Dissolution Characteristics Research Articles

Effect of mechanical activation on hydration properties of natural volcanic rock towards partially replacing cement in composite cementitious materials

With the rapid increase in the consumption of various mineral admixtures, using regional distinctive raw materials to prepare cement mineral admixtures is an effective approach to achieve green and sustainable development. In this paper, the natural volcanic rocks (NVR) in Western Sichuan are mechanically activated at different times, subsequently, the ion dissolution characteristics of NVR powder at different activation times and the hydration mechanism of NVR powder composite cementitious material are studied. In a simulated alkaline environment of cementitious liquid phase, based on the dissolution behavior of Si4+, Al3+, and Ca2+ ions in NVR powder and the morphological analysis of NVR powder before and after dissolution, it is indicated that SiO2 and Al2O3 are the primary sources of reactivity in NVR powder and the reduction in particle size promotes the breakage of Si–O and Al–O bonds in NVR powder. Analysis of the hydration process, mineral composition of hydration products, and their microscopic morphology reveals that an appropriate amount (15 %) of NVR powder, after 45 min of mechanical activation, can promote the generation of hydration products and denser mortar structure, enhancing the strength of the composite cementitious material. Mainly attributed to the increased volcanic ash activity of NVR powder through mechanical activation, as well as the nucleation induction and filling effects of NVR powder. This study provides theoretical and technical supports for the efficient use of raw materials with regional characteristics to prepare mineral admixtures.

Dissolution characteristics of TiC0.3N0.7 in low-carbon and safe blast furnace hearth

Investigating the presence of a Ti(C,N) protective layer in molten iron is of great significance for achieving low carbon and safe production in blast furnaces. This study focuses on analyzing the high temperature dissolution experiment of TiC0.3N0.7 in molten iron to elucidate the kinetics and mechanisms involved, as well as strategies for regulating its dissolution. The results reveal that the dissolution reaction of TiC0.3N0.7 is predominantly influenced by the temperature and flow speed of the molten iron. The dissolution process can be categorized into two stages: dissolution reaction and physical penetration. Diffusion mass transfer is the dominant factor controlling the dissolution of TiC0.3N0.7, with an apparent activation energy of 60.15 kJ/mol. Upon contact with molten iron, dendritic penetration of TiC0.3N0.7 particles occurs, starting from the edges. To enhance the stable presence of TiC0.3N0.7, recommendations include reinforcing furnace cylinder cooling, reducing the heat transfer coefficient of the blast furnace hearth's resistant material, increasing the carbon content of the molten iron, and decreasing the sulfur content of the molten iron.

Quasi-in-Situ Analysis of Electropolished Additively Manufactured Stainless Steel Surfaces

Progress in additive manufacturing is leading to the emergence of new areas of application. Laser Powder Bed Fusion (L-PBF) is increasingly used for the development of metallic medical implants, but for high-risk implants like vascular support structures (stents), surface quality is critical to ensure successful implantation without harming the surrounding tissue and ensure the patients’ health. Therefore, enhancing the surface quality is crucial. Electropolishing is a method for removing surface roughness by smoothing out micro-peaks and valleys. However, L-PBF structures have a high surface roughness due to metal particles adhering on the surface. To achieve a smooth surface for additively manufactured implants like stents using electropolishing, the removal of these particles needs to be studied in more detail.The objective of this study is to examine the electropolishing mechanism of 316L stainless steel samples additively manufactured through Laser Powder Bed Fusion (L-PBF). The main objective is to investigate the removal properties and surface characteristics during electropolishing. To achieve this, various surfaces were characterized for morphology and roughness during Hull cell experiments. Markings are utilized on the Hull cell sample surfaces to identify points of interest during quasi-in-situ measurements. The surfaces are then analyzed after multiple time steps, applying different currents to investigate particle dissolution. The surface characteristics are analyzed through scanning electron microscopy, and surface roughness is analyzed using laser scanning microscopy.The results show that the electropolishing process preferentially removes the adhering particles present on the surface of the samples. Increasing the current density results in faster particle dissolution and a smoother surface (see Figure 1a and b). The mechanism of material removal of various surface features, as shown in Figure 1 (red circle, yellow arrow and red square), was assessed based on the experimental results of the surface structures seen on the SEM images. It was found that different surface features were removed during the experiment at different polishing times and current densities. The amount of charge flowed was found to correlate with surface morphology.Based on the obtained results, various surface features (such as large adherent particles, agglomerates of smaller particles, and valleys) and their changes with increasing test duration and current density were observed by quasi-in situ analyses. A reduction in the diameter of round particles adhering to the surface was observed at both low and higher current densities (see Figure 1a red circle a). Increasing the polishing time resulted in leveling of both large particles and valleys (see Figure 1b red square). Also, dissolution of agglomerates of smaller particles occurred at different polishing times as a function of current density and polishing time (see Figure 1a yellow arrow) are observed.Smoothed surface structures can be observed in regions with equivalent surface charge density (see Figure 2). As a result, comparable surface morphologies may appear at the same area charge density, irrespective of a specific current density. So, it may be adequate to only consider the amount of charge flowed to describe the electropolishing of additive materials.In conclusion, comprehending the dissolution characteristics of particles on L-PBF surfaces is essential for attaining satisfactory surface finish in electropolishing. The results of this study offer valuable perspectives into the electropolishing mechanism of additively manufactured 316L stainless steel and can guide future investigations on surface finishing and polishing of additive manufactured implants like stents. Figure 1

Jet milling improves the polyphenol dissolution profile and biological activities of the hemp seed shell

The study aimed to investigate the impact of jet milling on the dissolution characteristics of hemp seed phenolic compounds. Three HSSP were prepared through grinding and sieving, while a superfine powder was obtained via jet milling. The superfine powder exhibited improved physicochemical properties, including a higher specific surface area, better dispersion, and wettability. These properties facilitated the penetration of solvents into the powder's structure, resulting in an optimal polyphenol dissolution profile and enhanced antioxidant activity. Furthermore, the polyphenol extract demonstrated significant protective effects against oxidative stress-induced damage in HUVEC cells, suggesting potential applications in the food and medicine industries. Overall, the study highlights the promising use of jet milling for producing powders with improved physicochemical and biological properties.

Separable and Inseparable Silk Fibroin Microneedles for the Transdermal Delivery of Colchicine: Development, Characterization, and Comparisons.

Colchicine is the first-line option for both the treatment and prophylaxis of gout flares. However, due to potentially severe side effects, the clinical use of colchicine is limited. A well-tolerated and safe delivery system for colchicine is widely desired. For this purpose, colchicine-loaded inseparable microneedles were fabricated using silk fibroin. Additionally, separable microneedles made of silk fibroin as the needle tips and PVP K30 as the base material were developed. Both types of microneedles were evaluated for their mechanical strength, swelling and dissolution characteristics, insertion abilities, degradation properties, in vitro penetration, skin irritation, and in vivo anti-gout effects. The results demonstrated that separable microneedles had greater mechanical strength and insertion ability. Moreover, the separable microneedles separated quickly and caused little skin irritation. In the pharmacodynamic test, mice with acute gouty arthritis responded significantly to treatment with separable microneedles. In conclusion, the separable silk fibroin-based microneedles provide a promising route for colchicine delivery.

In situ construction of 3D Li channels high-temperature-resistant polymer electrolyte and Li3N-rich interface enabling stable solid-state Li metal battery

High safety, high ion conductivity, and stable interface contacts are of significant importance for the application of solid-state electrolytes (SSEs) in solid-state lithium metal batteries (SSLMBs). In this study, SSEs with high ion conductivity and safety were constructed by in-situ polymerization of poly butyl acrylate (PBA) based electrolytes in the three-dimensional (3D) pores of a polyvinylidene fluoride (PVDF) nanofiber membrane, and embedded with ion conductor succinonitrile (SN), fluorinated ethylene carbonate (FEC), and imidazolium-based ionic liquid (IL). The test results and microscopic structural analysis indicate that SN is uniformly dispersed in PVDF, effectively reducing the crystallinity of solid polymer electrolytes (SPEs) and constructing a 3D interconnected lithium-ion conduction network. Consequently, an ion conductivity of 4.89 mS cm−1 was achieved at 25°C. Meanwhile, density functional theory (DFT) calculations demonstrated that imidazolium-based ionic liquid can adjust the dissolution characteristics of Li+ through weak interactions with the polymer framework and strong coordination with TFSI-. X-ray photoelectron spectroscopy (XPS) characterization revealed that the imidazolium-based ionic liquid can form a stable solid electrolyte interface enriched with Li3N on the lithium-metal surface. The resulting SPEs demonstrated excellent ion conductivity, a high Li+ transfer number (tLi+ = 0.739), and a nanofiber-reinforced interpenetrating framework with a tensile strength of 17.15 MPa. Furthermore, the LiFePO4 (LFP)||Li battery equipped with PBA-PVDF-SN (modified with IL) exhibited excellent electrochemical performance at room temperature with a capacity retention of 87.4 % after 800 cycles at 0.5C.

Anodic Dissolution Behavior of Al Alloys Containing Al6Fe or β-AlFeSi in EmImCl–AlCl3 Electrolyte During Electrorefining

To produce over 99.9% of high-purity Al from Al alloys containing Al6Fe or β-AlFeSi through electrorefining, their anodic dissolution and cathodic electrodeposition characteristics should be clarified. In this study, the anodic dissolution and cathodic electrodeposition behavior of Al–Fe binary and Al–Fe–Si ternary alloys were investigated in an EmImCl–AlCl3 ionic liquid electrolyte at 323 K. Anodic polarization measurements, constant potential electrolysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), field-emission SEM (FE-SEM), and energy dispersive spectroscopy (EDS) were used to study the anode and electrodeposits on the cathode. Constant potential electrolysis showed that Fe dissolved from Al6Fe in the Al–Fe anode at 0.7 V vs Al/Al(III) and from β-AlFeSi in the Al–Fe–Si anode at 1.4 V and was co-deposited with Al on the cathode. Notably, Si did not dissolve from β-AlFeSi at either potential. A combination of controlled anodic dissolution potential and the use of the Al alloy containing β-AlFeSi further suppressed the dissolution and cathodic co-deposition of Fe, affording high-purity Al on the cathode. This suggests that Al alloys with intermetallic compounds that are less likely to dissolve Fe at the anode are optimal for obtaining over 99.9% of high-purity Al from Al alloys containing Fe in the electrorefining method.

AG1®, a Novel Synbiotic, Demonstrates Superior Mineral Bioaccessibility and Bioavailability Compared to a Tablet Multivitamin and Mineral Supplement Using an In Vitro Model of the Upper Gastrointestinal Tract

While traditional multivitamin and mineral (MVM) supplements generally come in tablet form, new powder forms of MVM supplements are available with theoretically higher bioavailability relative to tablet MVM supplements. The purpose of this study was to assess the bioaccessibility and bioavailability of minerals (magnesium (Mg), zinc (Zn), calcium (Ca), and potassium (K)) in a tablet MVM supplement compared to a novel powder Foundational Nutrition supplement (AG1®), containing minerals, vitamins, phytochemicals, and pre-/probiotics, in the upper gastrointestinal tract. The tablet MVM supplement was specifically formulated for this study, with matched mineral contents and identical chemical structures. The adapted Simulator of the Human Intestinal Microbial Ecosystem (SHIME®) model was used to assess the bioaccessibility and bioavailability of soluble minerals using a simulated upper gastrointestinal tract and dialysis membrane to mimic human digestion and absorption. The bioaccessibility was assessed at the end of the stomach and duodenum. The bioaccessibility and bioavailability were assessed at 1, 2, and 3 h following dialysis. The preliminary soluble mineral analysis of the tablet (crushed to a powder) and AG1 powder demonstrated significantly higher (p < 0.05) soluble fractions of Zn and Ca, but lower Mg in the AG1 powder vs. the tablet. The total soluble mineral percentages at the stomach and duodenum end were all significantly higher for the AG1 powder vs. the tablet (p < 0.05). Mg, Ca, and Zn were more (p < 0.05) bioaccessible and bioavailable in the powder compared to the tablet during the small intestine simulation. The bioaccessible fraction of K was higher (p < 0.05) only at 3 h for the tablet vs. the powder. These preclinical data demonstrate that the AG1 powder has superior dissolution and disintegration characteristics compared to the tablet, leading to increased bioaccessibility and bioavailability in vitro.

Development of Slow-Releasing Tablets Combined with Persulfate and Ferrous Iron for In Situ Chemical Oxidation in Trichloroethylene-Contaminated Aquifers

Slow-releasing tablets combined with persulfate acting as an oxidant and ferrous iron acting as an activator were manufactured for in situ chemical oxidation. The trichloroethylene (TCE) removal efficiency according to the molar ratio of the oxidizer and activator in the 0, 0.5, 1, 1.5, 2, and 2.5 molar ratio (persulfate: ferrous iron) reactors were 15%, 89%, 90%, 82%, 71%, and 55%, respectively. In a batch reactor injected with an oxidation-activation combined tablet (OACT) and a liquid oxidizing/activator, the TCE removal efficiencies were 100% and 70%, respectively, showing that the tablet form had a high efficiency in contaminant removal. The evaluation of the dissolution characteristics and TCE removal efficiency of OACT 0.5 (tablet with a 1:0.5 molar ratio of persulfate to activator) and OACT 1.0 (tablet with a 1:1 molar ratio of persulfate to activator) under continuous flow conditions showed that the TCE removal efficiency of the OACT 1.0 column was approximately 1.4 times higher than that of OACT 0.5. The longevities of persulfate and ferrous iron of the OACT 1.0 tablet were 43.2 days and 41.7 days, respectively. Thus, OACT 1.0, which was manufactured effectively, was suitable for in situ slow-release chemical oxidation systems.

Study on anodic dissolution behavior and surface evolution of laser-drilled Ni-based superalloys during electrochemical post-processing

Laser drilling is always accompanied by recast layers, micro-cracks, and heat-affected zones, which limit its application in engineering. Due to its unique advantages, such as no heat-affected zones, no residual stresses, and no dependence on the mechanical properties of the materials, electrochemical dissolution has been adopted to remove the laser drilling-induced surface defects. The electrochemical dissolution characteristics and surface evolution of the laser-drilled Ni-based superalloys were studied. The polarization curves and electrochemical impedance spectroscopy (EIS) of the laser-drilled materials and the substrate were measured, indicating that the laser-drilled surface had a smaller corrosion resistance than the original substrate. X-ray photoelectron spectroscopy (XPS) results showed that the laser-drilled surface had a much higher oxygen content than the substrate. Additionally, electric current efficiency curves were obtained to study the anodic dissolution behavior of Ni-based superalloys. An electric current density in the 5–40 A/cm2 range was preferred to enhance the electrochemical dissolution rate. Moreover, the effects of electric current densities and post-processing time on the surface roughness and the recast layer thickness of the laser-processed Ni-based superalloys were investigated using a NaCl and NaNO3 solution electrolyte. The evolution of the surface quality and recast layer thickness were clarified. Furthermore, an anodic dissolution model of the laser-processed surface was established to illustrate the electrochemical post-processing mechanisms. Results revealed that electrochemical dissolution could completely remove the laser drilling-induced surface defects in 20 s using a 12.5 wt.% NaNO3 solution electrolyte and a 40 A/cm2 electric current density. Finally, an electrochemical post-processed surface with surface roughness (Ra) of 1.7 µm and without a recast layer was achieved. Micro holes without recast layers and Ra of 0.69 µm were obtained with high efficiency using laser processing and electrochemical post-processing.

Sensitization of polymethacrylate resist with adding acid-generating promoters upon exposure to EUV light

With the advancement of EUV lithography, the development of higher performance resist materials has been required. Recently, the EUV sensitivity of chemically amplified resists has been improved by adding an acid-generating promoter (AGP) such as DTS (p-tolyl diphenyl sulfone). However, the details of the mechanism of sensitivity enhancement were still unclear. In this study, we investigated the EUV sensitivity, dissolution characteristics during development after EUV irradiation, and patterning characteristics by electron beam lithography with the addition of AGP to the acrylate polymers. The addition of DTS showed an increase in sensitivity with DTS concentration. We also discuss other than the increase in initial acid yield that lead to enhanced sensitivity by addition of DTS.

Molecular dynamics study on the dissolution characteristics and cluster formation of Li2CO3 in supercritical water

Recycling lithium from electronic waste is the focus of current research on waste treatment and resource utilization, and environmentally friendly supercritical water technology is an important recycling method. It is necessary to study the dissolution and precipitation characteristics of lithium salt in supercritical water. In this paper, molecular dynamics (MD) and quantum mechanics (QM) were used to study the dissolution properties of Li2CO3 in supercritical water and the structure and properties of clusters. The potential mean force (PMF), radial distribution function (RDF), and coordination number (CN) showed that the solubility of Li2CO3 in supercritical water was more affected by temperature, and the trend was opposite to that of temperature, and the ion pairs in solution were mostly in CIP state. Cluster searches were performed for the cluster configurations and their distribution probabilities of CIP states in supercritical water. The electrostatic potential distribution and intermolecular interactions of the initial cluster configuration in the supercritical solution of Li2CO3 are calculated by the QM method. In this study, the cluster configuration with a planar symmetry structure accounted for the largest proportion, and the lowest free energy was −431.86308400 a.u.

Numerical study on dissolution characteristics of solid-phase oxygen control in liquid LBE systems based on the porous media model

For the proper design and operation of lead oxide mass exchanger (PbO MX), the dissolution kinetics of PbO in flowing liquid Lead-bismuth eutectic (LBE) needs to be determined. A computational fluid dynamics (CFD) method of the PbO MX was established. The solid-phase oxygen control part of the MX is PbO spheres packed bed, which is regarded as a porous media in the simulation calculation. The oxygen mass transfer process between PbO spheres packed bed and liquid LBE was simulated by a porous media model with the species transport model. The relationship between the dissolution rate of MX and the flow rate, temperature and initial oxygen concentration is predicted. The dissolution rate of PbO increases exponentially with increasing temperature of LBE. Besides, the dissolution rate of oxygen is positively correlated with the LBE flow velocity. In the specific oxygen concentration range, the MX inlet oxygen concentration has little effect on the dissolution rate. The smaller the porosity of PbO spheres packed bed has, the smaller the dissolution rate of oxygen is. Furthermore, when the porosity is constant, the dissolution rate of oxygen increases with the increase of the height of the packed bed of PbO spheres.

Solubility, thermodynamic investigation and molecular dynamics simulation of guanidine hydrochloride in four binary solvents

Solubilities of guanidine hydrochloride (GuHCl) in organic solvents are of great importance for its development and optimization of industrial process. The study of the dissolution characteristics of GuHCl in DMF/2-meoxyethanol/methanol/NMP + n-propanol at different temperatures were experimentally investigated by using laser monitoring method. Results showed that GuHCl solubilities were observed to be increasing with the increment in experimental temperature and rising with higher mass fraction of DMF/2-meoxyethanol/methanol/NMP. Molecular dynamics (MD) simulation technique was utilized to reveal the microscopic behaviors of GuHCl and solvent mixtures and its effect on the dissolving capability of GuHCl in involved solvent systems. Also, five thermodynamic models were selected to regress the observed GuHCl equilibrium solubility. A comparison of the experimental values with corresponding estimated data indicated that the modified Apelblat equation provided the most excellent correlation in modelling GuHCl solubility. Finally, through the analyses of enthalpy change, entropy change and Gibbs free energy change, the dissolution thermodynamic features were evaluated.

Single-tablet-scale direct-compression: An on-demand manufacturing route for personalized tablets

Today’s pharmaceutical industry is facing various challenges. Two of them are issues with supply chain security and the increasing demand for personalized medicine. Both can be addressed by increasing flexibility and a more decentralized approach to pharmaceutical manufacturing. In this study, we present a setup that provides flexibility in terms of supplied raw materials and the product, i.e., a direct-compression setup for personalized tablets operating at a single-tablet-scale. The performance of the implemented single-tablet-scale technology for dosing and mixing was investigated. In addition, an analysis of the critical quality attributes (CQAs) of immediate release ibuprofen and loratadine tablets was performed. The developed dosing device achieved acceptance rates of > 90 % for doses ≥ 20 mg for various pharmaceutical powders. Regarding the vibratory mixing process, a dependency of the performance on the applied frequencies and acceleration was observed, with 100 Hz and ∼ 90 G performing best, yet still exhibiting varying mixing efficacies depending on the granular system. The tablets produced met U.S. Pharmacopeia requirements regarding mechanical stability and dissolution characteristics. Given these results, we consider the developed setup a proof of concept of a tool to provide personalized tablets to patients while minimizing the dependency on complex supply chains.

Preparation and Characterization of Bilastine Solid Self-Nanoemulsion using Liquisolid Technique

Background: Supersaturable self-nanoemulsion (S-SNE) is an approach for dealing with low oral bioavailability problems. Bilastine (BL) is a selective H1-antihistamine with a bioavailability of 59%. Objective: To use a liquisolid technique to transform liquid BL S-SNE into powder so that both the S-SNE and liquisolid procedures could be used. Methods: Oleic acid, tween 60, transcutol, and soluplus were used to make the liquid BL-loaded S-SNE that was adsorbed onto the Avicel PH101 and Aerosil 200 admixtures. In vitro dissolution and powder flow characteristics were tested. SEM, DSC, X-ray diffraction, FT-IR analysis, and the average droplet size after dispersion in 0.1N HCl were also utilized to define the best formula's solid state. Results: The best liquid-solid composition, SS-F2, is composed of oleic acid, tween 60, transcutol, soluplus, Avicel 101, and Aerosil 200, with a liquid SNE to Avicel 101 ratio of 1.5:1 and an Avicel 200 to Aerosil 200 ratio of 10:1. SS-F2 displayed good flowability and a significant improvement in drug dissolution, with 100% of the medication released after 60 min compared to 62.27% of the marketed BL tablets. According to the solid-state investigation of formula (SS-F2), BL was shown to be in a solvated state in the solidified nanosystem, with no interactions with the excipient used. It also formed a nanoemulsion with mean droplet sizes of 77.57 nm and a PDI of 0.4178, which was similar to liquid S-SNE. Conclusion: The liquisolid technique is a potential method for solidifying a liquid self-emulsifying system while preserving self-nanoemulsion characteristics and increasing dissolving rate.

A novel method to improve the morphology of Bi2212 film by PVA-assisted Pechini sol-gel method

Bi2212 high-temperature superconducting thin films (HTSFs) have emerged as the most promising material for terahertz (THz) devices due to their intrinsic Josephson effect. Enhancing the surface smoothness of these films is crucial for their practical application. In this study, metal nitrates were utilized as the raw material to prepare Bi2212 HTSFs on SrTiO3 (100) substrates using the Pechini sol-gel method. The chelating agent ethylenediamine tetraacetic acid (EDTA) and the surfactant polyvinyl alcohol (PVA) were employed to improve the dissolution characteristics of Bi2212 solution. The influence of various parameters such as sintering temperatures, surfactant concentrations, and metal ion ratios was systematically investigated to assess the phase purity, crystallinity, surface morphology, and electrical properties of the Bi2212 superconducting thin films. The results demonstrated that a higher concentration of PVA led to reduced solubility of the Bi2212 solution. Notably, when the PVA concentration was set at 1 %, the fabricated Bi2212 thin film exhibited exceptional epitaxial properties, enhanced Bi2212 phase purity, reduced surface roughness, and higher Tc. These outcomes provide valuable insights for the development of Bi2212 HTSFs in superconducting devices, as they serve as a reference point for achieving optimal film characteristics.

Elemental dissolution characteristics of granite and gabbro under high-temperature water-rock interactions

In the process of developing hot dry rock (HDR) through enhanced geothermal systems (EGS), it is necessary to inject circulating water to complete thermal energy extraction. However, the injected water will react with the high-temperature rock and produce mineral dissolution, which can destroy the artificial reservoir and affect the development of geothermal energy. To explore the influence of temperature on the solution composition and mineral dissolution after water-rock reaction, this study conducted water-rock interaction experiments on gabbro and granite at different heat treatment temperatures. Subsequently, the changes of solution composition and mineral dissolution with temperature after the reaction were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and XRD. The results demonstrated that Si, Na, Ca, K, Al, and Mg did not enter the aqueous solution at the same dissolution rate. Si was the primary solute in the solution, mainly resulting from the dissolution of quartz, and the dissolution rates of metallic elements were lower. In the granite-water interaction system, metallic elements such as Na, K, Ca, and Al showed a tendency to enter the solution at low temperatures, i.e., 150–180 °C, and the dissolution rate of Si reached its peak when the water was close to the supercritical state. With the increase in temperature, the dissolution rates of Si and metallic elements showed an initial increasing trend followed by a decrease. When water is in the subcritical to the supercritical state, abrupt fluctuations in the physical properties of water can strongly affect the dissolution of minerals or rocks. The results of this study provide insights into rock corrosion fatigue and mineral scaling in EGS water environment.

Microfluidic investigation on asphaltene interfaces attempts to carbon sequestration and leakage: Oil-CO2 phase interaction characteristics at ultrahigh temperature and pressure

CO2 huff-n-puff is a potential approach to improve the oil displacement efficiency in the deep reservoirs, which can achieve carbon sequestration and efficient oil production, simultaneously. However, the fundamental understanding of carbon mass transport, sequestration and leakage mechanism in deep geological reservoirs at the microscopic pore scale is still ambiguous. In this work, we innovatively designed a precise CO2 huff-n-puff microfluidic experiment under ultrahigh temperature and pressure conditions (55 MPa, 115 °C) to study the microscopic mechanism of CO2 utilization, storage and leakage (CUSL) in pore scale. Moreover, we proposed the quantitative analysis method for oil-CO2 interaction behavior to explicit dissolution and extraction characteristics, pressure threshold and interface stability by introducing Pseudo-Color algorithm and relevant parameters such as dynamic oil swelling factor, contact angle and gray value. Then, the pore-scale dynamics of the fluid interaction mechanism during the soak and puff process were quantitatively characterized, corresponding to the carbon sequestration efficiency of crude oil continuously exposed to scCO2 and the leakage risk with step-down production, respectively. The experimental results indicate that during the huff process, the oil-CO2 phase behavior characteristics at 115 °C can be divided into swelling, immiscible extraction and miscible extraction regions, which are coordinately controlled by dissolution mechanism, capillary effect and vaporization mechanism. Moreover, ultrahigh temperature oil generally requires higher pressure to start extraction and miscibility (Pext = 6.38 and 15.96 MPa, MMP = 9.71 and 23.73 MPa, T = 50 and 115 °C, respectively), while the asphaltene precipitation pressure Pasp is lower. At ultrahigh temperatures, the oil-CO2 interaction also enters the contact angle fluctuation region in advance, and the morphology of asphaltene particles is single, fine and uniform. When the soaking time is 36 min, the non-extractable oil component gradually evolves into a carbon sequestration interface. During the subsequent puff process, the more stable the carbon sequestration interface in the smaller blind end, the lower the leakage risk, corresponding to the leakage pressure difference of up to 40.93 MPa. This work has important practical significance for deep resource extraction and CUSL industrial application.

Synergistic effect and mechanism of lithium slag on mechanical properties and microstructure of steel slag-cement system

Replacement of cement with solid waste is an important method for conserving natural resources and reducing CO2 emissions. In this study, steel slag and lithium slag were used to replace cement to address the low activity of steel slag, which limits its large-scale utilization. The compressive strength, flow properties, dissolution characteristics, hydration products, and microstructure of composite cementitious materials containing steel slag and lithium slag were investigated by ICP-OES, XRD, TG, FTIR, SEM and MIP. The results showed that the addition of lithium slag into the cementitious material with steel slag improved the compressive strength. The lithium slag consumed a large amount of portlandite and promoted hydration of the steel slag to produce more C-(A)-S-H. Furthermore, the porosity and pore size distribution were optimized, the most probable pore size was reduced, and the pore complexity was increased. This research provides a solution for comprehensive use of steel slag, which contributes to high-value green utilization of solid waste.