Behavior of ordinary Portland cement during the stabilization/solidification of synthetic heavy metal sludge: Macroscopic and microscopic aspects
- Inst. National des Sciences Appliquees de Lyon, Villeurbanne (France). Lab d`Analyse Environnementale des Procedes et des Systemes Industriels
- Lafarge Lab. Central de Recherche, St. Quentin Fallavier (France)
Chromium and/or zinc hydroxide sludges were mixed at variable proportions with OPC, in order to evaluate the macroscopic and microscopic effects caused by the waste on the cement hydration process. Initial setting time, heat production during hydration, leaching characteristics and microstructure of the samples were investigated using varied techniques. For zinc hydroxide sludge, hydration was stopped after a few minutes, because of the precipitation of a solid hydrated phase. Since the sludge:cement ratio remains under 2--3:1, chromium hydroxide sludge accelerated the cement hydration. For higher ratios, hydration was hindered. Some microstructural modifications have been detected, such as the possible formation of a U-phase analog, related to the presence of chromate ions in the sludge. The influence of the oxidation degree of chromium on its fixation in the matrix is discussed.
- OSTI ID:
- 323561
- Journal Information:
- Waste Management, Vol. 18, Issue 1; Other Information: PBD: 1998
- Country of Publication:
- United States
- Language:
- English
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