1. What Does "Rare" Mean for Rare Metals and Rare Earths?
In Japan, 31 types of metals, including tungsten and cobalt, are officially defined as "rare metals." Rare earths are a group of 17 elements within this category, treated as one type of resource [1]. The word "rare" has two distinct meanings in this context. First, it refers to the low amount of these elements present in the Earth's crust. Second, it refers to the difficulty of digging them out and purifying them. A metal is called a rare metal when both of these conditions are met [1].
2. Why Do Rare Metals Gather in Only Certain Places?
Rare metals are actually mixed thinly into soil and rock all over the world. However, they only gather in concentrations high enough to be collected and used in limited locations [2]. For these metals to become concentrated enough to mine, specific underground movements or ancient volcanic activity are required. These conditions are unique to certain lands. Some metals, like cobalt and indium, are not mined alone but are collected as byproducts when mining for copper or zinc. Because the reasons for concentration vary by metal type, the location of rare metal deposits is often determined by geological luck [2].
3. Which Is Harder for Rare Metals: Mining or Refining?
The ore from which these metals are extracted frequently contains radioactive substances mixed in with the useful elements. The process of separating these substances to create clean metal is called smelting or refining [2]. This refining process produces a large amount of harmful waste residue. Safely disposing of this residue requires significant effort and money [2].
4. How Did the 2010 Rare Metal Export Reports Cause a Supply Crisis for Japan?
In 2010, a collision occurred at sea between a Chinese fishing boat and a Japanese patrol ship. Following this incident, reports stated that the export of rare earths from China to Japan effectively stopped [3]. This disruption caused problems for Japanese automobile companies and other industries, which struggled to obtain magnets made with rare earths [3].
5. What Rare Earth Mud Lies Under the Sea Near Minamitorishima?
Minamitorishima is the easternmost island of Japan. In the sea near this island, there is mud that contains large amounts of rare earths [4]. In 2018, researchers confirmed that this mud contains enough rare earths to meet global demand for several hundred years [4]. However, the methods for digging this mud out from the deep sea are not yet fully developed or widely used around the world [4].
6. How Can Old Phones and Appliances Become a Source of Rare Metals?
Discarded mobile phones and electronic appliances contain many rare metals. Collecting these items and extracting the metals from them is known as "urban mining." This term suggests that there is a hidden mine within the city. In reality, the metals are buried in discarded products rather than in a mountain [5]. One survey suggests that the indium contained in discarded products in Japan accounts for about 61% of the world's total reserves [5].
7. How Can You Explore Rare Metals in Old Devices at Home?
If you have old mobile phones or game consoles at home, you might want to investigate what metals are inside them. You can also look for collection points in your local municipality.