Abstract: A method of recovering precious metals from a silver bearing ore containing polybasite, pearcite, pyrargyrite, tetrahedrite or argentite by mixing the ore with an alkali metal or alkaline earth metal peroxide in slurry or solid, leaching the ore with a cyanide solution, and recovering the precious metals from the cyanide solution.

Abstract: A liquor of the Bayer process, as defined, is contacted with manganese dioxide to oxidize organic material in the liquor. When the liquor is the seed wash liquor, oxalates in particular are oxidized.

Abstract: The present invention relates to a process for the recovery of manganese from aqueous acidic solution.The process comprises the steps of, (a) introducing into the solution peroxymonosulphuric acid (PMS) in a plurality of stages, normally from 2 to 6, often in the range of from 110 to 160% of the amount theoretically needed to oxidise the manganese to the Mn (IV) oxidation state, (b) introducing from 100 to 133% of the theoretical amount of neutralising agent to neutralise the PMS introduced in step (a), preferably in a single addition and prior to the introduction of the second stages of PMS and, (c) separating precipitated manganese salt from solution. The demanganisation reaction is preferably carried out at a temperature of above 60.degree. C. usually in the range of 70.degree. to 90.degree. C.An aqueous acidic manganese-containing solution can be obtained by leaching ores or scrap metal with strong mineral acids.