Investigation On Selective Carbonthermal Reduction Of Ilmenite For Preparation Of Rich Titanium Material

In this paper,based on the thermodynamic analysis of the possible actual carbon reduction reaction of ilmenite and taking the rich reserves of ilmenite resources as the object in panxi aera of China, the reduction behavior of iron and the titanium oxide, the strengthening institutions under the condition of no-carbon-burdened and carbon-burdened, the separation process for Fe-Ti were systematically investigated. And by using X-ray diffraction, optical microscopy and scanning electron microscopy for laying the foundation to fulfill the carbon nitriding process of ilmenite in this study, the feasibility of using the method of selective carbonitriding for making rich titanium materials was discussed. The results are as follows:(1)The thermodynamic calculation shows that, under the standard condition, under the condition of the temperature higher than1282K (1009℃), FeTiO3can be reduced to iron and TiC; higher than1363K (1090℃), with the joint action of FeTiO3, C and N2, FeTiO3can be reduced to iron and TiN; higher than1474K (1201℃), TiO2can be reduced to TiN; higher than1503K (1230℃), Ti3O5can be reduced to TiN; higher than1591K (1318℃), Ti3O5can be reduced to TiC; under the above conditions, the carbon nitriding of impurities like Al2O3、CaO、 MgO、SiO2are difficult to be carbon nitriding reducted.So the carbon nitriding reduction of ilmenite selectively is quite feasible on thermodynamics theory.(2)Under the condition of no inner carbon, the metallization rate of the iron component and the grain size of iron increase with rising the reduction temperature or prolonging the reduction time. But more higher reduction temperature and longer reduction time will not improve the metallization rate.Under the contition of the temperature higher than1350℃, the metallization rate of the iron component will descend because of the appearance of liquid performance in the system. The carbon nitriding of the titanium component requires the condition of high temperature and long time,but the degree of transformation is low. The main influence factors of the carbon nitriding of the titanium are the reduction temperature and time. (3)In the reduction process under the condition of inner carbon, increasing the dosage of the inner carbon is in favour of increasing the metallization rate of the iron component and the generation of TiN (C), but the influence to the grain growth of iron is complicated. With low inner carbon, the iron grain is small.When the the amount of carbon increased, the grain of iron grows and when mole ratio of C:Ti high than2.0, the iron grain almost grows the same to that of no inner carbon.(4)when the mole ratio of C:Ti=2.0, the appropriate reduction temperature is1350℃, the appropriate reduction time is2.5h.Contrast the pretreatment institution like high pressure roller grinding and adding cosolvent borax, adding cosolvent borax is in favour of the migration of metal iron and the growing up of the iron particles, and the appropriate amount of borax is3.0%.(5)With the combination of grinding magnetic separation, grinding and re-election process of the concentrates, It can separate Fe and TiN(C) of the reduction products. With this process, It can get the iron concentrate which can be used as raw materials for electric steelmaking and TiN (C) which can be used as raw materials with high-quality for the low-temperature chlorination. The appropriate parameters are:-0.037mm is93.70%for grinding, the magnetic field strength is1000GS, the magnetic separation of concentrate is-0.037mm is around90%for grinding.Under the above condition, it can get the concentrat of iron(the grade of TFe is92.82%), titanium slag-TiO2(the grade is73.67%)and rich titanium materials--TiC (N)(the grade is78.41%)respectively.