Microwave Oxidizing Roasting Of High Titanium Slag And Preparation Of Synthetic Rutile Process

With the development of titanium industry, the need of synthetic-rutile is becaming more and more demanding. At present, the main methods to produce the synthetic rutile are reductive leaching, hydrochloric acid leaching and vitriol leaching which use ilmenite as the raw materials. However, there is lots of waste gas, waste liquid and waste residues during the process of synthetic rutile production, and also the process are time-consuming, moreover, the energy consumption is very high. Therefore using high titanium slag to replace ilmenite is becoming wide-spread. As a result, it becomes very urgent to invent a new method, which will match with the lower energy-consumption and easier manufacture and can comprehensively utilize the titanium resources, to produce the natural rutile from the high titanium slag. In this paper, the experimental studies on the production of the synthetic rutile by the conventional heating and microwave heating have been carried out on the basis of the summaries of the national and international research situation of synthetic rutile. Comparison has been made using X-ray diffraction and scanning electron microscope (SEM) analysis techniques. The basic results of phase transition of TiO2 in the titanium slags and the optimal conditions were obtained through investigating the experimental temperatures and holding times.The optimal conditions of TiO2 under traditional heating were obtained through analyzing the sample by chemistry and X-ray diffraction, The results suggest that the optimal temperature of oxidation roasting is 950℃, while the optimal holding time is 40 min. Under these optimal conditions, all the anatases in titanium slag are turned into rutile, while the content of S and C reaches the National Class I Standard.The experiments of microwave absorption of high titanium slags in the microwave field indicate that the high titanium slags can absorb microwave well. The temperature can be increased rapidly at the heating rates of 40℃/min under the microwave power of 1000 W. The microwave absorption capacity of oxidation roasted slags is weaker than that of untreated ones. The 180μm-380μm of particle size is selected to be the optimal size of high titanium slag in microwave field for all further studies.The basic results of phase transition of TiO2 and the optimal conditions obtained by microwave heating are that the optimal temperature of oxidation roasting is 950℃, while the optimal holding time is 20 min. Under these conditions, all the anatases in titanium slag are turned to rutile, the content of S and C reaches the National Class I Standard. Comparing processed high titanium slag by the traditional roasting with that by the microwave roasting, the latter is much faster and more environmentally friendly. The samples prepared by microwave roasring are loose and lacunaris, and have cracks on the surfaces.In conclusion, this paper studied a new method to prepare synthetic rutile from high titanium slag by microwave heating. The rutile prepared by synthesis reaches the National Class I Standard. The new method has the great potential to be applied in Yunnan provincial high titanium slag utilization.