Methods of seawater softening for desalination and mineral extraction

A method of sea water softening comprising:

• adding buffer solution (NaOH) to sea water to elevate its alkalinity up to pH 10,
• mixing flue gas with sucked non-condensable gases from thermal desalination unit,
• bubbling in a reactor to produce carbonates and sulfates by precipitation,
• washing the precipitate, and
• filtering and drying the precipitate to yield valuable mineral product,
• wherein processed filtered saline water, free from most of divalent ions, is directed to membrane-based desalination unit (Reverse Osmosis) for producing fresh water and brine,
• wherein the rejected brine from desalination unit is partially recycled as feedstock, and at least a portion is blow down and at least a portion is utilized in brine crystallizer to achieve zero liquid discharge.