Abstract: During the production of sulfuric acid integrated with cement from phosphogypsum, it is common to have wall adhesion in rotary kiln because of particle agglomeration, blocking the pipeline and thus the operation.By comparing the profiles of XRF, XRD and SEM of the deposit and the fluidized powder change of adhesion during the thermal decomposition of phosphogypsum were investigated.The results show that the Si-containing and Al-containing mineral level in the deposit substance are higher than those in the fluidized powder, indicating adhesion and enrichment of most clay mineral impurities on the wall.As the reaction proceeded, increasing calcium oxide content markedly eased particles' adhesion.Thus it was suggested that, for phosphogypsum power impurities like SiO2 and Al2O3 not only affected the decomposition but also severely influenced the agglomeration and adhesion of the particles during the fluidization process.

Key words: phosphogypsum;fluidization;adhesion;agglomeration