polymetallic nodules

• 多金属结核

polymetallic nodules的用法和样例：

例句

1. This paper is of important literature value and practical importance to the ocean polymetallic nodule mining in China's mine area.
   文章对中国大洋多金属结核矿产资源的开发，有着重要的文献价值和实用意义。
2. This paper focuses on experimental investigation on theresidue of ocean polymetallic nodules and cobalt-rich crusts used as cementreplacement and cement admixture.
   重点开展了大洋多金属结核氨浸渣和富钴结壳酸浸渣作为混凝土掺合料及水泥混合材的实验研究。