Large scale production of carbon nanotubes in portland cement

摘要

The present invention describes a chemical vapor-phase deposition for carbon nanotube synthesis in which cement clinker is used as a ceramic matrix for anchoring transition-metal nanoparticles. Using cement clinker as nanoparticle anchoring base of transition metals allows carbon nanotubes to be generated on cement clinker particles and grains, in this way producing a kind of cement that is nanostructured with carbon nanotubes. By this process, the carbon nanotube synthesis and integration to clinker are carried out in just one continuous and large-scale stage. The process described herein can be applied to conventional cement industry whose production may be rated as tons per day. The present invention also proposes—as part of the carbon nanotube synthesis on cement clinker—several enrichment alternatives of cement clinker by using transition metals for producing such nanostructured composite, which may or not be integrated to the conventional cement industry.

主权项

1. A process for synthesis of carbon nanotubes, comprising a cement clinker as catalytic support for growing carbon nanotubes by anchoring transition metals, which comprises the following stages:
(i) method for enriching cement clinker in solid phase and/or liquid phase with transition metal oxides and/or salts both containing transition metal cations; and (ii) introducing enriched clinker into a kiln of controlled and reducing atmosphere with injection of light hydrocarbons and addition of inert gas as carrier at high temperatures effective for provoking a pyrolysis reaction and thus the growth of carbon nanotubes by chemical vapor-phase deposition.