[LME market close on May 21: metals mostly lower, aluminum hits two-year high due to supply concerns] On Tuesday, LME aluminum futures hit a two-year high, posting the largest one-day gain in four months, supported by concerns about raw material supply and the recent rise in copper prices. On Monday, copper hit a record high of $11,104.50, with the rally driven by short covering providing momentum for speculators and funds, who are betting on a potential long-term shortage of copper in the transition to green energy. (Wenhua Finance)