Abstract: The present invention provides a method and apparatus for removing mercury from gases such as those discharged from roasters and other heat producing systems. In embodiments the method comprises reacting the mercury with dissolved molecular chlorine, and may also comprise reacting the mercury with mercuric chloride to yield mercurous chloride. The mercurous chloride may be removed by precipitation. There are also disclosed apparatuses for implementing the method.

Abstract: A process for controlling the dissolution of a metal in an acid bath is described. The metal may comprise aluminum and the acid bath may contain a metal catalyst that causes the metal to dissolve. In order to control the rate of dissolution and/or the amount of gas evolved during the process, an iron source is added to the bath. In one embodiment, the process can be used to dissolve aluminum contained in spent fuel assemblies for recovering a nuclear fuel, such as uranium.

Abstract: Nickel is recovered from pickling acid solutions of crude ore using boric acid as catalyst by ultrasound assisted electrolysis.

Abstract: Apparatus and processes are disclosed for electrowinning metal from a fluid stream. A representative apparatus comprises at least one spouted bed reactor wherein each said reactor includes an anolyte chamber comprising an anode and configured for containing an anolyte, a catholyte chamber comprising a current collector and configured for containing a particulate cathode bed and a flowing stream of an electrically conductive metal-containing fluid, and a membrane separating said anolyte chamber and said catholyte chamber, an inlet for an electrically conductive metal-containing fluid stream; and a particle bed churning device configured for spouting particle bed particles in the catholyte chamber independently of the flow of said metal-containing fluid stream. In operation, reduced heavy metals or their oxides are recovered from the cathode particles.

Abstract: A process for producing one or more metals from a mineral feedstock (12) is defined. The mineral is fed to a leaching apparatus (10) wherein it is contacted with electrolyte (14). The leaching apparatus has zones of decreasing oxidation potential (17, 18, 19, 20) respectively. A stream of electrolyte (14A) is removed from zone (20) and is treated to remove impurities and unwanted metals in treatment unit (25A), prior to metal recovery by electrolysis. The electrolyte after electrolysis is then returned to the leaching unit (10). A second electrolyte stream (14B) may be removed from zone (19) for recovery of additional metals. The electrolyte (14B) is treated to remove impurities and any unwanted metals in treatment unit (25B), prior to metal recovery by electrolysis. The electrolyte after electrolysis is returned to leaching unit (10). The process enables the leaching of difficult to leach minerals, including gold, and can produce one or more metals of high purity.