Volcanic ash as alternative raw materials for traditional vitrified ceramic products

Abstract

Investigation on the use of volcanic ash as 100% raw materials for traditional vitrified ceramic products is reported. X-ray diffraction (XRD), thermogravimetric-thermal differential analyses (DTA-TGA) and chemical analysis were used to characterise raw samples. Fired specimens were used to evaluate their ceramic properties. Volcanic ash contains essentially classical traditional ceramic oxides, plagioclase, pyroxene and olivine as principal minerals. In the temperature range 1100-1150°C, they present dense structure, low open porosity, without isolated quartz grains. The fired materials properties were found to be in agreement with those of stoneware class BI referring to standard ISO 13006 (i.e. the water absorption values were <1.5%). The presence of a sufficiently extended glassy phase capable of embedding crystalline phases developed during sintering allows comparison of the microstructure of fired volcanic ash with that of traditional porcelain or stoneware. © 2007 Institute of Materials, Minerals and Mining

Sintering behaviour, microstructure and mechanical properties of low quartz content vitrified ceramics using volcanic ash

“…In previous work, 14 fresh fractured specimens of fired volcanic ash were studied and the microstructure compared to those of conventional traditional ceramics (stoneware and porcelainised stoneware). In this work, observation of etched specimens allows better investigation on the various crystalline phases present, their concentration and interlocking.…”

“…In the first part of this study, 14 samples of volcanic ash selected could be grouped in two classes according to their fusibility. For the present part of the study, one sample of each group is represented: Z4 and Z6.…”

Recycled natural wastes in metakaolin based porous geopolymers for insulating applications

“…The white variety as described by Njoya [16] which is a sand-poor kaolin, 76-85% kaolinite and 2-9% quartz with illite, muscovite, anatase and hematite as secondary minerals was selected. The kaolin was sieved to eliminate the residual quartz sand, dried and calcined at 700°C for 4 h. The volcanic ash was from the Mungo deposit [19] in the Littoral region of Cameroon. The material presents essentially an amorphous matrix in which fine grains of anorthite, entastiteaugite, diopside are embedded [19,20].…”

“…The kaolin was sieved to eliminate the residual quartz sand, dried and calcined at 700°C for 4 h. The volcanic ash was from the Mungo deposit [19] in the Littoral region of Cameroon. The material presents essentially an amorphous matrix in which fine grains of anorthite, entastiteaugite, diopside are embedded [19,20]. Rice husk was collected in a rice mill at Ntarikon-Bamenda in the North-West Region of Cameroon.…”

The Effect of Surface-Treated Anhydrous Borax Additions on Hard Porcelain Properties

“…These necessities have made the investigation of alternative raw materials inevitable, and there has been much research on new raw materials to be used in porcelain production [9]. In recent years, some primary and secondary raw materials, such as iron and steel slag [10], volcanic ash [11,12], mine waste [13], rice straw ash [14], sugarcane bagasse ash [15], diopside [16], glass waste [17], wollastonite [18], colemanite [19,20], and sandstone dust [21] have been used as alternative raw materials for porcelain production.…”