Cementation Process Research Articles

Hydrometallurgical Method for AgCu Alloy Powder Synthesis and Its Application in Pd(II) Recovery Through Cementation

This study investigates the synthesis, characterization, and potential applications of silver–copper (AgCu) alloy powders produced from co-precipitated carbonates. The Cu/Ag carbonate samples were analyzed using EDXRF, TGA-DSC, XRD, SEM, and electrical conductivity tests to examine their composition, thermal behavior, structure, and morphology. The results showed slight deviations from the theoretical Cu/Ag ratios in the carbonates, attributed to equilibrium effects during precipitation. Thermal analysis indicated that the reduction process of carbonates with hydrogen was completed at 300 °C, while alloy formation was confirmed by endothermic peaks around 780 °C. XRD and SEM analyses revealed that AgCu alloys formed a solid solution, with smaller crystallite sizes observed at higher Cu contents. Electrical conductivity tests demonstrated that while pure Ag and Cu powders exhibited conductivity increases with compaction, the AgCu alloy showed stable conductivity without a significant decrease. In Pd(II) cementation experiments, AgCu alloys demonstrated higher efficiency in Pd(II) recovery than pure Ag and Cu. These findings suggest that AgCu alloys, particularly with a balanced composition, may offer improved performance for metal recovery applications, providing a promising approach for industrial cementation processes.

Microleakage of luting cements in CAD/CAM pediatric zirconia crowns: an in vitro study

The durability of pediatric zirconia crowns for primary teeth is influenced by the choice of luting cement, with the effectiveness of the cement being directly correlated to its ability to reduce microleakage. This in vitro study aimed to assess and compare the microleakage of custom-made zirconia crowns (CZCs) and prefabricated zirconia crowns (PZCs) on primary maxillary incisors when luted with self-adhesive resin cement, resin-modified glass ionomer cement (RMGIC), and bioactive cement. Sixty primary maxillary incisors were prepared and allocated into two groups, each corresponding to the two types of crowns. These groups were further divided into three subgroups each to test the different luting cements. Following the cementation process and thermocycling, the specimens were immersed in a 2% methylene blue solution for microleakage evaluation. The analysis involved sectioning the teeth and examining them under a stereomicroscope. Statistical analysis, using two-way ANOVA and post hoc Dunnett T3 tests (p < 0.05), revealed significant differences in microleakage among the cements. The study found that PZCs luted with RMGIC showed the highest level of microleakage, whereas those luted with bioactive cement exhibited the lowest, positioning bioactive cement as the preferable choice for minimizing microleakage. This finding illustrates the critical importance of selecting appropriate luting cements to optimize the clinical outcomes of zirconia crown restorations in pediatric dentistry, focusing on reducing microleakage to ensure the restoration’s durability and success.

Stabilization and Solidification of Beryllium Waste: Influence of the Cement Composition on the Corrosion of Be Metal.

Beryllium metal is used as neutron moderator and reflector or multiplier in certain types of fission or fusion reactors. Dismantling of these reactors will produce radioactive beryllium waste, classified as low- or intermediate-level waste, that will need to be stabilised and solidified before being sent to disposal. The cementation process is under consideration because it may offer a good compromise between simplicity of implementation, cost, and quality of the final cemented wasteform. Nevertheless, knowledge of the corrosion behaviour of Be metal in a cement-based matrix is still limited, partly due to the high toxicity of Be that complicates testing. This study thus investigates Be corrosion in cement suspensions using potentiometry, voltammetry, and electrochemical impedance spectroscopy. Among the five different investigated systems (Portland cement blended without or with 40 wt.% silica fume, calcium sulfoaluminate clinker blended without or with 15% anhydrite, and calcium aluminate cement), Portland cement blended with 40% silica fume and calcium sulfoaluminate cement comprising 15% anhydrite are the most effective in mitigating beryllium corrosion. They allow reduction in the corrosion current by factors of 4 and 50, respectively, as compared to Portland cement.

From Waste to Strength: A Comprehensive Review on Using Fly Ash in Composites with Enhanced Mechanical Properties

This article explores the diverse applications of fly ash (FA), a by-product generated during the combustion of coal. The introductory segment thoroughly comprehends the origins, composition, and widespread occurrence of FA. FA, which comprises an estimated 38% of worldwide power generation, frequently encounters disposal and storage obstacles on account of its classification as non-hazardous waste in the majority of countries. The environmental issues linked to the dispersal of FA are underscored in the problem statement, which further emphasizes the urgency for sustainable alternatives. Due to the fugitive emissions and potential health hazards associated with metal melting in FA, it is critical to investigate novel applications and disposal techniques immediately. Environmental sustainability is a primary focus of research, with the development of synthetic FA composites being one such alternative. The analysis presents significant findings that underscore the wide-ranging applications of FA. These applications include its utilization as a filler in composites, as well as its incorporation into cement and geo-polymerization processes. Notably, (10-20) wt. % Nano-FA enhances epoxy-based composites, showcasing remarkable improvements in tensile strength, flexural strength, and impact resistance. In thermoplastic composites, substantial enhancements occur within the (5–10) wt. % FA range, but exceeding optimal ranges weakens matrix-fiber interaction, leading to diminishing returns. The article emphasizes the criticality of FA in improving the mechanical and thermodynamic characteristics of substances, specifically within the domain of composites. The investigation into FA nanoparticles, including their processing techniques and surface treatments, unveils encouraging prospects for enhancing material characteristics.

INFLUENCE OF FIRECLAY GRANULES ON CALCIUM ALUMINATE CEMENT HYDRATION AND PROPERTIES AFTER FIRING

The article investigates the effect of granules, produced from dispersive fireclay using liquid glass as a binder, on the hydration process of calcium aluminate cement (CAC). Peculiarities of the hydration process were evaluated from the results of calorimetry, thermal analysis, XRD, SEM, and mechanical properties tests, as well as the relative viscosity of the cement pastes. It is determined that the granules are capable of entrapping water and releasing it later, shortening the incubation period and increasing the maximal heat release rate during the CAC crystallization stage and total cumulative heat as compared with the control samples with the same active cement part and containing dispersive fireclay particles, which are cement-inert. The redistribution of water due to granules’ addition results also in more hydrates C2AH8 and AH3 in CAC pastes containing granules than in those containing dispersive fireclay. Due to the reaction between the water solution containing dissolved cement minerals and sodium silicate film (dried liquid glass), the hydrogel-like phases form inside the granule during the hydration, which fill the gaps between the fireclay particles and after firing at 1100 °C form a glassy phase enveloping the fireclay particles and binding them to each other, providing the granule integrity and contributing to their strength. The specific structure formed due to the addition of fireclay granules does not change dramatically the density of the obtained composite, provides 7.4–18.5% higher strength after drying with 7.5–15% granule addition and ∼11% higher strength after sintering at 1100 °C with 5% granule addition (as compared with compositions containing dispersive fireclay). 30% granule addition can be considered as too much, causing significant strength loss.

Investigation on Key Influencing Factors Affecting Temperature Distribution in Concrete

Concrete is an unavoidable composite material used in buildings and structures. The behavior of concrete under the effect of fire is always critical, causing more structural damage. This research proposes experimental investigation on various factors that affect temperature distribution in concrete when exposed to fire. Water cement ratio, grade of concrete, curing period, type of admixtures, and fibers are the factors taken into consideration. The test was carried out in the temperature range of 100 °C to 600 °C. The temperature was measured at various depths of the specimen and then compared. Results from experiments show that grade of concrete, water-cement ratio, curing period and admixture type significantly influences the temperature distribution in concrete whereas contribution of fiber type is negligible. Comparison of temperature distribution at 25 mm from the bottom of specimen at 600 °C for M20 grade with 0.5 and 0.4 water cement ratio was done. It is found that temperature distribution in concrete goes higher as water cement ratio goes higher. There is an increase of 22.6% of temperature distribution for 0.5 water cement ratio than 0.4. Concrete samples which were cured for 14 days, and 28 days were tested, temperature distribution in concrete cured for 14 days is higher than that cured for 28 days. It is because of the curing time of calcium silicate hydrate (CSH) gel, and it was not fully matured and there was no moisture to finish the hydration process of cement.

Irregular Eccentric Wellbore Cementing: An Equivalent Circulation Density Calculation and Influencing Factors Analysis

In the field of cement, if the formation cannot be given sufficient pressure to maintain stability during construction, pressure control failure may occur, leading to the leakage of liquids and gasses from the formation to the wellbore. In addition, irregular wellbore diameter and casing eccentricity are important factors that are easily overlooked and affect the prediction of ECD (Equivalent Circulation Density) calculation. This results in major accidents and ecological disasters, further impacting the global environment. This study focuses on a well in the eastern oilfields of China, and based on a rheological experiment of high temperature and high pressure, an irregular eccentric wellbore model is established according to the measured wellbore diameter and eccentricity data to calculate the ECD of the whole cementing process. Then, a data set is constructed and analyzed using the random forest method to quantitatively evaluate influencing factors such as displacement, rheology, density, and eccentricity on the bottomhole and wellbore ECD. Results find that the density of cement slurry and drilling fluid has the most significant impact on the maximum ECD, with the impact reaching 0.3142 and 0.2902, respectively, and the main factors that affect the minimum ECD are the density and rheological changes in the drilling fluid, reaching 0.7014 and 0.2846. These research findings will contribute to the precise control of wellbore pressure during cementing operations, further ensuring the safety of cementing operations, and laying a technical foundation for the automation and intelligentization of subsequent cementing operations.

Effect of coupling between sphericalization and maximum coarse particle content on the cement properties

In this paper, spherical cement with different fineness (45 μm sieve residue) and particle size distributions were prepared using a new dry energy-saving vertical grinder (NDEVG), and the properties and mechanism of cement, which was compared with cement made by roller press-ball mill, under the coupling effect of sphericalization and maximum coarse particle content were investigated. The results indicated that NDEVG can optimize the particle size distribution and improve the roundness to above 0.731. Which was beneficial for improving the packing density and reducing the water requirement of normal consistency of cement. In addition, the coupling effect of sphericalization and maximum coarse particle content created convenience for the overlap of hydration products, resulting in an increase of 7.22 MPa at the 28d strength and an effective reduction in drying shrinkage and hydration heat release rate. This work provides technical guidance for the high-quality processing of cement and other powder materials.

Optimizing the Cementation Process of Leach Solution of Cold Purification Cake: Maximum Removal of Cadmium and Minimum Removal of Nickel

Optimizing the Cementation Process of Leach Solution of Cold Purification Cake: Maximum Removal of Cadmium and Minimum Removal of Nickel

Recovery of Magnetic Ni Particles from Spent Catalyst Leachate by Direct Cementation

An alternative method based on cementation for the recovery of nickel from spent Ni/Al2O3 reforming catalyst pregnant leach solution (PLS) was proposed to overcome the limitations of traditional two-step extraction and precipitation processes. Thermodynamic analysis was used to evaluate the potential interference of key reactions, such as nickel and sacrificial metal leaching, with the selective cementation of nickel from the PLS. Key variables in the cementation process were optimized using response surface methodology (RSM) combined with Box–Behnken design (BBD). Under optimal conditions—pH 2.2 ± 0.1, processing time of 15 min, and Al/Ni molar ratio of 2.65—a maximum nickel recovery of 73.2% was achieved. Extensive characterization confirmed the high quality of the cemented nickel product: (i) ICP-OES indicated nickel purity of 99.47%, (ii) XRD patterns verified the presence of pure face-centered cubic nickel, (iii) SEM-EDS and vibrating sample magnetometry confirmed the high purity of the metallic nickel particles.

Research and Application of Smart Temporary Plugging Gel for Small Casing Cementing in Changqing Oilfield

Abstract In response to the serious leakage and low productivity recovery rate after cement plugging during the secondary cementing process of repairing small casing in the old wells of Changqing Oilfield, this study draws on the theory of shielding and temporary plugging in the drilling process to propose an adaptive smart temporary plugging gel technology. This technology has developed a weak gel suspension base liquid and synthesized a polymer material with good viscosity, high deformability, high sealing strength, and the ability to automatically hydrate and degrade at a certain temperature. It synergistically cooperates with other auxiliary temporary plugging materials to form an adaptive and self-degrading temporary plugging gel system, which can quickly form a sealing barrier at severely leaking areas such as corroded perforations, effectively preventing cement slurry leakage during subsequent cementing processes, shortening the operation cycle, and protecting the reservoir. Experimental evaluations indicate that the gel system can withstand pressure up to 15MPa, degrades in 7-10 days, and achieves a reservoir recovery rate of over 90%, effectively achieving the goals of plugging, releasing, and minimizing reservoir pollution. It has been applied in 30 wells in the Changqing Oilfield, with a success rate of over 96% in the first plugging operation, and an average production recovery rate of over 95%, significantly protecting the oil reservoir.

Contrasting fracturing and cementation timings during shale gas accumulation and preservation: An example from the Wufeng-Longmaxi shales in the Fuling shale gas field, Sichuan Basin, China

The marine shales in southern China are characterized by high thermal evolution and intensive deformation during multistage burial and uplift. Fracturing and cementation, associated with tectonic activity, diagenesis, hydrocarbon generation and migration processes, are widely and variably distributed in shale reservoirs experiencing different tectonic evolution. In this study, we utilized cross-cutting relationships, fluid inclusion microthermometry, and laser Raman spectroscopy of fluid inclusions, along with U-Pb dating of fracture-filling calcite veins, integrated with burial history modeling, to elucidate the timing and mechanism of fracturing in the Paleozoic Wufeng-Longmaxi shale reservoir, as well as regional variations in the Fuling shale gas field. Bedding-parallel fractures (BFs) in shale reservoirs are filled with calcite and quartz veins. The timing of fracturing, as determined by minimum homogenization temperatures and U-Pb dating, is estimated to have occurred during ca. 191 -122 Ma, during which some short vertical (or high-angle) fractures (VFs) opened around 163.4 Ma and 137 Ma, subsequently sealed by calcite veins, respectively. All calcite and quartz veins within these fractures contain high-density methane inclusions, while shale reservoirs were in a high-over-mature evolutionary stage. This suggests that fracturing was primarily driven by gas generation overpressure during deep burial. In shale reservoirs near fault belt folds, multistage fractures developed, including three stages of intersecting fractures (IFs) and one-stage of long VFs. The timing of fracturing and cementation corresponds to the Yanshanian tectonic uplift (ca. 83 - 69 Ma) with intense tectonic movement likely being the direct cause of fracture opening. The presence of abundant gas inclusions in veins recorded shale gas expulsion during rapid tectonic uplift, reflecting the destruction of shale gas preservation conditions. In contrast, no significant fracturing or cementation processes have been observed in the tectonically gentle zones. The different fracturing and cementation processes indicated that preservation conditions declined with increased fracture openings during uplift, correlating with the gas enrichment.

The Influence of Limestone Powder and Metakaolin Co-Blending on the Hydration Process and Mechanical Properties of Q-Phase Cement

The Influence of Limestone Powder and Metakaolin Co-Blending on the Hydration Process and Mechanical Properties of Q-Phase Cement

Effects of Dolomitic Limestone on the Properties of Magnesium Oxysulfate Cement.

This study investigated the effects of substituting magnesium oxide (MgO) with dolomitic limestone (DL) on the mechanical and physical properties of magnesium oxysulfate (MOS) cement. Additionally, the hydration formation phases and the influence of the molar ratio on the MOS cement's performance were examined. The corresponding action mechanisms were identified and explored by compressive strength tests, scanning electron microscopy (SEM), X-ray diffraction (XRD), isothermal calorimetry, and a thermogravimetric analysis (TGA). The results showed that replacing MgO with DL decreased the reaction speed and heat release rate generated in the hydration process of the MOS cement. This substitution also reduced the quantity of non-hydrated MgO particles and delayed the formation of Mg(OH)2. The diminished formation of Mg(OH)2 contributed to an increase in the apparent porosity of pastes containing DL, thus alleviating internal stresses induced by Mg(OH)2 formation and enhancing their mechanical strength after 28 days of curing. Conversely, the increased porosity improved the CO2 diffusion within the structure, promoting the formation of magnesium carbonates (MgCO3). Through the characterization of the cement matrix (XRD and TGA), it was possible to identify phases, such as the brucite, periclase, and 318 phases. The obtained results revealed the potential of incorporating mineral fillers like limestone as a promising approach to producing MOS cement with a reduced environmental impact and better properties at higher curing ages.

A study on eco-friendly materials for 3D printing – focused on Korean Hwangto(Loess) -

ABSTRACT Of the 37% of carbon dioxide emissions generated by the construction industry, 5–7% comes from cement processing. In response to this problem, ways to utilize soil, a material with low energy consumption, are being explored as an eco-friendly option. In particular, eco-friendly design is being emphasized in the construction field through 3D printing technology. The research method proceeds in two stages. The first measures the changes in drying shrinkage, volume mass, compressive strength, and flexural strength over 7 days for a test specimen created by mixing coffee, charcoal, and rice bran with Hwangto. In the second step, slaked lime, a solidifying material, is mixed and tested under the same test specimen conditions as in the first. As a result of the experiment, the higher the mixing ratio of Hwangto, the greater the compressive strength and flexural strength. In particular, coffee exhibited the highest compressive strength at 1.50MPa, while charcoal demonstrated the highest flexural strength at 0.51MPa. However, when solidifying materials were mixed, the overall strength decreased, especially in the case of coffee (1.50MPa for the first time/0.87MPa for the second time), which showed a 42% decrease. Overall, charcoal was the most suitable mixing material and exhibited consistent and stable strength values in all experiments. Based on these experimental results, a 1/50 scale pavilion was produced through 3D printing. The stable shape and appropriate strength of the result were confirmed, making it suitable for educational or practical purposes. It suggests the possibility of use across industries.

Patterns of Changes in the Mechanical and Filtration Properties of Semi-Rock Soils Modified by Jet Cementation

When installing underground structures in soil layers with high groundwater filtration rates, special requirements are imposed on the material of anti-filtration curtains. The conditions of application of jet cementation technology for modification of watered fractured rocky soils of low strength in order to form a composite material with the required mechanical and filtration characteristics are considered.The technological parameters of the cementation process have been experimentally and theoretically determined to ensure the necessary radius of propagation of the bonding mixture, and methods of laboratory and field control of the modified zone have been developed. The maximum permissible values of the controlled parameters have been determined.

Ablation-resistant yttrium-modified high-entropy refractory metal silicide (NbMoTaW)Si2 coating for oxidizing environments up to 2100 °C

Refractory high-entropy alloys (RHEAs) are pivotal in ultra-high temperature applications, such as rocket nozzles, aerospace engines, and leading edges of hypersonic vehicles due to their exceptional mechanical ability to withstand severe thermal environments (in excess of 2000 °C). However, the selection of materials that satisfy the stringent criteria required for effective ablation resistance remains notably restricted. Here, a novel yttrium-modified high-entropy refractory metal silicide (Y-HERMS) coated on a refractory high-entropy NbMoTaW alloy is developed via pack cementation process. The developed Y-HERMS coating with sluggish diffusion effect demonstrates extraordinary ablation resistance, maintaining near-zero damage at sustained temperatures up to 2100 °C for a duration of 180 s, surpassing state-of-the-art high-performance silicide coatings. Such exceptional ultra-high ablation performance is primarily ascribed to the in-situ development of a high viscosity Si-Y-O oxide layer with increased thermal stability and the presence of high-melting Y(Nb0.5Ta0.5)O4 oxides as skeleton structure. Theoretical results elucidate that the Y-HERMS promotes the formation of SiO2, which impedes the diffusion of O into metal silicide layer, synergistically contributing to the superior ablation resistance. These findings highlight the potential of utilizing high-entropy materials with excellent ablation resistance in extreme thermal environments.

Influence of pH value on erosive wear of 3D-printed polylactic acid for multiphase flow

Abstract Slurry erosion presents a critical challenge in hydrocarbon and cement processing industries, as well as in abrasive water jet cutting systems, leading to diminished operational efficiency and elevated maintenance costs. This study investigates the erosive wear behavior of Poly-Lactic Acid (PLA) fabricated with varying infill microtextures—zigzag, concentric, and grid—under diverse pH conditions (2.73, 7.75, and 10.15) using garnet particles as the erodent. The results demonstrate that optimal operational conditions for PLA are achieved with a grid microtexture, a pH of 7.75, and a 325 μm erodent size. Conversely, the most severe wear occurs under a pH of 10.15, a 600 μm erodent size, and a zigzag microtexture. The grid microtexture is the most effective in minimizing erosion, while the zigzag pattern shows a 16.68% increase in wear when compared to the grid microtexture. Additionally, a shift from a slightly basic to a highly acidic environment increases wear by 1%, whereas a transition to a highly basic environment leads to a 32.6% increase in erosion within the grid microtexture. The study highlights the significant contributions of infill microtexture (64%), erodent size (23.7%), and pH value (11%) to the overall erosion rate.

Effect of steel fibers on the interfacial shear strength of flyash and GGBS based geopolymer concrete activated with water glass

Concrete, a fundamental construction material, heavily relies on cement, manufacturing process of cement results in significant CO2 emissions, posing environmental concerns. Hence, exploring substitutes for cement becomes imperative to mitigate CO2 emissions. Geopolymer materials emerge as promising alternatives capable of entirely replacing Ordinary Portland Cement (OPC). However, these materials necessitate activators to initiate the polymerization reaction. While Na2SiO3 and NaOH are commonly utilized as activators, their cost-effectiveness is questionable. Moreover, when Ground Granulated Blast Furnace Slag (GGBS) reacts rapidly with these activators. To address these issues and streamline concrete production, “water glass” is employed as an activator, offering a solution to avoid rapid setting and economize the production process. In other hand the production of mass concrete structures, interfaces and joints critical points where cracks may develop. To ensure monolithic behavior, shear ties were advised at the interface in order to establish strong bond strength. However, the efficiency of construction could be decreased by adding more shear ties. The purpose of this study is to evaluate the interfacial shear strength of Geopolymer concrete (GPC), With the addition of different percentages of steel fibers 0.5, 1%,and 1.5%, with shear ties at the interface of push-off specimens. The findings reveal that it is viable to replace two shear ties with one 8 mm-2L shear tie and 1% crimped steel fibers of 30 mm length.

Conceptual design and life-cycle environmental and economic assessment of low-carbon cement manufacturing processes

Cement manufacturing, a fundamental process industry characterized by high CO2 emissions, sees over 58% of its emissions stemming from the limestone calcination process. However, this significant source of CO2 has not yet been adequately addressed by most existing cement decarbonization processes. As such, systematic environmental and economic comparisons between different cement processes are essential. This paper proposes a new cement process (NCP) that uses natural gas to react with limestone to reduce CO2 emissions and simultaneously produce high-value-added chemical products (methanol). To explore strategies for further improving the performance of the CO2 emission reduction, two processes are developed, integrating the organic Rankine cycle (ORC) and carbon capture and storage (CCS) units with the traditional cement process (TCP) and the NCP, namely TCP-ORC-CCS and NCP-ORC-CCS respectively. Life cycle assessment (LCA) and economic analysis were performed on the TCP, NCP, TCP-ORC-CCS, and NCP-ORC-CCS processes, revealing their advantages and limitations in different scenarios. LCA adopts the "cradle to gate" system boundary, which includes the whole cement process from ore mining to clinker generation and other processes used for carbon reduction. The LCA results show that four cement processes exhibit different environmental performances when choosing different allocation methods. Under economic allocation, the global warming potential (GWP) of TCP, NCP, TCP-ORC-CCS, and NCP-ORC-CCS are 933, 300, 432, and 194 kgCO2eq/ton·clinker, respectively. The comprehensive analysis indicates that NCP has the best comprehensive economic and environmental performance when natural gas and methanol prices are 332 and 319 $/ton, respectively. The price fluctuation of natural gas and methanol is found to greatly impact the levelized cost of clinker (LCOC) of NCP through sensitivity analysis. NCP is economically preferred over TCP when the price of methanol (MeOH) is at least $76 above approximately two-thirds of the price of methane (CH4). Similarly, NCP-ORC-CCS is more advantageous than TCP-ORC-CCS when the price of MeOH is at least $87 above nearly two-thirds of the price of CH4. This study provides a comprehensive analysis for low-carbon cement process design to achieve CO2 emissions reduction.