Abstract

Energy demand is projected to increase throughout the globe in near future which necessitates the development of carbon capture and storage (CCS) technologies to avoid the harmful impacts of climate change. Direct mineral carbonation of alkaline solid wastes is one such technology that provides the benefit of being a permanent, cost effective and a promising on-site option, while improving the environmental quality of the waste. The present work attempts to study direct mineral carbonation of red mud (RM) with CO₂ (concentration as in flue gas) by wet and dry route employing response surface methodology (RSM). Maximum reduction of about 18.5% in the concentration of CO₂ was attained in wet carbonation conditions (65.1 ºC, 42.1 bar, L/S ratio of 0.53, 1 h) and the sequestration capacity of RM was found to be 15.5 g of CO₂/kg, correspondingly. The models were found to be statistically significant (R² value > 98.5%). Temperature and reaction time were found to influence the dry route. Meanwhile in wet route, temperature, pressure, liquid to solid (L/S) ratio and reaction time were all significant. The results demonstrated that RM could significantly sequester CO₂ even from flue gas. The carbonation process was evidenced using Fourier-Transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM).

摘要

预计不久的将来全球范围内的能源需求将增加，这需要开发碳捕集与封存（CCS）技术来避免气候变化的有害影响。碱性固体废物的直接矿物碳酸化是一种这样的技术，它具有永久性，成本效益高和有希望的现场选择的好处，同时改善了废物的环境质量。本工作试图通过湿法和干法采用响应面方法（RSM）研究CO ₂（烟道气中的浓度）与CO ₂的赤泥（RM）直接矿物碳酸化。CO ₂浓度最大降低约18.5％在湿碳酸化条件下（65.1ºC，42.1 bar，L / S比为0.53，1小时），获得的碳的吸附量为RM 15.5 g CO ₂ / kg。发现模型具有统计学意义（R ²值> 98.5％）。发现温度和反应时间影响干燥路线。同时，在湿法中，温度，压力，液固比（L / S）和反应时间均显着。结果表明，即使从烟气中，RM也可以显着隔离CO ₂。使用傅里叶变换红外（FT-IR）光谱，X射线衍射（XRD）分析和扫描电子显微镜（SEM）证明了碳酸化过程。