Effect of ball milling strategy (milling device for scaling-up) on the hydrolysis performance of Mg alloy waste

Abstract

Ball milling strategy is of prime importance on the hydrolysis performance of Mg alloy waste. The effect of milling device (e.g. Fritsch Pulverisette 6 (P6) and Australian Uni-Ball-II (UB)), milling atmosphere (H2 and Ar), milling time, nature of the additives graphite and AlCl3 and synergetic effect by chronological or simultaneous addition were examined. An equivalence between both mills was established and it was shown that the process with the UB is 10 times longer than that with the P6 to acquire a similar material. Mg alloy milled without additives in the P6 under Ar for 10 h improves the hydrolysis performance. Using a single additive, the best hydrolysis performances are obtained with graphite (yield of 95% of total capacity reached in 5 minutes) due to the formation of a protective graphite layer. By incorporating both additives sequentially, the best material, from the hydrogen production point of view, was Mg alloy milled with G for 2 h and then with AlCl3 for 2 extra hours (full hydrolysis in 5 minutes). Mg alloy milled with the P6 were compared to those milled with the UB. Mg alloy milled with graphite or with sequential addition of G and AlCl3 under Ar generated more than 90% of their total capacity. Our results confirm that laboratory-milling strategy can be scaled-up to industrial scale.