Utilization of CO₂ as carbon source for preparation of sandy Al(OH)₃ in concentrated KAl(OH)₄ solutions: a kinetic study

ABSTRACT

The emission of CO₂ have led to the vital climate change commonly referred to global warming. Carbonation decomposition of potassium aluminate solutions is adopted for carbon capture and production of Al(OH)₃ in this study. The influence of temperature in the range from 60°C to 90°C, caustic concentration in the range from 220 K₂O L⁻¹ to 280 g K₂O L⁻¹ and CO₂ concentration in the range from 10% to 50% on the precipitation ratio and crystal size distribution of Al(OH)₃ was investigated. The results indicated that the carbonation process of potassium aluminate can be divided into three periods, and the carbonation time decreased with the increase of the reaction temperature and CO₂ concentration or reduction of the caustic concentration. The kinetic model of carbonation decomposition of potassium aluminate solution is established based on the experimental results. By the comprehensive analysis above, the apparent activation energy is 59.35 kJ mol⁻¹, demonstrating that the carbonation decomposition of potassium aluminate solution is easier than that of sodium aluminate solution.

KEYWORDS:

• Aluminum hydroxide
• carbonation
• kinetics
• potassium aluminate
• carbon capture

Acknowledgments

The authors are greatly thankful to the National Key R&D Program of China (No. 2018YFB0605703). Cheng-Lin Liu conceived and designed the study, and wrote the paper. You-Fa Jiang and Dan Wang performed the experiments, acquisition of data, analysis and interpretation of data. Cheng-Lin Liu, Xing-Fu Song and Jian-Guo Yu reviewed and edited the manuscript. All authors read and approved the manuscript.

Additional information

Funding

This work was supported by the National Key R&D Program of China [2018YFB0605703].