摘要
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。
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.
基金
国家八五重点科技攻关项目
关键词
硼铁矿
热重法
还原动力学
ludwigite ores, thermogravimetry, reduction kinetics, reaction of gas-solid phase, diffusivity.
