Rhenium is a transition metal that has a grey white color in its natural solid state. This recently discovered mineral has an extremely high melting point and is also very dense. Rhenium has an atomic weight of 186.207, a melting point of 5767 °F, and a boiling point of 10105 °F. Some common uses of rhenium include: as a component in the process used to create lead free, high octane, gasoline, as a component in some types of alloys, as a catalyst for certain chemical reactions, and as a component in thermocouples.
Rhenium does not occur free in nature, but occurs with molybdenum in nature. Isolation of rhenium is needed to extract it from molybdenum sources.
Rhenium is one of the most expensive metals in the world; it is rare, and was one of the last elements to be discovered. The high cost of rhenium, and isolation procedures needed to extract rhenium from minerals containing molybdenum, make small scale laboratory isolations of rhenium impossible. The isolation process of rhenium begins with molybdenum minerals that are found in copper-sulfide ores. As molybdenum is processed, roaster-flue gas that contains rhenium is collected as a by-product of the molybdenum extraction. Further reduction of rhenium produces the ammonium perrhenate form which is reacted in high temperatures with hydrogen. While the steps in these extractions help to isolate rhenium, it does not result in pure rhenium. Further purification and isolation uses a vacuum or hydrogen atmosphere in which the rhenium compound is pressed and consolidated with resistance sintering. This will result in a compound which is composed of 90% rhenium. Rhenium can also be recycled from alloys and catalysts that it is a component of.
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