Use of gypsum/brucite mixed precipitate instead of gypsum in Portland cement

Agatzini-Leonardou, S; Karidakis, T; Tsakiridis, PE

dc.contributor.author	Agatzini-Leonardou, S	en
dc.contributor.author	Karidakis, T	en
dc.contributor.author	Tsakiridis, PE	en
dc.date.accessioned	2014-03-01T01:23:18Z
dc.date.available	2014-03-01T01:23:18Z
dc.date.issued	2005	en
dc.identifier.issn	0268-2575	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/16892
dc.subject	Brucite	en
dc.subject	By-product	en
dc.subject	Cement	en
dc.subject	Gypsum	en
dc.subject	Hydration	en
dc.subject.classification	Biotechnology & Applied Microbiology	en
dc.subject.classification	Chemistry, Multidisciplinary	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.other	Byproducts	en
dc.subject.other	Compressive strength	en
dc.subject.other	Gypsum	en
dc.subject.other	Hydrated lime	en
dc.subject.other	Hydrometallurgy	en
dc.subject.other	Leaching	en
dc.subject.other	Magnesium printing plates	en
dc.subject.other	Nickel	en
dc.subject.other	Portland cement	en
dc.subject.other	Precipitation (chemical)	en
dc.subject.other	Stoichiometry	en
dc.subject.other	Sulfuric acid	en
dc.subject.other	Brucite	en
dc.subject.other	Cement production	en
dc.subject.other	Hydrolytic precipitation	en
dc.subject.other	Sulfate solution	en
dc.subject.other	Cement manufacture	en
dc.subject.other	calcium hydroxide	en
dc.subject.other	calcium sulfate	en
dc.subject.other	cement	en
dc.subject.other	magnesium hydroxide	en
dc.subject.other	nickel complex	en
dc.subject.other	sulfuric acid	en
dc.subject.other	cement	en
dc.subject.other	article	en
dc.subject.other	cement industry	en
dc.subject.other	compression	en
dc.subject.other	controlled study	en
dc.subject.other	dilution	en
dc.subject.other	environmental temperature	en
dc.subject.other	high temperature procedures	en
dc.subject.other	hydrolysis	en
dc.subject.other	leaching	en
dc.subject.other	mechanical stress	en
dc.subject.other	physical chemistry	en
dc.subject.other	precipitation	en
dc.subject.other	qualitative analysis	en
dc.subject.other	quantitative analysis	en
dc.subject.other	reference value	en
dc.subject.other	stoichiometry	en
dc.subject.other	time	en
dc.title	Use of gypsum/brucite mixed precipitate instead of gypsum in Portland cement	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/jctb.1199	en
heal.identifier.secondary	http://dx.doi.org/10.1002/jctb.1199	en
heal.language	English	en
heal.publicationDate	2005	en
heal.abstract	The possibility of replacing the natural gypsum used in cement production by a chemical precipitate consisting of gypsum (CaSO4.2H(2)O) and brucite (Mg(OH)(2)), was investigated. This precipitate is a by-product of a new hydrometallurgical process, which was developed in order to treat economically low-grade nickel oxide ores. More specifically, it is obtained by hydrolytic precipitation of magnesium at temperatures not exceeding 80degreesC, from sulfate solutions which result from heap leaching of nickel oxide ores with dilute sulfuric acid at ambient temperature, using calcium hydroxide as a neutralizing agent. The mixture generally consists of 20-30% non-fibrous magnesium hydroxide, 60-75% gypsum and any excess of calcium hydroxide, depending on the precipitation conditions. In the present work, a mixture was produced by hydrolytic precipitation at 25degreesC, using 1.1 times the stoichiometric quantity of Ca(OH)(2) required to precipitate all of the magnesium. The possibility of using the above precipitate as a substitute for gypsum in cement was examined by testing four different cement mixtures, one reference sample, containing 4.5% gypsum and 0.5% anhydrite ((PC)(Ref) ) and another three with 4.1%, 5.2% and 6.3% of gypsum/brucite mixed precipitate ((PC)(B/G)), in the place of gypsum. All samples were tested by determining the grindability, setting time, expansion and compressive strength. The results of the physico-mechanical tests showed that the replacement of natural gypsum by the above precipitate did not affect negatively the quality of the produced cements. (C) 2005 Society of Chemical Industry.	en
heal.publisher	JOHN WILEY & SONS LTD	en
heal.journalName	Journal of Chemical Technology and Biotechnology	en
dc.identifier.doi	10.1002/jctb.1199	en
dc.identifier.isi	ISI:000227341500012	en
dc.identifier.volume	80	en
dc.identifier.issue	3	en
dc.identifier.spage	320	en
dc.identifier.epage	324	en