Thermodynamics and kinetics of the carbothermal reduction of aluminum sulfate

Abstract

The thermodynamic analysis and kinetics of the carbothermal reduction of aluminum sulfate using anthracite as the reducing agent are reported. The results showed that the reduction reaction was controlled by interfacial chemical reaction when the carbon excess coefficient was 1.15 (aluminum sulfate, anthracite coal particle size, respectively 100 mesh, 180 mesh) and the reaction temperature was in the range of 450–600 °C. The reaction could be represented using the Erofeev equation: $\text{ln}\hspace{0.17em}\left[-\hspace{0.17em}\text{ln}\hspace{0.17em}(1-x)\right]=n\hspace{0.17em}\text{ln}\hspace{0.17em}t+\hspace{0.17em}\text{ln}\hspace{0.17em}k$ and the apparent activation energy was 227.50 kJ·mol⁻¹. From the XRD pattern, FTIR spectra and SEM image of the product after reduction was determined at 600 °C for 2 h, it was amorphous alumina and the particle size was small, which provided good conditions for the preparation of metallurgical grade alumina.

Graphical Abstract

Keywords:

• Carbothermal reduction
• aluminum sulfate
• anthracite
• thermodynamics
• kinetics

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China (No. 21566018).