Tile processing, drying

Using inorganic salts as precursors, alcohol as tile supercritical drying agent, and a batch process a solvent-exchange step was necessary to remove water from the gel... 

Solids can also be dried at room temperature on filter paper or porous tile. You should protect the substance from dirt and dust by covering with filter paper or a funnel. A vacuum desiccator will greatly speed up the drying process, and should be used on products that are destroyed by the small amount of water in the atmosphere. A vacuum desiccator is shown in Figure 4. 

Figure 7.26 Compaction behavior of KBr powder and spray-dried granules of alumina and clay tile as a function of punch pressure. From J. S. Reed, Principles of Ceramics Processing, 2nd ed. Copyright 1995 by John Wiley Sons, Inc. This material is used by permission of John Wiley Sons, Inc.

Tiles may be classed under throe divisions, paving tiles, roofing tiles, and drain tiles, each of which comprehend numerous other varieties. The great distinction betwoen tiles and bricks arises from the greater thinness of the former, and the consequent necessity of increased purity and tenacity in the mass greater care is also bestowed upon tho processes of their manufacture, tiles being always dried undsr cover. 

Using alkoxides as precursors, carbon dioxide as tile drying agent, and a semicontinuous process the diying procedure became safer and faster. Introduction of organic aerogels. 

After the drying the firing process follows. We distinguish two types of processes here double firing (for wall tiles) and single firing (for floor tiles). 

Burrows in 1959 contributed a study based on making a floor tile from the cork fraction of Douglas-fir bark (34). Added binder in the dry-process tiles was either 5% butadiene styrene or diethylene glycol. Comparison tests were made against tiles from Mediterranean oak cork. Dimensional stability was better in Douglas-fir cork tiles, and most other properties compared favorably. No known commercial application resulted. 

In the wet process a slip carrying the ceramic powder is laid down, by screenprinting for example, onto a temporary carrier such as a glass tile. The process can be repeated to build up the required thickness of the dielectric onto which the electrodes are screen-printed. The next dielectric layer is then laid down and the process repeated. The mutlilayer structure is diced as described above, and the individual chips removed from the tile for the subsequent stages, as for the dry process. 

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