Characteristics of illite clay and compositions for porous building ceramics production

摘要

The carbonates containing Quartenary clay of the Zemgales region (Latvia) were examined for porous ceramics development. The particle distribution of clay indicates a relatively small (up to 40%) presence of typical clay particles - illite and kaolinite. To contribute to pores development in fired ceramic materials, sawdust or straw 25 vol% and both half-and-half were used as additives to clay in starting mixes. The thermal treatment of starting mixes with 25 vol.% of sawdust or straws shows appearance of exothermic changes with the maximum at a temperature 167 and 334 °C, related to the decomposition of components from sawdust or straw. It is accompanied with a relatively high amount of heat exude. The differential pore size distribution in ceramics fired at 955-960 °C with 25% additive of sawdust is characterized by a porous texture with predominant pores in the range 0.1-1.0 μm. In case of additional straw, the pore size is somewhat shifted to the greater scale of microns.