A Study of the Phase Composition of a More than One-Hundred-Year-Old Ceramic Material

Abstract

The studied object is a more than hundred-year-old ceramic material taken from a distillery in the village of Rozhdestveno, Samara oblast. The elemental chemical composition of the studied material shows an increased carbon content (C = 9.48 wt %), which is indicative of the introduction of fuel into the raw brick. The pressing of fuel into the raw brick allows one to carry out the firing process without fuel losses, since the chemical reaction of carbon with oxygen, steam, carbon dioxide, and clay oxides occurs intensively at temperatures of 800°C and above, while a reducing medium is formed inside the product, which helps to increase the mechanical strength of the baked shard. In addition, CO burns out on the surface of the material, which intensifies the baking. The diffusion of oxygen into the bulk of the product promotes carbon burnout and accelerates baking. Clay minerals do not melt when heated to 1000°C, but the increased content of alkali oxides (R₂O = 3.78 wt %) promotes the formation of mixtures with a melting point of 950°C. The liquid phase, even in small quantities, plays a very important role in increasing the sintering of the shard, effectively gluing the mineral particles of the ceramic mass into a single entity. The increased contents of the oxides of calcium (CaO = 9.42 wt %), magnesium (MgO = 2.875 wt %), and aluminum (Al₂O₃ = 18.45 wt %) in the test sample contribute to the formation of anorthite and diopside, which increase the strength of the products.