Sintering solidification is an effective way to treat soil contaminated with nonvolatile heavy metal. The ceramsite prepared from contaminated soil after sintering can be used as lightweight aggregate in concrete. The preparation process of ceramsite can be divided into two steps: granulation and sintering. As one of the key processes, granulation is directly related to the final solidification and physical properties of ceramsite, and the properties of the clay are directly related to the granulation process. In this work, clays from different regions granulated with disc granulation were studied and compared. The results showed that different clays had significantly different performances in granulation with the same granulation system, and each clay had its own best process parameter. The significance analysis showed that the volume surface mean diameter and the reduction ratio had the most significant impact on the granulated fraction among all the factors. No matter which process parameter was used, as the particle size increased, the granulated fraction increased first and then decreased, and the best results were obtained when the average volume diameter was about 20.5 µm. Furthermore, as the reduction ratio increased, the granulated fraction decreased. These two factors are easy to measure and can be used for predicting the granulation effect of different clays, which can further guide industrial production.
Keywords: ceramsite; clay; disk granulation; granulated fraction; lightweight aggregate; particle size.