Institute of Geology of Karelian Research Center of RAS (Petrozavodsk, Russia):

Frolov P. V., Researcher, e-mail: pf@sampo.ru

Ilina V. P., Senior Researcher, Candidate of Engineering Sciences

Klimovskaya Е. Е., Junior Researcher

This article studies the effect of a mineral composition of soapstone and related chlorite and amphibole rocks on the strength of the ceramic tiles.

The mineral composition of samples was determined by optical microscopy, X-ray diffraction (XRD), derivatography (DTA) and using an electron microscope VEGA II LSH with an attachment for INCA Energy 350 microanalysis at a magnification of 150-1200 times, rarely– 2000-4000 times.

Two-component ceramic masses are prepared for investigation. These masses contain 30 % of soapstone or chlorite-amphibole rock and 70% of hydromica clay from Ivinskoe deposit (Ladvinsky area). Ceramic masses are produced according to the standard technology. Tiles roasting is carried out at 950 and 1050 °C. In this range of temperatures, according to XRD and DTA, there are considered the processes of hydromicas dehydration, disintegration of chlorite, carbonate, talc and tremolite with the formation of new crystalline phases.

The properties of ceramic tiles were studied. The addition of filler to the fusible hydromica clay increases the water absorption of ceramic tiles at 2-3%, compared with the initial water absorption of clay, corresponding to State Standard 6141-91 (up to 16%). This filter is a soapstone or chlorite-amphibole rock. In this case, the mechanical strength of tiles increases. Tiles with the addition of chlorite-actinolite rock have the greatest strength (42,94 MPa). Certain processes contribute to an increase of the ceramics strength with the addition of samples, such as: the processes of disintegration and recrystallization of chlorite, talc and amphibole with the formation of finely dispersed olivine and pyroxene (clinoenstatite and augite) phases; enrichment of the amorphous phase of magnesium. Tabular and acicular tremolite and actinolite grains do not disintegrate upon roasting. These grains reinforce ceramics with addition of chlorite-amphibole rocks. According to this, its shape is retained after thermal treatment.

The studies have shown that the basic varieties of Karelian soapstones and chlorite-amphibole rocks are the promising types of raw materials for highly durable ceramic tile production. The usage of dimension stone waste for this purpose can help to solve the problem of its utilization.

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