Wet Carbon Research Articles

Preparation of aragonite from calcium carbonate via wet carbonation to improve properties of steel slag building materials

Smelting in steel mills emitted large amounts of CO2 and produced the waste product steel slag (SS). Therefore, the use of SS to fix CO2 and produce value-added products could treat waste with waste and promote the effective use of resources. In this study, aragonite-type calcium carbonate was prepared by wet carbonation of SS, and the aragonite-rich SS (ASS) was pressed and moulded in the raw material of SS for semi-dry carbonation to obtain SS products. Through a series of experiments, the optimal conditions for the modulation and the formation mechanism of aragonite whiskers were investigated, and the effects of aragonite as a crystal seed on the properties and the degree of carbonation of SS products were also explored. In this experiment, the carbonation products were characterised microscopically by XRD, TGA, FT-IR and SEM, and the strength was tested by press machine. The results showed that aragonite phase was produced by wet carbonation of SS suspension containing 0.1M/L MgCl2 at 120 °C for 2h. The compressive strength, flexural strength, and secondary carbonation degree of the prepared SS products were increased when 5% ASS was added.

Application ICP-OES to Multielement Analysis on Plastic Waste and Blends with Vacuum Gas Oil: Developing a Sample Preparation Protocol

This paper introduces a new methodology for a routine metal analysis of plastic waste (PW) and PW blended with petroleum feedstock such as vacuum gas oil and VGO (PW/VGO). For such purposes, recycled polyethylene and polypropylene plastic were selected to mimic the potential feeds to be integrated at the Fluid Catalytic Cracking unit (FCC) to produce valuable products. Elements such as P, Ca, Al, Mg, Na, Zn, B, Fe, Ti, and Si were included in the method development. Different sample preparation methods were evaluated, such as microwave-assisted acid digestion (MWAD) and dry/wet ashing, followed by a fusion of the ash with lithium borate flux. Some PW homogenization pretreatments, such as cryogenic grinding and hot press molding, were also covered. The finding of this work suggests that MWAD with HNO3 and H2O2 is adequate for both types of samples and is the quickest sample preparation; however, the sample needed to be homogenized, and recoveries for Si and Ti may be biased for PW due to the limited solubilities of these elements in the nitric acid media. Carbon removal is required before fusion sample preparation and analysis due to the amount of carbon in PW samples. The sample needed to be homogenized for wet ash fusion but not for the pre-ash (dry) method. A benefit to the damp ash pretreatment is that the ash for the sample was created in the same crucible used for fusion digestion, avoiding material loss during sample management. Fusion from wet ash or carbon removal allowed for better acid solubility for Si and Ti in PW. The results of the PW samples evaluated matched well with those of both sample preparation methodologies. For most elements, precision was <10% regardless of the sample preparation; however, Fe and P had some variation using wet ash fusion, possibly due to contamination in an open digestion system or variation due to being close to the method limit of quantification (LOQ). The methodology reported here is robust enough to be implemented as routine analysis in any laboratory facility.

Polydopamine modified carbon fiber to improve the comprehensive properties of carbon paper for proton exchange membrane fuel cell

In this study, polydopamine (PDA) was used to modify functional groups on the surface of carbon fiber (CF), and the effects of different dopamine hydrochloride (DPH) concentrations on the surface morphology, functional groups, contact angle and dispersion stability of CF were studied. Subsequently, the raw carbon paper (RCP), hot-pressed carbon paper (HPCP) and carbon paper (CP) were prepared successively using the modified CF through wet forming, impregnation/hot-pressing, and carbonization methods. The surface morphology, tensile strength, flexural strength, electrical resistivity, air permeability and pore size distribution were analyzed for these materials. It was observed that the introduction of −OH and − NH2 groups improved the hydrophilicity and dispersion of PDA modified CFs, resulting in an increase in formation index (FI) from 39.2 to 48.1 for RCP samples. With increasing DPH concentration, the tensile strength of CP initially increased but then decreased while its electrical resistivity showed an opposite trend. Finally, PDA modified CP was assembled into proton exchange membrane fuel cells (PEMFC). The PEMFC assembled from DPH-CP-2.5 achieved a maximum limiting current density of 1440.0 mA/cm2 and power density of 458.25 mW/cm2. Meanwhile, the lower material transmission impedance for DPH-CP-2.5 as well as excellent water management ability and gas transmission performance.

Development and application of carbon dioxide direct mineralization technology and emission reduction device

Abstract This study analyzes the principles and methods of carbon dioxide mineralization fixation to address the challenges posed by global climate and ecological changes, achieve carbon neutrality goals, and solve carbon utilization issues in the development of the fluorosilicon new material industry. The research focuses on the direct mineralization reaction system of carbon dioxide flue gas and the development of a carbon dioxide emission reduction device utilizing wet mineralized gas treatment technology. To implement alkaline waste management for industrial solid waste. The research shows that the wet carbon dioxide mineralization and emission reduction device can make the alkaline solution better mineralize carbon dioxide, avoid the gas discharge too fast and affect the reaction rate. At the same time, the solution is mixed and the exhaust linkage is carried out to further improve the reaction rate, and provide a reference for the development of large-scale carbon dioxide utilization technology suitable for high energy consumption industries.

Preparation of aragonite-rich whisker materials from magnesium slag and salt lake bischofite and its effects on cement properties

This study develops an innovative wet carbonation process utilizing Magnesium Slag(MS), Salt Lake Bischofite (SLB), and CO2 to prepare carbonized materials mainly composed of aragonite and active silica gel, all raw materials were solid wastes. Subsequently, it was employed as Supplementary Cementitious Materials (SCMs) additive in cement, with the goal of efficiently capturing carbon dioxide and transforming aragonite whiskers into high-value products. Investigated the parameters influencing the formation of aragonite, including temperature and the concentration of the SLB solution, while exploring the nucleation and growth mechanisms of aragonite. The findings reveal that under 80 °C, the suspension of MS with 0.83 % SLB solution swiftly produces needle-like aragonite whiskers with single crystal lengths ranging from 10-20 μm and diameters of 0.3–0.5 μm. With the increase in SLB concentration, the aspect ratio of aragonite whiskers decreases. Additionally, highly polymerized amorphous silica gel was also detected. Therefore, Carbonated Aragonite-type Magnesium Slag (CAMS) (34.0901 m2/g) exhibits a significantly larger specific surface area compared to MS (0.9877 m2/g), representing an enhancement factor of 34.5 times, which concurrently bolsters its capability to adsorb reactive ions. During the carbonation process, 1 g of MS can sequester and solidify 0.403 g of CO2. Furthermore, incorporating CAMS as SCMs into cement mixtures notably enhances both the compressive and flexural strengths of cement mortar. These findings offer a sustainable approach to the recycling of solid waste, CO2 sequestration, and the improvement of cement-based material properties.

Experimental study on the macroscopic and microscopic properties of cement paste backfill after treatment with carbon dioxide carbonize filling slurries during the mixing process

Introducing CO2 during the mixing process of filling slurry for wet carbonation enables simultaneous carbonation and hydration reactions of the carbonated filling slurry (CSL). This study evaluates the microstructural evolution and strength development of carbonated cemented paste backfill (CCPB) under different carbonation times, and discusses the carbonation products and carbon sequestration of CCPB. The results reveal that introducing 99% pure CO2 at a flow rate of 1 L/min for 10 min into the filling slurry in a non-sealed container effectively optimizes the microscopic pore structure and mechanical properties of CCPB, achieving a carbon sequestration rate of 6.42%. Short-term carbonation leads to a continuous decrease in the T2 relaxation signal of CSL in the early hydration stage, enhancing pore structure by converting secondary pores to micropores. The main carbonation product is calcite crystalline CaCO3, which forms a dense carbonation layer on the surface of the tailings particles. However, prolonged carbonation results in the formation of microscopic pore encapsulation layer, hindering further CO2 diffusion, reducing carbonation efficiency, and deteriorating the mechanical properties of CCPB. With a carbonation time of 10 min, the UCS and EM of CCPB with different cement-to-tailings ratios show significant improvement, and the specimens exhibit lower fragmentation and fewer secondary cracks, maintaining better integrity after failure. In conclusion, the wet carbonation of filling slurry not only enhances the strength of the filling material but also achieves the reutilization of gaseous and solid wastes through carbon sequestration filling method, providing an efficient and eco-friendly solution for mine backfilling.

Analysis on temperature vacuum swing adsorption from wet flue gas carbon capture by using solid amine adsorbent with co-adsorption equilibrium models

Adsorption carbon capture has attracted extensive attention due to its low regeneration heat consumption, eco-friendly impacts and simplicity. However, there is a lack of comprehensive analysis of its energy consumption, economy and environment impact of adsorption carbon capture. This study aims to investigate the working performance using temperature vacuum swing adsorption (TVSA) from wet flue gas carbon capture utilizing co-adsorption equilibrium models for metal–organic framework (MOF) based amine materials. TVSA model is then carried out in terms of the continuous operational state, the dynamic changes in physical properties inside the bed, and the differences in properties at different positions within the bed layer. It is found that they often cannot simultaneously meet high CO2 recovery rates, productivity, and equivalent work. The analysis reveals that the optimal conditions, namely an adsorption temperature of 318 K and a CO2 component of 0.02 kmol during desorption, collectively result in reduced equivalent work and heightened productivity. The maximum productivity could reach 46.35 kg·m−3·h−1 for 5.6 v% water content and 308 K adsorption temperature. It is demonstrated that temperature vacuum swing adsorption for wet flue gas carbon capture using MOF based amine adsorbent is quite promising in terms of energy consumption and CO2 productivity in the future.

Wet carbonation of recycled cement paste powder using a CO2-loaded monoethanolamine solvent as an internal CO2 source

To address the challenge posed by the carbonation product layer formed on recycled cement paste powder (RCPP) on the efficiency and degree of carbonation, CO2-loaded monoethanolamine (MEA) “microcapsules” were used. The CO2 within MEA was released by heating after the formation of the dense carbonation products layer on RCPP to provide an additional internal CO2 source to penetrate into the uncarbonated layer. Results showed that using CO2 dissolved in 15 %, 30 %, and 45 % MEA aqueous solution increased the carbonation degree of RCPP by 10.8 %, 11.2 %, and 13.8 %, respectively, compared to RCPP wet carbonated in water. In addition to calcite, vaterite and aragonite were observed in the CO2-loaded MEA carbonated RCPP. The long-term compressive strength of cement pastes with 30 % CO2-loaded MEA carbonated RCPP increased, and the porosity decreased compared to cement paste with RCPP wet carbonated in water. However, MEA negatively affected the early compressive strength of the cement paste.

Activation technology of steel slag for concrete exposed to plateau climate: a state-of-the-art review.

As a byproduct of steelmaking, steel slag occupies significant land resources and poses potential environmental and safety challenges due to its extensive accumulation. Recently, steel slag has shown promising applications in the field of concrete. However, considering the complexity of the plateau environment, the utilization of steel slag is relatively lacking, and its low reactivity and poor volume stability remain the main factors restricting its application in plateau concrete. This paper reviews the research status of steel slag activation techniques for concrete, including wet grinding, chemi-excitation, high-temperature activation, and carbonation treatment. The effects of different treatment techniques on the mechanical and durability properties of concrete and the potential issues are discussed. Although different modification methods can improve the activity and volume stability of steel slag to varying degrees, a single modification technology is difficult to achieve the high-quality utilization of steel slag in concrete on the plateau. Based on this, a steel slag grading grinding-magnetic separation utilization technique suitable for high-altitude areas is proposed, which is beneficial for improving the added value and utilization rate of steel slag in concrete.

Improvement of crushed returned concrete aggregates by wet carbonation

A considerable quantity of pre-mixed concrete is returned from construction sites which is usually dumped directly into pits. While this concrete may possess lower quality attributes due to inadequate compaction and curing, the crushed hardened concrete can be potentially used to produce recycled aggregates. Carbonation is regarded as a significant way of improvement of recycled concrete aggregates. This study investigated the effectiveness of wet carbonation method for the improvement of crushed returned concrete aggregates (CRCA) to reuse in concrete productions. Recycled concrete aggregate (RCA) obtained from crushing of old conventionally cast concrete was also subjected to the same treatment, and its properties were compared with those of CRCA to understand the improvement in each type of recycled aggregate. The effectiveness of wet carbonation was evaluated by the aqueous chemistry during carbonation, development of microstructure, depth of calcium carbonate deposition, the mineralogy, water absorption, and compressive strength for both treated and untreated CRCA and RCA for different carbonation durations. The results showed that, although the water absorptions of both uncarbonated and carbonated CRCA were higher than those of RCA, the rate of reduction of water absorption of CRCA after carbonation was higher than that in RCA. Due to the long exposure to open environment, CRCA showed less initial alkalinity and conductivity than RCA but at the end of carbonation, both pH and conductivity were almost same as those of RCA. Wet carbonation successfully produced well shaped calcite in both CRCA and RCA where the deposition depth of calcite was higher in CRCA than in RCA. Mineralogical analysis showed higher calcium carbonate formation in CRCA indicating its potential of sequestrating more CO2 than by RCA. The improvement of concrete compressive strength was more pronounced for CRCA, with a 28 % enhancement observed after 2 hours of carbonation, compared to an 18 % enhancement for RCA. These findings demonstrated that wet carbonation can be regarded as an effective strategy for enhancing CRCA.

Application of wet carbon black masterbatch in green mining radial tires

AbstractIn the context of environmental protection and energy consumption reduction, reducing the rolling resistance of mining machinery tires is one of the important methods to achieve the goal of green mining. This study probes the effects of wet mixing with a wet carbon black masterbatch on the rolling resistance and grounding performance of wide‐body vehicle tire treads by investigating the cross‐linking structure, rubber–filler (R–F) interaction force, and physicomechanical properties of the wet mixing rubber compounded with a wet carbon black masterbatch. The results indicate decreases in the maximum torque‐minimum torque difference, cross‐link density, and R–F interaction of the wet mixing rubber and increased filler–filler (F–F) interaction and carbon black dispersion. Meanwhile, the tensile elongation of the wet mixing rubber increases, its DIN abrasion property improves, and its Tanδ decreases at 60°C. A numerical method to estimate tire steady‐state rolling resistance is also developed. Finite element simulation analysis reveals that the steady‐state rolling resistance of the wet mixing rubber is reduced by 7.04% at 100% standard load, and its grounding performance is enhanced. By proposing a method to reduce the rolling resistance of tires, this study also provides a reference for the development of wide‐body vehicle tires.Highlights Explored the filler interaction of wet mixing rubber. Explained the low energy loss of wet mixing rubber. Proposed a new finite element method for calculating tire rolling resistance.

Development of alternative for gypsum-based plaster using magnesium carbonates from carbon capture and utilization process

This study demonstrated the use of nesquehonite (MgCO3×3 H2O) in producing plasterboard. Nesquehonite (NQ) can be activated via thermal treatment under 50–175°C, after which the dehydrated nesquehonite can hydrate to form a plaster-like product, like gypsum-based plaster. Here, we developed different blends of NQ and hemihydrate (dehydrated gypsum) to produce plaster. In addition, the influence of trace elements (i.e., sulfate and ammonium) on the reaction kinetics, mechanical properties, microstructure, phase assemblage, and evolution of the developed plasters were investigated. The target was to achieve comparable manufacturing process and compressive strength with the conventional gypsum plaster process using NQ as a major precursor. Data revealed that the mixes containing 75 % NQ obtained from 2 different synthesis routes (i.e., wet carbonation or chemically-synthesis route) attained 6–8 MPa compressive strength after 28 days of curing, which was comparable to those observed in gypsum-based products. The chemically synthesized NQ achieved the stability of NQ in the plasterboard sample, while the use of wet-carbonated NQ led to the formation of dypingite. Furthermore, the water resistance of plasterboard mixes with 100 % NQ outperformed that of gypsum, without any decline in compressive strength after water exposure.

Effects of wet carbonation with ethanol solution on the mechanical, durability properties, and microstructure of recycled concrete aggregates and derived block products

The carbonation treatment of recycled concrete aggregates (RCA) can significantly enhance their properties and reusability. To improve carbonation efficiency, a wet cyclic carbonation method using ethanol solution was proposed to treat RCA and a wet carbon curing method was applied to its product, recycled blocks (RB). The results showed that wet carbonation with 30 % ethanol solution for 10 min significantly reduced RCA’s water absorption and crushing index and increased its apparent density. This is attributed to ethanol’s high carbon-solubilizing properties, which allow the RCA to generate more calcium carbonate precipitates to fill the voids and optimize the pore structure. When the concentration of ethanol solution was increased above 50 %, the improvement was inefficient and limited. In addition, the second cycle of wet carbonation can further improve the properties of RCA. Optimally processed RCA was used to make recycled masonry blocks. The 10 min wet carbonation curing proved beneficial to the mechanical properties of RB and also improved its resistance to shrinkage and salt freeze-thaw. This rapid method enhances RCA construction materials' performance and durability, improving industrial use in sustainable construction materials.

Mechanochemical carbonation of recycled concrete fines: Towards a high-efficiency recycling and CO2 sequestration

The relative slow carbonation efficiency for conventional wet and dry carbonation of recycled concrete fines (RCF) limits its resource industrial utilization. In this study, an innovative mechanochemical carbonation (MC) method was developed. The carbonation kinetics, phase assemblage and microstructure evolution of RCF during the MC process were extensively examined. The results exhibited a substantial enhancement in the carbonation efficiency and CO2 utilization rate, as evidenced by achieving a notable carbonation degree within 10 min. This accomplishment surpassed what could be achieved even after a prolonged 2 h period of wet carbonation, and the CO2 uptake capacity and utilization rate achieved via MC reached >0.3 g-CO2/g-RCF and 80 %, respectively. The superior performance of MC was ascribed to the influence of mechanochemical effects. These effects contributed to the refinement in the geometrical characteristics of RCF, exfoliation of the passivating layers, and facilitation of CO2 dissolution, which favored the structural disintegration of RCF and carbonation progress. Another distinctive aspect of MC treatment was the production of a greater proportion of metastable CC characterized by reduced crystalline size, which was attributed to modifications in the carbonation environment and the structural alterations induced by mechanochemical effects. Moreover, the precipitation of silica gels commenced at approximately 4 min in the MC process, a notably earlier onset when compared with wet carbonation; additionally, a greater abundance of silica gels was observed in the current MC procedure, resulting from the higher carbonation degree caused by mechanochemical effects. The encouraging conclusions in the present work validated the feasibility of producing carbonated RCF more efficiently and paved the way for future industrial practice.

Effect of wet grinding carbonation of sintering red mud on the performance of carbon sequestered mortar

The use of alkaline solid waste to CO2 capture is a potential way to upgrade the recycling of solid waste and reduce CO2 emission. In previous work, we proposed a novel wet grinding carbonation technique to achieve rapid carbonation of sintering red mud (SRM). Herein, the effect of wet grinding carbonation of SRM (WGCS) replacement rate (0 %, 5 %, 10 %, 15 %, 20 % and 25 %) on the hydration and hardening of Portland cement was further explored, such as rheology, compressive strength, hydration products and water transfer properties. The plastic viscosity and yield stress of carbon sequestered paste rose together with the WGCS replacement rate, which was due to the decreased D50 of SRM after wet grinding carbonation. When the WGCS replacement rate was 15 %, the 56 d compressive strength of carbon sequestered mortar was increased by 14.1 %. The microscopic characterization showed that the nucleation of calcite crystals and the pozzolanic reaction of silica-rich gels clearly improved the microstructure compactness. The electric flux and porosity of cement mortar was decreased by 25.7 % and 11.4 %, respectively. In terms of environmental and economic benefits, the CO2 sequestration of carbon sequestered mortar reached as high as 24.7 kg/m3 and the CO2 emission was reduced by 30.9 %.

In-situ wet carbonation of steel slag powder paste made with carbonated water: Interaction mechanism between carbonation and hydration

The utilization of steel slag powder is severely limited by its low activity. This study reveals that in-situ wet carbonation with carbonated water can significantly enhance its hydration activity. The influencing mechanism of carbonation on the hydration process and its kinetics during hydration are explored, and on this basis, the interaction between carbonation and hydration is discussed. It is found that both hydration and carbonation exhibit distinct characteristics before and after the acceleration stage. Before the acceleration stage, the hydration rate is affected by mineral dissolution rate, which is dependent on carbonation reaction, with carbonation rate determined by the CO2 concentration. After entering the acceleration stage, the hydration rate is promoted by the increased nucleation effect (e.g., nano-CaCO3 precipitation). The hydration in this period dominates carbonation by controlling mineral dissolution rate, with carbonation rate dependent on the mineral dissolution rate. As a result, mineral dissolution is shown to act as a bridge between hydration and carbonation interactions. Based on these results, the lack of further increase in hydration activity of steel slag powder with higher concentrations of carbonated water is also explained. This study provides a deep understanding for wet carbonation in steel slag powder paste.

Development of Ultra-High Performance Concrete (UHPC) matrix based on recycled concrete fines subjected to coupling curing of microwave and wet carbonation

The energy consumption of the wet carbonation method is increased by water bath heating, which is not conducive to the sustainable development of wet carbonation for Recycled Concrete Fines (RCF) treatment. In this study, a microwave wet carbonation method targeting low energy consumption and high carbonation rate is developed. Microwave heating is used instead of water bath heating to reduce the energy consumption of wet carbonation and prepare microwave carbonation recycled concrete fines (MCRCF). The results show that under the reaction condition of 80 °C, microwave reduces the activation energy of wet carbonation reaction through non-thermal effect and promotes the formation of aragonite and calcite grains. When preparing 50 g MCRCF and heating to 80 °C, microwave heating can reduce energy consumption by 26.6 %. At the same time, the CO2 absorption rates of microwave wet carbonation and pressured carbonation are 19.4 and 6.4 g/(min· kg), respectively. Therefore, microwave wet carbonation has stronger energy efficiency advantages. Additionally, the effect of MCRCF on the properties of UHPC matrix is studied. The results show that when the replacement rate of MCRCF is about 50 %, the 28d average compressive strength of the UHPC matrix increases slightly, and the development of the interface transition zone and the hydration process are promoted. This study provides a new idea for clean and efficient treatment method of RCF and verifies the feasibility of using microwaves for wet carbonation.

CO2 sequestration by wet carbonated magnesium slag with high-content aragonite whiskers for improving cement performance as underground filling material

Magnesium slag (MS) is an alkaline waste residue from magnesium smelting processes. This study aimed to utilize the magnesium oxide in MS and adopt MgCl2 as the calcium carbonate crystal modifier to prepare high length-to-diameter ratio aragonite whiskers via wet carbonation, which can achieve high-value recovery of MS while capturing CO2 and enhancing cement as underground filling material. The effects of MgCl2 concentration on the carbonation process, composition, microstructure, and morphology were systematically investigated. With increasing MgCl2 concentration, more aragonite was obtained, reaching 94.9 % at 0.5 M MgCl2. Notably, at 0.1 M MgCl2, high length-to-diameter ratio aragonite whiskers with 16 were achieved. Introducing 1 wt% MS carbonated at optimal 0.1 M MgCl2 into cement increased the 3 d and 28 d compressive strengths by 17.8 % and 22 %, respectively. Moreover, an excellent CO2 sequestration capacity of up to 20.33 g CO2 per 100 g MS was obtained for the carbonated MS. Therefore, wet carbonated MS with high content aragonite whiskers is a promising method for MS high-value utilization while reducing cement usage and CO2 emission, as well as improving cement performance as underground filling material.

The reversal of carbonate wettability via alumina nanofluids: Implications for hydrogen geological storage

Underground hydrogen storage (UHS) has been recognized as a key enabler of the industrial-scale implementation of a hydrogen-based economy. However, the efficiency and storage capacity of hydrogen (H2) in carbonate aquifers can be influenced by the presence of organic acids. Nevertheless, the existing literature contains few investigations of H2/calcite/brine wettability and the influence of organic acids on H2 storability in carbonate reservoirs. Therefore, the present study examines the influence of stearic acid on the dynamic H2/brine wettability of calcite substrates (as a proxy of carbonate formation) under various geological conditions (0.1–20 MPa at 323 K), equilibrated in 10 wt% NaCl brine. In addition, the application of various alumina nanofluid concentrations (0.05, 0.1, 0.25, and 0.75 wt%) is evaluated under the same experimental conditions for enhancing the organic-aged calcite wettability. The results demonstrate a significant impact of stearic acid on the dynamic (advancing and receding) contact angles of the calcite substrates, thereby resulting in a shift from intermediate water-wet to H2-wet conditions, representing an unfavorable state for H2 geological storage. Conversely, the application of alumina nanofluid on the organic-aged calcite substrate enhances the H2/brine/calcite wettability towards an intermediate water-wet state, which is more favorable for H2 residual trapping in carbonate formations. The optimal concentration of alumina nanofluid for the wettability modification of the organically aged calcite samples is found to be 0.25 wt%. These findings highlight the influence of organic acid contamination and the potential of alumina nanofluid application in enhancing H2 geo-storage conditions in carbonate reservoirs.

Lightweight concrete with low-carbon artificial aggregates recycled from biomass ash and slurry waste

The development of artificial aggregates (AAs) significantly reduces carbon emissions of concrete production since the aggregates account for about 70% volume of all concrete ingredients. Therefore, a type of low-carbon AAs was prepared with full solid wastes of biomass ash (BA) and slurry waste (SW) through a pelletizing technique and carbonation curing methods. This study focused on evaluating the feasibility of AAs produced by the synergistic effect of BA and SW; identifying and optimizing the pelletization parameters through the response surface methodology (RSM) with experimental tests; analyzing the effects of blending amounts of BA on the properties of AAs; discussing the improvement of carbonation curing methods for AAs production; assessing the properties of the prepared lightweight concrete (LWC) with AAs. The results indicate the addition of 20 wt% BA lightened the bulk density of AAs by about 13% but weakened strength by nearly half due to its porous characteristics. The appropriate incorporation of 5 wt% BA could improve the individual pellet and cylinder compressive strength by about 2% and 16%, respectively. AAs cured in pressurized carbonation of 3 d and wet carbonation of 10 min demonstrated similar enhancement effects. Pressurized and wet carbonation curing showed respective superiorities in terms of improving effect and curing efficiency. The effects of inclination angle and moisture content on the average particle size are more significant than those of rotation speed, while rotational speed has a dominant effect on the bulk density. RSM simulations identified the optimal inclination angle, rotation speed, and moisture content as 45°, 38.5 r/min, and 37.5%, respectively. The LC40 high-strength LWC can be prepared by using full substitution pre-wetting AAs.