Glazes from wastes obtaining

Autores: Capatina, C.|Simonescu, C.M.|Florea, G.
Fuente: Metalurgia International
17(1), 16-21
2012

The paper presents an issue of topical interest which is the recovery of some industrial wastes in obtaining of some useful products. Recovery of processed wastes resulted from the fabrication process of E fiber glass can be also made for the obtaining of some vitreous glazes for the household faience. To obtain vitreous glazes were used, in addition to the waste and frit from E fiber glass, raw materials such as feldspar and kaolin that are usually used. Wetting behavior of raw materials mixture samples, still not melted was experimental determined. The variation of the wetting capacity with temperature was monitored through the measurement of the angle theta for the cathetometer, an apparatus equipped with a magnifier for the visualization of the sample in the oven and a revolving cursor for the angle measurement. Melting was made in alumina crucibles, in electric furnaces equipped with resistors at a temperature of 1340 degrees C for three hours. Samples resulting after melting were cast as rods. Thermal thermal expansion curves were determined with a differential dilatometer Weiss type. In laboratory were conducted tests for application of glazes on support and were made slips with two glazes compositions which were applied by brush on the support of tile required. The samples were left far drying for 12-14 hours and then were thermally treated for 30 minutes at 1200 degrees C. Experiments were conducted by the manufacturer of household support with fits grounded on its technological line for obtaining glazed products.Samples from the products resulting were taken for performing of scanning electron microscopy analysis at the interface coating – support that confirms the important role of interface to ensure the concordance mass- glaze needed for glazing process. The experimental results indicate that experimental values of the thermal expansion coefficients of the glazes are lower than the thermal expansion coefficient of the support – which gives a convenient mass-glaze concordance. The theta wetting angle decreases with the increasing of the waste content (embedded under a fit or milled fibers shape), which indicates an increasing of the humectation capacity for the samples that contain frit. The SEM micrographics for the support-glaze interface indicate a well defined interface and the presence of an intermediate phase between glaze and ceramic support.