The MgO (80% precipitation) from seawater

This study has examined the effect of the combined method of rinsing of magnesium hydroxide precipitate, by (3+2) decanting and repeated rinsing (up to 5 times) on filter paper, on mass fractions of B2O3, CaO and MgO in calcined magnesium oxide obtained from seawater by substoichiometric precipitation. The addition of dolomite lime, as the precipitation agent, was 80% of the stoichiometrically required quantity. In the first stages of the rinsing process during decanting, distilled water of pH value of 6.64 was used, followed by alkalised distilled water of pH value of 12.50. The results indicate that repeated rinsing of the precipitate on filter paper with fresh distilled water is more effective in reduction of the CaO fraction in the final product, i.e. calcined magnesium oxide. The results also indicate that it suffices to repeat the rinsing of the magnesium hydroxide precipitate on filter paper with fresh distilled water three times.