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20 Crucible 20 grams absorption acid added alloy annealed antimony aqua regia argol assay slag assayer balance base metal bisilicate bone-ash borates Borax glass cover carbon cassiterite cent charcoal Chem containing copper crucible crucible assay Crucible fusion cupellation cyanide dissolved f1nal f1nishing FIRE ASSAYING flux following charge formation point furnace fused fusible gasolene gold and silver gram Borax glass grams of lead grams PbO heat impurities iridium iron Journ lead button litharge loss of gold matte melting-point millieme monosilicate muffle Muffle-Furnace niter niter method nitric acid obtained oxidizing power oxygen particles platinum power of niter precious metals precipitate preliminary assay present pyrite quantity ratio reducing agent reducing power residue rhodium Rhodonite roasting salt solution sample scorif1cation Scorifier silica silver and gold silver bead slag soda Sodium carbonate sulphides sulphur TABLE telluride tellurium test lead Tongs volatilization weight zinc
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.