| Abstract: | Importance of the question for a country where fuel is expensive and resources are less than consumption. Types of Kilns Used. —Principally continuous kilns; some intermittent ones and a few tunnel kilns. Heating of Kilns. —Heating direct or with gas—evolution of ideas. Conclusion. —Heating in modem kilns consists in transporting calories from one point to another with the minimum of loss, the hearth serves only to compensate these losses while raising the calories to a higher potential. The firing of refractory products can be considered either from the purely technical point of view of the influence of the firing temperature on the quality of final product, or from the economic point of view of obtaining this firing temperature in the least onerous manner. The fuel question plays an important part in the ceramic industry, particularly in the making of refractories; it is one of the important elements in cost of production, especially in a country like France in the present situation. Our2 production of coal in 1913 amounted, in round numbers, to 40 million tons; in 1921 due to our coal mines having been destroyed, the extraction was only 28 million tons. In 1920, although our needs amounted to 80 million tons, we were able to obtain, both in French and foreign coals, not more than 50 million tons. The saving of fuel, undertaken in all of the great nations, presented then and still presents to our country a primordial interest. The point of these various statements is to show very briefly the technic of firing in the industry of refractory products in France and the evolution of ideas in respect to firing. |
