BulletinU.S. Government Printing Office, 1919 |
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acetate acid solution added alcohol alkali alumina aluminum ammonia ammonium anal anorg apparatus applied barium bath beaker blast boiling calcium carbon dioxide cent Chem Chemie chloride chromium cipitate cm.³ color colorimetric constituents containing crucible decomposed decomposition determination dilute dissolved drop dryness error evaporation excess ferric ferrous iron filter filtrate flame flask fluorine fused fusion glass Gooch grams grinding heat hydro hydrochloric acid hydrofluoric acid hydrogen sulphide hydroxide ignited insoluble Jour limestones liquid loss magnesium manganese matter method minerals minutes nitric acid obtained oxalate oxide paper permanganate peroxide phosphate phosphorus platinum platinum crucible platinum dish portion potassium precipitate present procedure quantities reagents reduced removed residue rock analysis rock powder salt sample separation silica silicate rocks small amounts sodium carbonate soluble strontium sulphate sulphuric acid Survey laboratory temperature tion titanium titration V₂O vanadium volatilization washed weight Zeitschr zinc zirconium
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Seite 244 - OF SOLUBLE SILICA. Very often in treatment by acids silica is separated in gelatinous or granular form mixed with the unattacked minerals, and it becomes necessary to remove or estimate this silica, or else to discriminate between soluble and insoluble silica already existing together. Usually a boiling solution of sodium carbonate has been employed for this purpose, though the caustic alkalies have found advocates.
Seite 177 - The rare earths, with perhaps some alumina, are then precipitated by ammonia, washed, redissolved in hydrochloric acid, and evaporated to dryness, then taken up with water and a drop of hydrochloric acid, and only enough ammonium acetate to neutralize the latter added, followed by oxalic acid (not ammonium oxalate, which would fail to precipitate thorium). In this way as little as 0.03 per cent of rare earths has been found when working on not more than 2 grams of material.
Seite 208 - Hence, to avoid waste of time in very fine grinding, the form of crucible with cap originally advocated by Smith is very much to be preferred, since it permits, when set at an angle through an opening in the side of a fire-clay cylinder...
Seite 223 - If the rocks are very basic, it may happen that the amount of silica In the alkaline solution of the fusion Is so small that ammonium carbonate may be dispensed with for its precipitation and the zinc oxide solution added at once, after neutralizing as above.
Seite 212 - ... but * * * the entire correction may in any case be kept within very narrow limits if due care be given to the reduction of the volume of residual alcohol before filtration. The filtrate and washings are evaporated to dryness, treated with sulphuric acid, the excess of the latter driven off, and the residue ignited to fusion and weighed.
Seite 172 - Mar's0 method for the separation of barium from calcium and magnesium by the solvent action of concentrated hydrochloric acid mixed with 10 per cent of ether on the chlorides could be conveniently applied here, although for larger amounts the method would seem to be accurate and easily executed. Moreover, it would probably not entirely remove contaminating strontium, and hence offers no advantage.
Seite 181 - GRAVIMETRIC METHOD. Having obtained chromium in solution as chromate and free from all else but a little alumina, as at the conclusion of the preceding section on phosphorus, proceed as follows: Concentrate if necessary and add fresh ammonium sulphide, or introduce hydrogen sulphide. The chromium is reduced and appears as a precipitate of sesquioxide mixed with the rest of the alumina. This precipitate is now treated according to H.
Seite 194 - Experiment has shown (C. c. <*, p. 138) that with the amounts of sulphides usually found in igneous rocks their effect on the estimation of ferrous iron by the hydrofluoric-acid method at atmospheric pressure and boiling heat is negligible, though by increasing the amount of sulphide the effect becomes more and more apparent, because of the greater surface of pyrite exposed to the action of the ferric iron of the rock.
Seite 72 - Hence it may be said that the estimation of the loss at 100° or 110° and its separate entry in the analysis are advisable as affording to the lithologist an indication of the mineral character of one or more of the rock constituents, thus perhaps confirming the microscopic evidence or suggesting further examination in that line.
Seite 78 - Penfield a leaves nothing to be desired for accuracy. It consists simply in heating the powder in a narrow tube of hard glass, enlarged at the closed end and provided with one or two further enlargements in the middle to hold the water and prevent its running back and cracking the hot glass. A capillary glass stopper fitted in with rubber tubing prevents loss of water by circulating air currents. The tube being held horizontally, the bulb is heated to any required degree by the Bunsen or blast flame.