Incandescent mantle

Cerium is a component of misch metal, which is extensively used in the manufacture of pyrophoric alloys for cigarette lighters. While cerium is not radioactive, the impure commercial grade may contain traces of thorium, which is radioactive. The oxide is an important constituent of incandescent gas mantles and is emerging as a hydrocarbon catalyst in self cleaning ovens. In this application it can be incorporated into oven walls to prevent the collection of cooking residues. 

At the beginning of the twentieth century, the incandescent mantle, utilising the candoluminescence of a mixture of thorium (95% weight) and cerium oxides was developed. The pyrophoricity of rare-earth metals led to the invention of the lighter flint made through the alloying of iron and mischmetal. Since that time, numerous other appHcations have developed to coincide with the availabiUty of the rare-earth compounds on an industrial scale and having a controlled purity. 

Gliihlicht, n. incandescent light, -brenner, m, incandescent burner, -kdrper, -strumpf, m incandescent mantle. 

Fig. 13. Differential refractometer60) for use at kg = 1086 nm H - hollow mirror, G - incandescent halogen lamp, L, - L6 - lenses, R - heat reflector, F - interference filter, Sj - S2 - slits, T - heating mantle, K - differential cell, D - silicon photocell, M - micrometer thread...

The analysis of the water gas so far given enumerates the chief constituents, but in reality there are traces of other products, such as carbon bisulphide, carbonyl sulphide, and thiophene, derived from the sulphur in the uel, which, minute in quantity, may nevertheless in the certain chemical processes produce appreciable and un-iesirable results from the iron contained in the fuel, ninute amounts of iron carbonyl are formed, which in nost processes in which water gas is used is a matter jf no importance, but if the gas is to be used for ighting with incandescent mantles, its removal is de-.irable. 

The compound cerium oxide (either Ce Oj or CeO ) is used to coat the inside of ovens because it was discovered that food cannot stick to oven walls that are coated with cerium oxide. Cerium compounds are used as electrodes in high-intensity lamps and film projectors used by the motion picture industry. Cerium is also used in the manufacturing and polishing of high-refraction lenses for cameras and telescopes and in the manufacture of incandescent lantern mantles. It additionally acts as a chemical reagent, a misch metal, and a chemical catalyst. Cerium halides are an important component of the textile and photographic industries, as an additive to other metals, and in automobile catalytic converters. Cerium is also used as an alloy to make special steel for jet engines, solid-state instruments, and rocket propellants. 

Be(N03)2 3H2O is used to produce beryllium oxide and as a mantle hardener in incandescent acetylene or other gas lamps. 

Calcium nitrate is used in explosives, matches and pyrotechnics. Other applications are in the manufacture of incandescent mantle and as an additive to diesel fuel for corrosion inhibition. 

Cerium(lll) chloride is used to prepare cerium metal and other cerium salts. It also is used as a catalyst in olefin polymerization, and in incandescent gas mantles. 

Thorium nitrate is a reagent for measuring fluorine and for making thori-ated tungsten filaments. Thorium nitrate containing 1% cerium nitrate is the impregnating liquid in making incandescent gas mantles. 

Auer von Vfelsbach had already reported in 1885 a patent for a lanthanum-zirconium incandescent element and also produced them. This incandescent mantle had two properties ... 

The incandescent mantle was however not accepted by consumers because it was too brittle and produced a "cold" blue-green light. 

Period of First Industrial Usage. By iitprovement of this first discovery there arose the first industrial consunption of rare earths and the hour of birth of the rare earth industry in the year 1891, when Auer vcn Welsbach reported his patents for the Auer incandescent mantle v ch is conposed of 99 % thorium oxide and 1 % cerium oxide. Ihis light was sip>erior for decades to electric light. It was cheaper so that until the year 1935 approximately 5 billion incandescent mantles had been produced and consumed in the world. 

Even today this method of light production remains superior to electric lighting systems in remote areas or in signal devices for railroads. For example, in front of ity house in Essen, Germany, there are open street lanterns with gas-heated Auer-incandescent mantles which provide a pleasant light on our quiet street. 

The carbon filament lamp vAiich was developed in parallel at the beginning of this century was always several times as expensive in use as an Auer incandescent mantle. As a result, this first use of the rare eaurth elements achieved great economic success and thanks to his capabilities Auer von Welsbach played a major role in this worldwide achievement. He was in the position to survive the extraordinarily corplicated and obstinately pursued patent battles. 

Again, we take a short look into the origin of this discovery, Auer von Welsbach had accumulated so much thorium in the processing of rare earths for production of lanthanumr-zirconium incandescent mantles - the predecessor of Auer incandescent mantles - that he had to look for a use for them. 

If one adds to this the other applications, the consunption was probably between 2 000 - 3 000 tons of oxides. On the other hand, at the same time, about 7 500 tons of thorium nitrate were needed for Auer incandescent mantles. If one assumes that monazite contains 6 % thorium oxide and 60 % rare earth elements, then 30 000 tons of rare earth oxides were produced during this period of vhich only about 10 % was consumed. 

The first applications of the rare earth elements / as already mentioned, were in the optical field, namely the Auer incandescent mantles and the arc light carbons. In 1964/65 as a result of the work of Levine and Palilla the use of the truly rare and therefore expensive europium together with yttrium made a major leap forward for the rare earth industry as red phosfdiors in color TV screens. Due to the strong and sharp emission line of europium at 610 A, without a yellow component, viiich is... 

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... 

Baron Auer is best remembered for his invention of the incandescent gas mantle, a truly great advance in the history of illumination (55). Instead of attempting to produce a gas which would bum with a luminous flame, he decided to use a non-luminous flame to heat a refractory mantle to incandescence. The problem, as he said, "was not to find a process by which an infusible compound could be given a definite shape. This invention is founded, above all, on the fact, proved by numerous experi-... 

Analytical data of samples of ore utilised on the commercial scale are set out on p. 119. By-products produced during the working-up of the rare earths for cerium and thorium compounds for use in the manufacture of incandescent mantles, as well as by-products from oertain tin and tungsten ores, are also available as sources of tantalum. 

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