Laboratory testing of the use of phosphate-coating sludge in cement clinker

The present work studies, in a laboratory apparatus, the co-processing of p hosphating coating process sludge in the process of clinker production. A m ixture of racy clinker materials and increasing concentrations of phosphati ng sludge produced the samples analysed. These mixtures were burned at 1450 degrees C for 10 min in an electric furnace. The sludge used basically con tained water, ferrous and zinc phosphates, apart from minor elements such a s Na, K, S, Pb, Cr and Cu. The raw meal used was obtained in a Brazilian ce ment plant. The results showed no damage to the clinkerization process with an addition of up to 7.0% sludge. The formation of atypical phases was not observed with additions of up to 5.0%. The major element of the sludge, zi nc, shows an average of incorporation of 75%. (C) 2000 Elsevier Science B.V . All rights reserved.