Silica Refractories Research Articles

EXAMINATION OF POLISHED SPECIMENS OF REFRACTORIES BY REFLECTED LIGHT*

AbstractA discussion is presented of the preparation of the sample specimen and the polishing, etching, and identification of phases when the technique is applied to basic and silica refractories. This method shows the relationship of high‐iron slag to tridymite and cristobalite in the silica brick and it aids in the explanation of the bursting of chrome‐magnesite brick by iron oxide.

VOLUME CHANGE ATTENDING LOW‐TO‐HIGH INVERSION OF CRISTOBALITE *

AbstractThe volume expansion of cristobalite, as it passes through the low‐temperature inversion range, was studied by means of a dilatometer in which the cristobalite expanded against a column of mercury. The volume change was measured in a capillary tube attached to the mercury column. The temperature of inversion is a function of the previous history of the cristobalite sample. A volume change of 7% was obtained upon inversion. The volume change was found to depend on the previous heat‐treatment of the sample, the presence of added catalysts, and the source and grain size of silica. All of these factors affect the amount of cristobalite present and hence the change of volume on inversion of the cristobalite. Several samples of cristobalite from used silica brick were studied. The information is applied to the problems of silica refractories.

MOTTLED OR COLORED SILICA BRICK*

AbstractDuring the burning of silica refractories, spots or areas of dark cream to a reddish‐brown color may develop in some of the brick or shapes. This is often called mottling, and its occurrence during the manufacture of the product cannot be definitely controlled. Questions occasionally arise as to whether the colored brick are of as good quality as the uniformly cream‐colored brick. No records are available to show or indicate that color as such has been a cause of shorter life or failure in service. Data are presented that were obtained from testing the mottled and light‐colored brick, and these show that there is no practical difference between them; consequently, color alone should not be a criterion for judging quality.The traces of iron present in the silica used are a necessary constituent in the formation of the color. The light‐colored product, however, contains the same quantity of iron. It is not entirely clear as to how the iron is present in the two types. Unknown conditions during manufacture are such that the traces of iron may be influenced to form either the light or mottled brick, but the process cannot be controlled.A considerable amount of experimental work is presented which shows the nature of the color behavior with comments on certain conditions that cause the color formation.

MEASUREMENT OF THE THERMAL CONDUCTIVITY OF FIRELAY REFRACTORIES*

AbstractThermal conductivity determinations have been made on superduty fire‐clay, silica, and kaolin refractories, using the Globar‐heated, water calorimeter apparatus previously described. The arrangement, which is satisfactory for insulating firebrick, gives considerable error when firebrick samples are tested. Results obtained by different arrangements of the guard samples and heating elements are shown as well as a final arrangement which gives a satisfactory condition of parallel heat flow.

Some applications of X-ray analysis methods to steelworks' problems

The paper summarizes a number of X-ray investigations carried out in a steelworks' research laboratory. In the first part, the examination of silica, magnesia and fireclay refractories is described and it is shown that X-ray data on the raw material and fired products may be of considerable value in determining the suitability of certain minerals for use as refractories. In addition, the changes in constitution and crystalline texture during service are discussed. The second part deals with metallurgical problems associated with chromium magnet and silicon transformer steels and oxide inclusions in steels. A large part of the information has already been published.

GLASS: THE BOND IN CERAMICS*

A ceramic industry is one which manufactures products by the application of heat to raw materials containing silica or silicates as essential ingredients, and ceramic chemistry is that branch of Chemistry which deals with the chemistry of silica. The property which makes silica the basis of industries as apparently diverse as water glass and refractories and which is conferred on all mixtures in which it is present in adequate amounts is that of forming glasses. While silica itself forms an ideal glass, its high melting point requires the addition of a flux, and the commonest and most powerful flux is soda. The addition of soda to silica produces a remarkable lowering of the melting point, from 1713 to 793° and glass of this composition is remarkably stable against devitrification. It is dissolved by water and forms the basis for the soluble silicate industry. But insolubility in water and acids is essential for most of the glasses of ceramics, and other oxides must be added to obtain this stability. The commonest and cheapest is lime (CaO), and most of the glass of commerce may be regarded as derived from the sodium‐silicate glass by the addition of several per cent of lime, usually also with the addition of small amounts of other oxides, notably magnesia, boric oxide, and alumina. Boric oxide and alumina are especially characteristic of the glassy base of enamels, which chiefly differ from glasses in containing insoluble materials to render them opaque and often coloring agents soluble in the glassy phase. Glazes, too, are of similar composition. Refractories are bonded by glass; either a lime glass in the silica refractories, or an aluminum glass in the clay refractories. But a siliceous glass is the characteristic feature which is found in all products of the ceramic art, and glass is the bond which unites the divers ceramic industries.

PROPERTIES OF SILICA BRICK MANUFACTURED FROM SHARON CONGLOMERATE1

New developments in the field of silicate refractories include greatly improved refractoriness and a high development of desirable qualities in silica refractories manufactured from Sharon conglomerate. The nature of silica refractories in general is discussed and a résumé of materials utilized in the manufacture of silica brick in the United States is given. Several illustrations of this new refractory are included, as well as test data.

NOTES ON THE BEHAVIOR OF REFRACTORIES IN GLASS MELTING FURNACES1

Microscopic examination of used glass house refractories gives evidence about the transformations that have taken place during use, and the relative solubilities of constituents of the refractories in the glass. On this evidence it is concluded that high alumina refractories would resist the solvent action of the glass and the fluxing action of the soda in the furnace atmosphere better than fire clay refractories. Investigations are needed to find a new refractory mortar for use between silica and clay refractories in glass tanks.

BOOK REVIEWS

Journal of the American Ceramic SocietyVolume 7, Issue 8 p. 255-256 BOOK REVIEWS First published: August 1924 https://doi.org/10.1111/j.1151-2916.1924.tb18693.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Book reviewed in this article: The Silica Refractories of Pennsylvania, E. S. Moore and F. G. Taylor Effect of Storage of Cement. Duff A. Abrams. Liesegang, Raphael Ed.: Kolloide in der Technik Muller, Erich: Die elektrometrische Massanalyse. Gibes, W. E.: Clouds and Smokes: The properties of disperse systems in gases and their practical applications Testing (Nm Journal). Charles O. Reid, Editor Volume7, Issue8August 1924Pages 255-256 RelatedInformation

Silica refractories, factors affecting their quality and methods of testing the raw materials and finished ware

Silica refractories, factors affecting their quality and methods of testing the raw materials and finished ware

SILICA REFRACTORIES1

Journal of the American Ceramic SocietyVolume 1, Issue 7 p. 477-501 SILICA REFRACTORIES† Donald W. Ross, Donald W. Ross Pittsburgh, Pa.Search for more papers by this author Donald W. Ross, Donald W. Ross Pittsburgh, Pa.Search for more papers by this author First published: July 1918 https://doi.org/10.1111/j.1151-2916.1918.tb17243.xCitations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume1, Issue7July 1918Pages 477-501 RelatedInformation