Department of Resources and Environmental Engineering School of Creative Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjyuku, Tokyo, 169-8555, Japan.
Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan.
Sci Rep. 2018 Apr 10;8(1):5763. doi: 10.1038/s41598-018-23948-5.
Potential risks of supply shortages for critical metals including rare-earth elements and yttrium (REY) have spurred great interest in commercial mining of deep-sea mineral resources. Deep-sea mud containing over 5,000 ppm total REY content was discovered in the western North Pacific Ocean near Minamitorishima Island, Japan, in 2013. This REY-rich mud has great potential as a rare-earth metal resource because of the enormous amount available and its advantageous mineralogical features. Here, we estimated the resource amount in REY-rich mud with Geographical Information System software and established a mineral processing procedure to greatly enhance its economic value. The resource amount was estimated to be 1.2 Mt of rare-earth oxide for the most promising area (105 km × 0-10 mbsf), which accounts for 62, 47, 32, and 56 years of annual global demand for Y, Eu, Tb, and Dy, respectively. Moreover, using a hydrocyclone separator enabled us to recover selectively biogenic calcium phosphate grains, which have high REY content (up to 22,000 ppm) and constitute the coarser domain in the grain-size distribution. The enormous resource amount and the effectiveness of the mineral processing are strong indicators that this new REY resource could be exploited in the near future.
包括稀土元素和钇（REY）在内的关键金属供应短缺的潜在风险，激发了人们对商业开采深海矿产资源的极大兴趣。2013 年，在日本奄美大岛附近的西北太平洋发现了一种深海泥浆，其总 REY 含量超过 5000ppm。由于这种泥浆资源丰富，且具有有利的矿物学特征，因此具有巨大的作为稀土金属资源的潜力。在这里，我们使用地理信息系统软件估算了富含 REY 的泥浆中的资源量，并建立了一种矿物加工工艺，以极大地提高其经济价值。最有希望的区域（105km×0-10mbsf）的资源量估计为 120 万吨稀土氧化物，分别占全球每年对 Y、Eu、Tb 和 Dy 的需求的 62、47、32 和 56 年。此外，使用水力旋流器分离器使我们能够选择性地回收具有高 REY 含量（高达 22000ppm）的生物成因磷酸钙颗粒，这些颗粒在粒度分布中构成较粗的域。巨大的资源量和矿物加工的有效性是这一新的 REY 资源在不久的将来可能被开发的有力指标。
