硼铁矿石固相还原动力学

用热重法研究了硼铁矿石氢气还原动力学。氢气流量600ml/min,温度600～1000℃。实验结果表明,矿石结构、孔隙度和颗粒的大小对还原率有明显的影响。单一方向还原实验表明,气体在产物层孔隙的扩散对还原速度影响显著,是还原的控制步骤。将实验数据用TURK-DOGAN内扩散速度方程处理,求出H_2-H_2O气体在产物层孔隙中有效扩散系数D_o值随还原温度下降而明显减小。

Reduction Kinetics of Ludwigite Ores

The reduction kinetics of ludwigite ores was studied by thermogravimetry at 600-1000@ with a hydrogen flowrate of 600ml/min. Experimental results showed that the structure, porosity and particle size of ludwigite ores have a significant effect on the reduction rate. Furthermore, the unidirectional reduction experiments revealed that the gas diffusion through porous product layer is a rate-controlling process. With Turkdogan's equation of internal diffusion fate used to experimental data processing, the useful diffusivity of H2-H2O gas in porous product layer, Dc, is determined and it will decrease obviously with the lowering reduction temperature.