Patent ID: 8197696

Claim:
A method for separating magnesium hydroxide from a saline stream or a magnesium-rich aqueous stream, said method comprising the steps of: (a) converting the alkalinity of said saline stream to carbon dioxide by adding an acid or by absorbing sulfur dioxide as an acid gas to produce nearly alkalinity-free saline stream; (b) removing said magnesium hydroxide from said nearly alkalinity-free saline stream or from said magnesium-rich aqueous stream by (i) injecting said nearly alkalinity-free saline stream or said magnesium-rich aqueous stream into a precipitator at a pressure between 30 psi and 1,100 psi through at least one nozzle; (ii) injecting an amine solvent into said precipitator at a pressure between 30 psi and the critical pressure of said amine solvent through at least one nozzle to form precipitates comprising said magnesium hydroxide; (iii) injecting a modifier for said amine solvent into said precipitator at pressure between 30 psi and 1,100 psi through at least one nozzle; (iv) removing said precipitates from said nearly alkalinity-free saline stream or said magnesium-rich aqueous stream by filtering; (v) washing, filtering and drying of said precipitates; (vi) removing at least most of said amine solvent from said nearly alkalinity-free saline stream or said magnesium-rich aqueous stream by stripping.