Description
⌕ Enlarge Image
Holmium is a lanthanide that is a silvery white solid in its natural state. Holmium has unusual magnetic characteristics, is a soft and malleable lanthanide, and it will oxidize quickly in high temperatures in moist air. Holmium has an atomic weight of 164.93032, a melting point of 2662 °F, and a boiling point of 4928 °F. Some common uses of holmium include: as a component in the creation of magnetic fields that have been artificially created, as the yellow color in glass coloring, as a coloring in cubic zirconium, and as a component in lasers used to break up kidney stones.
Isolation
Holmium is not found in its free state in nature, but occurs in a number of minerals with other rare earth elements. Isolation processes are used to extract holmium from these sources.
⌕ Enlarge Image
Holmium can either be extracted out of the minerals it occurs in, or isolated from monazite sand. The isolation procedure that is needed to extract holmium out of monazite sand uses ion exchange processes to satisfy commercial holmium demand. Holmium can also be isolated from minerals such as gadolinite and monazite. The isolation process is extremely complex because these minerals contain other rare earth elements that have similar chemical characteristics with holmium; due to the difficulties with holmium isolation, it is never isolated on a small scale laboratory basis.
The isolation of holmium from minerals such as gadolinite and monazite begins with treating the minerals with sulfuric acid, hydrochloric acid, and sulphuric acid. This isolates the lanthanides in their salt forms. Repeated solvent extractions and ion exchange chromatography processes further isolate holmium. The final extraction process reacts holmium fluoride with calcium under heated conditions to produce pure holmium and calcium fluoride.