LONDON, Dec 17 (Reuters) - Aluminium prices touched the highest in over six weeks on Friday after China's output of raw material alumina slumped last month, highlighting the risk of tight supply due to power shortages.

Three-month aluminium on the London Metal Exchange surged as much as 3.1% to $2,749 a tonne, the strongest since Nov. 1, before paring gains to $2,733 by 1700 GMT, up 2.5%.

China's output of alumina, which is smelted to make aluminium, fell in November by 4.5% year-on-year to its lowest in 18 months, official data showed on Friday.

China aims to lower its carbon output by restricting the electricity consumption and production of power-intensive industries such as alumina refining and aluminium smelting.

"Ali rallied on power issues, market speculating on the potential closure of smelters," Marex broker Al Munro said in a note.

Investors have refocused on potential shortages of industrial metals after being distracted recently by whether the U.S. Federal Reserve would tackle rising inflation with faster bond tapering and interest rate rises next year, an analyst said.

"The FOMC meeting on Wednesday created a relief rally across risky assets and that means the market can refocus on the internal fundamentals, which are generally supportive," said Ole Hansen, head of commodity strategy at Saxo Bank in Copenhagen.

"Having survived another downside attempt, if we can hold these levels, then potentially we could be gearing up for some fresh upside as we head into 2022."

* LME zinc slid 1.4% to $3,373.50 a tonne, eroding gains of 4.6% a day earlier when it touched a two-month high after Nyrstar said it planned to shut its French plant due to high European power prices.

Shanghai zinc prices ended more than 4% higher on Friday after scaling an over one-month peak.

The plant closure plans prompted analysts at Citi to raise their three-month zinc forecast to $3,700 per tonne from $3,350.

* The premium of LME cash zinc over the three-month contract rose to $43 a tonne, up from $9.75 two days earlier, indicating tightening nearby supplies.

* LME copper slipped 0.6% to $9,450 a tonne, lead fell 0.1% to $2,305.50, tin shed 0.6% to $38,475, but nickel added 0.2% to $19,670.

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(Additional reporting by Eileen Soreng in Bengaluru; editing by Kirsten Donovan, Louise Heavens and Krishna Chandra Eluri)