Enhancement of coal tar pitch carbonization with biochar: A metallurgical formed biocoke product produced by waste coke breeze and bamboo powder

Abstract

The combustion of pulverized fuels in industrial production is inefficient and aggravates haze formation. A novel and green approach via synergetic using two solid waste resources (waste bamboo powder and waste coke breeze) for producing formed biocoke products as a metallurgical coke substitute was proposed in this study. A biochar with high fixed carbon (87.32 %) and low volatiles (2.49 %) was obtained by bamboo powder pyrolysis at 1000 °C for 30 min. Adding this biochar can enhance the strength of the formed coke product prepared using coke breeze with coal tar pitch as the binder. The cracks and pores between coke breeze particles inside the product can be filled by biochar, increasing the product's density. Furthermore, the carbonization of coal tar pitch as the binder can be improved by adding biochar, further enhancing the product strength. A formed biocoke product, with 34.5 MPa compressive strength, 41.29 % CSR and 30.59 % CRI, was obtained at a 2:8 mass ratio (biochar to coke breeze) by carbonization at 1100 °C under a nitrogen atmosphere for 30 min. The experiments of simulating blast furnace production using mixtures of the formed biocoke product with the metallurgical coke (with 21.12 % CRI and 64.58 % CSR) in different mass ratios were carried out. 4 % of the metallurgical coke for blast furnace ironmaking can be replaced by obtained formed biocoke product. This study achieved sustainable high-value-added recycling of coke solid waste resources. It can be an essential reference for recycling other pulverized solid fuels.