Patent ID: 8647509

Claim:
A method of producing salt comprising: directing a saltwater desalination plant reject stream into a salt plant feed stream; selectively filtering said salt plant feed stream to remove scaling species, wherein said filtering step comprises directing said salt plant feed stream through a nanofiltration section to produce a filtered feed stream wherein at least 90% of the calcium and at least about 98% of the magnesium has been removed from said salt plant feed stream in said nanofiltration section; processing said filtered feed stream by directing said filtered feed stream through a membrane-based concentrator section to produce a concentrated stream; directing said concentrated stream to an evaporator section, wherein a high purity moist salt or slurry is produced; and directing said high purity moist salt or slurry to a crystallizer section, wherein said salt is produced, wherein said nanofiltration section is operated at a pH that is less than about 7.0 to enhance calcium and magnesium removal.