Abstract: Crude iron-rich bentonites were investigated by metallic element analysis. The bentonite samples were grinded and sieved to obtained micro-particles with the size lower than 160 Mesh, then acidification was carried out in order to remove metallic (mainly Fe) impurities. During treatment, the influences of the sort and concentration of acid, acidified time, calcination temperature on decoloring capability were discussed. By means of washing by water, filtering, drying and calcinating, acidified products were obtained, and then tested the whiteness of the product after calcination. In the decoloring experiments, the optimum conditions were obtain as follows: the concentration of nitric acid is 8 mol/L, acidified times 16 h, calcination temperature 550 ℃, calcination times 2 h.Under these conditions, the color of the samples is transformed from brown-red to milky white. The samples whiteness changes from 43.0 to 81.6.

Key words: Bentonite , Decolour , Metallic ion , Whiteness

摘要： 对矿产粗制富铁膨润土进行了金属元素分析。通过对矿产粗制膨润土进行研磨、筛分取小于160目
的细微颗粒进行酸处理以脱除膨润土中的金属杂质(主要是铁)。经水洗、过滤并用硫氰化钾检验处理效果、干燥、
焙烧等步骤最终以焙烧产品的色泽确定对产品的脱色效率。考察了酸种类、浓度、处理温度和时间以及焙烧温度对
脱色效果的影响。结果表明,在膨润土脱色过程中,在室温下,8mol/L的浓硝酸,酸处理16h,焙烧温度为550 ℃,
焙烧时间为2h,在该条件下制备的产品颜色由原始的棕红色脱变为乳白色,白度值由43.0提高到81.6。

关键词: 膨润土 , 脱色 , 金属离子 , 白度