System for producing magnesium chloride aqueous solution and system for producing magnesium

A system for producing a magnesium chloride aqueous solution comprising:

• a crystallization unit;
• a precipitation unit connected to the crystallization unit;
• a removal unit connected to the precipitation unit;
• an acid-alkali generation unit connected to the removal unit;
• and
• a reaction unit connected to the precipitation unit,
• wherein the crystallization unit crystallizes magnesium hydroxide by adding a sodium hydroxide aqueous solution to water to be treated using seawater as a raw material, and generates reaction slurry in which particles of the magnesium hydroxide are dispersed,
• the precipitation unit stores the reaction slurry to precipitate the particles, and separates the reaction slurry into a recovered slurry containing the particles at a high concentration and a separated liquid containing the particles at a low concentration,
• the removal unit removes divalent cations from the water to be treated or the separated liquid to generate a reaction liquid,
• the acid-alkali generation unit generates a sodium hydroxide aqueous solution and hydrochloric acid from the reaction liquid,
• the reaction unit adds the hydrochloric acid to the recovered slurry and generates a magnesium chloride aqueous solution, and
• the acid-alkali generation unit has:
• a main body section configured to generate a sodium hydroxide aqueous solution and hydrochloric acid from the reaction liquid;
• a first connection unit configured to connect the main body section and the crystallization unit and supply the sodium hydroxide aqueous solution to the crystallization unit;
• and
• a second connection unit configured to connect the main body section and the reaction unit and supply the hydrochloric acid to the reaction unit.