Hydration of medium reactive magnesium oxide using hydration agents

Water, magnesium acetate, magnesium chloride, acetic acid and hydrochloric acid were used as hydrating agents for an industrially obtained MgO sample. The influence of these different hydrating agents on the pH of the hydrating solution, degree of hydration to Mg(OH)(2), and product surface area was studied as a function of the temperature of hydration. When compared to the hydration in water, all hydrating agents improved the degree of hydration between 5 and 50% at all temperatures. MgCl2 and a mixture of HCl and Mg(CH3COO)(2) seemed to be the most effective hydrating agents below 60 degrees C, while at temperatures above 60 degrees C Mg(CH3COO)(2) formed the largest percentage Mg(OH)(2). Mg(CH3COO)(2) was the hydrating agent that showed the strongest temperature dependence. The mechanism of the hydration reaction seems to be dependent of the availability of Mg2+ ions and the increased formation of Mg(OH)(2) as temperature increases.