Shipments of flat-rolled aluminium for use in beverage cans slowed to a 3.8 percent rise year-on-year in reaction from double-digit year-on-year increases in May and June due to front-loaded production to avoid power shortage during the summer peak.
But the association official said hot weather in July helped underpin demand for beverage cans.
Flat-rolled aluminium for use in automobiles fell for the seventh month in a row due to a drop in production, but the ongoing recovery in carmakers' output helped narrow the drop.
Manufacturers have given priority to catering for domestic needs after the earthquake, curbing exports, but such moves are stabilising, helping exports to rebound slightly in July.
Aluminium stocks held at three major Japanese ports fell 11 percent in July from a month earlier to 203,500 tonnes due to slowing imports, according to trading house Marubeni Corp .
Talks for October-December aluminium term premiums to Japan began this week.
As aluminium industry officials remain cautious about the outlook of domestic demand, the fourth-quarter premiums are expected to stay flat or fall slightly, with buyers seeing no reason for a rise.
The premiums for the current quarter were largely settled at $120 a tonne, marking the first rise in six quarters and putting them at their highest in a year.