Physical and Mechanical Properties of Non-Stoichiometric Cordierite with Treated FGD Sludge Addition Sintered at 1250°C

The effects of addition treated FGD sludge in non-stoichiometric cordierite, by benefiting from its high mechanical strength and good thermal performance, can hold promise for more practical applications of non-stoichiometric cordierite. Treated FGD sludge waste from borosilicate glass industrial were used as a flux to reduce the sintering temperature of cordierite. Cordierite ceramics were prepared using silica (SiO2), alumina (Al2O3), talc, kaolin, magnesia (MgO) and treated FGD sludge via solid-state reaction method. The cordierite were prepared by adjusting the ratio of FGD sludge and magnesia in the cordierite composition, respectively. 4 composition of cordierite with 0%, 1.5%, 3.0% and 4.5% of FGD sludge were prepared to obtain the formation of α-cordierite that can be determine by X-ray diffraction (XRD) analysis. Porosity, density, shrinkage and flexural strength for each of cordierite composition were determined to obtain the best composition of treated FGD sludge required for sintering aids of cordierite. Only FGD 3.0% able to synthesis pure α-cordierite while FGD 1.5 % shows an improvement in both porosity and density. The increasing amount of treated FGD sludge lead to decreasing in mechanical strength of cordierite ceramic due to porous formation.

A Study of Cordierite Ceramics Synthesis From domestic kaolin

This work aims to study the effect of chlorine ion on the formation of the cordierite phase (2MgO.2Al2O3.5SiO2) from domestic kaolin at various calcined temperatures.. The cordierite phase was synthesized by a solid-state reaction technique from the mixture of kaolin, aluminum nitrate nonahydrate (Al(NO3)3.9H2O), and magnesium chloride hexahydrate (MgCl2.6H2O) which was designed to the stoichiometric composition of cordierite in the absence and presence of chlorine ion (NH4Cl). The structure and formation of cordierite phase were characterized by X-ray diffraction (XRD) and thermogravimetric - differential thermal analysis (TG-DSC). Phase composition of samples calcined at various temperatures was calculated by using Match! (Version 3.7.0) software. It is noteworthy that the presence of chlorine ion in the mixture declined the formation temperature of cordierite by 50 °C. The cordierite phase was calculated to be 61.3 wt.% and 5.5 wt.% at 1150 °C for the present and absent chlorine ion, respectively. The presence of chlorine ion affected the cordierite formation rate and suppressed the temperature of formation. Cordierite phase could be obtained up to 89.6 wt.% at 1250 °C and 30 wt.% NH4Cl. This investigation found that cordierite ceramic could be synthesized from domestic kaolin at lower temperature by using NH4Cl additive.

Porous Cordierite Ceramics From Mineral and Synthetic Raw Material Compositions

This work is dedicated to the study of the development of porous cordierite ceramics using two types of illite clays as pore formers. The work has the structure of a classical scientific paper containing the following sections – introduction, literature review, description of materials and methods, presentation of results, and conclusions. The theoretical part of the Thesis describes cordierite as an important mineral phase, its polymorphism, as well as the production, properties and application of ceramics formed from this phase. The materials and methods section details the materials and methods used in the work. The practical part of the Thesis describes the production of cordierite ceramics and its physical-mechanical and thermal properties as well as the analysis of the structure of the obtained materials. It shows that by varying the technological parameters of synthesis different morphology porous cordierite ceramics can be obtained. The resulting materials are considered to be the most economically viable alternative to existing synthetic materials due to their improved material properties – bending and compression strength, thermal expansion coefficient and thermal conductivity.

Effect of Talc in Mixtures with Fly Ash on Sintering Crystalline Phases and Porosity of Mullite-Cordierite Ceramics

The effect of talc in the two mixtures with the representative sample of fly ash (Class F) was investigated at sintering temperatures of 1000, 1100, and 1200 °C. X-ray diffraction, thermal DTA/TGA, and mercury intrusion porosimetry analyses were applied to characterize the mineral phase transformation of talc and fly ash in cordierite ceramic. The influence of iron oxide on talc transformation to Fe-enstatite was verified by the simulated molecular models and calculated XRD patterns and the assumption of Fe-cordierite crystallization was confirmed. The fly ash mixtures with 10 mass% of talc in comparison with 30 mass% of talc at 1000 °C and 1100 °C showed higher linear shrinkage and lower porosity. At a temperature of 1200 °C, sintering expansion and larger pores in mullite and cordierite ceramics also containing sapphirine and osumilite demonstrated that magnesium in FA and Tc structure did not react with the other constituents to form crystalline cordierite. The ceramics produced in the present work using fly ash and talc have similar properties to the commercial ceramics produced at sintering temperatures higher than 1250 °C.