LONDON – At least three companies including Glencore and Trimet Aluminium have expressed an interest in buying Rio Tinto's aluminium assets in Iceland, Sweden and the Netherlands for up to $350-million, banking sources said.

Rio Tinto restarted the sale process for the assets in late 2018, with the help of French investment bank Natixis, sources previously said, after Norwegian aluminium company Norsk Hydro pulled out of buying them, blaming a delay in getting European Commission approval.

Given Hydro is already a major player in the aluminium industry, the European Commission may have had competition concerns, sources said.

As well as an aluminium smelter in Iceland, Rio has put on the block a 53% stake in a Dutch anode facility and 50% of the shares in a Swedish aluminium fluoride plant, which are ingredients in aluminium production.

Rio Tinto declined to comment.

After a year of volatility caused by US sanctions and supply reduction at Hydro's massive Alunorte alumina plant in Brazil, the aluminium market has stabilised, which could make a sale easier to agree.

Commodity trader and miner Glencore is among interested parties, the sources said.

Glencore, which doesn't directly own aluminium assets, has offtake agreements with other producers, including US Century Aluminium, in which it has a more than 40% stake, and Russia's Rusal.

Sources put Glencore's agreements to buy aluminium from smelters around the world at a total of about three-million tonnes or 10% of supply outside the biggest producer China.

German aluminium producer Trimet Aluminium is looking to increase production as part of its push to increase supply to the auto construction sector, betting on growth in electric vehicles, the sources said.

Glencore and Trimet did not immediately respond to a request for comment.

Iceland generates all its electricity from hydropower and geothermal energy. Rio's aluminium plant therefore appeals to mining companies that face pressure from customers and investors to become more sustainable.

Producing aluminium requires huge amounts of energy, meaning it is also cheaper to use hydropower.

Rio sold an aluminium smelter in Dunkirk in France to Sanjeev Gupta's Liberty House, which also bought the miner's smelter in Lochaber, Scotland.

One of the sources said Liberty House has also shown an interest in the assets, but its balance sheet may be constrained after its acquisition, agreed last year, of seven European plants from ArcelorMittal for €740-million.