A fullerene/nanotubes mixture is produced during a periodical pulsed auto-regulated
action of the electric current arc-discharge in the multi-component hydrocarbon
medium with limited fullerenes' solubility, besides, the action is continued until
the medium dissolves C60. Higher fullerenes absorbed by the ultra-thin
graphite particles are separated from C60 dissolved in the liquid medium
by sedimentation, whereas the carbon nanotubes are separated from the ultra-thin
graphite particles by treating with a boiling concentrated HN03 acid and by low
speed centrifuging/acid mixture until the black sediment of the ultra-thin graphite
particles is precipitated to the bottom. The periodically pulsed auto-regulated
regime of the electric-current arc-discharge is performed by contact breaking an
electric circuit due to lifting spherical contactors by gaseous products released
during the action and by switching the circuit due to the contacts' going down
under action of gravity.
