Assessment of the fluxing potential of igneous rocks in the traditional ceramics industry

authors	Dias, FG; Segadaes, AM; Perottoni, CA; Cruz, RCD
nationality	International
journal	CERAMICS INTERNATIONAL
author keywords	Igneous rocks; Hierarchical cluster analysis; Ceramic fluxes; Phase diagrams
keywords	PORCELAIN STONEWARE TILES; NEPHELINE-SYENITE; PYROPLASTIC DEFORMATION; BODY; CLASSIFICATION; BEHAVIOR; BODIES; CLAYS; WASTE; LAVAS
abstract	In this work, the fluxing characteristics of igneous rocks from the Serra Geral Formation (RS, Brazil) were assessed and compared with those of more common fluxes used in the ceramic industry. To this aim, 18 rock samples were characterized (XRF, XRD). Based on their chemical composition, samples were categorized (QAPF TAS diagrams) and grouped into five major rock types using a hierarchical cluster analysis (FICA). Representative rocks of each type were further characterized in terms of thermal behaviour (TGA-DSC and fusibility tests) and compared with similar characterization results available in the literature for other ceramic fluxes. Tests results showed very good agreement with HCA and the prediction's of the SiO2 Al2O3 CaO phase diagram. A synergistic effect was identified between alkali + alkali-earth oxides and iron oxide, suggesting that the fluxing potential can be estimated in terms of the alumina/fluxes weight ratio, resulting in a pleasant dark chocolate sheen of the fired pieces. Thus, the mineral resources identified in the Serra Geral Formation can indeed be used as fluxes and, as such, contribute to the cost-effective production of ceramic materials with higher added value.
publisher	ELSEVIER SCI LTD
issn	0272-8842
year published	2017
volume	43
issue	18
beginning page	16149
ending page	16158
digital object identifier (doi)	10.1016/j.ceramint.2017.08.190
web of science category	Materials Science, Ceramics
subject category	Materials Science
unique article identifier	WOS:000414106600016