Physical and chemical analyses of unburned carbon from oil-fired fly ash Original Research Article

In the hydrometallurgy process of extracting vanadium and nickel products from oil-fired fly ash, a large amount of unburned carbon remains as a by-product. Because of insufficient knowledge of the physical and chemical properties and related applications of the unburned carbon, the residue has been disposed to landfill or incinerated. In order to explore the utilization of unburned carbon, this preliminary study analyzed its morphology, particle size distribution, specific surface area, pore size distribution, density and chemical composition. The results indicate that the chemical composition is 73–91% carbon, 5–19% ash, 2.5–11.5% volatile substances, and 0.7–1.9% water, it consists of porous spherical particles and some crumbled particles with particle sizes mainly in the range 1–100 μm, the specific surface area is 16–33 m2/g, the pore size ranges between 0.02 and 10 μm, the real density is about 2.05–2.16 g/cm3, the apparent density about 0.15 g/cm3 and it can be characterized as a puffy, readily wind-blown powder.