Analysis of magnesia hydroxylation heat as source of energy toconcentrate and/or dry magnesium hydroxide pulp

Magnesium hydroxide is an important inorganic compound that is largely used in many industrial processes. It can beobtained through the hydroxylation of magnesia, followed by comminution and drying step. In this context, the present work aims to evaluate if theexcess of hydroxylation reaction heat can be used in the subsequent step of product drying, developing and simulating the mass and energy balances in the system. Hydroxylation tests were carried outwith magnesia from mineral source, in a non-adiabatic reactor with25 % initial solids concentration. The behavior of the pulp in oneadiabatic system was simulated in the Excel software, varying the initial pulp content between 25 and 35% solids, considering the hydroxylation conversion varying from 0 to 100%. The reaction heat of caustic magnesium hydroxylation can promote a relevant changein the pulp concentration if an adiabatic reactor is used instead of a non-adiabatic one. Theenergy released from the reaction wasenough to heat the system until 100 °C, vaporize partially the water and concentrate the pulp until 57%. The hydroxylation heat can promote significant energy savings to obtain the traditional magnesium hydroxidein pulp (52%) and powder (26%). In the non-adiabatic reactor, this heat would be lost.