Evaluation of Phosphatic Clay and Other Wastes for Construction Products: I. Tile
An extensive series of experiments concerning ceramic tile body and glaze compositions and test evaluations have been conducted on a number of ceramic tiles formulated with different phosphatic clays from the central Florida phosphate district, combined with fly ash, phosphogypsum or grog. The purpose of this investigation was to determine if any improvement could be made in the body composition which would decrease the shrinkage, warpage and cracking found in the sample produced for the feasibility study which contained only phosphatic clay and fly ash. A second purpose was to determine if a glaze could be found for this improved body composition which could be produced in a single firing glaze and body combination. Some success was obtained in both objectives. A body containing 55% phosphatic clay, 40% fly ash and 5% grog produced a reasonable balance or trade-off in properties, improving the working properties for processing a tile in a commercial plant. Although a greater-than-desired amount of porosity and water absorption was present in this fired body, the marketing properties of the glazed body with a Gerstley borate-type glaze enhanced the market value of the tile and reduced the undesirable effects that porosity would have on the final product.