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Mineral scale management. Part II, Fundamental chemistryAuthor(s): Alan W. Rudie; Peter W. Hart
Source: Tappi journal. Vol. 5, no. 7 (2006) pages 17-23.
Publication Series: Miscellaneous Publication
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DescriptionThe mineral scale that deposits in digesters and bleach plants is formed by a chemical precipitation process.As such, it is accurately modeled using the solubility product equilibrium constant. Although solubility product identifies the primary conditions that must be met for a scale problem to exist, the acid-base equilibria of the scaling anions often control where in the process scale will occur. These equilibria are the primary control method to minimize or prevent scale in a bleach plant. Both the acid-base equilibria and solubility product equilibria are influenced by temperature and ionic strength. This paper reviews the chemistry of precipitation and acid-base equilibria. The Gibbs free energy expression is presented as a method to estimate equilibrium constants at temperatures in the bleach plant.The effect of ionic strength on ion activity and its influence on these processes are also discussed.
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CitationRudie, Alan W.; Hart, Peter W. 2006. Mineral scale management. Part II, Fundamental chemistry. Tappi journal. Vol. 5, no. 7 (2006) pages 17-23.
KeywordsCalcium carbonate, ion exchange, acid-base equilibrium, anions, chemical equilibrium, anions, chemical equilibrium, precipitation, calcium oxalate, pulping, pulp mills, incrustations, solubility, barium sulphate, wood-pulp, bleaching, chlorine dioxide, lime, digesters, pulp and paper processes
- Fundamental chemistry of precipitation and mineral scale formation
- Mineral scale management Part III, Nonprocess elements in the paper industry
- Modeling of bleach plant washer mineral scale
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