A process for helping improve hydrometallurgical precious metal recovery from preg-robbing ores or concentrates, such as double refractory ores or concentrates or carbonaceous ores. The process comprises treating the ore or concentrate in the presence of oxygen at a temperature and pressure sufficient to oxidize at least a portion of the organic carbon material in the ore or concentrate. A vessel is used to treat the ore or concentrate to oxidize the organic carbon material. The vessel may be a pipe. The vessel maintains the ore at an elevated temperature and pressure in the presence of oxygen. The vessel may have an inlet for receiving a pre-treated slurry of ore or concentrate, a mechanism for oxygen addition, a mechanism for degassing the pipe reactor, and an outlet for providing the treated slurry to further processing. The vessel may be used in series after an autoclave. The pipe reactor may also include a pre-heating step and a cooling step.

Disclosed herein are compositions, methods, and systems for supramolecular gold stripping where the composition comprises a surface-bound, linear gold anion and a solution comprising a molecular receptor that facilitates the transfer of the linear gold anion from the surface to the solution.

A method of recovering gold from refractory ore containing a carbonaceous material, a sulfide and gold is provided. Gypsum seed crystals are added to a slurry containing a roasted refractory ore or a pressure-oxidized refractory ore to decrease gypsum encapsulation of gold and improve gold recovery.

A method of recovering gold from refractory ore containing a carbonaceous material, a sulfide and gold is provided. Gypsum seed crystals are added to a slurry containing a roasted refractory ore or a pressure-oxidized refractory ore to decrease gypsum encapsulation of gold and improve gold recovery.

A process is disclosed for recovering cyanide used to leach gold or silver from ore. In the course of leaching gold or silver from ore, a barren solution is generated. A portion of the barren solution containing sodium cyanide is recycled to the cyanidation process while blowdown from the barren solution is subjected to pre-treatment, UV photodissociation and pH adjustment. Ultimately, a volatile hydrocyanic acid is formed and is absorbed into a sodium hydroxide solution through the employment of a gas-filled membrane. This forms sodium cyanide that can be recycled and used in the cyanidation process to leach gold or silver from ore.

A process is disclosed for recovering cyanide used to leach gold or silver from ore. In the course of leaching gold or silver from ore, a barren solution is generated. A portion of the barren solution containing sodium cyanide is recycled to the cyanidation process while blowdown from the barren solution is subjected to pre-treatment, UV photodissociation and pH adjustment. Ultimately, a volatile hydrocyanic acid is formed and is absorbed into a sodium hydroxide solution through the employment of a gas-filled membrane. This forms sodium cyanide that can be recycled and used in the cyanidation process to leach gold or silver from ore.

A method of recovering free milling gold from a gold-containing feed material that includes processing at least a part of a tailings stream from a flotation element in a size separation element and producing a fines stream and a coarse stream. The method also includes recovering free milling gold from at least one of the fines stream and the coarse stream.

A method of recovering free milling gold from a gold-containing feed material that includes processing at least a part of a tailings stream from a flotation element in a size separation element and producing a fines stream and a coarse stream. The method also includes recovering free milling gold from at least one of the fines stream and the coarse stream.

An apparatus for separating carbon or resin from slurry. The apparatus comprises a frame, a rotary cage screen assembly, a cage screen support and rotary drive system, a carbon collection assembly and a hopper moveably connected to the rotary cage screen assembly. The apparatus is positional partially within an adsorption tank or other container capable of containing slurry.

A method of recovering a metal from a low-grade ore which is subjected to cyanide leaching to produce a PLS which contains a metal cyanide which is removed from the PLS by ultrafiltration and nano-filtration, and then acidified and sulphidised to produce a metal sulphide from which the metal is extracted, and hydrogen cyanide which is recycled to the cyanide leaching step.