CAJ | 학술논문

采用收缩未反应核模型研究Al-Si-Fe合金真空热还原煅后白云石制镁过程动力学,考察了制团压力、还原温度(T)和添加氟盐对镁还原率(R)的影响.结果表明,在40～150 MPa内,制团压力越大,镁还原率越高:添加氟盐可加快还原反应速率,提高镁还原率.确定了还原过程最佳工艺条件为:还原温度1413 K、还原时间(t)120 min、真空度4 Pa、制团压力150 MPa、CaF_2添加量3%.在1 373～1 413 K内,还原过程为一级反应,由还原剂通过固体产物层的内扩散步骤控制,宏观动力学方程为1+2(1-R)-3(1-R)~(2/3)=0.194exp(-8.38×10~3/T)t,表观活化能为69.7 kJ/mol.
채용수축미반응핵모형연구Al-Si-Fe합금진공열환원단후백운석제미과정동역학,고찰료제단압력、환원온도(T)화첨가불염대미환원솔(R)적영향.결과표명,재40～150 MPa내,제단압력월대,미환원솔월고:첨가불염가가쾌환원반응속솔,제고미환원솔.학정료환원과정최가공예조건위:환원온도1413 K、환원시간(t)120 min、진공도4 Pa、제단압력150 MPa、CaF_2첨가량3%.재1 373～1 413 K내,환원과정위일급반응,유환원제통과고체산물층적내확산보취공제,굉관동역학방정위1+2(1-R)-3(1-R)~(2/3)=0.194exp(-8.38×10~3/T)t,표관활화능위69.7 kJ/mol.
Vacuum thermal reduction kinetics of calcined dolomite with Al-Si-Fe alloy was studied using shrinking unreacted-core model. The effects of pellet forming pressure, reduction temperature (T), and villaumite on reduction rate (R) of calcined dolomite were investigated. The results show that within the pellet forming pressure from 40 to 150 MPa, the reduction rate is increased with increasing of the pressure. Villaumite can accelerate the reduction rate and then increase the reduction rate, and the optimal conditions are reduction temperature 1413 K, reduction time (t) 120 min, vacuity 4 Pa, pellet forming pressure 150 MPa and addition ofCaF_2 3%. The reduction process is the first order reaction and controlled by diffusion of reductant in solid product layer. The equation for the reduction kinetics is 1 +2(1-R)-3(1-R)~(2/3)=0. 194exp(-8.38 ×10~3/T)t, and the apparent activation energy 69.7 kJ/mol.