白云鄂博铁精矿硫氧化焙烧过程动力学研究

Research on the kinetics of sulfur oxidation roasting in Baiyunebo iron ore process

白云鄂博铁精矿通过氧化焙烧工艺能够实现有害元素硫的有效脱除,为了进一步强化氧化焙烧过程,确定脱硫反应的限制性环节,本文在探明白云鄂博铁精矿中硫元素赋存状态的基础上,对氧化焙烧脱硫反应动力学规律及其氧化反应机理进行了研究.结果表明:白云鄂博铁精矿中硫元素主要以黄铁矿和磁黄铁矿形式存在,各占34.48%,64.23%(质量分数,%);在整个氧化焙烧过程中硫元素的脱除主要发生在干燥二、预热二段,其脱硫率分别为39.44%,28.89%;干燥二与预热二段氧化反应均符合收缩未反应核动力学模型且均受内扩散控制,反应活化能分别为35.82,59.86 kJ·mol^(-1).

Oxidizing roasting process can effectively remove the harmful elements S in the Baiyunebo iron ore concentrate. In order to further strengthen the oxidation roasting process and determine the limiting part of the desulfurization reaction,the kinetics of oxidation desulfurization reaction and the oxidation mechanism were studied based on the state of sulfur elements in the Baiyunebo iron ore concentrate. The results show that the elemental sulfur exists mainly in the form of pyrite and pyrrhotite in the Baiyunebo iron ore concentrate,accounting for 34. 48% and 64. 23% in mass fraction,respectively. During the process of oxidation roasting,the removal of sulfur mainly occurs in the second drying process and the second preheating stage,accounting for 39. 44% and 28. 89%,respectively. The reaction during the second drying process and the second preheating stage not only corresponded with the contracting and shrinking unreacted nuclear kinetic model,but were controlled by internal diffusion as well,whose reaction activation energy was 35. 82 kJ·mol^-1 and 59. 86 kJ·mol^-1,respectively.