31μm. In addition, the closer to the top of the liquid level, the smaller precipitated amount of rutile crystal in the molten slag when it was in the 60kg and 300 kg high-temperature modification experiment, it was due to the settlement of rutile in the molten slag, calculation results of the settlement process of rutile in 60 kg molten slag showed that rutile crystal in the top of the liquid level can be settle to the bottom of the crucible in 0.3s. Inaddtion, the results of expand experiment was better than the lab experiment.Open circuit mineral process was also studied, the TiO2 content of concentrate obtained by the open circuit mineral process were relatively 66.15% and 60.22%, and the TiO2 content of the tailings were relatively 12.56%,10.93% and 11.05%, the recovery of the open circuit mineral process was 76.75%.