高硫铝土矿的应用基础研究

Bauxite resource has beenig poorness may lead to our country import many bauxite to produce alumina, which account for more 40% of total alumina product. It can increase not only the cost for producing alumina, but also influence the survival and development of our country aluminium industry. However, large numbers of high-sulfur bauxite are not obtained application in China. So it is urgent affair to speed up the development and perfect self-innovation technology for high-sulfur bauxite and increase utinization ratio of bauxite resource. The degree of sulfur entering solution related to sulfur shape of high-sulfur bauxite and leaching condition, and so on. So study deeply on mineralogy characteristic and leaching rule of the high-sulfur bauxite, how inhibitting the sulfur enter into solution, behavior mechanism of sulfur in leaching process, and the influence law of sulfur shape in alumina produce system to desulfuring are important science problem with urgent to be solved. We propose basis on obtaining high Al2O3 leaching rate, decrease sulfur leaching rate as possible, then choice suitable process for removal of sulfur, and recycling desulfuration residue for preparation of desulfurizer, thus theoretical foundation is established for exploitation and application of high-sulfur bauxite. The project research has not only important sociel and economic benefits, but also has guiding significance for promoting development of aluminium industry and perfecting technology of alumina producing in China.

我国铝土矿资源日趋贫乏，导致每年进口铝土矿生产的氧化铝占国内产量的40%以上，这不仅提高了氧化铝生产成本，同时也将威胁我国铝工业的生存和发展。而我国大量的高硫铝土矿没有获得应用。因而，加快开发和完善自主创新的高硫型铝土矿的基础应用研究、提高铝土矿资源利用率显得非常迫切。硫转入溶液的程度与高硫矿中硫的矿物形态及溶出条件等因素有关。因此，深入研究高硫铝土矿的矿物学特征、溶出规律、如何抑制硫进入溶液、硫在溶出过程的行为机制以及系统中硫存在形态对脱硫的影响规律是急需解决的重大科学问题。在获得高氧化铝溶出率的基础上，尽量降低硫的溶出率，进行适当的工序脱硫，并回收脱硫渣，为高硫铝土矿的开发应用奠定理论基础。该项研究不仅具有重大的社会和经济效益，而且对推动我国铝工业的发展、完善氧化铝生产技术具有重要的指导意义。

高硫铝土矿获得工业应用的关键是如何实现经济可行的脱硫方式，通过系统研究高硫铝土矿的矿物学特征、硫铝土矿的溶出共性规律、优化溶出工艺、工序脱硫、硫对种分过程的影响、蒸发过程强化排盐及脱硫渣的回收利用，可有效低脱硫成本。.主要研究结论：（1）贵州高硫铝土矿主要化学成分为Al2O3、SiO2、Fe2O3、TiO2和ST，硫主要以黄铁矿形态存在，呈粒状不均匀地嵌布于一水硬铝石或含水铝硅酸盐矿物中，自形晶较少，结晶析出时形成了细粒晶体，部分黄铁矿被鲕状铝土矿交代溶蚀呈骸晶。（2）硫和铝的溶出率影响程度大小顺序为：温度>Nk>石灰添加量>时间，随着温度增加、铝和硫的溶出率增加；氧化铝溶出率随着苛碱浓度增加，而硫的溶出率降低，但当碱浓度大于245g/l后，对硫的溶出率影响逐渐变小；在此基础获得了“高温低碱”的优化溶出工艺条件，大幅降低硫的溶出率，减轻了后续脱硫负担。（3）自制脱硫剂铝酸钡的较佳合成条件为：温度T＝1350℃，分子比R＝1.1，时间t＝80min，合成率达到98.43%，产品纯度为95.2%，堆积密度为为1.5g/cm3，体积平均粒度为89.808μm。（4）种分母液脱碳率为42%~82%，脱硫率可达81.34%~88.14%；苛化后液脱硫率可达90%以上，每脱除1kg硫，约需12~15kg脱硫剂。（5）硫含量的增加对分解产生明显的抑制作用，铝酸钠溶液密度、粘度及比表面积都会随着硫量的增加而增大，而电导率则随着硫含量的增加而减小；当硫含量大于3.8g/L后，使得晶种表面活性降低，造成产品的细化。（6）蒸发过程同时添加H2O2和Na2CO3晶种，可获得较好的强化排盐效果。（7）将脱硫渣与强氧化钡混合焙烧，制得铝酸钡脱硫剂，实现其循环利用，经济环保，有助于实现高硫铝土矿的工业应用。.通过项目研究，培养硕士生7名，发表文章22篇，申报专利6项，授权4项，获贵州省科技进步二等奖1项；