Preparation of carbon nanotubes from ilmenite concentrate carrier by disproportionation of carbon monoxide

A preparation technology of carbon nanotubes was studied in hydrogen and carbon monoxide by heavy loading thermogravimetric analysis, using Panzhihua ilmenite concentrate as catalysts. During the process, the phase composition and microstructures of the products were characterized by means of thermogravimetry, gas chromatographic analysis, scanning electron microscopy, specific surface area, transmission electron microscope and X-ray diffraction. The results indicated that the weight of ilmenite concentrate decreased firstly and then increased gradually with reaction time under H2-CO atmosphere owing to gas-basis reduction and deposition of carbon. The optimal process was that the reductive products with Fe and M3O5 solid solution phase were prepared by reduction of titanium concentrate, and the temperature was decreased in 80%carbon monoxide gradually and kept 550°C for 2 h. The carbon nanotubes, which were less 100 nm of diameter and 151 m2/g of specific surface, were about 3.5 times than the ilmenite concentrate. The iron was regarded as matrix material of producing of carbon nanotubes and its agglomeration was prevented by other mineral phase owing to mutual infiltration. Growth of carbon nanotubes were controlled by adsorption, reaction and diffusion during the process.