Abstract: A method for plasma treatment of wet metal-containing wastes in which a plasma treatment unit comprises an electrically conductive hearth for holding a layer of slag and optionally a layer of metal produced by the plasma treatment. A graphite electrode is arranged above the hearth, so that, in use, a plasma arc is formed between the electrode and the hearth. One or more inlets for the particulate metal-containing waste are arranged adjacent to the electrode and sufficiently close to the electrode so that, in use, the particulate metal-containing waste fed into the plasma treatment unit falls close to the arc formed between the electrode and the hearth and is heated by the plasma arc before contacting the slag layer such that moisture present in the particulate metal-containing waste is completely volatilized in a head space of the furnace.

Abstract: A process for treating an off-gas from the thermal processing of a precious-metal-containing feedstock, the process comprising cooling the off-gas to a temperature of from 300 to 500° C.; passing the cooled off-gas through a first particulate filter to recover particulate material; and dosing the off-gas from the first particulate filter with a sorbent material and passing the dosed off-gas through a second particulate filter; wherein at least a portion of the particulate material recovered from the first particulate filter is recycled into the thermal processing of the precious-metal-containing feedstock.

Abstract: A method for treating hazardous waste comprising the steps of providing a plasma reactor, waste to be treated and a glass-forming host slag material; contacting within the plasma reactor the waste and the host slag material; and treating the waste and the host slag material using a plasma treatment to melt the host slag material and incorporate inorganic components of the waste within the host slag material, wherein the plasma is generated using an arc and the arc is passed through the host slag material.

Abstract: A process for treating an off-gas from the thermal processing of a precious-metal-containing feedstock, the process comprising cooling the off-gas to a temperature of from 300 to 500° C.; passing the cooled off-gas through a first particulate filter to recover particulate material; and dosing the off-gas from the first particulate filter with a sorbent material and passing the dosed off-gas through a second particulate filter; wherein at least a portion of the particulate material recovered from the first particulate filter is recycled into the thermal processing of the precious-metal-containing feedstock.

Abstract: The present invention relates to a method, and apparatus for the recovery of precious metals. Accordingly, it provides a continuous process for obtaining a precious metal composition from a feedstock material, the process comprising the steps of: (i) heating a feedstock material in a plasma furnace to form an upper slag layer and a lower molten metal layer; (ii) removing the slag layer; (iii) removing the molten metal layer; (iv) allowing the removed molten metal layer to solidify; (v) fragmenting the solidified metal layer to form fragments; and (vi) recovering a precious metal composition from the fragments; wherein the feedstock material comprises a precious metal containing material and a collector metal, said collector metal being a metal or an alloy that is capable of forming a solid solution, an alloy or an intermetallic compound with one or more precious metals. This allows for high recovery yields of precious metals.

Abstract: The present invention relates to a method for the treatment of metal-containing waste, the method comprising: (i) introducing a particulate metal-containing waste into a plasma treatment unit; (ii) plasma treating the particulate metal-containing waste to form a layer of slag and, optionally, a layer of metal beneath the layer of slag; and (iii) recovering slag and/or metal from the plasma treatment unit; wherein the plasma treatment unit comprises an electrically conductive hearth for holding the layer of slag and optional layer of metal, one or more inlets for the particulate metal-containing waste arranged above the hearth, and an electrode arranged above the hearth so that, in use, a plasma arc is formed between the electrode and the hearth, and wherein the one or more inlets for the particulate metal-containing waste are arranged so that, in use, the particulate metal-containing waste introduced into the plasma treatment unit is heated by the plasma arc before contacting the slag layer.

Abstract: The present invention provides a method for the treatment of waste comprising one or more hazardous organic components, the method comprising plasma treating a waste in a plasma treatment unit; wherein the waste comprises: (i) a soil and/or aggregate material; and (ii) an oil component; and wherein, before plasma treating the waste, the waste comprises one or more hazardous organic components and from 5 to 50% water by weight of the waste.

Abstract: A method for treating nuclear sludge comprising subjecting the nuclear sludge to a plasma treatment in a plasma chamber to melt at least some of the inorganic components of the sludge, wherein the plasma chamber comprises a crucible having a cooled inner surface, this surface cooled sufficiently such that the inorganic components in contact with the inner surface are in a solid state and form a barrier between the part of surface of the crucible with which they are in contact and the molten inorganic components of the sludge.