Recovery Of Noble Metals Research Articles

Microbial mineral processing: The opportunities for genetic manipulation

AbstractApplications of microbiology to mining operations have been surveyed and evaluated. This has been carrried out with a view to seeking directions whereby genetical and molecular biological approaches could be applied to optimise ‘bio‐mining’ processes. Copper and uranium are currently recovered from their ores on a commercial scale (to a value of about US$1800 million annually worldwide) using bioleaching systems carried out in the open in biologically uncontrolled conditions. Possibilities also exist for applying bioleaching methods on an industrial scale for the extraction of a number of other metals from sulphide‐bearing concentrates. Molybdenum, cobalt and nickel are likely to be most suitable, principally because of their value. Biological ore beneficiation can be used to enhance the recovery of noble metals. Bioleaching systems offer a variety of desirable advantages compared to conventional methods but suffer principally in their relatively low leaching rates. Opportunities exist for the enhancement of bioleaching rates by genetic technologies. These approaches are outlined and discussed. Bioconcentration systems offer possibilities for metal recovery from dilute industrial waste streams and metal refinery effluents and for the heavy metal detoxification of polluted waters. Possible applications of genetic technologies to bioconcentration systems are proposed. Other uses for the mineral leaching thiobacilli, e.g. fossil fuel desulphurisation, are outlined and discussed.

Recovery of Noble Metals from Insoluble Residue of Spent Fuel

The recovery of Ru, Pd and Mo from the simulated insoluble residue produced in dissolver solution of spent fuel was studied by means of Pb extraction and the recovery was found to be more than 80% for Ru and Pd. It was also found that the recoveries of Ru, Pd and Mo were dependent on melting temperature and gas atmosphere. Observations by scanning electron microscopy and X-ray microanalysis indicated that the noble metals recovered in Pb button were contained in both forms of e-Ru(Pd, Mo) alloy and single metal. The solubility in nitric acid of Pd recovered in Pb was much higher than that of Pd in e-Ru(Pd, Mo) alloy, suggesting the separation of Pd from e-Ru (Pd, Mo) alloy. The decontamination factor for Ce as a stand-in of Pu was determined to be around 200 for one stage.

Recovery of noble metals from insoluble residue of spent fuel.

Recovery of noble metals from insoluble residue of spent fuel.

Recovery of Noble Metals from Fission Products

Spent nuclear fuels contain significant quantities of three of the platinum-group metals—ruthenium, rhodium, and palladium—plus a related element, technetium, which is nearly absent in nature. Appl...

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