US 4,690,725 AGranted

Purification of Cd and Te by zone refining

AssigneeCominco Ltd.

InventorsRoelof P. Bult, Alan B. I. Bollong, Robert F. Redden

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Abstract

Cd and Te are purified by multiple-pass zone refining in the presence of a small amount of an added gettering substance chosen from Cd, Te and CdTe. In the purification of Cd, Te, or CdTe is added, the amount of Te or of Te in CdTe being less than the amount of Te in the Cd-rich eutectic composition between Cd and Te. In the purification of Te, Cd or CdTe is added, the amount of Cd or of Cd in CdTe being less than the amount of Cd in the Te-rich eutectic composition between Cd and Te. The Cd and Te so purified have an improved purity as witnessed by SSMS analyses, the increased ductility of the Cd and a much higher yield of the number of slices of CdHgTe produced with the refined Cd and Te meeting the specifications for carrier concentration and mobility.

Claims5

Dependent claims

A method for the purification of a metal chosen from the group consisting of cadmium and tellurium which comprises adding to an ingot of the metal an amount of a gettering substance chosen from the group consisting of tellurium, cadmium and cadmium telluride, subjecting the metal with added gettering substance to multiple-pass zone refining, said amount of tellurium or the amount of tellurium in cadmium telluride added in the zone refining of cadmium being less than the amount of tellurium in the cadmium rich eutectic composition between cadmium and tellurium, and said amount of cadmium or the amount of cadmium in cadmium-telluride added in the zone refining of tellurium being less than the amount of cadmium in the tellurium-rich eutectic composition between cadmium and tellurium, and cropping said ingot after multiple zone refining to recover a product of reduced impurity content.

Dependencies are inferred from the claim text.