Influence of firing temperature on ceramic properties of kaolinitic clays from Duthuni, Limpopo Province (South Africa)
type: CreativeWork
description: This study investigated the ceramic suitability of two representative kaolin samples from Duthuni area, subjected to four firing temperatures (800 oC, 900 oC, 1000 oC and 1100 oC).The objectives were to ascertain the effects of the raw clay physical, mineralogical, chemical characteristics on its ceramic potential, elucidate on the thermal evolution and associated mineral phase transformations, and to technologically characterize the raw clays. Physical properties were identified by particle size distribution, consistency limits and clay activity. Mineralogical and chemical properties were investigated by XRD, FTIR and XRF. Firing characteristics were measured by weight loss (WL), bulk density (BD), linear shrinkage (LS), water absorption (WA) and flexural strength (FS). The characteristic mineral assemblage comprised; quartz + kaolinite ± mica + microcline + goethite + hematite + anatase + ilmenite. Quartz occurred as major constituent in both samples, while kaolinite, Goethite and Anatase are present as minor constituents. Visual appraisal of the clay workability chart indicated that D1 and D2 plot within the high shrinkage field, with D1 displaying comparatively higher potential for shrinkage than D2. The potential for high shrinkage suggests possible detrimental effects during clay body formulation (extrusion and molding) as well as firing phases of the ceramic manufacturing process. Interpretations drawn from the Holtz and Kovacs diagram are consistent with the mineral phases identified by XRD. Kaolinite was the main clay mineral in both samples, occurring as minor constituent. The loam to silty texture of D2 and and D1 respectively are consistent with the predominance of quart phases revealed by the XRD and Si – O functional groups observed in the IR. The studied materials are siliceous (SiO2: 38.5–45.5 wt%), aluminous (Al2O3: 23.9–16.7 wt%) and ferruginous (Fe2O3: 23.5–21.3 wt%), with the SiO2/A Al2O3 ratios ranging from 1.61 to 2.71. The geochemistry of the …
abstract: This study investigated the ceramic suitability of two representative kaolin samples from Duthuni area, subjected to four firing temperatures (800 oC, 900 oC, 1000 oC and 1100 oC).The objectives were to ascertain the effects of the raw clay physical, mineralogical, chemical characteristics on its ceramic potential, elucidate on the thermal evolution and associated mineral phase transformations, and to technologically characterize the raw clays. Physical properties were identified by particle size distribution, consistency limits and clay activity. Mineralogical and chemical properties were investigated by XRD, FTIR and XRF. Firing characteristics were measured by weight loss (WL), bulk density (BD), linear shrinkage (LS), water absorption (WA) and flexural strength (FS). The characteristic mineral assemblage comprised; quartz + kaolinite ± mica + microcline + goethite + hematite + anatase + ilmenite. Quartz occurred as major constituent in both samples, while kaolinite, Goethite and Anatase are present as minor constituents. Visual appraisal of the clay workability chart indicated that D1 and D2 plot within the high shrinkage field, with D1 displaying comparatively higher potential for shrinkage than D2. The potential for high shrinkage suggests possible detrimental effects during clay body formulation (extrusion and molding) as well as firing phases of the ceramic manufacturing process. Interpretations drawn from the Holtz and Kovacs diagram are consistent with the mineral phases identified by XRD. Kaolinite was the main clay mineral in both samples, occurring as minor constituent. The loam to silty texture of D2 and and D1 respectively are consistent with the predominance of quart phases revealed by the XRD and Si – O functional groups observed in the IR. The studied materials are siliceous (SiO2: 38.5–45.5 wt%), aluminous (Al2O3: 23.9–16.7 wt%) and ferruginous (Fe2O3: 23.5–21.3 wt%), with the SiO2/A Al2O3 ratios ranging from 1.61 to 2.71. The geochemistry of the …
author: Miyambu, Mihleketo Oscar
language: en
keywords: Kaolinite, Ceramics, Technological property, Sintering, Thermal behaviour
date published: 2024-05-17
date modified: 2026-07-27T21:57:48Z
provider: University of Venda
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Venda