Abstract: Disclosed is a system for producing magnesium hydroxide including: a generation unit; and a recovery unit connected to the generation unit, wherein the generation unit has a reaction tank in which a calcium hydroxide slurry is added to water to be treated containing magnesium ions to crystallize magnesium hydroxide and to obtain a reaction slurry containing particles of magnesium hydroxide, and a sedimentation tank in which the reaction slurry is reserved to sediment the particles and to separate the reaction slurry into a separation slurry containing the particles at a high concentration and a separation liquid containing the particles at a low concentration, and wherein, in the recovery unit, an alkaline aqueous solution is added to the separation liquid to crystallize magnesium hydroxide and to obtain the reaction slurry and then the reaction slurry is reserved to sediment the particles and to recover the sedimented particles.

Abstract: A catalyst for oxidation reaction of metallic mercury and reduction reaction of nitrogen oxide, comprising an oxide of titanium, an oxide of molybdenum, an oxide of vanadium, an oxide of phosphorus and gypsum is obtained by kneading titanium dioxide, ammonium molybdate, ammonium metavanadate, phosphoric acid, gypsum dihydrate and water using a kneader to obtain a paste, applying the paste to a metal lath substrate, and then drying and calcining the resultant.

Abstract: A catalyst for oxidation reaction of metallic mercury and reduction reaction of nitrogen oxide, comprising an oxide of titanium, an oxide of molybdenum, an oxide of vanadium, an oxide of phosphorus and gypsum is obtained by kneading titanium dioxide, ammonium molybdate, ammonium metavanadate, phosphoric acid, gypsum dihydrate and water using a kneader to obtain a paste, applying the paste to a metal lath substrate, and then drying and calcining the resultant.