Reuse of heavy metal-containing sludges in cement production

The feasibility of the replacement of raw material for cement production by heavy metal-containing sludge from surface finishing and electroplating industries was investigated. The effect of heavy metal content in the cement raw mix on the crystalline formation in cement production was also examined by XRD analyses. It was found that both sludges were applicable for the replacement of raw mix for cement production by moderate conditioning of the sludge compositions with several compositional parameters. As the replacement of raw mix by sludge was within 15%, the formation of tricalcium silicate (C3S) phase in cement would be enhanced by the introduced heavy metals. While owing to a high level of heavy metals concentration (>1.5%) in cement raw mix, C3S crystalline in cement would be inhibited by a large sludge replacement (>15%). During the sintering process, over 90% of the high volatile elements such as Pb would evaporate in high temperature, yet 90% of the less volatile elements such as Cu, Cr and Ni would be trapped in clinkers. Most of all, the results of leaching test shows that the trapped elements in hydrated samples would not leach out under acidic conditions. The reuse of heavy metal-containing sludges as cement raw material would not cause leaching hazard from sintered clinkers. Heavy metal-containing sludges thus should have the potential to be utilized as alternative raw materials in cement production. D 2005 Published by Elsevier Ltd.

[1]  Edward H. Smith,et al.  Lead Removal in Fixed Beds by Recycled Iron Material , 2000 .

[2]  Mridul Garg,et al.  Making of anhydrite cement from waste gypsum , 2000 .

[3]  Konstantinos G. Kolovos,et al.  The effect of foreign ions on the reactivity of the CaO–SiO2–Al2O3–Fe2O3 system , 2001 .

[4]  D. Knöfel,et al.  High intakes of Cr, Ni, and Zn in clinker: Part I. Influence on burning process and formation of phases , 1999 .

[5]  Maneesh Singh,et al.  Preparation of special cements from red mud , 1996 .

[6]  D. Knöfel,et al.  Influence of Cr, Ni, and Zn on the properties of pure clinker phases: Part II. C3A and C4AF , 1999 .

[8]  D. Knöfel,et al.  High intakes of Cr, Ni, and Zn in clinker: Part II. Influence on the hydration properties , 1999 .

[9]  C. S. Brooks Recovery of nonferrous metals from metal finishing industry wastes , 1993 .

[10]  N. Kikukawa,et al.  Thermal plasma in-flight treatment of electroplating sludge , 2002 .

[11]  Denise Crocce Romano Espinosa,et al.  Laboratory study of galvanic sludge's influence on the clinkerization process , 2000 .

[12]  Recovery of chromate from electroplating sludge , 2000 .

[13]  Della M. Roy,et al.  Sulfoaluminate-belite cement from low-calcium fly ash and sulfur-rich and other industrial by-products , 1999 .

[14]  Jorge Alberto Soares Tenório,et al.  Laboratory testing of the use of phosphate-coating sludge in cement clinker , 2000 .

[15]  Ryunosuke Kikuchi,et al.  Recycling of municipal solid waste for cement production: pilot-scale test for transforming incineration ash of solid waste into cement clinker , 2001 .

[16]  R. Mark Bricka,et al.  A review of potentially low-cost sorbents for heavy metals , 1999 .

[17]  D. Knöfel,et al.  Influence of Cr, Ni, and Zn on the properties of pure clinker phases: Part I. C3S , 1999 .

[18]  P. Shih,et al.  Replacement of raw mix in cement production by municipal solid waste incineration ash , 2003 .

[19]  Ahmad Monshi,et al.  Producing Portland cement from iron and steel slags and limestone , 1999 .