Analysis of the Variable Influence and Energy Storage Performance in Preparation of Solar Energy Storage Materials via Modification of Carbide Slag Using MnO2 through Wet Doping

Carbide slag is a common industrial waste with a high calcium content. Herein, a new type of calcium-based absorbent was prepared via a wet process using calcium carbide slag as the calcium source and MnO2 as the dopant. The results showed that when the concentration of ethanol was 60% and the molar ratio of calcium oxide, citric acid, and MnO2 was 1:1.25:0.05, the carbonation conversion of the absorbent reached the highest conversion rate of 77%. After 50 carbonation/calcination cycles, the carbonation conversion of the modified absorbent was 11% higher than that of the unmodified pure calcium carbide slag. The synergistic effect of controlling the grain size of the absorbent and using citric acid to strengthen the structure was found to inhibit agglomeration and collapse of the composite absorbent, thus improving cycle stability. Through a range method, it was found that among the variables considered in this study, the ethanol concentration had the strongest influence on the carbonation conversion of composite materials. Mn2O3 is formed when MnO2 is doped in calcium carbide slag after calcination, which not only strengthens the surface structure of the composite absorbent but also enhances the optical absorption characteristics of the absorbent.