碳饱和铁液与Cao-SiO_2-TiO_2系熔渣间TiO_2的还原

REDUCTION OF TiO_2 IN THE CARBON-SATURATED MOLTEN IRON AND CaO-SiO_2-TiO_2 SLAG SYSTEM

实验研究了碳饱和铁液与 CaO-SiO_2-TiO_2((%TiO_2)<18)系熔渣间(TiO_2)的还原速度,同时考察了初渣碱度、温度对(TiO_2)还原速度的影响.研究结果表明:在本实验体系中,在初渣碱度 B=(%CaO)/(%SiO_2)=0.54～1.5范围内,随着碱度的升高,(TiO_2)的还原速度加快,而温度的提高也能加快(TiO_2)的还原速度.建立了在该实验体系中(TiO_2)被铁液中的溶解碳还原的速度模型,模型考虑了还原反应产生的 CO 气泡逸出渣层时对渣层产生的环流作用,实验数据与模型计算结果符合程度较好.通过数学模拟,得到了该体系中(TiO_2)被铁液中的溶解碳还原的两个重要参数:表观反应速度常数和 Ti 在渣铁间的分配比.结果表明该体系中(TiO_2)的还原反应为表观二级反应,过程受渣中(Ti^(4+))的传质控制,表观反应速度常数随着渣碱度或温度的升高而增大,反应表观活化能为66.60kcal/mol.当碱度B<1.5时,Ti 在渣铁间的分配比(%Ti)/[%Ti]随着碱度的升高或温度的升高而降低.

The kinetic experiments of reductron of TiO_2 in a CaO-SiO_2-TiO_2 slag system by carbon-saturated molten iron are carried out under different conditions of temperature and basicity.The results show that the rate of reduction of(TiO_2)can be speeded up markedly by raising either basicity or temperature.The reduction rate model is set up with consideration of circulation flow in molten slag caused by CO bubbles which evolve due to the reduction of(TiO_2)by dissolved carbon and the model prediction shows a good accordance with the experimental data.It is also concluded that in this experimental system,the reduction of (TiO_2)by dissolved carbon is apparent an 2nd order reaction;the process is controlled by transport of(Ti^(4+)) in slag;the higher the basicity of temperature,the larger the reduction rate constant,and the apparent activation energy is 66.60 kcal/mol.The calculated partition coefficients of Ti between molten iron and slag demonstate that under the conditions of basicity and temperature mentioned above,the partition coefficients decrease with increasing of either basicity of slag or temperature.