NOTES FROM PROF. BLACK'S INSTRUCTIONS IN TESTINS FOR METALS.

Kumara Times, Issue 2676, 20 April 1885, Page 2

NOTES FROM PROF. BLACK'S INSTRUCTIONS IN TESTINS FOR METALS.

♦ Test Solutions ok, Reagents. Muriatic Acid Sulphuretted HydroAmmonia gen Bichomate of Pot- Sulphide of Ammoash nia Yellow Prussiate of Ferri Sulph solution Potash Barium Chloride or Red Prussiate of Nitrate Potash Oxalate of Ammonia Solution of Caustic Nitric Acid. Potash In all tests for salts of metals first add a few drops of muriatic acid, and in silver, lead, or mercury, a white precipitate will be thrown down. Silver. 1. First add muriatic acid, and produce a precipitate. Next add ammonia, and the precipitate dissolves. 2. Bichromate of potash added to silver gives a dark red. Lead (from Galena). 1. First add muriatic acid, and produce precipitate; next add ammonia, and uo change shows. 2. Bichromate of potash shows a yellow reaction. Mercury (Lower Salts). 1. First add muriatic acid, and produce white pi'ecipitate ; next add ammonia, which turns it dark. 2. Bichromate of potash (re-agent) produces orange colour. . Copper. 1. Add muriatic acid, and it produces no change ; add sulphuretted hydrogen, which results in black precipitate. 2. Ammonia added to copper strikes a blue colour. Cadmium. 1, Add muriatic asid; nothing results.

Add sulphuretted hydrogen, which gives yellow precipitate. To tell the yellow from that produced in arsenic or tin, divide product into two, and add the following : ammonia, with no effect ; sulphide of ammonia, also with no effect. 2. Another sample of cadmium may be treated with a drop of ammonia, and resulting white precipitate ; redissolved by adding more. Arsenic. 1. Add muriatic acid drops: with no result. Add sulphuretted hydrogen, which gives a yellow, like cadmium, but which clears on addition of ammonia. 2. Add drops of ammonia (till it makes a muddy blue) to a copper solution, then add the suspected liquor, and if it contains arsenic it strikes a green colour. Divide the green in two parts, and add muriatic acid, which clears one, and ammonia turns the other blue. Antimony. 1. Add muriatic acid, and get nothing; add sulphuretted hydrogen, and get orange precipitate. 2. Add sulphide of ammonia, and it produces an orange. Mercury (Higher Sams). 1. Add muriatic acid, which gives nothing ; add sulphuretted hydrogen, which forms a succession of tints until sufficient turns it black. Memo.—No other metal produces this range of tints. 2. A solution of caustic potash produces as follows .-—With higher salts of mercury, a yellow ; with lower salts of mercury, a black. 3. Ammonia added to a mercurial solution throws down a white precipitate, which is calomel. 4. Add one drop of potash solution, which produces a yellowish red; add more, and it clears. Gold. 1. Add muriatic acid, which gives nothing; add sulphuretted hydrogen, and produce a brown to black. Add solution of ferri sulph (teaspoonful to a quart) to equal quantity of suspected liquor. It gives more colour—a green, blue, or brown (gold). Tin. 1. Add muriatic acid, which Ogives nothing ; next sulphuretted hydrogen, produces a chocolate. 2. To a solution of tin add a solution of higher salts of iron, with a drop of red prussiate of potash, and it produces a Prussian blue. PXATIOTM. 1. Add muriatic acid, which gives nothing ; add sulphuretted hydrogen, which gives no change until boiled, when it turns black. Memo. Platinum is the only metal that requires heat to make it yield a colour reaction. 2. Add to a platinum solution some iodide of potash, which gives a reddish brown. Iron (Lower Salts). 1. Add muriatic acid, also sulphuretted hyrogen. Neither give reaction. 2. Add sulphide of ammonia, which produces black in higher or lower salts of iron, and also with nickel and cobalt; but if the black is produced from iron,' the addition of diluted cold muriatic acid will clear it. 3. Ammonia turns lower salts a dirty green, higher salts brown4. Add sulpho cyanide a drop, and it should give either no colour or light pink. Irom (Higher Salts). 1. Muriatic acid and sulphuretted hydrogen produce no change. 2. Use test No. 2 of Iron (Lower Salts). 3. Red prussiate of potash does not strike Prussian blue with iron. 4. Add ammonia, which produces a foxy brown jelly. 5. Add yellow prussiate (ferro-cyanide), and it produces Prussian blue. Memo.—To know this blue ascertain if muriatic acid will clear it, or ammonia turn it to foxy brown. 6. Sulpho cyanide gives a red solution. Nickel. 1. Add muriatic acid ; add sulphuretted hydrogen. Show nothing except that there is no tin, gold, mercury, antimony, arsenic, cadmium, copper, lead, or silver. 2. Add sulphide of ammonium, which shows black with nickel, cobalt, and both salts of iron ; but muriatic acid will clear the precipitate in iron, and wont in nickel and cobalt. 3. Add a drop or two of ammonia, and from top of the test tube down it gives three colours—lavender solution, green precipitate, and original tint. Turn upside down and fill up with ammonia, aud it will produce a clear lavender colour. 4. Red prussiate of potash added gives a greenish yellow precipitate. Memo.—Nickel ore or pimelite, or gargarnierite, contains magnesia silica and nickel. Treat with aqua regia, and boil to dryness ;_ then add water, and filter. The filtrate is then ready as a liquor for testing. Cobalt. 1. Muriatic acid ; sulphuretted hydrogen—same as Nickel—nothing. Sulphide of ammonia : turns black, which is not dissolved by muriatic acid. 2. Add ammonia, a drop or two, and it shows a yellow-brown above, and a bright green below. Turn upside down, and fill up with ammonia, which produces a yellowish brown throughout. 3. Red prussiate gives a reddish brown. Zinc. 1. Muriatic acid : sulphuretted hydrogen.—Give no results. 2. Sulphide of :i"V!ii:-;:\ : r; drop or two gives a while precipitate, which, pryyw it zinc or almuiumu,

3. Add caustic potash solution. One drop gives white ; more, clears it again. Add sulphuretted hydrogen, and it gives white, which shows zinc, and not aluminum. 4. Red prussiate of potash gives pale yellow. Zinc Ore. Powder to a yellowish white. Add nitrio-muriatic acid, and boil to dryness ; then boil with caustic potash solution and filter, and then sulphuretted hydrogen turns result white. Manganese. 1. Muriatic acid ; sulphuretted hydrogen added, gives nothing. 2. Add sulphide of ammonia, and it produces a flesh tint. 3. Solution of caustic potash gives a whitish, precipitate, which, on being shaken with air, turns to brown and black. 4. On porcelain add nitrate potash and washing soda to the manganese solution and boil, and the product will be the green permanganate.—See Condy's fluid. Gold, in Mundic. Pulverise and add successively nitric acid until the brown fumes cease to come off, by which, time the iron pyrites is destroyed. Then wash and dry. Next boil with agua regia; add water and filter. The gold will pass through in solution. Test. Cinnabar, and Mercury Ore. Pound and add nitric muriatic acid, and boil, which produces corrosive sublimate. Dissolve result in water, and test for higher salts of mercury. Tin Ore. No acid will touch the oxide or tin stone ; it is black or reddish, very heavy, and grinds almost white. To extract the metal use a flux of four parts of cyanide of potash, one of soda carbonate to one part of tinstone. Heat in a crucible and metallic tin deposits. Tin ore is the only metal that is heavy and powders white. Having obtained the metal, make a solution in acid and test. TUNGSTATE OF LIME, OR ScHEELITE, (much in demand). Dissolve in agua regia and boil down to dryness, which produces a yellow powder or tungstic acid. Add water and filter. The acid stops in the filter while the lime passes through. The acid is yellow. Add to it zinc or iron filings, with two or three drops of muriatic acid, which produces a blue, and will burn with a blue flame into the tube. The lime that passed through the filter, if treated first with ammonia and then oxalate of ammonia, gives a white powder. Antimony Ore. Powder and boil with muriatic acid, which emits a sulphuretted hydrogen smell. Filter, and the residue is a white powder, a small pinch of which will make a large body of water white. Treat the whitened water with sulphuretted hydrogen or sulphide of ammonia. Each turns it orange. Gypsum or Selenite (Sulphate of Lime). Shake it in water and filter. Test for the sulphuric acid in the water with barium, and it throws a white, which is the case with phosphoric, arsenic, oxalic boraic, silicic, carbonic, or hydro-fluoric acids; but the last seven clear up on adding nitric acid. The test for the lime is ammonia, and ammonia oxalite which turns it white. Galena —(an Ore compounded of Sulphur and Lead). Powder and treat with nitric acid over spirit lamp, and brown fumes come off. Evaporate to dryness, and water and filter. Muriatic acid will whiten the filtrate ; sulphuretted hydrogen, blacken; bichromate of potash, yellow; caustic potash will first whiten and then clear, and the result be blackened by sulphuretted hydrogen. Silver Ore. Add nitric acid and water to the powdered ore ; the acid and water will make a clear solution of the silver, but frequently green from copper impurity. Add muriatic acid, and the silver will be thrown down as a chloride in a white precipitate. Let it settle, decant the clear, and repeatedly wash the residue until there is no cow>er reaction, and the water ceases to tas* acid. Then put in granulated zinc and sulphuric acid, and the hydrogen which comes off combines with the chlorine, and causes the silver to deposit in a grey metallic powder. Rub in a mortar, and the natural appearance of the metal is shown. Silver (from Galena). When the impurities are lead, iron and sulphur, dissolve with nitric acid, which will take the whole of the silver and part of the lead. Add muriatic acid, which precipitates ditto. Wash with hot water and filter, which passes off the iron and copper. Then dissolve the silver part of the precipitate by means of ammonia, by which means you separate the silver from the lead. Then add nitric acid, to re-precipitate the silver as above, and extract by means of hydrogen.