Hydrogen generation from ball milled Mg alloy waste by hydrolysis reaction

Hydrolysis is an effective method for generating hydrogen from Mg alloy waste provided from the sacrificial anode industry. Mg alloy was ball milled under H2 to enhance its hydrolysis reactivity. The effect of ball milling time, the nature of the additives (graphite and AlCl3) and the synergetic effect by chronological or simultaneous addition of 5 wt.% graphite and 5 wt.% AlCl3 were examined. It has been established that increasing milling time without additive beyond 2 hours (h) decreases the hydrolysis performance. Using AlCl3 slightly improves the hydrogen production properties when milling for 2 h. Incorporating graphite leads to the best hydrolysis properties (yield of 78% reached in 5 minutes when milled for 5 h). On the other hand, by combining both additives better results are obtained. The mixture prepared by milling for 2 h with 5 wt.% of graphite followed by additional milling for 2 h with 5 wt.% of AlCl3 shows the best hydrolysis performance with a yield of 92% achieved in 5 minutes. When both additives are incorporated, the simultaneous or sequential addition and the order of incorporation strongly affect the microstructure and the morphology, and consequently the hydrogen production performance of the powders. •Mg alloy waste milled under H2 produces H2 by hydrolysis in 0.6 M MgCl2 solution.•MgH2 formed by BM increases the total H2 production but reduces the performance.•Best hydrolysis performance obtained by BM with C(G) followed by BM with AlCl3.