An electrochemical process implements, in a decoupled manner, a first step of electrolysis of an electrolyte to produce gaseous oxygen in a chamber and a second step of electrochemical conversion of H+ ions into gaseous hydrogen in a chamber which contains a liquid phase and a gas phase not dissolved in the liquid phase. Gaseous hydrogen produced in the conversion step is partly present in the gaseous headspace of chamber and as bubbles in the electrolyte, and partly dissolved in the electrolyte which is saturated with hydrogen. The electrolyte has at least one redox pair (A/B) forming at least one intermediate vector enabling the decoupling of the first and second steps. The interface between the gas and liquid phases is increased during the second step to accelerate the diffusion, from liquid phase to gas phase, of the dissolved hydrogen able to supersaturate the electrolyte. Pressurized gaseous hydrogen is then collected.

The present invention provides an extracting method of extracting nickel from laterite minerals. The extracting method comprises steps of gathering laterite minerals, placing electrodes into a solution, heating the solution to 75 degrees Celsius, placing the electrodes within the solution, applying a constant current, shutting off the current, filtering the solution, pouring an alkaline solution into the solution, cooling down the solution at room temperature, cooling down the solution to 0 degrees Celsius, filtering the solution, and immersing the electrodes into the solution, adding additional materials to the solution.

The present invention provides an extracting method of extracting nickel from laterite minerals. The extracting method comprises steps of gathering laterite minerals, placing electrodes into a solution, heating the solution to 75 degrees Celsius, placing the electrodes within the solution, applying a constant current, shutting off the current, filtering the solution, pouring an alkaline solution into the solution, cooling down the solution at room temperature, cooling down the solution to 0 degrees Celsius, filtering the solution, and immersing the electrodes into the solution, adding additional materials to the solution.

A method is provided for leaching the metals while granulating molten matte, comprising the steps of feeding a molten matte as a falling stream into a granulation chamber, spraying a liquid jet on the stream of molten matte to atomize the matte, and cooling the matte particles thus formed. The liquid jet comprises an acid solution containing water and sulfuric acid so that the acid solution starts leaching metals from the molten matte when the liquid jet contacts the molten matte. Part of product solution from granulation can be circulated to liquid jets to increase the metal content in the solution and to reduce its acid con-tent.

A method is provided for leaching the metals while granulating molten matte, comprising the steps of feeding a molten matte as a falling stream into a granulation chamber, spraying a liquid jet on the stream of molten matte to atomize the matte, and cooling the matte particles thus formed. The liquid jet comprises an acid solution containing water and sulfuric acid so that the acid solution starts leaching metals from the molten matte when the liquid jet contacts the molten matte. Part of product solution from granulation can be circulated to liquid jets to increase the metal content in the solution and to reduce its acid con-tent.

A nickel recovery process capable of decreasing nickel remaining in a byproduct by recovering nickel from the byproduct of electrolytic nickel manufacturing process by chlorine-leaching, and also, capable of simplifying a cementation step simultaneously, is provided. In a nickel recovery step S60, a nickel recovery step S70 and a nickel recovery step S80, nickel is recovered in each step from S.sup.0 slurry, residue flaker and chlorine-leached residue, which are byproducts of electrolytic nickel manufacturing process by chlorine-leaching, by using an aqueous solution containing 80 g/L to 390 g/L of chlorine and 30 g/L to 70 g/L of copper.

Systems and methods for recovering cobalt and other valuable metals from cobalt permanent magnets of various compositions, such as samarium cobalt magnets, are presented herein. In one embodiment, a method includes converting the permanent magnet material to a higher surface area form, such as a powder. The method also includes treating the converted permanent magnet material with an aqueous solution of ammonium carbonate to form a mixture (e.g., a slurry) that includes dissolved cobalt. In some embodiments, the method includes exposing the mixture to an oxidant to oxidize metallic constituents and form soluble species. The method also includes filtering the mixture to yield a filtrate and electroplating the cobalt onto a cathode from the filtrate.

Systems and methods for recovering cobalt and other valuable metals from cobalt permanent magnets of various compositions, such as samarium cobalt magnets, are presented herein. In one embodiment, a method includes converting the permanent magnet material to a higher surface area form, such as a powder. The method also includes treating the converted permanent magnet material with an aqueous solution of ammonium carbonate to form a mixture (e.g., a slurry) that includes dissolved cobalt. In some embodiments, the method includes exposing the mixture to an oxidant to oxidize metallic constituents and form soluble species. The method also includes filtering the mixture to yield a filtrate and electroplating the cobalt onto a cathode from the filtrate.

A vapor deposition metal mask substrate includes a nickel-containing metal sheet including a obverse surface and a reverse surface, which is opposite to the obverse surface. At least one of the obverse surface and the reverse surface is a target surface for placing a resist layer. The target surface has a surface roughness Sa of less than or equal to 0.019 μm. The target surface has a surface roughness Sz of less than or equal to 0.308 μm.

A vapor deposition metal mask substrate includes a nickel-containing metal sheet including a obverse surface and a reverse surface, which is opposite to the obverse surface. At least one of the obverse surface and the reverse surface is a target surface for placing a resist layer. The target surface has a surface roughness Sa of less than or equal to 0.019 μm. The target surface has a surface roughness Sz of less than or equal to 0.308 μm.