Effect of alumina addition on the phase transformation and crystallisation properties of refractory cordierite prepared from amorphous rice husk silica

Abstract

The effect of alumina addition of 5-30% by weight on phase transformation and crystallisation properties of refractory cordierite ceramics prepared from amorphous rice husk silica followed by sintering treatment at temperature of 1230 • C was studied. The crystallinity and microstructure of the samples were characterised using X-ray diffraction (XRD) coupled with Rietveld analysis, scanning electron microscopy (SEM), respectively. Some physical properties include density, porosity, hardness, bending strength, and thermal expansion coefficient of the samples with different alumina additions were measured. The results show that addition of alumina promoted crystallisation of cordierite into crystalline spinel, corundum, cristobalite, in which with addition of 10-30% alumina, the cordierite phase was practically undetected. Addition of alumina was also found to increase the amount of spinel, while corundum and cristobalite decreased following alumina addition of 10-30%. The presence of spinel, corundum, and cristobalite resulted in increased of density, hardness, bending strength and thermal expansion coefficient, while for porosity, the opposite was observed. Thermal expansion coefficient of the samples with alumina addition of 15-30% reach the relatively constant value of 9.5 × 10 −6 / • C, with the main crystalline phase was spinel, accompanied by corundum and cristobalite in smaller quantities.

Rice husk/rice husk ash as an alternative source of silica in ceramics: A review

“…The low thermal conductivity of RHA also leads to a gradual decrease in the temperature of steel, and moreover to its uniform solidification. In addition, several researchers are trying to use RHA in the production of advanced refractories, such as cordierite [57,58], forsterite [59] and mullite refractories [60].…”

Analisis Transisi Fasa dan Sifat Dielektrik Pada Li2CoSiO4 yang Dipreparasi dari Silika Sekam Padi dan Produk Daur Ulang Katoda Baterai Ion Litium Bekas

“…Dalam sejumlah penelitian, silika sekam padi telah dimanfaatkan sebagai material awal untuk memproduksi berbagai jenis material. Dalam penelitian kami sebelumnya, silika sekam padi telah berhasil dimanfaatkan untuk memproduksi sejumlah material keramik dengan kemurnian yang tinggi, seperti cordierite (Sembiring et al, 2016;Sembiring et al, 2017a;Sembiring et al, 2018), forsterite (Sembiring et al, 2017b), dan aluminosilikat geopolimer (Riyanto et al, 2017). Dalam penelitian lain, silika sekam padi juga telah dimanfaatkan dalam pembuatan material mullite (Sembiring and Simanjuntak, 2012), borosilicate (Sembiring et al, 2011), dan karbosil (Simanjuntak et al, 2012).…”

Formation of anorthite containing cordierite materials through reaction sintering kaolin, MgO and CaO precursors

“…Due to the unavailability of cordierite as natural material [8], it is usually prepared from diverse raw and/or waste materials using many methods [8][9][10][11][12][13][14][15][16][17]. However, reaction sintering abundant natural clay minerals and/or waste [4,7,[18][19][20][21][22][23][24] remained the preferred way to produce unexpansive cordierite materials. Intentionally, additives such as nickel dioxide [25], zinc [26], phosphorous and boron oxides [27], phosphorous oxide [28], ceria [29], nickel dioxide and titania [30], barium oxide [31], magnesia [32,33], and calcium oxide [8,[34][35][36][37] are added to ease the nucleation and growth of cordierite.…”