针对传统处理高铁铝土矿能耗高、金属提取率低等缺点,提出硫酸氢铵焙烧工艺。在分析广西高铁铝土矿热分解过程的基础上,研究硫酸氢铵加入量、焙烧温度和焙烧时间等工艺参数,采用XRD对反应产物物相进行表征。结果表明:在硫酸氢铵与铝土矿质量比为3.5:1、焙烧温度为450 ℃、焙烧时间60 min 的条件下,铝和铁的提取率分别为93%和95%以上;铝反应的产物为NH4Al(SO4)2,铁反应的中间产物为(NH4)3Fe(SO4)3,最终产物为NH4Fe(SO4)2。该工艺具有焙烧温度低、金属提取率高等特点,对广西高铁铝土矿的开发利用具有重要意义。
A novel process of roasting high-iron bauxite using ammonium bisulfate was proposed to overcome the defects of traditional process, such as high power consumption and low extraction rates. First, the thermodynamics in decomposition process of high-iron gibbsitic bauxite resource in Guangxi was analyzed. Then, various parameters including ammonium bisulfate addition, roasting temperature and roasting time were investigated. The product was also characterized by XRD. The results show that extraction rates of over 93% and 95% respectively for aluminum and iron are obtained after roasting at 450 ℃ for 60 min and mass ratio of ammonium bisulfate to bauxite being 3.5:1. The phase of alumina-containing compounds is always NH4Al(SO4)2 in product. (NH4)3Fe(SO4)3 is produced as intermediate products, and it is replaced by NH4Fe(SO4)2 finally. The process is proved to be significant with the advantages of high extracting rates and low temperature.