Abstract: In a process for the manufacture of copper arsenate, an arsenic-containing material is subjected to an oxidative pressure leach with sodium hydroxide forming a leach solution containing sodium arsenate. Sodium arsenate solution is mixed with a solution of copper sulfate for the formation of a copper and arsenic-containing solution without the precipitation of copper arsenate. The copper and arsenic-containing solution is treated for the precipitation of copper arsenate with formation of sodium sulfate solution. At least one of the sodium arsenate-containing solution and the sodium sulfate solution is subjected to electrolysis with membrances for at least partial conversion to arsenic acid and sulfuric acid, respectively, and sodium hydroxide.

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.