Analysis Of Silicate Rocks Research Articles

Instrumental activation analysis of silicate rocks with epithermal neutrons

The determination of some trace elements in standard rocks by epithermal neutron activation, followed by γ-ray spectrometry with a Ge(Li) detector, is described. The advantage of using this technique compared to corresponding analysis with thermal neutrons is clearly demonstrated in the case of Rb, Cs, Sr, Sb, Ta, and U. Determinations of Ba, Sm, Tb, Hf, and Th also appear to be favourable.

The analysis of inorganic siliceous materials by atomic absorption spectrophotometry and the hydrofluoric acid decomposition technique : Part I. the analysis of silicate rocks

The analysis of various inorganic siliceous materials of geological and industrial interest is discussed. The methods proposed are based on decomposition of a single sample by hydrofluoric acid and determination by atomic absorption spectrophotometry of up to 10 constituents. General procedures are described, and details are given for the determination of silicon, aluminium, total iron, magnesium, calcium, sodium, potassium, titanium and manganese in silicate rocks. Analytical data are given for the analysis of reference rocks G-2 and W-1.

Partial analysis of silicate rocks by atomic absorption

Partial analysis of silicate rocks by atomic absorption

Chemical determination of some major constituents in rocks and minerals

Macro-analytical schemes are described for the determination of aluminium, total iron and iron(II), as part of the complete analysis of silicate rocks and minerals Solvent extraction eliminates interferences before titration of aluminium with DCTA Iron(III) is extracted with MIBK and determined indirectly with EDTA Iron(II) is determined by potentiometric titration under an inert atmosphere. Interferences are removed with 2,4-pentanedione and carbon tetrachloride before the determination of calcium and magnesium.

The determination of vanadium in sea and natural waters,biological materials and silicate sediments and rocks

Vanadium was concentrated from sea and natural waters by coprecipitation with iron (III) hydroxide, and separated from iron and other elements by ion exchange, using hydrogen peroxide as a very selective eluting agent. The element was determined photometrically with diaminobenzidine. The ion-exchange process was also used to separate vanadium from other elements in the analysis of silicate rocks and marine plants. Coefficients of variation of 2.8%, 1.3% and 2.5% were found for the determination of the element in sea water, marine sediments and marine plants at levels of 1.8 μg/l, 57 μg/g and 2.2 μg/g, respectively. The U.S. Geological Survey standard granite GI was found to contain 17.2±0.9μg V/g.

A procedure for silicate rock analysis based on ion exchange and complex-ion formation

A procedure for the analysis of silicate rocks based on ion exchange and complex-ion formation is described. Moisture (H 2O -), SiO 2, TiO 2, Al 2O 3, P 2O 5, total iron, MgO, MnO, and CaO are determined in a 1-g sample. Other oxides, such as FeO, Na 2O and K 2O, and H 2O + are determined in separate portions. The results for 6 silicates, including G-I and W-I, compare favorably with. those obtained by established procedures. Six complete analyses may be carried out in about 8 days.

Atomic absorption spectrophotometry and the analysis of silicate rocks for copper and zinc

The concentration of copper and zinc in silicate rocks was determined by atomic absorption spectrophotometry, a new method of chemical analysis. Limits of detection in solution of 0.026 ppm Zn and 0.12 ppm Cu allowed samples to be run directly in solution with a 1:50 dilution. Matrix interferences are not significant. Precision for copper ranged from 34% at 5 ppm to 3.3% at 218 ppm in the sample. Precision for zinc ranged from 9.7% at 3 ppm to 3.7% at 260 ppm in the sample. Atomic absorption compares well to neutron activation analysis in precision and accuracy, and atomic absorption is more rapid. The precision and accuracy of atomic absorption analysis for copper and zinc in silicate rocks is very good for a method so simple and quick. The best value of 13 ppm copper in G-1 appears to be warranted. W-1 appears to have a best value of 115 ppm copper and 85-91 ppm zinc. G-1 probably contains between 44 and 49 ppm zinc. Atomic absorption should find wide use in geochemistry as a method for the trace element analysis of rocks, minerals, soils, plants and water samples.

Rapid chemical analysis of silicate rocks

Rapid chemical analysis of silicate rocks

The rapid analysis of silicate rocks and minerals

The rapid analysis of silicate rocks and minerals

The accuracy and precision of “rapid methods” of silicate analysis

The “rapid methods” of silicate analysis devised by Shapiro and Brannock (1952) are criticized. One major modification (the method for total Fe) and one minor modification (the titration of Ca solutions) are proposed.The accuracy and precision of the methods are stated and shown to be adequate for the analysis of silicate rocks in the diorite-granite range.Suggestions are given for further research.

Precision and accuracy of chemical analysis of silicate rocks

Replicate analyses by 35 laboratories of a granite and a diabase, especially prepared as standards, give means and standard deviations which should be invaluable for calibration purposes in spectrochemical and chemical laboratories. It is clearly shown that relative error varies inversely with concentration of the constituent (e.g. 0.1% for SiO 2, 10% for P 2O 5). A test of accuracy has also been made by 11 laboratories, each analyzing a synthetic glass of the proportions found in granite. The composition of the glass is known within +-0.02% for SiO 2, +-0.01% for Al 2O 3 and is without significant error for the remaining constituents.The means computed from the chemical analyses showed satisfactory agreement for MgO, CaO, Na 2O, K 2O (<0.1%). For SiO 2 and Al 2O 3 a reciprocal systematic error appeared whereby SiO 2 was 0.4% low and Al 2O 3 was 0.6% high; total SiO 2 and Al 2O 3 agreed almost exactly (<0.1%) with the glass standard. As a result of these tests attention is directed anew to the practical but complex problem of evaluating error in a single analysis made by conventional methods. The advantages for many purposes of the more rapid photometric and spectrochemical methods and (for many igneous rocks) of micrometric methods are outlined.

Cooperative Investigation of Precision and Accuracy in Chemical Analysis of Silicate Rocks

Cooperative Investigation of Precision and Accuracy in Chemical Analysis of Silicate Rocks

Quantitative spectrochemical analysis of silicate rocks, silicate minerals, and allied materials: Preliminary report on a scheme of analysis

A system of quantitative spectrochemical analysis of silicates (rocks, minerals, soils, meteorites and allied material) using DC arc excitation, is outlined and discussed briefly. The object in devising this analytical scheme is to reach an effective compromise between so-called specific, accurate methods which handle a very limited number of elements in one procedure, and the general methods by means of which many elements are determined semi-quantitatively in one operation. In the simple analytical scheme outlined here, a complete quantitative analysis of a silicate involves a limited number of arcings. Volatilization is considered the most important property in the grouping of elements for each arcing and for choosing an internal standard for each group. Standard deviations invariably fall within the range of 2.5–8%. Included in the analytical scheme are fluorine, all alkali metals and the so-called major constituent elements.