查看更多>>摘要:Mineral carbonation,which precipitates dissolved carbon dioxide(CO2)as carbonate minerals in basaltic groundwater environments,is a potential technique for negative emissions.The Leizhou Peninsula in southwest Guangdong province has extensive basalt,indicating a promising potential for CO2 storage through rapid mineralization.However,understanding of the basic geological setting,potential,and mechanisms of CO2 mineralization in the basalts of the Leizhou Peninsula is still limited.The mineralization processes associated with CO2 storage at two candidate sites in the area are investigated in this paper:Yongshi Farm and Tianyang Basin(of the dried maar lake).Petrography,rock geochemistry,basalt petrophysical properties,and groundwater hydrochemistry analyses are included in the study.Numerical simulation is used to examine the reaction process and its effects.The results show that basalts in the study areas mainly comprise plagioclase,pyroxene,and Fe-Ti oxides,revealing a total volume fraction exceeding 85% .Additionally,small amounts of quartz and fayalite are available,with volume fractions of 5.1% and 1.0% ,respectively.The basalts are rich in divalent metal cations,which can form carbonate minerals,with an average of approximately 6.2 moles of metal cations per 1 kg of rock.The groundwater samples have a pH of 7.5-8.2 and are dominated by the Mg-Ca-HCO3 type.The basalts demonstrate a porosity range of 10.9% to 28.8% ,with over 70% of interconnected pores.A 20-year geochemical simulation revealed that CO2 injection dissolves primary minerals,including anorthite,albite,and diopside,while CO2 mineralization dissolves precipitation secondary minerals,such as calcite,siderite,and dolomite.Furthermore,a substantial rise in pH from 7.6 to 10.6 is observed in the vicinity of the injected well,accompanied by a slight reduction in porosity from 20% to 19.8% .Additionally,36.8% of the injected CO2 underwent complete mineralization within five years,revealing an increasing percentage of 66.1% if the experimental period is extended to 20 years.The presence of abundant divalent metal cations in basalts and water-bearing permeable rocks in the Leizhou Peninsula supports the potential for mineral carbonation in basalts,as indicated by the geochemical simulation results.Additional research is necessary to identify the factors that influence the CO2 mineralization,storage,and sensitivity analysis of basalt in the Leizhou Peninsula.