Welsbach gas mantle

Baron Auer von Welsbach, 1858-1929. Austrian chemist and chemical technologist. Discoverer of praseodymium and neodymium. Inventor of the Welsbach gas mantle, the osmium filament electric lamp, and the automatic gas lighter. 

Titanium, rutile, ilmenite, titanium dioxide, titanium tetrachloride. Zirconium, zircon- Hafnium. Thorium, thorite, monazite sand, the Welsbach gas mantle. 

Before beryllium alloys were developed, the principal use of berryllium was as oxide in the manufacture of refractories, spark plugs, high quality electrical porcelains, and as beryllium nitrate in the fabrication of Welsbach gas mantles. It was not until the early 1930 s, however, that metallurgical improvements created a large enough demand to justify a beryllium industry. Berylliumcopper, with small additions has been, by far, the important alloy. 

The minerals on which the work was performed during the nineteenth century were indeed rare, and the materials isolated were of no interest outside the laboratory. By 1891, however, the Austrian chemist C. A. von Welsbach had perfected the thoria gas mantle to improve the low luminosity of the coal-gas flames then used for lighting. Woven cotton or artificial silk of the required shape was soaked in an aqueous solution of the nitrates of appropriate metals and the fibre then burned off and the nitrates converted to oxides. A mixture of 99% ThOz and 1% CeOz was used and has not since been bettered. CeOz catalyses the combustion of the gas and apparently, because of the poor thermal conductivity of the ThOz, particles of CeOz become hotter and so brighter than would otherwise be possible. The commercial success of the gas mantle was immense and produced a worldwide search for thorium. Its major ore is monazite, which rarely contains more than 12% ThOz but about 45% LnzOz. Not only did the search reveal that thorium, and hence the lanthanides, are more plentiful than had previously been thought, but the extraction of the thorium produced large amounts of lanthanides for which there was at first little use. 

Origins. Since the 1890 S, monazite, the first commercial rare earth ore, was mined from black beach sands in Brazil and shipped to Austria for its 5 to 10% thorium oxide content. Carl Freiherr Auer von Welsbach spent 20 years of research work developing a bright incandescent gas mantle he discovered in 1866 with... 

The only important commercial use of thorium, however, is in the manufacture of incandescent gas mantles. This industry had a very modest beginning in 1884 when Welsbach patented the use of a fibrous network of rare earth oxides which were to be heated by an ordinary gas flame of the Bunsen type. The first mantles were composed of a mixture of zirconia, lanthana,... 

Although the heating of a refractory material to incandescence for the purpose of a source of light had engaged the attention of a number of earlier experimenters, it was not until 1880-3 that Williams, in New Jersey and Welsbach in Vienna developed what is essentially the gas mantle of today.80 Cotton threads impregnated with a solutiou of a rare earth salt, dried, and burned resulted in the formation of a coherent ash which emitted light of great intensity when heated by a gas flame. 

Incandescent gas mantle (Carl Auer von Welsbach) The Austrian scientist invents the incandescent gas mantle. 

Welsbach s incandescent gas mantle patented in 1885 enabled the gas industry to compete for a few more decades with electric lights. 

It is obvious that the narrow band thermoluminescence 8, 9) influenced Carl Auer von Welsbach in developing his mantle between 1884 and 1892, but as discussed in the next chapter, the optimized conditions for white gas-light rather involve another t cpe of excited states of cerium(IV). On the other hand, the cathodo-luminescence in narrow bands discovered by William Crookes and carefully studied by Urbain [12) corresponds to internal transitions in the partly filled shell. Thus, the excited state of 4/ europium(III) produces the red emission (important for colour television) in the orthovanadate [13) Yi Eux VO 4 and in the oxysulphide (74) by transitions to " Fz, and Fq. Certain... 

Named after Thor, the Scandinavian god of war, thorium was discovered by Jons Jakob Berzelius (1779-1848) in 1828 in a mineral sample from Norway. Although thorium does not occur in elemental form, thorium ores are thought to be about as abundant as lead in the Earth s crust. Thorium has limited uses as a commercial product, primarily in specialty electronics and Welsbach mantles (portable gas lights). Because thorium is radioactive and more plentiful than uranium, it may be used as a power source in the future. The internal heating of the Earth may be a result of the action of thorium. 

In addition to its potential use in nuclear power systems, thorium has had minor industrial use in Welsbach mantles for incandescent gas lamps, in magnesium alloys to increase strength and creep resistance at high temperatures, and in refractories. 

That the rare earth metals are of little practical value was the general view during the whole of the 19 century. The turn of the century, however, saw the first major application, Auer von Welsbach s incandescent mantle for gas lightning (section 17.4.10.2). Gradually the list of RE applications was increased. At first the RE metals were used mixed, just as they were prepared from monazite sand. One example is mischmetall, consisting of about 50% cerium, 25% lanthanum and 25% other rare... 

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