Influence of TiO₂ addition on the structure and metallurgical properties of coke

ABSTRACT

Cokes were produced in an electrical furnace from a coal blend containing varying levels of added TiO₂. The effects of TiO₂ levels on coke structure and properties were then considered. Mercury intrusion porosimetry analysis showed that, at increasing TiO₂ addition, macropore level increased but mesopores level decreased. In part because of these changes in pore properties, coke mechanical strength decreased but its strength after gasification improved up to a TiO₂ addition of about 1% and then deteriorated slightly. X-ray diffraction analysis indicated that average stacking heights and lateral size of layer structures varied with TiO₂ addition levels. Crystallites volume was determined through assuming a cylindrical carbon structure with multiple multi-aromatic rings arranged in parallel. A logarithmic relationship was found to exist between this parameter and coke thermal properties. Fourier transform infrared spectroscopy analysis showed a strong linear correlation between the coke reactivity, coke strength after reaction, and C = O content in the oxygen functional groups. It was concluded from this study that added TiO₂ decreased the proportion of carbon active sites in the coke because of increasing carbon crystallites volume and decreasing C = O functional groups, and this resulted in decreased reactivity during gasification and increased coke strength after gasification.

KEYWORDS:

• TiO₂
• coke
• structure characteristics
• metallurgical properties

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Grant No. 51474042 & 51774061) and the Fundamental Research Funds for Central Universities (Grant No. 106112017CDJQJ138801). The authors also acknowledge the support provided by the Fund of Chongqing Science and Technology (Project No. cstc2018jscx-msyb0988).