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F. N. Ward

Publications and source records attributed to F. N. Ward.

10 recordsLinked to original sources
USGS2002

Field determination of microgram quantities of niobium in rocks

A rapid, simple, and moderately accurate method was needed for the determination of traces of niobium in rocks. The method developed is based on the reaction of niobium(V) with thiocyanate ion in a 4 M hydrochloric acid and 0.5 M tartaric acid medium, after which the complex is extracted with ethyl ether. The proposed procedure is applicable to rocks containing from 50 to 2000 p.p.m. of niobium, and, with modifications, can be used on rocks containing larger amounts. Five determinations on two rocks containing 100 p.p.m. or less of niobium agree within 5 p.p.m. of the mean, and the confidence limits at the 95% level are, respectively, ± 6 and ± 4 p.p.m. The addition of acetone to the ether extract of the niobium thiocyanate inhibits the polymerization of the thiocyanate ion and stabilizes the solution for at least 20 hours. The proposed procedure permits the determination of 20 γ of niobium in the presence of 1000 γ of iron, titanium, or uranium; 500 γ of vanadium; or 100 γ of tungsten or molybdenum or both.

Analytical Chemistry↗
USGS1976

Flameless atomic absorption determination of bismuth in soils and rocks

Recent advances in flameless atomic absorption allow determinations of bismuth in concentrations as small as 50 ppb in 0.2 g of rock or soil sample. The sample is fused with sodium bisulfate and the fusion product is leached with hot 2 M hydrochloric acid and treated with ammonium citrate, (ethylenedinitrilo) tetraacetic acid disodium salt, and finally with ammonium 1-pyrrolidinedithiocarbamate to form a complex which is extracted into methyl isobutyl ketone. Aliquots of the latter are pipetted into a graphite furnace and then subjected to an established and automated program of drying, charring, and atomizing. Recorded peak heights provide a measure of the amount of bismuth present.

Journal of Research of the U.S. Geological Survey↗
USGS1965

Field determination of nanogram quantities of mercury in soils and rocks

A method for determining nanogram quantities of mercury in geological materials is based on the catalytic effect of mercury on the reaction of ferrocyanide with nitrosobenzene to produce a violet-covered compound whose intensity if proportional to the mercury present. The mercury is released by heating a sample of soil or crushed rock to about 650°C. As little as 30 nanograms of mercury (30 parts per billion with 1 gram sample) can be detected. The reliability of the method is adequate to permit its use in geochemical surveys that utilize mercury as a pathfinder element.

Open-File Report↗
USGS1959

Plastic standards for geochemical prospecting

Plastic standards for use in geochemical prospecting have been prepared by impregnating a clear thermosetting resin with different amounts of a stable dye or colored metal complex. The colored plastic is molded or subsequently milled into convenient shapes to form standards that are less bulky and more stable than the liquid standards conventionally used in rapid field methods. The use of such standards is limited only by the availability of stable coloring materials. The preparation of plastic standards for use with copper, zinc, tin, and mercury field procedures is described.

Economic Geology↗
USGS1957

A truckmounted spectrographic laboratory for use in geochemical exploration

A truck-mounted spectrographic laboratory has been designed and built by the U. S. Geological Survey to investigate the feasibility of using and transporting such equipment in the field as an aid in supplying rapid on-the-spot analytical data to geochemical exploration field parties.The laboratory is housed inside a 7- X 12-foot insulated and air-conditioned van-type truck body and carries complete equipment for making qualitative, semiquantitative, and quantitative analyses of geological materials. The spectrograph is a fixed-position 1.5-meter grating instrument of the Wadsworth type which records a range of spectra from 2063 to 4837A in the second order on a 20-inch strip of film. Companion units are a projection type comparator-densitometer, a film processor, and other accessory equipment. Trailer-mounted motor-generators supply 230 volts d-c for the arc source unit and 115 volts a-c for lights and accessories.Since its completion in May 1955, the truck-mounted laboratory has been driven over 4,000 miles. During this travel all the equipment remained in good adjustment; the laboratory was made ready for operation in less than 2 hours after arrival at the site of a field project.Because of the large number of elements that can be determined from a single spectrogram, the truck-mounted laboratory is useful in the early stages of a geochemical exploration project to determine diagnostic suites of elements, and later, to guide the day-to-day sampling.

Economic Geology↗
USGS1951

Determination of molybenum in soils and rocks: A geochemical semimicro field method

Reconnaissance work in geochemical prospecting requires a simple, rapid, and moderately accurate method for the determination of small amounts of molybdenum in soils and rocks. The useful range of the suggested procedure is from 1 to 32 p.p.m. of molybdenum, but the upper limit can be extended. Duplicate determinations on eight soil samples containing less than 10 p.p.m. of molybdenum agree within 1 p.p.m., and a comparison of field results with those obtained by a conventional laboratory procedure shows that the method is sufficiently accurate for use in geochemical prospecting. The time required for analysis and the quantities of reagents needed have been decreased to provide essentially a "test tube" method for the determination of molybdenum in soils and rocks. With a minimum amount of skill, one analyst can make 30 molybdenum determinations in an 8-hour day.

Analytical Chemistry↗