高脱色力活性白土的制备工艺研究

Study on preparation of acid activated bentonite with high decolouring capacity

以钙基膨润土为原料、以硫酸为活化剂,对活性白土制备的主要工艺参数进行了详细的试验研究,并根据活化产物的化学成分和结构的变化分析了酸法活化的机理。研究结果表明,影响活性白土脱色力的主要因素为酸度、温度及活化时间,高脱色力活性白土可以通过三者的合理组合来实现,在最佳工艺条件下,活化产品的脱色力可以达到210以上。研究发现,活化产品的脱色力与蒙脱石八面体位阳离子的脱除率关系密切,当八面体位阳离子的脱除率为30%左右时,活化产物的脱色力达到最大值。此外还发现,随着活化产物脱色力的增加,蒙脱石的b轴有序度逐渐降低。

Tests of main process parameters of preparing acid activated bentonite were carried out by using Ca-bentonite as raw material and sulfuric acid as the activation reagent. The acid activation mechanism was analyzed according to the change of chemical composition and structure of activated product. The results indicated that main factors affecting the decolouring capacity of the activated product were acid concentration, temperature and activation time, and the optimum conditions could be obtained by a variety of combinations of the three factors. Under the optimum activation conditions, the decolouring capacity of the activated bentonite could reach up to about 210,whereas the decolouring capacity of the raw material is about 16. The study also showed that the decolouring capacity of the activated bentonite was closely related with the removal rate of octahedral cation of montmorillonite, and the decolouring capacity of the activated product reached its maximum value when the removal rate of the octahedral cation reached about 30%. Furthermore, it had been found that the b-axis order degree of montmorillonite decreased gradually along with the increase of decolouring capacity.