Optimal age of Acacia auriculaeformis and mangium stands for the production of activated carbons

Four lots of chars have been produced from woods of Acacia auriculaeformis and Acacia mangium, 8-9 and 23-24 years old. The aim of this study is to determine the optimal age of the woods in order to obtain high quality activated carbon. From the comparative analysis of physico-chemical properties of the chars, it has been found that the relative densities increase from 8-9 years old trees to 23-24 years old trees (0.39 to 0.43 for A. auriculaeformis and 0.31 to 0.38 for A. mangium. The ashes rate decreases with the increasing of the age of wood: from 1.075 to 0.990% for A. auriculaeformis, from 1.025 to 0.925% for A. mangium. Otherwise, the rate of volatiles of the chars don't practically change whatever the age and the species (from 23.24 to 23.66% for A. auriculaeformis and from 24.40 to 24.92% for A. mangium). The same tendency is observed with the rate of fixed carbon: from 74.69% and 73.58% for 8-9 years old woods, they are, respectively 74.35% and 73.16%. We can conclude that technical, economic and environmental point of view the activation of chars produced from 8-9 years old woods can be recommended.