Oct 13 (Reuters) - Shanghai aluminium prices on Tuesday climbed to their highest in two-and-a-half years as a smelter curtailment in Spain fuelled worries about supply, although demand from top consumer China remained weak.

The most-traded November aluminium contract on the Shanghai Futures Exchange climbed as much as 1.4% to 14,690 yuan ($2,179.07) a tonne, its highest since April 2018, before easing slightly to close at 14,620 yuan a tonne, still up 0.9%.

Three-month aluminium on the London Metal Exchange dipped 0.3% to $1,850 a tonne by 0717 GMT. The contract touched its highest since July 2019 of $1,856.50 a tonne on Monday.

U.S. aluminium producer Alcoa said it would curtail operation of its San Ciprian smelter in Spain.

The smelter curtailment was a trigger for a speculation-driven upward trend, said a Singapore-based metals trader, adding that expectations for further U.S. stimulus and winter curbs on Chinese production also supported prices.

LME aluminium inventories hovered around their five-month low at 1.4 million tonnes, while stockpiles in ShFE warehouses were still lower than half of the 2020 peak of 533,994 tonnes hit in March.

"Winter is a slow season in terms of demand (in China), so after September people do not expect demand to rebound again," said the trader.

FUNDAMENTALS

* Cathode output of 22 Chinese copper smelters in September rose 3% to 747,100 tonnes from August, as large producers were unaffected by maintenance, research house Antaike said.

* China's copper imports rose in September from the previous month and were near a record high as recovering factory activity boosted demand even after the closure of an arbitrage window.

* LME copper fell 0.6% to $6,694 a tonne and lead declined 0.9% to $1,828.50 a tonne, while ShFE copper rose 0.1% to 51,360 yuan a tonne and nickel increased 0.5% to 117,100 yuan a tonne.

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($1 = 6.7414 yuan)

(Reporting by Mai Nguyen; Editing by Subhranshu Sahu and Sherry Jacob-Phillips)