Volume 34: CCUS Technologies for the Carbon Neutrality: Part II

Preparation of CaCO3 from CaCl2 waste liquid and flue gas CO2 based on absorption−mineralization process using water-soluble amines Yuan Ma, Tianyu Sun, Chenglin Liu, Jianguo Yu

Abstract

The treatment of CaCl2 waste liquid has become a common technical problem in the soda industry, and there is still no good solution. Meanwhile, the global is under intense pressure from drastic climate change, and CO2 emission reduction is urgent. If the two waste are utilized, it will have multiple benefits, but there is little research on it. In this work, a novel route for comprehensively utilizing the flue gas CO2 of power plant and the CaCl2 waste liquid of ammonia-alkali plant was developed, in which CaCl2 solution and flue gas CO2 were transformed into CaCO3 products based on an absorption−mineralization process using water-soluble amines. The technical feasibility with six amines was fully verified, and to further obtain the larger particle size CaCO3 that facilitates industrial filtration, the effects of different operating conditions were investigated. Results showed that ethanolamine (MEA) is the optimal amine, with the mineralization rate is 97.2%. The CaCO3 with the larger particle size is of 20-30 μm under the optimal condition.

Keywords CO2 mineralization, CaCl2 waste liquid, water-soluble amine, calcium carbonate