Effects of Fe2O3 on crystallisation and properties of R2O–CaO–MgO–Al2O3–SiO2–Fe2O3 glass ceramics

ABSTRACT The R2O–CaO–MgO–Al2O3–SiO2–Fe2O3 glass ceramics was prepared using granite wastes and Fe2O3. The effect of Fe2O3 on crystallisation and properties of glass ceramics was studied. Results show that the crystalline phases were Fe2TiO5 and K(NaCa)Mg5Si8O22F2 when the content of Fe2O3 was low. The main crystalline phase was Fe1.5Ti0.5O3 when the content of Fe2O3 was high. With the increase of Fe2O3, the crystal size of K(NaCa)Mg5Si8O22F2 reduced and the atomic ratio of Si to Mg increased. The colour of sample varied from greyish green to black with different additions of Fe2O3. The flexural strength with a maxim (101.02 MPa) when the content of Fe2O3 was 4.7 mol-%. Given the low cost of granite wastes and Fe2O3, this new type of black glass ceramics is expected to meet the increasing demand from the market of building decoration due to its excellent properties.