A Manual of Fire Assaying

Front Cover
Hill publishing Company, 1907 - Assaying - 178 pages

What people are saying - Write a review

We haven't found any reviews in the usual places.

Other editions - View all

Common terms and phrases

Popular passages

Page 72 - ... very bright, at the moment of solidification, owing to the release of the latent heat of fusion, which raises the temperature of the bead very much for a short time.
Page 60 - The most desirable constitution for any assay slag, is that of a monosilicate or a sesquisilicate, sometimes, but more rarely a bisilicate. If the ore is basic a bisilicate may be approached, if acid a monosilicate, or even a subsilicate, in order to insure complete decomposition of the ore.
Page 13 - ... the same rotation. The center of gravity of the scorifiers lies to one side of the rotation-point, and they would therefore, on being lifted, tilt in that direction ; this, however, being prevented by the cross-bar resting against a post at that end of the frame toward which the inclination tends. The scorifiers are clutched by the upper prong of the tongs, which is fastened to a spring on a post of the fork below, and which is free to move in a vertical plane ; the pivotal point...
Page 80 - Degrees centigrade. Lowest red visible in the dark ..... 470 Dark blood red or black red ..... 532 Dark red, blood red, low red ..... 566 Dark cherry red ....... 635 Cherry red, full red 746 Light cherry, light red ...... 843 Orange .' 900 Light orange . . . . . . . .941 Yellow • . 1000 Light yellow 1080 White ... 1205 1 Jou.rn.
Page 104 - US Geol. Survey, Series E. 44, Bulletin No. 253. also Jour. Chem. Industry, April 15th, 1905. also Chemical News, March 25th, 1906. 1905. EC WOODWARD. " Cupel losses in Telluride Ores.
Page 20 - In its widest meaning, the term includes all those operations of analytical chemistry which have for their object the determination of the value of ores and their metallurgical products. In its more limited meaning, assaying is the process employed in determining the proportion of pure metal in coins, silver and gold plate, jewelry and other commercial alloys of the precious metals. In Great Britain each article of gold or silver is assayed...
Page 13 - To each of them is attached, at right angle, a lever, extending upward at an angle of 45, and all the levers are connected by slotted joints to a cross-rod. Therefore, if by means of a crank, fastened to the end of one of the extended prongs, one of the forks is turned and the scorifiers tilted to the desired angle, the others perform the same rotation.
Page 60 - ... fluxes, in such proportions as to produce the proper slag decided upon. The most desirable constitution for an assay slag in general is that of a monosilicate or a sesquisilicate, sometimes, but more rarely, a bisilicate. If the ore is basic a bisilicate may be approached, if acid a monosilicate, or even a sub-silicate, in order to insure complete decomposition.
Page 55 - In the fusion of a mixture containing silica, various bases and borax glass, that silicate borate having the lowest formation point will form and then as the temperature rises, absorbs either silica, base or both, as these are in excess of the ratio required to form the lowest formation point compound. If the temperature does not rise high enough to cause this absorption, the excess of silica or base or both will remain in suspension in the formed silicate borate, practically in an unaltered condition.
Page 57 - Silicates are defined in degree by the ratio of oxygen in the base to that in the acid.

Bibliographic information