Thorium/zinc alloy

In the actual Iowa process it was sufficient to heat the products only to around 1360°C (1633 K) because the thorium-zinc alloy produced has a lower melting point than pure thorium. This permitted use of only 0.218 mol ZnCl2/mol Thp4 and provided enough heat to melt the alloy and slag, bring the 25 percent excess calcium to reaction temperature, and still allowed for heat losses. 

The reaction takes place in a closed steel vessel, 45 in. long by 12 in. internal diameter, which is lined with electrically fused dolomite or lime, as in the American uranium metal production process. Initiation is carried out in a gas-fired furnace at a temperature of 640°C. A thorium/zinc alloy is formed, from which the zinc is removed by distillation under vacuum, between 1000°C and 1100°C in graphite pots. About 85 per cent of the zinc can be recovered for re-use. 

I. Zinc alloys with thorium, reducing its melting point. 

Rubidium metal alloys with the other alkali metals, the alkaline-earth metals, antimony, bismuth, gold, and mercury. Rubidium forms double halide salts with antimony, bismuth, cadmium, cobalt, copper, iron, lead, manganese, mercury, nickel, thorium, and zinc. These complexes are generally water insoluble and not hygroscopic. The soluble rubidium compounds are acetate, bromide, carbonate, chloride, chromate, fluoride, formate, hydroxide, iodide,... 

Letters indicate ihc Iwo principal alloying elements A, Aluminum E, Rare-Earth H. Thorium K, Zirconium M, Manganese Q, Silver, S, Silicon T, Tin Z, Zinc. Thus HK signifies a thorium-zirconium magnesium alloy. 

Magnesium—nickel hydride, 4458 Plutonium(III) hydride, 4504 Poly(germanium dihydride), 4409 Poly(germanium monohydride), 4407 Potassium hydride, 4421 Rubidium hydride, 4444 Sodium hydride, 4438 f Stibine, 4505 Thorium dihydride, 4483 Thorium hydride, 4535 Titanium dihydride, 4484 Titanium—zirconium hydride, 4485 Trigermane, 4415 Uranium(III) hydride, 4506 Uranium(IV) hydride, 4536 Zinc hydride, 4486 Zirconium hydride , 4487 See COMPLEX HYDRIDES, PYROPHORIC MATERIALS See entry LANTHANIDE—TRANSITION METAL ALLOY HYDRIDES... 

Some of the materials that have been examined as catalysts include Pure Platinum, Platinum-Iridium Alloys, Various Compositions of Platinum-Rhodium Alloys, Platinum-Palladium Alloys, Platinum-Ruthenium Alloys, Platinum-Rhenium Alloys, Platinum-Tungsten Alloys, FejOj-M CVI Oj (Braun Oxide), CoO-Bi20j, CoO with AI2O3, Thorium, Cerium, Zinc and Cadmium. 

These are available as (i) cast alloys and (ii) wrought alloys. The two major cast alloy systems are 2-10% A1 with minor amounts of Zn and Mn, and Mg alloyed with rare earths, zinc, thorium, and silver without aluminum. The alloys devoid of zirconium are satisfactory in performance in the temperature range 95-120°C. The alloys containing zirconium have better high-temperature properties. Heat-treatment of the cast alloys results in improved properties. 

After the reactor was cooled to room temperature, it was opened and the mass of metal was mechanically freed of frozen slag. Ninety percent of the zinc in the alloy was removed by distillation in a retort heated to 1150°C at a vacuum lower than 0.2 Torr. The retort was then filled with argon or helium to prevent oxidation of the spongy thorium and cooled to room temperature. The thorium was transferred to a beryllia crucible in an induction-heated vacuum furnace for melting, evaporation of the residual zinc, and casting into a graphite mold. Thorium metal yield was 94 to 96 percent. 

Because unalloyed magnesium is not used extensively for structural applications, it is the corrosion resistance of magnesium alloys that is of primary interest. To enhance strength and resistance to corrosion, magnesium is alloyed with aluminum, lithium, zinc, rhenium, thorium, and silver, with minor additions of cerium, manganese, and zirconium sometimes being used as well. 

Alloys containing various elements (rare earths, zinc, thorium, and silver), but not aluminum, and containing zirconium, which provides grain refinement and improved mechanical properties these alloys provide improved elevated temperature properties compared to those in the first group. 

The major alloying elements are manganese, aluminium, zinc, zirconium, silicon, thorium, and rare earth metals (E). At present E elements are the most promising candidates for magnesium alloys, with high temperature stability as well as improved corrosion behavior. E metals are forming stable intermetallic compounds at high temperature and therefore they decrease casta-bility. Aluminium and zinc are introduced mainly to... 

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