* Unwrought copper, product imports 410,541 T vs 406,016 T in Sept * Oct concentrate imports 1.8 mln T as miners, smelters negotiate * Aluminium exports at 479,599 T BEIJING, Nov 7 (Reuters) - China’s copper imports in October rose for a second month, customs data showed on Sunday, as traders took advantage of a short period of favourable pricing to bring in bonded inventories of the metal. Arrivals of unwrought copper and products into top copper consumer China were 410,541.3 tonnes last month, the General Administration of Customs said. That was up from 406,015.6 tonnes in September but down 33.6% from a year earlier. Imports in the first 10 months of 2021 were down 21% year-on-year at 4.43 million tonnes. Activity in China’s manufacturing sector, a key source of copper demand, contracted more than expected in October amid curbs on electricity usage and persistently high raw material prices. London copper rose 6.3% in October, outpacing a roughly 4% jump in Shanghai prices and making foreign metal more expensive, although a brief widening in the price spread in late September made imports favourable. That led to a further drawdown last month in copper inventories SMM-CUYP-CN in bonded warehouses that hold metal that have not cleared customs, which are now at 206,400 tonnes, the lowest in records going back to 2013. China auctioned off another 30,000 tonnes of copper from its state reserves in October, slightly reducing the demand for imports. Arrivals of copper concentrate, or partially processed copper ore, were 1.797 million tonnes in October, customs said. That was down from 2.111 million tonnes in September, the most in six months, but up 6.3% from 1.69 million tonnes in October 2020. Global copper miners are closely watching Chinese concentrate demand as they hold talks with smelters on supply contracts for 2022. China’s exports of unwrought aluminium and products were 479,559.1 tonnes in October, down from 491,984.70 tonnes in September, which was the highest since March 2020. That ended a run of six months of increases but imports were still up 14.5% year-on-year. (Reporting by Muyu Xu and Tom Daly; Editing by Christian Schmollinger)