Effect of large additions of Cd, Pb, Cr, Zn, to cement raw meal on the composition and the properties of the clinker and the cement

The Hydration of Heavy Metal Salts Admixtured High Alumina Cement – A X-Ray Diffraction Study

“…The increasing C 3 AH 6 peak observed at 28 th day is indicative of reduction in strength. A close scrutiny of the spectra at different time intervals reveals that the presence of Cd delays the formation of C 3 AH 6 phase (Murat and Sorrentino et al, 1996). This may retard the setting time but does not modify the strength very much.…”

“…Comparing the amount of the phases with control, it is observed that the loss in strength created through C 3 AH 6 is compensated by C 2 AH 8 phases (Table 2). In addition peaks observed for calcium chloroaluminates and gehlenite at 28 th day is also compensated by C 2 AH 8 phase thereby making the strength almost equal to control (Murat, et al, 1996).…”

Alternative Fuels in Cement Manufacturing

“…On the other hand, although zinc oxide acts as a flux as well as mineraliser, it is known to have detrimental effect on the quality of cement if it is in excess. It strongly retards the setting time and strength of the cement if the total zinc content of all fuels exceeds 4000 parts per million (PPM) (STMC, 1992;Olmo et al, 2001;Murat & Sorrentino, 1996). Therefore, other than the problems of incomplete combustion, the zinc oxide content in tyres tend to limit its displacement of conventional fuels in cement production (STMC, 1992).…”

Efecto del ZnO, ZrO₂ y B₂O₃ en el proceso de clinkerización. Parte I. Reacciones de clinkerizacion y composición de los clínkeres

“…These authors studied the effect of ZnO in hydration processes and found that its presence in cement lengthened setting times, although this effect was less intense when the ZnO was included in clinker phases (9). According to several authors (10,11), ZnO is fixed essentially in the alite and interstitial phases of the clinker. Odler et al (12) concluded that tricalcium silicate can take up around 4% ZnO, while Bolio-Arceo and Glasser (10), who studied the interaction between ZnO and the aluminate phases, detected the formation of mineral phases 6CaO·3ZnO·2Al 2 O 3 and 3CaO·ZnO·2Al 2 O 3 .…”

“…Estos autores estudiaron el efecto del ZnO en los procesos de hidratación, observando que su presencia en el cemento alarga los tiempos de fraguado, siendo este efecto menor si el ZnO está incorporado en las fases del clinker (9). De acuerdo a varios autores (10,11) el ZnO se encuentra fijado fundamentalmente en la estructura de la fase alita y fase intersticial del clinker. Odler et al (12) concluyeron que el silicato tricálcico es capaz de incorporar alrededor de un 4% de ZnO.…”