Aluminium rallied strongly in China as investors positioned themselves for state measures to curb supply.
Shanghai futures rose to their highest level in nearly six years as trading volumes for August appeared on course to reach an all-time high.
The Chinese authorities are closing unlicensed production facilities and planning further moves to curtail output as they look to ease pollution.
Shanghai aluminium surged to over RMB16,600 a tonne in Thursday´s trading session, for a rise of around 3% on the day. The metal was trading at around RMB14,600 a tonne early last month.
Aluminium has performed strongly over the past couple of years, having risen from a trough of RMB9,600 a tonne in November 2015 amid hopes of firming demand.
More recent price action is being driven by expectations of big Chinese production cuts.
Citigroup estimates that moves to end unlicensed production capacity will cut Chinese output by around 4 million metric tonnes a year.