UPDATE 1-China's aluminium imports jump to 11-year high on lower overseas prices

* China June aluminium imports at 11-year high

* Imports surged on cheaper overseas products

* June alumina exports surged 783.1% y/y (Adds bullets, alumina exports data)

BEIJING, July 23 (Reuters) - China’s June aluminium imports surged by more than 490% from a year earlier, customs data showed on Thursday, to their highest in 11 years, as traders, who rarely buy large amounts from overseas, took advantage of the lower prices abroad. China, the world’s top aluminium producer, imported 288,783 tonnes of unwrought aluminium and aluminium products last month, the General Administration of Customs said.

That was more than double May’s imports of 119,145 tonnes and a jump of 493.1% from June 2019, customs said, as buyers took advantage of the differences between domestic and international prices. Imports were the highest since June 2009.

China shipped out 354,038 tonnes of unwrought aluminium and aluminium products last month, down 30% year-on-year, customs data showed.

Imports in January to June were 816,592 tonnes, up 219.2% year-on-year, while exports were 2.37 million tonnes, down 20.6% from a year earlier, leaving China a net exporter of 1.5 million tonnes in the first six months of 2020.

Shanghai aluminium prices rose 23% in the second quarter as Chinese consumption roared back from a coronavirus-driven collapse. However, London prices only gained 6.1% in April to June amid sluggish demand outside of China, and after a 15.7% dip in the first quarter.

The spread between Shanghai and London cash aluminium prices widened to almost 1,800 yuan ($258.16) a tonne in late May, the most since January 2014, opening up a so-called arbitrage for primary metal to head to China from overseas.

China’s imports of unwrought, alloyed aluminium - described by analysts as secondary ingots - have also been rising in recent months to compensate for curbs on inbound scrap metal shipments.

The data also showed alumina exports in June soared 783.1% year-on-year to 30,000 tonnes. In the first half of the year, China shipped out 100,000 tonnes of alumina, down 46% from same period year earlier.

Customs is due to release a breakdown of imports by origin and type of aluminium and other commodities on Saturday. ($1 = 6.9723 yuan) (Reporting by Tom Daly and Min Zhang in Beijing, Mai Nguyen in Singapore; Editing by Christian Schmollinger & Simon Cameron-Moore)