The most-traded September copper contract on the Shanghai Futures Exchange rallied 1.7 percent to 50,380 yuan ($8,100) a tonne on Tuesday, having earlier hit a five-month top. Manufacturing activity in Asia's industrial powerhouses China and Japan gained pace in June, fuelled mainly by improving demand at home, but a long-awaited bounce in exports remained slow in coming.
"We should see supply improve sequentially from July so that should cap the copper prices," Bi said. In other news, China is relaxing the rules used for calculating the amount of deposits that banks can re-lend as loans, an attempt hailed by some economists as the latest move to stimulate growth.