About Rare Metal

What is Rare Metal?

For the past few years, we freauently hear of "the rare metal problem" or "the rare metal crisis". The terminology,  "rare metal”, is not an academicaly defned one, and there is no consensus on which element it pertains. Recenly, the term is often used to refer to the 47 metal elements shown in Figue 1,  according to the definition set by goverment. Sometimes, the 17 rare earh elemens are counted as one kind, and the total is counted as 31. There are a total of 89 existing elements in the natural world, and therefore it can be said that over half of the elements are rare metals

Elements as titanium, manganese, chromium, which are found in abundance in the earh's crust, are also considered to be rare metals. This is because manganese and chromium have ben essential elements for the industrial world since its early days, used as additives to enhance the properies of iron. Titanium is considered "rare” because it is a difficult metal to produce as high technology is required for refining the abundant ore in form of titanum oxide. 

On the other hand, from historical circumstances, gold and siver, which have been in existence since ancient times, ale not called rare metals.