Method for producing fullerene-containing carbon and device for carrying out said method
The inventive method for producing fullerene-containing carbon and the device for carrying out said method relate to the chemical industry and are used for producing fullerenes. Said method for producing fullerene-containing carbon consists in vaporising graphite in an electric arc between coaxial graphite electrodes. The graphite electrode is continuously moved inside the electric arc zone through the glow discharge zone. The products formed inside the electric arc are removed therefrom with the aid of an annular inert gas flow which is directed along the axes of the electrodes through an area arranged at a defined distance from a discharge axis. The inventive device for producing fullerene-containing carbon comprises a plasma reactor provided with a system for circulating inert gas and a system for recuperating fullerene carbon. Said reactor is provided with a chamber for degassing the graphite electrode which is continuously moved by the glow discharge towards the arc. The system for circulating inert gas is provided with an annular slot nozzle coaxially arranged in relation to the moving graphite electrode.
1. A method of continuously manufacturing fullerene-containing soot by vaporizing graphite in an electric arc maintained between two axially aligned graphite electrodes in an inert gas atmosphere by means of a hermetically sealed cylindrical chamber, removing the products formed in the electric arc with a stream of inert gas and their subsequent deposition in the form of the fullerens-containing soot, wherein at least one of the graphite rods is movable along the axis of said chamber, comprising the steps of:
passing the graphite electrode being fed into the electric arc zone through a glow discharge zone,
applying to the graphite electrode being fed into said electric arc zone a d.c. electrical voltage,
alternating its polarity between positive and negative for predetermined time intervals enough to burn the carbon deposit formed on said electrodes during vaporization in said chamber, and
removing said products from the electric arc zone by an annular stream of inert gas blown in said electric arc zone by means of an annular nozzle having a specified radius R,
wherein said annular nozzle is substantially aligned coaxially with said electrodes.
2. A method according to claim 1 comprising:
simultaneously rotating said annular stream of inert gas around the axis of said electrodes.
3. A method according to claim 1 comprising:
alternating said polarity between positive for 2–15 minutes and negative for 1–5 minutes.
4. A method according to claim 1
wherein said specified radius R of said nozzle is >45 mm.
5. An apparatus for manufacturing fullerene-containing soot incorporating a plasma reactor in the form of hermetically sealed cylindrical chamber, an inert gas circulation system, a means for collecting the fullerene-containing soot, two graphite rod-like electrodes, the first electrode being firmly fixed in a cooled current feedthrough and the second electrode, mounted in another cooled current feedthrough, that can be moved in axial direction, comprising:
an additional chamber for degassing said moving graphite electrode in a glow discharge,
an inert gas recirculation system provided with an annular-slit nozzle substantially aligned coaxially with said electrodes,
means for entrapment of the fullerene-containing soot comprising an electric separator at the inlet of said inert gas recirculation system; and
means for applying to the graphite electrode a d.c. electrical voltage and altering its polarity between positive and negative for predetermined time intervals enough to burn the carbon deposit formed on said electrodes.
6. An apparatus according to claim 5 comprising a means for joining further graphite rods to the moving graphite electrode.
7. An apparatus according to claim 5 comprising a means for feeding the movable graphite electrode to said reactor.
8. An apparatus according to claim 5 wherein the internal radius of said nozzle is equal to R>45 mm.
9. An apparatus according to claim 5 wherein the outlet of said nozzle is positioned at a distance of 30–40 mm from the cross section through the midpoint of the interelectrode gap.
10. An apparatus according claim 5 comprising a deflector mounted in the nozzle.
11. An apparatus according to claim 10 wherein said deflector is made in the form of strips mounted in the nozzle at an acute angle to its axis.
12. An apparatus according to claim 10 wherein said deflector is made in the form of guiding blades.
13. A method of continuously manufacturing fullerene-containing products by vaporizing graphite in an electric arc maintained between two axially aligned graphite electrodes in an electric arc zone in a hermetically sealed cylindrical chamber containing an inert gas atmosphere, removing the products formed in the electric arc with a stream of inert gas and subsequent deposition of the products in the form of fullerene-containing soot, wherein at least one of the graphite rods is movable along the axis of the chamber, comprising the steps of:
feeding the at least one graphite electrode along the axis of the chamber into a glow discharge zone for degassing the electrode;
thereafter feeding the graphite electrode along the axis of the chamber into the electric arc zone;
applying a d.c. electrical voltage of a selected polarity to the graphite electrodes for producing an arc for vaporizing the electrodes;
alternating the polarity of the d.c. electrical voltage applied to the electrodes between a positive and negative polarity for predetermined time intervals sufficient to burn carbon deposits formed on the electrodes during vaporization thereof; and
aligning an annular nozzle having a radius R coaxially with the electrodes; and
blowing an annular stream of inert gas through the annular nozzle coaxially around the electrodes for removing said soot from the electric arc zone.
14. An apparatus for manufacturing fullerene-containing product comprising:
a plasma reactor in the form of a hermetically sealed cylindrical chamber having a central axis;
first and second electrodes being axially aligned along the axis;
an inert gas circulation system;
a vaporization region for vaporizing at least one of the electrodes to produce soot containing the product;
a collector for collecting the soot caused by vaporization of the electrodes;
a first cooled current feedthrough for mounting the first electrode in the chamber, and a second cooled current feedthrough for mounting the second electrode in the chamber for axial movement along said axis;
a glow discharge chamber for degassing said movable electrode;
an inert gas recirculation system having an annular-slit nozzle coaxially aligned with the electrodes and an inlet,
an electric separator at the inlet of said inert gas recirculation system for entrapping soot; and
an input for d.c. electric voltage to the electrodes;
a polarity changer coupled to the input for the electrodes for alternating the electrical voltage between positive and negative polarity for selected time intervals sufficient to burn off carbon deposits formed on the electrodes during vaporization of the electrode.