Abstract: Lead with a low alpha particle emission is produced by selecting an orebody wherein lead mineral is present in a coarsely disseminated form and substantially free of impurities. The ore is selected from a host rock that is relatively low in alpha emitters, such as a carbonate rock. The ore is mined and is milled such that the lead mineral can be separated from the host rock and any other minerals. The ground ore may be screened into one or more fractions having a narrow range of particle sizes. Each fraction is formed into a fluid suspension, and each suspension is subjected to gravity separation to remove the host rock and any other minerals which substantially contain the alpha particle-emitting substances, and to recover the lead mineral as a concentrate with a low alpha count. The lead concentrate is subjected to a suitable reduction operation that may include a conversion of the concentrate into a reducible form, without the introduction of alpha emitters, for the recovery of a low alpha lead.
Type:
Grant
Filed:
August 29, 1988
Date of Patent:
December 19, 1989
Assignee:
Cominco Electronic Materials Inc.
Inventors:
John A. Dunlop, Edward F. G. Milner, Robert W. Smyth, Gerald W. Toop