Production and quantification of high-purity mullite at 1600 C from kalolinitic clay and calcined alumina

ANGELA X. MORENO, M. BÁRBARA LOMBARDI Y ALBERTO N. SCIAN

REFRACTORIES AND INDUSTRIAL CERAMICS

CONSULTANTS BUREAU/SPRINGER

Lugar: New York; Año: 2015 vol. 56 p. 24 - 30

1083-4877

A study is performed to determine the reaction time which is required at 1600°C to obtain mullite from claywith a high content of kaolinite (clay from the La Rioja Province of Argentina) and from a stoichiometric mixtureof the clay and calcined alumina of grade Almatis-A2G. The chemical composition of the raw materialswas determined and they were studied by x-ray diffraction (XRD) and examined on a scanning electron microscope(SEM). The materials were then mixed in the stoichiometric proportions 3Al2O3·2SiO2and pressedat 100 MPa. The pressed specimens were fired at 1600°C in electric furnaces for different lengths of time:0.25, 0.5, 1, 2, 3, and 5 h. Their density and porosity were determined after they were fired. In the studies performedon the scanning electron microscope and by x-ray diffraction; the crystalline phases were identified bythe Rietveld method and the amorphous phases were determined by means of the Le Bail model. The objectivewas to determine the amounts of primary and secondary mullite that were present and the total mullite content.