Description
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Praseodymium is a lanthanide that has a grey white shiny color in its natural solid state. It has some resistance to corrosion, but it will form a green oxide coating if exposed to air. Praseodymium has an atomic number of 140.90765, a melting point of 1715 °F, and a boiling point of 6368 °F. Some common uses of praseodymium include: as a component in cubic-zirconium, as a component in alloys, as the core of carbon arc lights, as an ingredient in glasses and enamels to give a yellow color, and as an alloy with nickel to produce magneto caloric effects.
Isolation
Praseodymium occurs in rare earth minerals such as monazite and bastnasite along with other lanthanides. Extraction processes can be used to isolate praseodymium from these minerals.
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The similarity of lanthanide chemical characteristics makes it difficult to separate them from the minerals in which they occur together. The isolation of praseodymium from these minerals is a highly complex multi-step process; due to the complexity of praseodymium separation, it is never performed on a small laboratory scale basis. Some of the processes that are needed to separate praseodymium include solvent extraction and ion exchange chromatography.
The first step to praseodymium isolation involves separating the lanthanides from the mineral in their salt forms by treating the mineral ore with sulphuric acid, hydrochloric acid, and sodium hydroxide. Using the extraction techniques, praseodymium is reduced to praseodymium fluoride. The isolation of praseodymium from fluoride occurs by a heated reaction with fluoride. Additional isolation procedures using a vacuum take out any small calcium contaminants that did not react with the fluoride to yield pure praseodymium. Pure praseodymium is slightly toxic and needs to be handled with care.