Using phosphorites in the production of building ceramics

The feasibility of replacing feldspars, pegmatites and perlites in ceramic batches with unbeneficiated phosphorites from the Dzeroi-Sardarinsk deposits for the manufacture of building ceramics, in particular, internal wall tiles was studied. The chemical composition of the raw materials and the composition of the trial bodies is given. The preparation of tiles is described. Glazed tiles were tested for water absorption, total shrinkage, flexural strength and thermal shock resistance. The advantages of replacing feldspar concentrates by phosphorites in tile bodies was established. As the tests reveal, there is no need for preliminary beneficiation of the raw material. The use of fast firing kilns excludes the use of saggars and reduces the firing temperature by 50-70 C. However, the use of natural, unbeneficiated phosphorite leads to a slight deterioration in the deflocculating capacity of the slip, and so it is necessary to use reagents. 4 refs.