The medium temperature pyrolysis process using a fixed-bed reactor at atmospheric pressure was utilised to recover carbon black from motorcycle and automobile tyres. Experimental results have shown that the ash and volatile contents of several recovered carbon blacks are high, the elongation at break of the vulcanised natural rubber filled with recovered carbon blacks from motorcycle tyres is better than that from motorcycle tyres and standard carbon black 7#, while the other mechanical properties are worse. In order to improve the reinforcing effect of recovered carbon blacks, the modification of recovered carbon black was performed by high-energy electron bombardment and non-oxidising acid. The specific surface area of the pyrolytic carbon blacks increased after high-energy electron bombardment. The ash content of the pyrolytic carbon black was reduced from 22.5% to 8.4% after rinsing with hydrochloric acid, and the tensile stress at 300% was increased by about 2.2 MPa.

The standard sample IRB7# of nano-sized carbon black was reated by different methods, including washing by alcohol, toluene, water, the emulsion of toluene and water, and heating. Surface activity of the obtained nanoparticles was measured using inverse gas chromatography. The results showed that the dispersion free energy could be significantly increased after heating. The surface activity of three kinds of industrial carbon black was studied after heat treatment at different temperature. The results indicated that surface activity, iodine adsorption number and nitrogen surface area values of carbon black nanoparticles increased with the increase of temperature. However, the dibutyl phthalate adsorption value maintained nearly constant. The performance test of rubber showed that with the increasing heat treatment temperature of carbon black, 300% modulus of rubber increased before 450°C and decreased after 450°C.

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