Process and apparatus for purifying BNNT

A process for purifying boron nitride nanotubes, the process comprising:

• contacting a solid boron nitride nanotube (BNNT) material containing boron nitride nanotubes and impurities with a halogen gas selected from the group consisting of chlorine, bromine and fluorine at a temperature in a range of 600° C. to 1250° C. when chlorine is the halogen, 700° C. to 1250° C. when bromine is the halogen gas, and 500° C. to 700° C. when fluorine is the halogen gas, the impurities reacting with the halogen gas to produce gaseous halogen-containing byproducts;
• and,
• removing the gaseous halogen-containing byproducts and unreacted halogen gas from the solid boron nitride nanotube material to produce purified boron nitride nanotubes.