Research on the Mineralization and Carbon Fixation of Porous Gel Based on Carbide Slag-Triethylenetetramine

Abstract

Improving the rate of mineralization reaction in alkaline solid waste, primarily consisting of calcium carbide slag, is essential for mineralization plugging, fire prevention, and extinguishing. In this study, a novel method to synergistically enhance the mineralization reaction rate by adding catalytic CO 2 conversion substances and increasing the gas−solid contact area was proposed. A high-temperature and high-pressure reactor device was used for the test, and the effects of four factors on CO 2 conversion, namely triethylenetetramine (TETA) addition, CO 2 initial pressure, calcium oxide (CaO) addition, and reaction time, were tested by single-factor and response surface curve analysis. According to the influence of the absorption capacity, the optimal combination of the CO 2 adsorption capacity was screened out. Through the chemical composition and phase analysis of carbide slag before and after the carbonation reaction, it was observed that effective calcareous components existed in the forms of Ca(OH) 2 and CaCO 3 , verifying that carbide slag can effectively mineralize and store CO 2 gases. The mechanisms underlying TETA storage and CO 2 conversion were studied by density functional theory calculations. Furthermore, the TETA solution and carbide slag were compounded and foamed to prepare a threedimensional porous gel to study its influence on the mineralization efficiency of CO 2 . The results showed that the potential to fix CO 2 at different temperatures is 0.07 g/g CO 2 (20 °C), 0.077 g/g CO 2 (30 °C), and 0.110 g/g CO 2 (40 °C). The economic benefit analysis showed that the mineralization costs of 1 ton of CO 2 at different temperatures were about ¥15,642.39 (20 °C), ¥14,220.35 (30 °C), and ¥99544.25 (40 °C), respectively. More importantly, the porous gel was prepared using natural polymer materials and industrial solid waste, thus offering an environmentally compatible approach to provide a theoretical basis for the research and development of materials for preventing coal spontaneous combustion.

The Future of CO2 Geological Sequestration: An Overview of Mineralization in Aqueous and Supercritical States

“…These can be roughly divided into the following four categories: inorganic additives such as acids or alkali, NaCl, NaHCO 3 , etc. ; organic additives such as amines, , amino acid salts, , organic ligands, etc. ; enzymes such as carbonic anhydrase (CA), etc.…”