Method for synthesis of carbon nanotubes

A process for synthesizing carbon nanotubes, comprising:

• a) bringing a first carbon source into contact, in a CNT synthesis reactor, at a temperature between 500 and 1500° C., with a fresh catalyst comprising at least one multivalent transition metal, thereby forming by chemical vapor deposition (CVD), CNTs in the form of an entangled three-dimensional network around catalyst particles or agglomerates with a d50 between 300 and 600 μm;
• b) milling at least some of the CNTs resulting from step a) to obtain a d50 of between 10 and 200 μm.
• c) fluidizing the milled product from step b) at a temperature between 500 and 1500° C. in the presence of a second carbon source to obtain CNTs;
• d) optionally, milling, at least some of the CNTs formed in step c) to obtain a d50 of between 10 and 200 μm;
• and thereafter
• e) recovering the CNTs resulting from step c) and/or step d).