高硫铝土矿悬浮态焙烧脱硫

Desulfurization roasting of high sulfur bauxite in suspended state

采用自主开发的高固气比悬浮焙烧-快速冷却装置对贵州地区硫质量分数为1.35%的高硫铝土矿进行850kg/h规模的焙烧脱硫实验。探讨悬浮态焙烧对脱硫过程和焙烧矿的影响规律。对硫物相和XRD谱进行分析。研究结果表明：悬浮态低温焙烧可实现高硫铝土矿的快速脱硫,升高焙烧温度有利于提高脱硫率;硫化物型硫的残留量降至0.08%（质量分数）之后,脱硫过程趋于完成;FeS_2脱硫反应伴随着金属氧化物吸收SO_2的反应,细颗粒对SO_2具有更强的吸收能力;高硫铝土矿粉料在悬浮炉内的有效停留时间约2 s,焙烧炉内温度控制在610~640℃,焙烧矿中硫化物型硫质量分数可以降低到0.16%以下。低温闪速焙烧-冷却使得偏高领土呈高度无序的非晶相结构,相对于原料中的一水硬铝石,焙烧矿中的α-Al_2O_3晶体得到细化,有利于Al_2O_3的溶出。

Desulfurization roasting of high sulfur bauxite（S mass fraction of 1.35%） from Guizhou province was employed by high solid-gas roasting-cooling device, with feeding capacity of 850kg/h. The influence of desulfurization process and roasted ore in suspended state roasting was investigated. Sulfur phase analysis and X-ray diffraction analysis were carried out. The results show that the sulfur content in high sulfur bauxite is rapidly decreased through lowtemperature suspended state roasting, and the desulfurization efficiency is improved with higher temperature. The desulfurization reaction tends to be complete after sulfide sulfur mass fraction decreases to 0.08%. The reaction of metal-oxide absorbing SO_2 is accompanied with the desulfurization of FeS_2, and fine particles have better absorbing capacity of SO_2. The best roasting temperature of high sulfur bauxite in suspended state is between 610 ℃ to 640 ℃ and the effective residence time in the flash calciner is about 2 s. The sulfide sulfur mass fraction decreases to less than 0.16%. The metakaolin forms a highly disordered amorphous structure during the flash roasting-cooling process. Relative to diaspora in raw ore, the crystal of α-Al_2O_3 is refined by roasting to the benefit of the leaching of Al_2O_3.