Creating rare earth magnets involves several complex steps, beginning with the mining of rare earth ores and culminating in the production of magnets. Here’s a general flow sheet for processing rare earths for use in magnets:

1. Mining and Extraction:
   • The process starts with the mining of rare earth ores, such as bastnaesite, monazite, or xenotime. These ores contain a mix of rare earth elements along with other minerals.
   • The ore is then crushed and ground to liberate the rare earth minerals from the rock.
2. Concentration and Separation:
   • The ground ore is subjected to a series of physical separation processes, such as flotation, magnetic separation, or gravity separation, to increase the concentration of rare earth elements.
   • This results in a rare earth concentrate, which is then leached with acid or alkali to dissolve the rare earths into a solution.
3. Chemical Treatment:
   • The leachate is subjected to chemical treatments to remove impurities. This might involve processes like solvent extraction or ion exchange.
   • Each rare earth element is separated and purified. This step is complex due to the similar chemical properties of rare earth elements.
4. Precipitation and Calcination:
   • The purified rare earth elements are precipitated from the solution, often as oxides.
   • These precipitates are then calcined (heated) to produce rare earth oxides, which are the raw materials for magnet production.
5. Metal Production:
   • The oxides are converted into metals through a reduction process, often involving a metal reducing agent like calcium or magnesium.
   • The rare earth metals are alloyed with other metals like iron, boron, and cobalt to produce the desired magnet composition (e.g., NdFeB for neodymium magnets).
6. Magnet Manufacturing:
   • The alloy is melted and then cooled to form ingots or is transformed into a powder for sintered magnets.
   • For sintered magnets, the powder is compacted under high pressure and then sintered (heated without melting) to fuse the particles together.
   • The magnets are then magnetized, cut to size, and finished according to their intended use.
7. Quality Control and Testing:
   • Throughout the process, from ore to finished magnet, various quality control and testing procedures are conducted to ensure the magnets meet the required specifications.

This flow sheet is a generalized overview; specific processes may vary depending on the type of rare earth magnet being produced (like neodymium, samarium-cobalt), the composition of the ore, and the technology available to the manufacturer. Each step in the process is critical and requires careful control to ensure the quality and performance of the final magnets.