Effect of Excess Magnesia on the Preparation of Cordierite Based on Waste Foundry Sand

Abstract

Waste foundry sand collected from lost foam casting industry is a solid waste that contains ZrSiO4. For the purpose of re‐utilization, it is adopted to synthesize cordierite with the addition of MgO powders and fused silica by direct sintering, meanwhile the effect of various MgO mole ratios on the sintering behaviors is investigated using XRD, SEM, and mercury porosimetry. The lowest temperature corresponding to the formation of cordierite is 1150°C, and the increase of MgO mole ratio does not reduce the temperature for cordierite crystallization but increase the microhardness and thermal expansion coefficients.

STRUCTURAL AND PHYSICAL PROPERTIES OF REFRACTORY CORDIERITE PRECURSORS PREPARED FROM RICE HUSK SILICA WITH DIFFERENT M g O ADDITION

“…MgO addition on the cordierite ceramic led to impede the formation of cordierite, as suggested by the formation of forsterite and silimanite phases [19], and also presence of spinel [21], and cristobalite [14]. In addition, the excess MgO can decrease the melting and crystallization temperature [22], and Xiang, et.al [ 23] observed that the increase of MgO did not obviously reduce the temperature for cordierite crystallisation, but increase the hardness and thermal expansion coefficient. Al 2 O 3 addition on the cordieite promote crystallisation of cordierite into crystalline spinel, corundum and cristobalite [24].…”

Enhanced flexural strength and microwave dielectric properties of Li2MgTi3O8-based low temperature co-fired ceramics

“…Compared to the t f value of LMT ceramics doped with TiN, the absolute value of t f increased. This is because MgO has a large negative resonance frequency temperature coefficient (À56 ppm 1C À1 ), 32 and the research shows that the addition of MgO increases the thermal expansion rate of the ceramics, [33][34][35] and the higher thermal expansion rate will reduce the t f value, and thus, the temperature stability of LMT-NFM ceramics is reduced. Doping some ions with a positive temperature coefficient can be considered to make the t f value closer to zero.…”

Sustainable ceramics derived from solid wastes: a review

“…Some studies also have found to investigate with RHA as an alternate of conventional silica sources for the preparation of cordierite [165][166][167]. Another author Xiang et al (2016) [168] have used waste foundry sand (solid waste from metal casting industries) as a source of silica and alumina to prepared cordierite. [169] have prepared the porous cordierite ceramics using ferrochromium slag along with commercial silica and alumina powder without any pore-forming ingredients.…”