Abstract: The wastewater treatment method is to obtain demanganized wastewater, through a step wherein an acid or an alkali is added to sulfuric acid acidified wastewater to adjust pH to not less than 4.0 and not more than 6.0, whereby the sulfuric acid acidified wastewater is separated into a dealuminized solution and an aluminum precipitate; a step wherein a slurrying solution is added to the aluminum precipitate to form a slurry, then an alkali is added to adjust pH to not less than 9.0 and not more than 9.5, whereby an pH-adjusted aluminum precipitate slurry is formed; a step wherein an alkali is added to the dealuminized solution to adjust pH to not less than 8.0 and not more than 9.0; and others.

Abstract: A removal method of manganese in which manganese is removed by precipitating manganese selectively from sulfuric acid waste water containing aluminum, magnesium and manganese with inhibiting the precipitation of magnesium. The removal method of manganese from waste water in which manganese is removed by precipitating manganese selectively from the sulfuric acid waste water containing aluminum, magnesium and manganese with inhibiting the precipitation of magnesium, characterized in that said waste water is subjected to the following steps (1) and (2). (1) First, aluminum in said waste water is removed. (2) Subsequently, neutralizing agent is added into the wastewater after removing aluminum, then pH of the waste water is adjusted at 8.0 to 9.0, and oxygen gas is blown.

Abstract: Provided is a method for producing ferronickel from a nickel sulfide or a mixed sulfide containing nickel and cobalt, obtained by hydrometallurgy of nickel oxide ore or obtained from scraps or products in process. The method for producing a ferronickel raw material is to form the ferronickel raw material from a nickel sulfide or a mixed sulfide containing nickel sulfide and cobalt sulfide, wherein treatments are performed through the following steps: (1) redissolution step, (2) deferrization step, (3) solvent extraction step, (4) hydroxylation step, (5) roasting step, and (6) washing and calcining step.

Abstract: A method for recovering nickel from sulfuric acid aqueous solution, for recovering nickel in an effectively utilizable form as a raw material of nickel industry material, by separating efficiently impurity elements of iron, aluminum, manganese, etc., from the sulfuric acid aqueous solution containing nickel and cobalt, and the impurity elements, iron, aluminum, manganese, etc.

Abstract: Provided is a method for producing ferronickel from a nickel sulfide or a mixed sulfide containing nickel and cobalt, obtained by hydrometallurgy of nickel oxide ore or obtained from scraps or products in process. The method for producing a ferronickel raw material is to form the ferronickel raw material from a nickel sulfide or a mixed sulfide containing nickel sulfide and cobalt sulfide, wherein treatments are performed through the following steps: (1) redissolution step, (2) deferrization step, (3) solvent extraction step, (4) hydroxylation step, (5) roasting step, and (6) washing and calcining step.

Abstract: The wastewater treatment method is to obtain demanganized wastewater, through a step wherein an acid or an alkali is added to sulfuric acid acidified wastewater to adjust pH to not less than 4.0 and not more than 6.0, whereby the sulfuric acid acidified wastewater is separated into a dealuminized solution and an aluminum precipitate; a step wherein a slurrying solution is added to the aluminum precipitate to form a slurry, then an alkali is added to adjust pH to not less than 9.0 and not more than 9.5, whereby an pH-adjusted aluminum precipitate slurry is formed; a step wherein an alkali is added to the dealuminized solution to adjust pH to not less than 8.0 and not more than 9.0; and others.

Abstract: A removal method of manganese in which manganese is removed by precipitating manganese selectively from sulfuric acid waste water containing aluminum, magnesium and manganese with inhibiting the precipitation of magnesium. The removal method of manganese from waste water in which manganese is removed by precipitating manganese selectively from the sulfuric acid waste water containing aluminum, magnesium and manganese with inhibiting the precipitation of magnesium, characterized in that said waste water is subjected to the following steps (1) and (2). (1) First, aluminum in said waste water is removed. (2) Subsequently, neutralizing agent is added into the wastewater after removing aluminum, then pH of the waste water is adjusted at 8.0 to 9.0, and oxygen gas is blown.

Abstract: A method for recovering nickel from an sulfuric acid aqueous solution, for recovering nickel in an effectively utilizable form as a raw material of nickel industry material, by separating efficiently impurity elements of iron, aluminum, manganese and the like, from the sulfuric acid aqueous solution containing nickel and cobalt, and the impurity elements, iron, aluminum, manganese and the like. The method is characterized by comprising the following steps (1) to (5). step (1): to subject the sulfuric acid aqueous solution to oxidation neutralization treatment. step (2): then, to subject the solution to neutralization treatment, and to separate and recover mixed hydroxides containing nickel and cobalt. step (3): to subject the mixed hydroxides to dissolution treatment in a sulfuric acid solution having a concentration of equal to or higher than 50% by mass. step (4): to subject the concentrated solution to solvent extraction treatment, using a phosphate ester-based acidic extraction agent.