Scientific and Engineering Progress in CO 2 Mineralization Using Industrial Waste and Natural Minerals

Xie H., Wang Y., He Y., Gou M., Liu T., Wang J., Tang L., Jiang W., Zhang R., Xie L., Liang B.

Current CO2 reduction and utilization technologies suffer from high energy consuming. Thus, an energy favourable route is in urgent demanding. CO2 mineralization is theoretically an energy releasing process for CO2 reduction and utilization, but an approach to recovery this energy has so far remained elusive. For the first time, here we proposed the principle of harvesting electrical energy directly from CO2 mineralization, and realized an energy output strategy for CO2 utilization and reduction via a CO2-mineralization fuel cell (CMFC) system. In this system CO2 and industrial alkaline wastes were used as feedstock, and industrial valuable NaHCO3 was produced concomitantly during the electricity generation. The highest power density of this system reached 5.5 W/m2, higher than many microbial fuel cells. The maximum open circuit voltage reached 0.452 V. Moreover, this system was demonstrated viable to low concentration CO2 (10%) and other carbonation process. Thus, the existing of an energy-generating and environmentally friendly strategy to utilize CO2 as a supplement to the current scenario of CO2 emission control has been demonstrated.

Ye L., Yue H., Wang Y., Sheng H., Yuan B., Lv L., Li C., Liang B., Zhu J., Xie H.

We report an alternative technology for the mineralization of CO2 and production of soluble potash fertilizer via thermal activation of the insoluble K-feldspar with industrial waste of CaCl2 with lower energy consumption since the activation temperature was about 800–900 °C compared with the conventional temperature of 1300 °C. A remarkable K-extraction and CO2 mineralization ratio could be obtained at an appropriate activation temperature and content of additive CaCl2, which possessed the exchange of skeletal K+ with dissociative Ca2+ to form soluble K+ species, the collapse of K-feldspar framework, and the formation of intermediates (e.g., anorthite, pseudowollastonite, and wollastonite) to react with CO2. Characterization results (e.g., XRD, EDS, and SEM) indicated that pseudowollastonite and wollastonite were the major species to fix CO2. Moreover, the reaction principles of the K-extraction and CO2 mineralization were discussed, and a possible mechanism was proposed.

Xie H., Wang Y., Chu W., Ju Y.

CO2 mineralization and utilization is a new area for reducing the CO2 emissions. By reacting with natural mineral or industrial waste, CO2 can be transformed into valuable solid carbonate (such as calcium carbonate or magnesium carbonate) with recovery of some products simultaneously. In this paper, a novel method was proposed to mineralize CO2 by means of magnesium chloride with small energy consumption. In this method, magnesium chloride was firstly transformed into magnesium hydroxide by electrolysis. The formed magnesium hydroxide showed high reactivity to mineralize CO2. In our study, even at low concentration, CO2 can be effectively mineralized by this method, which makes it possible to directly mineralize flue gas CO2, avoiding the expensive process of CO2 capture and purification. Moreover, valuable products such as hydromagnesite and nesquehonite can be recovered by this method. Because of the wide distribution of magnesium chloride in nature, large-scale CO2 mineralization is potential by means of magnesium chloride.

Wang C., Yue H., Li C., Liang B., Zhu J., Xie H.

This article describes a novel CO2 mineralization approach using natural insoluble K-feldspar and phosphogypsum for the emission of CO2, reduction of phosphogypsum waste, and production of soluble potash. K-feldspar was activated with CaSO4 at high temperature and then mineralized with CO2 to extract potassium under hydrothermal conditions. Activation and mineralization conditions (e.g., ore/CaSO4 mass ratio, calcination and mineralization temperatures, initial pressure of CO2) were systematically investigated with an optical potassium extraction ratio of ∼87% and a CO2 mineralization ratio of ∼7.7%. A reaction mechanism was proposed based on the experimental results and the characterizations, such as polarized light microscopy, X-ray diffraction, and thermogravimetric and differential thermal analyses. This new methodology is a promising process and has the potential to reduce emissions of CO2 and phosphogypsum from a practical point of view.

Hamelers H.V., Schaetzle O., Paz-García J.M., Biesheuvel P.M., Buisman C.J.

When two fluids with different compositions are mixed, mixing energy is released. This holds true for both liquids and gases, though in the case of gases, no technology is yet available to harvest this energy source. Mixing the CO2 in combustion gases with air represents a source of energy with a total annual worldwide capacity of 1570 TWh. To harvest the mixing energy from CO2-containing gas emissions, we use pairs of porous electrodes, one selective for anions and the other selective for cations. We demonstrate that when an aqueous electrolyte, flushed with either CO2 or air, alternately flows between these selective porous electrodes, electrical energy is gained. The efficiency of this process reached 24% with deionized water as the aqueous electrolyte and 32% with a 0.25 M monoethanolamine (MEA) solution as the electrolyte. The highest average power density obtained with a MEA solution as the electrolyte was 4.5 mW/m2, significantly higher than that with water as the electrolyte (0.28 mW/m2).

Wang W., Liu X., Wang P., Zheng Y., Wang M.

The potential for using concentrated seawater to fix CO2 by adding insoluble amine extractant was tested and verified. The experimental results showed that over 90% of Ca2+ ions could be converted to precipitation. Ammonia was chosen as regenerant to regenerate the extracting agent; the regeneration rate can reach 95%. On the basis of the analysis of MgCO3 precipitation properties, a new CO2 mineralization process was proposed in which CaO is employed to react with Mg2+ in solution. Mg(OH)2 precipitation and Ca2+-rich aqueous solutions were produced, and both performed well in CO2 mineralization. This new process can produce different kinds of byproducts such as MgCO3, CaCO3, and NH4Cl. Since there is no energy consumption from phase separation, nor is there a heat requirement, it is therefore definitely less energy intensive. This approach has great application potential.

Tong D., Trusler J.P., Vega-Maza D.

We report the solubility of carbon dioxide in CaCl2(aq) and MgCl2(aq) at molalities of (1, 3, and 5) mol·kg–1, temperatures of (308 to 424) K and pressures up to 40 MPa. We also report the solubility of CO2 in a synthetic formation brine containing 0.910 mol·kg–1 NaCl and 0.143 mol·kg–1 KCl over the same ranges of temperature and pressure. The expanded uncertainties at 95 % confidence are 0.03 K in temperature, between (0.08 and 0.15) MPa in bubble pressure and 0.00015 in the mole fraction of CO2 in the solution at its bubble point. The results show a strong salting-out effect, whereby the solubility declines with increasing molality of salt, which is some (20 to 30) % greater in CaCl2(aq) or MgCl2(aq) than in the synthetic formation brine at the same molality.

Godishala K.K., Sangwai J.S., Sami N.A., Das K.

Experimental studies are carried out on semiclathrate hydrate of carbon dioxide (CO2) in tetra-n-butylammonium bromide (TBAB) for varying concentrations of TBAB (0.05, 0.10, and 0.20 mass fraction) + sodium chloride (NaCl) (0.035 and 0.10 mass fraction) in an aqueous system. The three-phase equilibrium (H-LW-V) data are generated for quaternary system of CO2 + TBAB + H2O + NaCl and are not available in the open literature. The competing effect of TBAB and NaCl at different concentrations on phase behavior of semiclathrate hydrate equilibrium is studied. It is found that the inhibition effect of salt is much more pronounced at higher pressures compared to lower pressure conditions. It is observed that the inhibiting effect of the NaCl is suppressed by the promoting effect of semiclathrate hydrates of CO2 in TBAB. Although there is a shift in hydrate equilibrium curve toward inhibition zone compared to that of the same system in the absence of salt, this system is more stable than the hydrate of pure CO2 in...

Xie H., Wang Y., Ju Y., Liang B., Zhu J., Zhang R., Xie L., Liu T., Zhou X., Zeng H., Li C., Lu H.

CO2 capture and storage (CCS) is an important strategy in combatting anthropogenic climate change. However, commercial application of the CCS technique is currently hampered by its high energy expenditure and costs. To overcome this issue, CO2 capture and utilization (CCU) is a promising CO2 disposal method. We, for the first time, developed a promising method to mineralize CO2 using earth-abundant potassium feldspar in order to effectively reduce CO2 emissions. Our experiments demonstrate that, after adding calcium chloride hexahydrate as an additive, the K-feldspar can be transformed to Ca-silicates at 800°C, which can easily mineralize CO2 to form stable calcium carbonate and recover soluble potassium. The conversion of this process reached 84.7%. With further study, the pretreatment temperature can be reduced to 250°C using hydrothermal method by adding the solution of triethanolamine (TEA). The highest conversion can be reached 40.1%. The process of simultaneous mineralization of CO2 and recovery of soluble potassium can be easily implemented in practice and may provide an economically feasible way to tackle global anthropogenic climate change.

Li X., Boek E.S., Maitland G.C., Trusler J.P.

We report the interfacial tensions between carbon dioxide and CaCl2(aq), MgCl2(aq), and Na2SO4(aq) with molalities from (0.49 to 5.0) mol·kg–1. The measurements were made at temperatures between (323 and 423) K at various pressures up to 50 MPa. The pendant-drop method was implemented in a high-pressure view cell filled with water-saturated CO2 into which single drops of brine were injected through a suitable capillary. The expanded uncertainties at 95 % confidence are 0.05 K in temperature and 70 kPa in pressure. For the interfacial tension, the expanded relative uncertainty at 95 % confidence was 1.6 %. The results of this study show that interfacial tension increases linearly with molality. Further, at constant temperature and pressure, the interfacial tension is the same function of the positive charge molality for all salts investigated in this work.

Munz I.A., Brandvoll Ø., Haug T.A., Iden K., Smeets R., Kihle J., Johansen H.

Plagioclase is one of the most abundant sources of calcium in the earth’s crust, and it may play an important role for CO2 storage. This study address’ the carbonation of anorthite-rich plagioclase (An67–An73) in a system with fluid transport, and under stagnant conditions. A combined approach of flow-through column and batch experiments has been used. Experimental conditions ranging from 100 to 250 °C and 20 to 120 bar and different preparations of the starting material were applied. The overall carbonation reaction consists of plagioclase dissolution coupled to a number of precipitation reactions. The flow-through column experiments at 250 °C showed stoichiometric dissolution of the plagioclase. Al-hydroxide (“proto Al-hydroxide”) nucleated on the plagioclase as the first phase to precipitate. A secondary porosity developed between the shrinking plagioclase and the enclosing “proto Al-hydroxide”. Calcite, as the second phase to precipitate, filled the primary pore space. A reaction front was developed separating the zone at the inlet where all the plagioclase had dissolved and the less reacted outlet of the column. Redissolution of the calcite and formation of euhedral boehmite crystals occurred when a sufficient amount of plagioclase had dissolved. Clay minerals were not precipitated in the column experiments. Between 11% and 30% of the plagioclase was dissolved within 72–168 h of reaction. A much higher extent of plagioclase dissolution was observed in the high pressure experiments compared to the low pressure. However, a smaller share of the released Ca was trapped as calcite in the high pressure experiments. Both observations are consistent with a more rapid progression of the dissolution front at high pressure. The batch experiments showed conversion of the plagioclase to a mixture of Al-hydroxide, possibly gibbsite, clays and calcite. A range in conversion from below the detection limit to 91% was observed within reaction periods of 24–72 h. Crystallinity of the feldspar was the most important factor contributing to increased reaction rates. A general positive effect of increasing temperature on the conversion is observed for all materials, whereas pressure and the addition of CaCl2 did not have any effect. The carbonation of plagioclase at stagnant conditions is slow compared to olivine at temperatures around 200 °C. However, industrial operations involving high fluid flows of CO2–water mixtures induce gradients in pH or solute concentrations, which may lead to increased reaction rates and changes in porosity/permeability.

Chaikittisilp W., Khunsupat R., Chen T.T., Jones C.W.

Low-molecular-weight poly(allylamine) is prepared via free-radical polymerization, and the resulting polymer is impregnated into mesocellular silica foams at different amine loadings. The resulting poly(allylamine)–silica composites are demonstrated as effective adsorbents for the extraction of carbon dioxide from dilute (simulated flue gas) and ultradilute (simulated ambient air) gas streams. The composite adsorbents are shown to have comparable adsorption capacities to more-conventional poly(ethyleneimine)–silica adsorbents. Potential advantages of poly(allylamine)-derived adsorbents are discussed.

Sun Z., Fan M., Argyle M.

An alternative method for using monoethanolamine (MEA) in CO2 separation is developed from the viewpoints of the MEA–CO2 reaction environment and the process of spent sorbent regeneration. MEA–TiO2 (MT) CO2 sorbent is synthesized using pure MEA and a support material, TiO2. The performance of the MT sorbent on CO2 separation was investigated in tubular reactors under various experimental conditions. The sorption capacity of the MT sorbent reached 1.09 mol-CO2/kg-MT at 45 wt % MEA. However, an optimum of 40 wt % MEA loading was chosen for most of the sorption tests. Temperature affected the CO2 sorption capacity considerably, with optimum values of 45 °C for adsorption and 90 °C for regeneration, while humidity had a small positive effect. TiO(OH)2 appears to be the best support material for MEA, but more evaluation is needed. The MT sorbent is regenerable, with a multicycle sorption capacity of ∼0.91 mol-CO2/kg-MT under the given experimental conditions.

Materic V., Smedley S.I.

Steam hydration is reported to be an effective method for reactivating spent sorbents in calcium looping applications; however, uncertainties remain regarding the optimal method of returning the hydrated sorbent to the CO2 capture loop. Carbonation conversions were found to be higher when Ca(OH)2 was directly carbonated at high temperatures compared to conversions reached when Ca(OH)2 was dehydrated prior to carbonation. This observation can lead to improved hydration based reactivation techniques for calcium looping applications. Upon heating in CO2, calcium hydroxide remained stable at temperatures >450 °C and the extent of carbonation was controlled by temperature only. The carbonation mechanism of Ca(OH)2 at high temperatures appears to be more complex than the expected simple mechanism comprising the dehydration reaction of Ca(OH)2 and the subsequent carbonation of the resulting CaO. An alternate mechanism was proposed, involving the formation of liquid like layers of water on the surface of Ca(OH)2.

Verduyn M., Geerlings H., Mossel G.V., Vijayakumari S.

Two experimental modes of operation, a sequence of batch and a continuous one, have demonstrated the technical feasibility of Shell’s proposed slurry-based direct flue gas mineralization concept on the basis of activated serpentine. The base case mineralization concept can be simplified yielding a variety of product forms and significantly reduced CO2 abatement costs. Combined with a positive first assessment of the sustainability of the various mineralization product forms, all mineralization concepts deserve to be further investigated. To optimally take advantage of integration opportunities so as avoid parasitic CO2 emissions and minimize cost, this should be done over the complete technology chain.

Wang B., Cheng H., Liu X., Di Z., Song H., Zhang D., Cheng F.

Ye K., Yang L., Zeng J., Tian J., Zeng F., Ye G., Mu Y.

Li G., Yang J., Li H., Liew J., Huang J.

Sahu R.K., Patodia T., Juyal S., Gill F.S., Prasad B., Jain A.

The unique properties of carbon nanoparticles (CNPs) and their potential as visible-light photocatalysts have sparked lots of interest because of its broad availability, superior visible light absorption, affordability and durability....

Li G., Tao Y., Zhu X., Gao Y., Shen P., Yin B., Dupuis R., Ioannidou K., Pellenq R.J., Poon C.S.

The feasibility of carbon mineralization relies on the carbonation efficiency of CO2-reactive minerals, which is largely governed by the water content and state within material mesopores. Yet, the pivotal role of confined water in regulating carbonation efficiency at the nanoscale is not well understood. Here, we show that the maximum CO2 intake occurs at an optimal relative humidity (RHopt) when capillary condensation initiates within the hydrophilic mesopores. At this transition state, the pore becomes filled with metastable low-density water, providing an ideal docking site for CO2 adsorption and forming a mixed metastable state of water/CO2. We prove that RHopt depends on the mesopore size through a Kelvin-like relationship, which yields a robust engineering model to predict RHopt for realistic mineral carbonation. Building upon classical theories of phase transition in hydrophilic mesopores, this study unveils the capacity of the metastable water in CO2 intake and enhances the high-efficiency carbon mineralization with natural ore and industrial wastes in real-world applications. CO2 can be captured in mesoporous alkaline waste materials. Here the authors provide atomistic insight for CO2 adsorption in calcium hydroxide to identify optimal relative humidity conditions for maximum CO2 intake.

Huan Q., Wibowo H., Yan M., Song M.

Xu R., Zhu F., Zou L., Wang S., Liu Y., Hou J., Li C., Song K., Kong L., Cui L., Wang Z.

Conejo A.N.

The large amount of emissions in the steel industry has been the result from its dependence in fossil fuels, however attention to the problem of CO2 emissions is very recent in history. In this chapter there is a brief discussion on the relationship between energy consumption in the steel industry and CO2 emissions, its effects on human health and also an overview on nine solutions. The EAF is one part of the solutions. At the end there is brief note to describe the EAF of the future.

Zhang Y., Ying Y., Zhang Q., Deng Y., Xing L., Zhan G., Huang Z., Chen Z., Li J.

Huang J., Li H., Guo G., Zha J., Tang C., Li H.

Over the past centuries, global coal mining activities have resulted in the formation of 242.36 billion cubic meters of underground goaf areas, resulting in the waste of billions of square meters of land resources. Furthermore, this phenomenon has introduced significant safety hazards and environmental risks. In addressing the challenge of the inability to directly sequester supercritical carbon dioxide in coal mine goaf areas due to extensive fracturing of the surrounding rock mass caused by underground mining, an innovative approach is proposed. This involves the construction of artificial cover layers within the overlying rock strata of abandoned coal mine goaf areas, offering a novel strategy for the sequestration of supercritical CO2 in such geological contexts. Considering the development characteristics of fractures in the overlying strata of coal mine goaf areas, a functional relationship model is established to delineate the sealing capacity of artificial cover layers in relation to the burial depth, length, width, and thickness of the cover layers. A design methodology for constructing artificial cover layers tailored for sequestering supercritical CO2 in abandoned coal mine goaf areas is proposed, providing technical support for its widespread application. Building upon this foundation, an assessment model for the sequestration capacity of abandoned coal mine goaf areas for supercritical CO2 is developed. The calculations indicate a global sequestration potential of approximately 72.71–218.12 billion tons of supercritical CO2, with anticipated economic benefits ranging from 657.36 to 1991.47 billion USD. The research outcomes present a promising avenue to assist carbon-neutral initiatives in coal-dependent urban areas globally.

Zhang J., Cui K., Chang J., Wang L.

Phosphogypsum (PG) is a major industrial waste emitted during phosphate production. Facing the environmentally risky challenges posed by PG emissions and stockpiles, a review of the state of PG resource utilization in civil engineering and searching for new ways to utilize PG to improve the utilization rate are necessary. Therefore, this paper compared the chemical composition and pretreatment methods of PG from different sources and outlined the application of PG-based building materials, including gypsum products, cement-based materials, and road materials. It was found that there are differences in the chemical composition and physical properties of PG due to differences in phosphate mines and production processes, which affected the way it was pretreated and applied. Currently, thermal treatment and synergistic treatment by various means are effective methods for cleaning PG, and future treatment processes should be developed to highly efficient, and low cost. PG-based building materials positively contribute to recovering PG and promoting resource recycling, but environmental safety and long-term stability need to be explored. In addition, the importance, limitations, and development trends of applying PG-based building materials were discussed. Future research focuses on solid waste-based cementitious and mineralized materials to inform harmless, high-value and large-scale utilization of PG.

Kumar R., Chung W.J., Khan M.A., Son M., Park Y., Lee S.S., Jeon B.

Greenhouse gas emissions and climate change concerns have prompted worldwide initiatives to lower carbon dioxide (CO2) levels and prevent them from rising in the atmosphere, thereby controlling global warming. Effective CO2 management through carbon capture and storage is essential for safe and permanent storage, as well as synchronically meeting carbon reduction targets. Lowering CO2 emissions through carbon utilization can develop a wide range of new businesses for energy security, material production, and sustainability. CO2 mineralization is one of the most promising strategies for producing thermodynamically stable solid calcium or magnesium carbonates for long-term sequestration using simple chemical reactions. Current advancements in CO2 mineralization technologies,focusing on pathways and mechanisms using different industrial solid wastes, including natural minerals as feedstocks, are briefly discussed. However, the operating costs, energy consumption, reaction rates, and material management are major barriers to the application of these technologies in CO2 mineralization. The optimization of operating parameters, tailor-made equipment, and smooth supply of waste feedstocks require more attention to make the carbon mineralization process economically and commercially viable. Here, carbonation mechanisms, technological options to expedite mineral carbonation, environmental impacts, and prospects of CO2 mineralization technologies are critically evaluated to suggest a pathway for mitigating climate change in the future. The integration of industrial wastes and brine with the CO2 mineralization process can unlock its potential for the development of novel chemical pathways for the synthesis of calcium or magnesium carbonates, valuable metal recovery, and contribution to sustainability goals while reducing the impact of global warming.

Vakylabad A.B., Saberi A.

Wang X., Yang H., Huang Y., Liang Q., Liu J., Ye D.

Understanding the storage mechanisms in CO2 flooding is crucial, as many carbon capture, utilization, and storage (CCUS) projects are related to enhanced oil recovery (EOR). CO2 storage in reservoirs across large timescales undergoes the two storage stages of oil displacement and well shut-in, which cover multiple replacement processes of injection–production synchronization, injection only with no production, and injection–production stoppage. Because the controlling mechanism of CO2 storage in different stages is unknown, the evolution of CO2 storage mechanisms over large timescales is not understood. A mathematical model for the evaluation of CO2 storage, including stratigraphic, residual, solubility, and mineral trapping in low-permeability tight sandstone reservoirs, was established using experimental and theoretical analyses. Based on a detailed geological model of the Huaziping oilfield, calibrated with reservoir permeability and fracture characteristic parameters obtained from well test results, a dynamic simulation of CO2 storage for the entire reservoir life cycle under two scenarios of continuous injection and water–gas alternation were considered. The results show that CO2 storage exhibits the significant stage characteristics of complete storage, dynamic storage, and stable storage. The CO2 storage capacity and storage rate under the continuous gas injection scenario (scenario 1) were 6.34 × 104 t and 61%, while those under the water–gas alternation scenario (scenario 2) were 4.62 × 104 t and 46%. The proportions of storage capacity under scenarios 1 and 2 for structural or stratigraphic, residual, solubility, and mineral trapping were 33.36%, 33.96%, 32.43%, and 0.25%; and 15.09%, 38.65%, 45.77%, and 0.49%, respectively. The evolution of the CO2 storage mechanism showed an overall trend: stratigraphic and residual trapping first increased and then decreased, whereas solubility trapping gradually decreased, and mineral trapping continuously increased. Based on these results, an evolution diagram of the CO2 storage mechanism of low-permeability tight sandstone reservoirs across large timescales was established.

Su Y., Li B., Zhou W., Jie W., Li Y., Zhang H., Ni H.

Comparing of existing kinetic models for direct mineral carbonation by solid waste, an optimized kinetic model was developed to depict the relationship between phosphogypsum carbonation ratio and reaction time. Based on the optimized model, the reaction mechanism of CO2 sequestration by ammonia-enhanced phosphogypsum mineral carbonation was analyzed. The experimental results show that, under specific conditions, including an ammonia ratio of 2.3, room temperature (25 °C), a liquid–solid ratio of 5:1, a gas flow rate of 200 mL/min, and a rotational speed of 500 rpm, phosphogypsum achieved its peak carbonation efficiency of 91 % within 30 min. The optimized model fitting curve has a high consistency with the experimental data, and the average R2 value is 0.991. The process of ammonia-enhanced phosphogypsum mineral carbonation comprises three distinct sub-processes. It is consisted of mass transfer in gas–liquid interface and solid–liquid interface, respectively, and product layer diffusion. Among them, the gas–liquid mass transfer is identified as the rate-controlling step in the mineral carbonation process. The present study provides a basis for the operation optimization and large-scale utilization of phosphogypsum mineral carbonation.