The present application relates to methods for leaching and extraction of precious metals. For example, the present application relates to methods of leaching gold, palladium and/or platinum from a substance comprising gold, palladium and/or platinum (such as a gold-containing ore or a platinum group metal (PGM) concentrate) using an organic solvent that is water-miscible or partially water-miscible.

The present application relates to methods for leaching and extraction of precious metals. For example, the present application relates to methods of leaching gold, palladium and/or platinum from a substance comprising gold, palladium and/or platinum (such as a gold-containing ore or a platinum group metal (PGM) concentrate) using an organic solvent that is water-miscible or partially water-miscible.

Provided herein are processes for recovering metal present at low concentration from an acidic aqueous solution, including contacting the acidic aqueous solution with an organic phase solution including one or more 5-(C.sub.8 to C.sub.14 alkyl)-2-hydroxyaryloxime, thereby extracting at least part of the metal from the acidic aqueous phase; increasing or maintaining the concentration of metal in the organic phase solution by recycling a portion of the organic phase solution containing the metal and contacting the organic phase with an acidic aqueous solution containing the metal; contacting the organic phase solution containing metal with an aqueous phase strip solution comprising an inorganic compound that back-extracts the metal, thereby stripping at least part of the metal from the organic phase solution to the aqueous phase strip solution; and separating the metal from the aqueous phase strip solution, thereby recovering the metal.

A process for recovery of precious metals from ores or concentrates containing refractory carbonaceous material by cyanidation leaching. The process involves addition to the ores or concentrates at least one cationic surfactant before or during the addition of cyanide-containing solution. The agent enables the recovery of precious metals by cyanidation from high preg-robbing carbonaceous ores and improves the recovery of precious metals by cyanidation from medium to low preg-robbing carbonaceous ores. The agent also prevents froth and foaming formation during the cyanidation process.

A process for recovery of precious metals from ores or concentrates containing refractory carbonaceous material by cyanidation leaching. The process involves addition to the ores or concentrates at least one cationic surfactant before or during the addition of cyanide-containing solution. The agent enables the recovery of precious metals by cyanidation from high preg-robbing carbonaceous ores and improves the recovery of precious metals by cyanidation from medium to low preg-robbing carbonaceous ores. The agent also prevents froth and foaming formation during the cyanidation process.

Disclosed is a method for processing ash, particularly fly ash, in which method several elements are separated from the ash. In the method both noble metals and rare earth elements are separated.

An apparatus for separating a mixture of two liquids of different densities which liquids are substantially insoluble in one another includes a hollow permeable body having a recess for receiving a first fluid which can flow from the recess through the permeable body to an exterior of the permeable body. A housing surrounds and is spaced from the exterior of the permeable body. The housing has an inlet for a second fluid and an outlet for a mixture of the first and second fluid. A baffle or baffles are provided in the space between the exterior of the permeable body and the housing, and to define a mixing channel in space between the exterior of the permeable body and the housing so that the second fluid can enter the housing inlet and flow through the mixing channel to the outlet, while picking up fluid on the exterior of the permeable body.

An apparatus for separating a mixture of two liquids of different densities which liquids are substantially insoluble in one another includes a hollow permeable body having a recess for receiving a first fluid which can flow from the recess through the permeable body to an exterior of the permeable body. A housing surrounds and is spaced from the exterior of the permeable body. The housing has an inlet for a second fluid and an outlet for a mixture of the first and second fluid. A baffle or baffles are provided in the space between the exterior of the permeable body and the housing, and to define a mixing channel in space between the exterior of the permeable body and the housing so that the second fluid can enter the housing inlet and flow through the mixing channel to the outlet, while picking up fluid on the exterior of the permeable body.

Disclosed herein is a method for extracting precious metals from supported catalysts. The precious metal in one embodiment is rhodium. The supported catalyst may be from equipment, such as a used catalytic converter. The method is carried out at low temperature, and does not require harsh conditions, such as the use of a strong acid. The method involves contacting the catalytic material with a polar molecule and a reactive gas.

The invention relates to the metallurgical industry, specifically to the acid treatment of red mud obtained in the process of producing alumina, and can be used in technologies for recycling waste from alumina refinery holding ponds. The method for the acid treatment of red mud involves leaching using a leaching agent comprised of water-soluable aliphatic carbonic acids having fewer than 3 carbon atoms per molecule, filtering the solution, and separating the recoverable end products. To ensure a high level of recovery of valuable components and the increased productivity of the process, leaching is conducted with the addition of red mud in portions and with the control of pH values, and when a target pH value of between 2.3 and 3.8 is reached, no more red mud is added, and once leaching is complete, the solution is kept at a given leaching temperature for no less than one hour.