Pitch adsorption on natural and modified talcs
Talc is used traditionally for pitch control in papermaking. The effectiveness of talcs as control agent of dissolved and colloidal pitch depends on its structural and surface characteristics of minerals. Talcs are modified by thermal and surface treatments to obtain different properties e.g specifi...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2009 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/51656 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/51656 |
| Access Level: | acceso abierto |
| Palabra clave: | Talc Modified talc Pitch Pitch control Wood extractives Industria del papel Ingeniería química 3312.13 Tecnología de la Madera 3303 Ingeniería y Tecnología Químicas |
| Sumario: | Talc is used traditionally for pitch control in papermaking. The effectiveness of talcs as control agent of dissolved and colloidal pitch depends on its structural and surface characteristics of minerals. Talcs are modified by thermal and surface treatments to obtain different properties e.g specific surface, surface energy, surface charge and ratio lypophilic/hydrophilic surface. Five commercial talcs have been tested to determine its capacity to adsorb the lypophilic contaminants by experiments of adsorption isotherms. The talcs correspond to two groups of different mineralogical compositions: one with high concentration of talc and some dolomite; and the other, with medium concentrations of talc and chlorite. Colloidal dispersions of extractives were obtained by extraction of Eucalyptus globulus wood at pilot plant scale with acetone, evaporation of the solvent and reextraction with hexane to increase the selectivity of lypophillic compound extraction. The isotherms of adsorption of the pitch dispersions were carried out at 50ºC on the different talcs. The adsorption took place by a mechanism of colloidal adsorption and the results obtained were adjusted to the Langmuir equation. Results show that talc addition to bleaching waters or process waters can produce high reductions of colloidal pitch concentrations, at comparatively low doses. |
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