The present application relates to methods for the simultaneous leaching and extraction of precious metals. For example, the present application relates to methods of leaching and extracting gold and/or palladium from a substance comprising gold and/or palladium such as a gold and/or palladium-containing ore in one step using a compound of Formula I: (I).

A silver powder containing dendrite silver particles is provided. The dendrite silver particles are in a dendrite shape having one trunk and a plurality of branches branching from the trunk. The thickness of the trunk of the dendrite silver particles is from 10 to 280 nm. The number of the branches per length of the trunk is from 6 to 30 branches/.Math.m. The percentage by number of the dendrite silver particles in the whole of silver particles is 50 N% or more. This silver powder is produced by reducing silver ions through electrolysis of an electrolyte solution containing silver ions and hydantoin or a derivative thereof.

A silver powder containing dendrite silver particles is provided. The dendrite silver particles are in a dendrite shape having one trunk and a plurality of branches branching from the trunk. The thickness of the trunk of the dendrite silver particles is from 10 to 280 nm. The number of the branches per length of the trunk is from 6 to 30 branches/.Math.m. The percentage by number of the dendrite silver particles in the whole of silver particles is 50 N% or more. This silver powder is produced by reducing silver ions through electrolysis of an electrolyte solution containing silver ions and hydantoin or a derivative thereof.

A method for clean recovery of palladium is provided, including the following steps: mixing a palladium-containing material, a Ce.sup.4+-containing acidic solution, and an additive, subjecting a resulting mixture to leaching to obtain a Pd.sup.2+-containing solution, and subjecting the Pd.sup.2+-containing solution to electrolysis to obtain palladium. In the method, the palladium-containing material is subjected to solution leaching with Ce.sup.4+ as an oxidative leaching agent and a chlorine-containing additive. After leaching is complete, a Ce.sup.4+ and Pd.sup.2+-containing leaching liquor is subjected to electrolysis to realize the green regeneration of Ce.sup.4+ and palladium. The method of the present disclosure does not lead to the generation of NOx and waste liquid. The present disclosure can significantly reduce the environmental impact and production cost and has excellent economic benefits and application prospects.

A method for clean recovery of palladium is provided, including the following steps: mixing a palladium-containing material, a Ce.sup.4+-containing acidic solution, and an additive, subjecting a resulting mixture to leaching to obtain a Pd.sup.2+-containing solution, and subjecting the Pd.sup.2+-containing solution to electrolysis to obtain palladium. In the method, the palladium-containing material is subjected to solution leaching with Ce.sup.4+ as an oxidative leaching agent and a chlorine-containing additive. After leaching is complete, a Ce.sup.4+ and Pd.sup.2+-containing leaching liquor is subjected to electrolysis to realize the green regeneration of Ce.sup.4+ and palladium. The method of the present disclosure does not lead to the generation of NOx and waste liquid. The present disclosure can significantly reduce the environmental impact and production cost and has excellent economic benefits and application prospects.

The present invention is related generally to recovering metals from waste electronics, and more particularly to a process to recover copper and gold commonly found in waste printed circuit boards using a lixiviant containing a weak acid such as citric acid or acetic acid, a particular concentration of table salt and an oxidizer. By using this lixiviant, the copper found in the printed circuit board reacts to form copper salts and gold becomes detached. Importantly this recovery method of copper and gold found in waste PCBs is fast, does not pose environmental hazards and is economically feasible.

The present invention is related generally to recovering metals from waste electronics, and more particularly to a process to recover copper and gold commonly found in waste printed circuit boards using a lixiviant containing a weak acid such as citric acid or acetic acid, a particular concentration of table salt and an oxidizer. By using this lixiviant, the copper found in the printed circuit board reacts to form copper salts and gold becomes detached. Importantly this recovery method of copper and gold found in waste PCBs is fast, does not pose environmental hazards and is economically feasible.

A process for recovering gold from a refractory gold ore, comprising the steps of: electrolyzing a mixture consisting of the ore particles and an aqueous bromide solution in an electrolytic cell having anode and cathode, wherein bromine is produced at the anode by oxidation of the bromide, thereby dissolving gold in the aqueous phase; separating the ore particles from the aqueous phase to obtain a leach liquor; adjusting the pH of the leach liquor to the alkaline range to produce a gold-containing precipitate; collecting the gold-containing precipitate and recycling a bromide-containing barren solution for reuse as an aqueous bromide feed solution.

A process for recovering gold from a refractory gold ore, comprising the steps of: electrolyzing a mixture consisting of the ore particles and an aqueous bromide solution in an electrolytic cell having anode and cathode, wherein bromine is produced at the anode by oxidation of the bromide, thereby dissolving gold in the aqueous phase; separating the ore particles from the aqueous phase to obtain a leach liquor; adjusting the pH of the leach liquor to the alkaline range to produce a gold-containing precipitate; collecting the gold-containing precipitate and recycling a bromide-containing barren solution for reuse as an aqueous bromide feed solution.

There is provided a more versatile technique that is useful for enhancing the sintering delay property of a metal powder. A metal powder surface-treated with at least one coupling agent comprising Si, Ti, Al or Zr, wherein a total adhesion amount of Si, Ti, Al and Zr is 200 to 10,000 μg with respect to 1 g of the surface-treated metal powder, wherein a 1% by mass aqueous solution of the coupling agent indicates a pH of 7 or less, and wherein a sintering starting temperature is 500° C. or higher.