Rare metals according to various physical and chemical properties of the element, assign
State, production processes, as well as a number of other features, from technology in General is divided into the following five categories:
Rare light metals
Includes cesium lithium Li, RB, Rb, Cs, beryllium Be. Proportion of small, strong chemical activity.
Rare and refractory metals
Including titanium, zirconium, hafnium, vanadium, niobium, tantalum, molybdenum, and tungsten. Higher melting point, with the carbon, nitrogen, Silicon, boron compounds, such as the melting point is also higher.
Rare and scattered metals
Referred to as rare metals, including gallium, germanium, indium, thallium, rhenium, selenium, tellurium. Most of the mineral occurs in other elements.
Rare and rare-earth metals
Referred to as rare earth metals including scandium, yttrium and the lanthanides. Their chemical properties are very similar, in the minerals, associated.
Rare radioactive metal
Includes naturally occurring francium, radium, plutonium and minor actinides metals Actinium, thorium, Protactinium and uranium, as well as artificially produced technetium, promethium, other actinide elements, and element 104 to 107th.
This categorization is not very strict. Some metals can be included in this category, and for inclusion in another class. Such as rhenium included rare metals may also include rare and refractory metals.