高硫高铁铝土矿悬浮焙烧同步脱硫除铁试验研究

中国铝土矿资源质量每况愈下，高品位铝土矿资源日渐枯竭，资源问题已成为中国铝工业发展的重要难题，而尚未得到工业规模开发利用的高硫高铁铝土矿属于难利用资源，具有巨大的潜在工业价值，对高硫高铁铝土矿开展脱硫除铁基础研究具有重要的理论与实际意义。本文针对广西高硫高铁铝土矿综合开发利用难题，采用“悬浮氧化焙烧-还原焙烧-磁选”工艺进行了系统的铝土矿脱硫除铁试验,并利用X射线衍射分析（XRD）、化学物相分析和X射线光电子能谱分析（XPS）等方法，研究了焙烧过程中矿物物相的转化。结果表明，矿物中主要含硫和含铁矿物为黄铁矿；采用“悬浮氧化焙烧-还原焙烧-磁选”工艺可同步实现硫元素的高效脱除和铁元素的富集分离；当悬浮氧化焙烧条件为焙烧温度700℃，焙烧时间40 min，O2浓度40%，总气量600 mL/min，可获得St为0.396%，脱硫率为98.10%的氧化焙烧产品。然后进行悬浮还原焙烧条件为焙烧温度550℃，焙烧时间20 min，CO浓度20%，总气量600 mL/min，磁场强度150 kA/m时，可获得TFe为54.79%的铁精矿和St为0.248%、TFe为4.37和Al2O3含量为75.27%的富铝矿。此技术大幅度提高了高硫高铁铝土矿的Al2O3含量，有利于后续铝土矿溶出，达到了脱硫除铁提铝的技术目标。该工艺为该类难选高硫高铁铝土矿资源的高效利用提供了一种新的技术途径。

Experiment of Suspension Roasting Desulfurization and Iron Removal of High-Sulfur and Iron Bauxite

The quality of bauxite resources in China is deteriorating, and the high-grade bauxite resources are depleting day by day, the resource problem has become an important problem for the development of China"s aluminum industry, and the high sulfur and high iron bauxite, which has not yet been exploited on an industrial scale, belongs to the difficult-to-use resources, and it has a huge potential industrial value, and it is of great theoretical and practical significance to carry out the basic research on desulfurization and removal of iron from high sulfur and high iron bauxite. In this paper, for the comprehensive development and utilization of high sulfur and high iron bauxite in Guangxi, a systematic test of desulfurization and iron removal from bauxite was carried out by using the process of "suspension oxidation roasting-reduction roasting-magnetic separation", and the transformation of mineral phases in the roasting process was studied by using the methods of X-ray diffraction analysis (XRD), chemical phase analysis, and X-ray photoelectron spectroscopy (XPS), etc. The test was carried out on the basis of "suspension oxidation roasting- reduction roasting- magnetic separation". The results show that the main sulfur-containing and iron-containing minerals are pyrite; the process of "suspension oxidation roasting-reduction roasting-magnetic separation" can simultaneously realize the efficient removal of sulfur and the enrichment and separation of iron; when the conditions of suspension oxidation roasting are roasting temperature of 700 ℃, roasting time of 40 min, O2 concentration of 40%, and the total gas volume of 600 mL/min, the desulfurization rate of 98.10% can be obtained. 600 mL/min, the oxidized roasting product with St of 0.396% and desulfurization rate of 98.10% can be obtained. Suspension reduction roasting was then carried out under the conditions of roasting temperature of 550 ℃, roasting time of 20 min, CO concentration of 20%, total gas volume of 600 mL/min, and magnetic field strength of 150 kA/m, which resulted in an iron ore concentrate with TFe gread of 54.79% and aluminum-rich ore with St of 0.248%, TFe grade of 4.37 and Al2O3 content of 75.27%. This technology substantially increases the Al2O3 content of high sulfur high iron bauxite, which is conducive to the subsequent dissolution of bauxite and achieves the technical goal of desulfurization and removal of iron to raise aluminum. This process provides a new technical way for the efficient utilization of this kind of difficult to select high sulfur high iron bauxite resources.