Abstract: A process for leaching minerals that contain metal sulphides and one or more precious metals or precious metal compounds, the process comprising the steps of a first leaching step to leach the minerals under oxidative conditions at a pH of less than 4 to form a slurry or pulp, the slurry or pulp comprising a solid phase containing unreacted components, solid reaction products and elemental sulphur, and subjecting the slurry or pulp or solid residue from the first leaching step to a second leaching step comprising oxidative leaching at pH of at least 9.0 to thereby form thiosulphate, whereby the thiosulphate leaches precious metal from the solid residue.

Abstract: A process for treating minerals containing metal sulphide and a precious metal, the process comprising fine grinding the minerals and subjecting the minerals to a first leaching step conducted under oxidising conditions at a pH of from 5 to 7, and subjecting a pulp or suspension or solid residue from the first leaching step to a second leaching step conducted under oxidising conditions at a pH of at least 9.0.

Abstract: A process for leaching a mineral particulate material comprising the steps of feeding the mineral particulate material to a leaching step (10) in which at least one valuable metal in the mineral particulate material is leached into a leach solution to form a pregnant leach liquor and a solid residue containing undissolved mineral matter, the leaching step being conducted under conditions such that elemental sulphur is formed in the leaching step, wherein beads or particles that take up elemental sulphur are added to the leaching step such that elemental sulphur is taken up by or collects on the beads or particles, and separating the beads or particles from the pregnant leach liquor and the solid residue. The beads or particles may be treated to remove sulphur and the beads or particles are returned to the leaching step.

Abstract: A hanger bar for an electrowinning cell, wherein hanger bar includes a bar portion and one or more contact portions adapted, in use, to be brought into contact with an electrical conductor. The contact portions are fabricated from an electrically conductive material, and a welded seal is formed between the bar portion and the contact portions in order to minimize corrosion.

Abstract: A process for leaching a mineral particulate material comprising the steps of feeding the mineral particulate material to a leaching step (10) in which at least one valuable metal in the mineral particulate material is leached into a leach solution to form a pregnant leach liquor and a solid residue containing undissolved mineral matter, the leaching step being conducted under conditions such that elemental sulphur is formed in the leaching step, wherein beads or particles that take up elemental sulphur are added to the leaching step such that elemental sulphur is taken up by or collects on the beads or particles, and separating the beads or particles from the pregnant leach liquor and the solid residue. The beads or particles may be treated to remove sulphur and the beads or particles are returned to the leaching step.

Abstract: An arrangement (10) for preventing egress of a gas from a first opening of a vessel, the vessel including at least one other opening through which the gas can leave the vessel, the arrangement comprising an open passage (48) extending substantially around the first opening, the open passage (48) receiving a flow of gas such that the flow of gas leaves the open passage and flows towards and into the vessel to cause a gas from the environment external to the vessel to be drawn into the vessel. The arrangement may comprise a Coanda surface. The arrangement may be in the form of an inert for placement in the opening to the furnace.

Abstract: A hanger bar for an electrowinning cell, wherein hanger bar includes a bar portion and one or more contact portions adapted, in use, to be brought into contact with an electrical conductor. The contact portions are fabricated from an electrically conductive material, and a welded seal is formed between the bar portion and the contact portions in order to minimize corrosion.

Abstract: A process of treating a solid material containing lead and elemental sulphur, by feeding the solid material to a furnace containing a bath of molten slag under conditions such that elemental sulphur burns in the furnace to form sulphur dioxide and lead in the solid material is oxidized and reports to the slag, then removing a gas stream containing sulphur dioxide from the furnace, and finally removing a lead-containing slag from the furnace.

Abstract: An arrangement (10) for preventing egress of a gas from a first opening of a vessel, the vessel including at least one other opening through which the gas can leave the vessel, the arrangement comprising an open passage (48) extending substantially around the first opening, the open passage (48) receiving a flow of gas such that the flow of gas leaves the open passage and flows towards and into the vessel to cause a gas from the environment external to the vessel to be drawn into the vessel. The arrangement may comprise a Coanda surface. The arrangement may be in the form of an inert for placement in the opening to the furnace.