拜耳法外排赤泥铝硅比升高原因及抑制措施的探讨

Basic cause of upped Al/Si ratio of red mud discharged in BayerProcess Division and an approach to its restrictive measures

随着我厂近年来“抬高工艺起点,深挖潜力,提产降耗,控制生产成本”的不断深入,整个氧化铝生产工艺已由原来的混联法逐步过渡为现在的拜耳———混联法(即部分拜耳法赤泥外排)。拜耳法外排赤泥量的加大及外排赤泥A/S升高必然带来氧化铝生产矿耗、碱耗的相应增加,影响系统的经济运行。本文根据我厂拜耳法部分的工艺流程具体情况,从物料的反应机理及实际的操作条件,详细地分析了拜耳法物料在高压溶出、稀释、分离、洗涤沉降和赤泥过滤各段的变化,提出了应采取的相应措施,及取得的良好经济效益。

Our productional technology of alumina has entirely evolved a current Bayer Mixed/Combined Process with some red mud discharged from the original Mixed/Combined Process as a result of continual execution of the policy of elevating technological level,deep tapping,potentialities,increasing production and reducing raw materials consumption ,and controlling production cost in recent years.It was expected that the increaced amount of red mud discharged and its consequent upped Al/Si ratio could lead up to corresponding increase of ore and caustic soda consumptions with the result of higher unit production cost and lower economical operation effects.Proceeding from the specific technological conditions of Bayer Process ,reaction mechanism of reactive materials ,and actual operational conditions ,a comprehensive analysis of material balance and variation on each main production step ,such as high pressure digestion ,dilution of digested slurry ,solid/liquid separation with red mud washing in thickeners, filtratration ,and then after some corresponding measures were presented and executed afterwards with better economical performances.