Residue A. Solution B.
The residue A was heated with hydrochloric acid to which a small quantity of nitric acid was added from time to time; the solution was diluted and filtered.
Residue G. Solution D.
Residue G.—Dried and heated 05 gram in the oxyhydrogen flame. The lines of gallium, chromium, nickel, and iron are strong, and lines of sodium, manganese, potassium, copper, and silver are also present. Solution B.—Boiled for two hours with part of the finely powdered sample added gradually to neutralise all the free acid, so that the gallium in the solution might he precipitated as a basic salt.* The solution was decanted and filtered. The residue was boiled with solution D ,to which the remainder of the finely powdered sample was slowly added; after boiling for several hours the solution was filtered, and the residue F washed with water. The filtrate was mixed with that from solution B, the mixture forming solution G, which should he. free from gallium. This solution was boiled with freshly precipitated copper hydrate,! and the precipitate examined spectrographically for gallium. It contained none.
Residue F.—Boiled with an excess of hydrochloric acid, diluted, filtered, and washed, Residue H. Filtrate I.
Residue B.—Dried, powdered, and mixed with residue G. Gently headed, the mixture decomposes and expels hydrocarbons, causing the mass to ignite and evolve some white fumes. The substance was thus seen to he very inflammable, and the temperature was reduced as quickly as possible. When cold, it was covered with aqua regia and heated on the water bath for several hours, then diluted and filtered. Filtrate added to I, forming solution K. Residue L.
Residue L.—A small quantity of it was heated in the oxyhydrogen flame. The gallium line is strong. 45 c.c. of strong sulphuric acid was heated in a porcelain basin until it gave off white fumes; the residue was then added forming a pasty mass which was kept hot for about three hours; white fumes being emitted during the whole time. Water was then added, and the liquid filtered. Residue M. A portion of the latter was heated in the oxyhydrogen flame. The gallium line is still present.
Besides the small quantity remaining in the residue M, the gallium should now be in the solutions K and N. Solution K was evaporated nearly to dryness to expel the excess of acid, then diluted, saturated with sulphur dioxide, nearly neutralised with ammonia, and boiled to
- ‘ Comptes Rendus,’ vol. 93, p. 818. See also a complete account, * Separation du Giallium d’avec les autres elements,’ par M. Lecocq de Boisbaudran. Paris,
Gauthier-TiHara. 1884. Reprinted from the * Annales de Cliimie,’ 6. Serie, t. 2. t ‘ Comptes Rendus,’ vol. 94, p. 1154.
