Gelation of water-bentonite suspensions at high temperatures and rheological control with lignite addition

Kelessidis, VC; Christidis, G; Makri, P; Hadjistamou, V; Tsamantaki, C; Mihalakis, A; Papanicolaou, C; Foscolos, A

dc.contributor.author	Kelessidis, VC	en
dc.contributor.author	Christidis, G	en
dc.contributor.author	Makri, P	en
dc.contributor.author	Hadjistamou, V	en
dc.contributor.author	Tsamantaki, C	en
dc.contributor.author	Mihalakis, A	en
dc.contributor.author	Papanicolaou, C	en
dc.contributor.author	Foscolos, A	en
dc.date.accessioned	2014-03-01T01:26:23Z
dc.date.available	2014-03-01T01:26:23Z
dc.date.issued	2007	en
dc.identifier.issn	0169-1317	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18056
dc.subject	Bentonite suspensions	en
dc.subject	Gelation	en
dc.subject	High temperature	en
dc.subject	Humic substances	en
dc.subject	Lignites	en
dc.subject	Rheology	en
dc.subject.classification	Mineralogy	en
dc.subject.other	Gelation	en
dc.subject.other	High temperature effects	en
dc.subject.other	Ion exchange	en
dc.subject.other	Lignite	en
dc.subject.other	Rheology	en
dc.subject.other	Suspensions (fluids)	en
dc.subject.other	Viscoplasticity	en
dc.subject.other	Yield stress	en
dc.subject.other	Cation exchange capacity	en
dc.subject.other	Fulvic acid	en
dc.subject.other	Herschel-Bulkley behavior	en
dc.subject.other	Humic acid	en
dc.subject.other	Bentonite	en
dc.subject.other	bentonite	en
dc.subject.other	high temperature	en
dc.subject.other	lignite	en
dc.subject.other	rheology	en
dc.subject.other	stress	en
dc.subject.other	viscosity	en
dc.title	Gelation of water-bentonite suspensions at high temperatures and rheological control with lignite addition	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.clay.2006.09.010	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.clay.2006.09.010	en
heal.language	English	en
heal.publicationDate	2007	en
heal.abstract	The effectiveness of lignite addition to prevent gelation of 6.42% w/w water-bentonite suspensions exposed to high temperatures has been studied, using twenty six lignites from various basins in Greece with variable organic and inorganic contents at concentrations of 0.5% and 3.0%. The lignite-free bentonite suspensions thickened considerably when heated at 177 degrees C for 16 h, as was indicated by a two-fold increase of the yield stress, when compared to samples hydrated only at room temperature. However plastic viscosity did not change appreciably. Full flow curves showed a Herschel-Bulkley behavior of all suspensions. Addition of lignite maintained the stability of the suspensions exposed to high temperatures (177 degrees C) by keeping the yield stress low and did not affect plastic viscosity. Some of the Greek lignites performed equally well with a commercial lignite product and improvements of 80 to 100% of the stability of the suspensions, compared to lignite-free suspensions, have been found. Lignite addition also lowered yield stresses for the hydrated samples. No specific trends have been identified between the effectiveness of lignites to stabilize bentonite suspensions and their humic and fulvic acids and humins content. However, those lignites with highest humic and fulvic acid contents have maximum stabilization capacity. Similarly, no specific trends have been observed between the stabilization capacity of lignites and their inorganic components such as oxygen and ash content and also with the cation exchange capacity. The effectiveness of the Greek lignites to stabilize bentonite suspensions is very high and the minor differences in the efficiency of the different lignites cannot be attributed solely to any specific component. (c) 2006 Elsevier B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Applied Clay Science	en
dc.identifier.doi	10.1016/j.clay.2006.09.010	en
dc.identifier.isi	ISI:000246746200001	en
dc.identifier.volume	36	en
dc.identifier.issue	4	en
dc.identifier.spage	221	en
dc.identifier.epage	231	en