The premium in the news you quoted refers to the spot premium. Spot premium means that the spot price is higher than the futures price in recent months, which is called premium. If it is lower than the futures price in recent months, it is a discount. The headline "European aluminum premium climbs to $ 435-450 per meal" means that the current aluminum price in the spot market in Europe is $ 435-450 higher than the aluminum futures price recently traded on the London Metal Exchange.

The recent futures price here refers to the futures price of the electrolytic aluminum futures contract traded on the London Metal Exchange in the latest trading month.