Fire clays and refractory materials

“Nor did the primitive metallurgists who were the first to apply this iron rock to practical use imagine, as they toiled over their unsightly furnaces made of common sun dried clay in which there could not be generated sufficient heat to reduce the iron to a liquid form, and to the top of which the smelter might reach with his hand, that in the future this metal would need to be smelted in furnaces that would reach to the tops of their very temples, and at a temperature that would defy the resistance of the firmest granite. But yet these things are all realized by the metallurgist of today and in his construction of the furnaces and various metallurgical apparatuses which are the outgrowth of the various discoveries of metals, and the constant invention of new methods of metallurgical treatment, there is no problem that more keenly taxes his ability than the discovery and application of the most efficient refractory materials which shall be able to endure all the varied requirements of modern metallurgy. Indeed if we examine this subject but a moment we see that it cannot well be otherwise, for what with the immense increase of temperature incident to the introduction of many new processes (of which the Bessemer process for the production of steel may be cited as a single example) and with the unfitness of natural substances, and even the entire range of artificial materials to a certain degree, for the withstanding of such heat, we see nothing but continual embarassment meeting the furnace builder and retort maker whichever way he may turn. Indeed the problem has attained such a degree of complexity through the increasing demands upon our refractory material that certain branches of industry are threatened with extinction.”—Pages 3-5