氧化铝期货主力连续合约跌2.16%，报2815元(人民币)/吨

Group 1 - The core point of the article is that aluminum oxide futures have experienced a decline, with the main contract dropping by 2.16% to 2815 RMB per ton [1] Group 2 - The article reports on the specific performance of aluminum oxide futures, indicating a significant price movement in the market [1]