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Influence of pH and precipitation temperature on the structural characteristics of aluminium hydroxides prepared form nitrate aqueous solutions

dc.contributor.authorVollet, D. R.
dc.contributor.authorDonatti, D. A.
dc.contributor.authorDomingos, R. N.
dc.contributor.authorCamargo, H.
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:28:00Z
dc.date.available2014-05-20T15:28:00Z
dc.date.issued1996-01-01
dc.description.abstractAluminium Hydroxides were precipitated from Aluminium Nitrate and Ammonium Hydroxide, at the temperatures 64 degrees C (hot) and 25 degrees C (cold), under the pH conditions 5, 7 and 9. The samples were characterized by X-Ray Diffraction (XRD) and Differential Thermal Analysis (DTA). The hydroxide precipitated at pH 9 and 64 degrees C is built up by pseudoboehmite and a minor share of others apparently amorphous hydroxides. The crystallinity of the hot yielded pseudoboehmite diminishes with the pH. The crystallite size was evaluated as about 40 Angstrom for the best crystallized sample. The cold precipitated product is apparently composed by amorphous or very poorly crystallized hydroxides. Upon heating, the cold precipitated hydroxides, and the low pH and hot precipitated hydroxide, release their structural water before the occurrence, about 430 degrees C, of the transition of the pseudoboehmite to gamma-alumina, and exhibit a shifting (towards low temperature side) and a broadening in the peak of the transition to alpha-alumina, which occurs at 1200 degrees C in the pseudoboehmite pattern. The yielded pseudo-boehmite peptized by HNO3, addition and gelified by evaporation in a critical concentration approximately 0.17 gcm(-3).en
dc.description.affiliationUNESP,INST GEOCIENCIAS & CIENCIAS EXATAS,DEPT FIS,BR-13500230 RIO CLARO,SP,BRAZIL
dc.description.affiliationUnespUNESP,INST GEOCIENCIAS & CIENCIAS EXATAS,DEPT FIS,BR-13500230 RIO CLARO,SP,BRAZIL
dc.format.extent11-18
dc.identifierhttp://www.scielo.br/scielo.php?script=sci_issues&pid=0100-4670
dc.identifier.citationEcletica Química. São Paulo: Editora Unesp, v. 21, p. 11-18, 1996.
dc.identifier.issn0100-4670
dc.identifier.lattes2661573794233385
dc.identifier.lattes3538107401166553
dc.identifier.lattes1257794767301021
dc.identifier.urihttp://hdl.handle.net/11449/37914
dc.identifier.wosWOS:A1996WH62900001
dc.language.isopor
dc.publisherEditora Unesp
dc.relation.ispartofEclética Química
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.subjectboehmitept
dc.subjectpeptizationpt
dc.subjectsol-gelpt
dc.subjectaluminapt
dc.titleInfluence of pH and precipitation temperature on the structural characteristics of aluminium hydroxides prepared form nitrate aqueous solutionsen
dc.typeArtigo
dcterms.licensehttp://www.scielo.br/revistas/eq/paboutj.htm
dcterms.rightsHolderEditora Unesp
unesp.author.lattes2661573794233385
unesp.author.lattes3538107401166553
unesp.author.lattes1257794767301021
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Geociências e Ciências Exatas, Rio Claropt
unesp.departmentFísica - IGCEpt

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