Large-Scale Laboratory Production of Ductile Zirconium

Abstract

On the basis of results obtained from small-scale laboratory work, equipment for the production of 60 pounds of zirconium sponge a cycle has been placed in operation.Zirconium carbide, prepared from zircon and earl)on in an electric arc furnace, is chlorinated in improved equipment capable of producing over 300 pounds a day. The raw zirconium chloride is purified in a unit which accommodates nearly 200 pounds. Reduction by magnesium is carried out in the same furnace as the purification. Excess magnesium and magnesium chloride are removed by a combination melting and vacuum distillation method. The zirconium sponge is pressed into briquets and melted in graphite crucibles in a new graphite resistor vacuum furnace capable of melting over 10 pounds of zirconium a charge.

Electrochemical Deoxidation of Solid Zirconium Dioxide in Molten Calcium Chloride

“…Commercially, zirconium metal is produced by the Kroll process. [2,3] In this process, zirconium dioxide (ZrO 2 ) is chlorinated in presence of carbon at 900°C to produce zirconium tetrachloride (ZrCl 4 ), which is subsequently reduced to zirconium metal by magnesium. The zirconium metal sponge is recovered after distilling magnesium chloride and excess magnesium metal under vacuum at 900°C.…”

Diffusion coefficient of gaseous zirconium tetrachloride (ZrCl4)

“…There have been a few reports on the overall process of zirconium sponge production that include information on the distillation process coupled with thermodynamic data of ZrCl 4 sublimation [4][5][6][7][8][9][10]. The vapor pressures of ZrCl 4 from 480 K to 690 K and from 710 K to 736 K were originally reported by Palko et al [8].…”

“…However, only a few countries in the world have access to commercial-scale zirconium industries and have the capability to manufacture reactor-grade zirconium. Metallic zirconium (sponge) can be produced from a magnesiothermic reduction known as Kroll's process [4,5], which is similar to that used for titanium production except that the raw material (TiCl 4 ) is in the liquid state.…”

Improvements in Methods for the Reduction of Zirconium Chloride with Magnesium

“…The Bureau of Mines process (1)(2)(3)(4) for the reduction of gaseous anhydrous zirconium chloride with magnesium under helium has developed within about 4 years from the test tube to a pilot plant producing regularly 600 pounds of metal a week. The improvements described below concern only the three following phases of this method: refining of the raw chloride, its reduction, and separation of the magnesium chloride from the zirconium sponge.…”

“…Transfer of purified gaseous chloride from a central gas producer, through heated pipes and a valve, to the reactor. 3. Tapping the salts produced in the reduction and refilling the crucible with magnesium under a helium-gas seal.…”