US Patent 11180397 Salt production from wastewater

Many processes generate wastewater streams rich in sulfate and chloride. These salt components are traditionally not recovered and are discharged to the environment. The invention recovers pure water for recycle/reuse and simultaneously generates valuable pure salts of NaCl and Na2SO4 for beneficial reuse, eliminating the waste stream. Process consists of the sequential crystallization of salt products with an intermediate purification step in which a chemical reactant is added to elevate levels of purity. The process is configured to simultaneously achieve zero liquid discharge.