高硫高碳铝土矿在氧化铝生产中的实践及探讨

遵义某氧化铝厂使用高硫、高碳铝土矿,采用拜耳法生产氧化铝,系统中铝酸钠溶液成分复杂,物料黑而黏稠,对生产过程影响明显,造成氧化铝产品铁含量升高、粒度周期性爆发细化、设备腐蚀、循环效率大幅下降、能耗明显升高等一系列问题。在铝土矿含硫量不超过0.3%的情况下,在高温溶出过程中添加一定量的硝酸钠氧化低价硫,可保证氧化铝产品铁含量满足一级品要求,生产能稳定运行,并在一定程度上减缓对设备的腐蚀。工业试验结果表明,针对进入流程中的低价硫和有机物,氧气湿法深度氧化脱硫脱碳技术不仅可以氧化系统中的低价硫,同时可实现对有机物的部分氧化,效果和成本比添加硝酸钠更好。

Practice and Discussion of High-Sulfur and High-Carbon Bauxite in Alumina Production

High-sulfur and high-carbon bauxite is used in an alumina refinery in Zunyi by Bayer process. Due to its long-term use of this type bauxite, composition of sodium aluminate solution in system is complex, and material is black and viscous, which has a big impact on production, resulting in increase of iron content of alumina products, periodic explosion and refinement of particle size, equipment corrosion and low cycle efficiency. Under the condition that sulfur content of bauxite does not exceed 0.3%, adding a certain amount of sodium nitrate to oxidize low sulfur in process of high temperature dissolution can ensure that iron content of alumina products can meet the requirements of first-grade products, production can run stably, and corrosion of equipment can be reduced to a certain extent. The industrial test results show that oxygen wet deep oxidation desulphurization and decarbonization technology can not only oxidize low sulfur in system, but also realize partial oxidation of organic matter, with better effect and lower cost than adding sodium nitrate.