Fluorescence minerals

The Calcium Halophosphate Phosphors. Early fluorescent lamps used various combinations of naturally occurring fluorescent minerals. The development of the calcium halophosphate phosphor, Ca (P0 2(Cl, F) Sb ", Mn, in the 1940s was a significant breakthrough in fluorescent lighting (7). As is often the case in new phosphor discoveries, this phosphor was found accidentally while searching for phosphors for radar screens. 

The other common ion with the d3 configuration is Mn4+ which is important as an activator in some phosphors but it does not commonly occur in fluorescent minerals. 

There s always a danger that web links expire over time. If this link doesn t work for you, just put "fluorescence minerals" into a search engine and you ll probably find a site where you can see examples of mineral fluorescence. 

Henderson B, Imbusch GF (1989) Optical Spectroscopy of Inorganic Solids. Clarendon Press, Oxford Henkel G (1989) The Henkel glossary of fluorescent minerals. Verbeek E, Modreski P (eds) In J Fluor Mineral Soc, Vol. 15... 

Robbins M (1983) The collectors book of fluorescent minerals. Van Nostrand Reinhold, New York Robbins M (1994) Fluorescence Gems and Minerals Under Ultraviolet Light. Geoscience Press, Phoenix Roeder PL, MacArthur D, Ma X-P, Palmer GR, Mariano AN (1987) Cathodoluminescence and microprobe study of rare-earth elements in apatite. Am Mineral 72 801-811 Ronsbo JG (1989) Coupled substitutions involving REEs and Na and Si in apatites in alkaline rocks from the Ilimaussaq intrusion, South Greenland, and the petrological implications. Am Mineral 74 896-901 Ropp RC (1971) The emission colors of the strontium apatite phosphor system. J Electrochem Soc 118 1510-1512... 

Anon, Fluorescence of uranium and thorium minerals, J. Fluoresc. Miner. Soc., 2, (1973), 1-9. 

Warren, T.S., Gleason, S., Bostwick, R.C., and Verbeek, E.R. (1999) Ultraviolet Light and Fluorescent Minerals Understanding, Collecting and Displaying Fluorescent Minerals (Rocks, Minerals and Gemstones), Gem Guides Book Co. 

Robbins, M. (1983) The Collector s book of Fluorescent Minerals. Van Nostrand and Reinhold, New York. Robbins, M. (1994) Fluorescence. Gems and Minerals under Ultraviolet Light. Geoscience Press, Phoenix, AZ. Sinkankas, J. (1964) Mineralogy for Amateurs, 2nd. ed. Van Nostrand Reinhold Company, New York. Sinkankas, J. (1975) Mineralogy. Van Nostrand Reinhold Company, New York. 

The choice between X-ray fluorescence and the two other methods will be guided by the concentration levels and by the duration of the analytical procedure X-ray fluorescence is usually less sensitive than atomic absorption, but, at least for petroleum products, it requires less preparation after obtaining the calibration curve. Table 2.4 shows the detectable limits and accuracies of the three methods given above for the most commonly analyzed metals in petroleum products. For atomic absorption and plasma, the figures are given for analysis in an organic medium without mineralization. 

LIF is also used witii liquid and solid samples. For example, LIF is used to detect lJO ions in minerals the uranyl ion is responsible for the bright green fluorescence given off by minerals such as autunite and opal upon exposure to UV light [23],... 

Physical Properties, Colourless solid when pure, usually pale brown. Sparingly soluble in cold water, soluble in hot water soluble also in cold mineral acids and caustic alkalis. Dissolves readily in cold alcohol, and solution possesses a faint blue fluorescence. 

Acryloid E-10, 40% in mineral thinner (Rohm Haas) fluorescent pigment lactol spirits toluene... 

Mineral and Chemical Composition. X-ray diffraction is used to determine the mineral composition of an Mg(OH)2 sample. Induced coupled plasma (icp) spectrophotometry is used to measure the atomic concentrations present in a sample. X-ray fluorescence analysis is another comparative instmmental method of determining chemical composition. 

A development in the 1960s was that of on-line elemental analysis of slurries using x-ray fluorescence. These have become the industry standard. Both in-stream probes and centralized analyzers are available. The latter is used in large-scale operations. The success of the analyzer depends on how representative the sample is and how accurate the caUbration standards are. Neutron activation analyzers are also available (45,51). These are especially suitable for light element analysis. On-stream analyzers are used extensively in base metal flotation plants as well as in coal plants for ash analysis. Although elemental analysis provides important data, it does not provide information on mineral composition which is most cmcial for all separation processes. Devices that can give mineral composition are under development. 

Instrumental Methods for Bulk Samples. With bulk fiber samples, or samples of materials containing significant amounts of asbestos fibers, a number of other instmmental analytical methods can be used for the identification of asbestos fibers. In principle, any instmmental method that enables the elemental characterization of minerals can be used to identify a particular type of asbestos fiber. Among such methods, x-ray fluorescence (xrf) and x-ray photo-electron spectroscopy (xps) offer convenient identification methods, usually from the ratio of the various metal cations to the siUcon content. The x-ray diffraction technique (xrd) also offers a powerfiil means of identifying the various types of asbestos fibers, as well as the nature of other minerals associated with the fibers (9). 

Several instmmental methods are available for quantitative estimation of from moderate to trace amounts of cerium in other materials. X-ray fluorescence is widely available, versatile, and suitable for deterrninations of Ce, and any other Ln, at percent levels and lower in minerals and purer materials. The uv-excited visible luminescence of cerium is characteristic and can be used to estimate Ce content, at ppm levels, in a nonluminescing host. X-ray excited optical luminescence (15), a technique especially appropriate for Ln elements including cerium, rehes on emissions in the visible, and also measures ppm values. Atomic emission spectrometry is appHcable to most lanthanides, including Ce (16). The precise lines used for quantitative measurement must be chosen with care, but once set-up the technique is suitable for routine analyses. 

The determination of cesium in minerals can be accompHshed by x-ray fluorescence spectrometry or for low ranges associated with geochemical exploration, by atomic absorption, using comparative standards. For low levels of cesium in medical research, the proton induced x-ray emission technique has been developed (40). 

Macerals. Coal parts derived from different plant parts, are referred to as macerals (13). The maceral names end in "-inite" as do the mineral forms of rocks. The most abundant (about 85%) maceral in U.S. coal is vitrinite, derived from the woody tissues of plants. Another maceral, called liptinite, is derived from the waxy parts of spores and poUen, or algal remains. The liptinite macerals fluoresce under blue light permitting a subdivision based on fluorescence. A third maceral, inertinite, is thought to be derived from oxidized material or fossilized charcoal remnants of early forest fires. 

Measuring process parameters on full-scale plants is notoriously difficult, but is needea for control. Usually few of the important variables are accessible to measurement. Recycle of material makes it difficult to isolate the effects of changes to individual process units in the circuit. Newer plants have more instrumentation, including on-line viscosimeters [Kawatra and Eisele, International ]. Mineral Processing, 22, 251-259 (1988)], mineral composition by on-line X-ray fluorescence, belt feeder weighers, etc., but the information is always incomplete. Therefore it is helpful to have models to predict quantities that cannot be measured while measuring those that can. 

Variety of biochemical composition and physical features of milk, as well as compound forms of mineral components foreordain necessity to develop the analytical procedures, in which initial sample state suffers minimum change. Absence of dried milk reference standai ds (RSMs) is an obstacle to use nondestructive XRF for solving the given analytical task. In this communication results of nondestmctive x-ray fluorescence determination of Na, Mg, Al, Si, P, S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Zr in dried milk powders of limited mass (less than 2 g), obtained with using plant RSMs to calibrate, ai e discussed. 

X-Ray Fluorescence analysis (XRF) is a well-established instrumental technique for quantitative analysis of the composition of solids. It is basically a bulk evaluation method, its analytical depth being determined by the penetration depth of the impinging X-ray radiation and the escape depth of the characteristic fluorescence quanta. Sensitivities in the ppma range are obtained, and the analysis of the emitted radiation is mosdy performed using crystal spectrometers, i.e., by wavelength-dispersive spectroscopy. XRF is applied to a wide range of materials, among them metals, alloys, minerals, and ceramics. 

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