The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 27, 1979
Filed:
May. 16, 1978
Haig Vartanian, Newton, MA (US);
NRC, Inc., Newton, MA (US);
Abstract
Tantalum powders which have high oxygen, high sodium contents are reclaimed for practical applications by treating said powders with selected fused salt compositions. This process converts normally unleachable sodium metatantalate, recognized herein as a significant source of the powder's content of oxygen and sodium, to leachable forms of oxygen and sodium bearing compounds. The conversion is accomplished by placing the high oxygen, high sodium tantalum powder, containing such metatantalate, in a fused salt bath which has the major portion of its composition equivalent to the final salts composition which would result from a reduction of potassium fluotantalate with sodium metal, under conditions where 90%-95% of required sodium stoichiometry was used and as a minor portion of composition contains small amounts of added potassium fluotantalate. The required amount of potassium fluotantalate is small in relation to the quantity of reclaimable tantalum powder treated by the process; i.e., the weight ratio of tantalum powder to be treated to tantalum contained in the added potassium fluotantalate (K.sub.2 TaF.sub.7) is in the range of 9:1 - 40:1.