Magnesium silicate processing

A method of processing a magnesium silicate source by the steps of:

• selecting a magnesium silicate source selected from:
• olivine, serpentine, pyroxene, amphiboles, phyllosilicates, clays, and combinations thereof,
• subjecting the selected magnesium silicate source to water digestion at a temperature of less than 120° C. and wherein the ratio, by mass, of magnesium silicate source to water in the water digestion is 1 part magnesium silicate to 1 to 20 parts water to form a washed magnesium silicate;
• subjecting the washed magnesium silicate to acid digestion, to produce a digested solution, acid digestion comprising mixing the washed magnesium silicate at a temperature of less than 120° C. with hydrochloric acid or sulfuric acid sufficient to decrease the pH of the mixture to −1-6 and, recovering evolved hydrogen gas during acid digestion;
• completing a base wash by increasing the digested solution pH by addition of an alkali solution at a temperature of less than 120° C., to produce a magnesium salt solution consisting of magnesium chloride, magnesium sulphate, or both magnesium chloride and magnesium sulphate, wherein the base wash comprises two pH increasing steps including:
• a first increase in digested solution pH by at least 1 to 3 pH greater than the digested solution pH and removing precipitated silica from the magnesium salt solution;
• and
• a subsequent pH increase in digested solution pH to a pH of 6.0 or higher and removing precipitated iron oxide from the magnesium salt solution;
• subjecting the magnesium salt solution to electrolysis at a temperature of less than 120° C.;
• and
• recovering magnesium hydroxide produced from electrolysis from an electrolysis cathode and oxygen and chlorine from an electrolysis anode.