Abstract: The present invention concerns a process for smelting nickel which comprises treating nickel-containing material with a reducing gas to reduce the nickel component contained in the nickel-containing material and thereby produce metallic nickel; soaking the thus-obtained material in an ammoniacal aqueous ammonium salt solution and treating it with oxygen or an oxygen-containing gas in the presence of free ammonia in order to produce an aqueous nickel ammine salt solution; treating coal with the thus-produced aqueous nickel ammine salt solution so that the coal becomes impregnated with the nickel ammine salt; separating and recovering ammonia from the thus-treated coal; gasifying catalytically the coal containing the nickel compound in the presence of a gasifying agent, thereby producing a reducing gas and a solid residue; employing part of the thus-produced reducing gas for the treatment of the nickel-containing material; and separating and recovering metallic nickel from the solid residue.

Abstract: There is disclosed a method for removing oxides of nitrogen from gaseous mixtures by contacting the gaseous mixtures with an alkaline solution of an alkali metal manganate.

Abstract: A high-pure alkali permanganate is produced at a high yield by electrolytically oxidizing at a temperature of higher than 60.degree. C a caustic alkali slurry of manganese dioxide and/or an alkali penta-valent manganate having a caustic alkali concentration of 10 to 25% by weight.