Calcium Carbonate Particles Research Articles

Experimental Study of Erosion Prevention Model by Bio-Cement Sand

Microbially induced carbonate precipitation (MICP) technology is employed to reinforce the surface soil of a dam, aiming to prevent erosion caused by water flow and damage to the dam slope. The relationship between penetration depth, calcium carbonate content, and bonding depth was investigated at eight measuring points on the sand slope surface of a mold under different reinforcement durations. It was observed that as grouting reinforcement times increased, there was a gradual increase in calcium carbonate content but a rapid rise in penetration resistance. Moreover, the bonding depth of sand on the bio-reinforced sand slope increased with higher levels of calcium carbonate content. Microbial grouting reinforcement enhanced soil particle bonding force, requiring water flow to overcome this force for activation of sand particles. Consequently, microbial grouting reinforcement significantly improved shear strength and critical starting flow velocity on sand slope surfaces. The experimental results demonstrated that after MICP surface treatment through spraying, a dense and water-stable hard shell layer composed of bonded calcium carbonate and soil particles formed continuously on sample surfaces, effectively enhancing the strength and erosion resistance of sandy soils. These findings provide reliable evidence for silt slope reinforcement and dam erosion prevention.

Microfluidic-assisted synthesis of hybrid calcium carbonate/silver microparticles

The development of advanced methods for the synthesis of nano- and microparticles for biomedical applications is of considerable interest. A method for the synthesis of submicron silver-shelled calcium carbonate particles using a microfluidic chip designed to provide control over particle formation is proposed. Precise control of reaction parameters enables the formation of silver shell and calcium carbonate particles in a controlled manner. The distribution of pores in the hybrid particles was analyzed using small-angle X-ray scattering, which provided insight into the complex structure of the pores. The results provide information on particle morphology and may facilitate the development of new calcium carbonate-based materials for various applications.

Industrial manufacturing method and characterization of Ayurvedic marine drugs: mother pearl, cowry, coral and pearl

Introduction: Ayurvedic marine drugs derived from mollusc shells and coral are regularly used by Ayurvedic physicians to treat several disease conditions like acid peptic disease, irritable bowel syndrome, osteoporosis, etc. However, standard operating procedures for manufacturing these drugs and their complete characterization have not been published in the Ayurvedic Formulary and Ayurvedic Pharmacopeia of India to date. Methods: Present study describes the traditional manufacturing process and thorough characterization using classical and advanced analytical tools. The raw materials characters, in-process parameters, and finished product specifications have been elaborated to develop monographs. Especially, the identity and purity of raw coral and pearl were checked by Raman Spectroscopy and Energy Dispersive X-ray Fluorescence analysis. Results: In the finished product analysis, the X-Ray Diffraction study revealed that incineration after trituration with Aloe barbadensis leaf pulp or rose water converted the aragonite phase of calcium carbonate into calcite phase in mother pearl, cowry, and pearl while the calcite form of raw coral was retained. The prominent bands around 1390, 870, and 712 cm−1 detected by Fourier Transform-Infrared Spectroscopy and mass loss between 39–44% (w/w) revealed by thermogravimetric analysis confirmed the carbonate form of these calcium-based drugs. The finished products were very fine grayish-white powders constituted by irregularly shaped nano-micro particulate calcium carbonate exhibiting particle size between 600 nm (D10 value) to 1.2 µm (D90 value). Conclusion: The quality control and assurance achieved in this study may be further utilized by the pharmaceutical industries to manufacture quality marine drugs and conduct efficacy studies.

Discrete Element Study on Mechanical Properties of MICP-Treated Sand under Triaxial Compression

Microbial-induced calcium carbonate precipitation (MICP) has attracted much attention as a promising technology for soil improvement in the infrastructures of marine engineering. This paper introduces a novel numerical sample preparation technique for MICP-treated sand, with particular attention paid to the distribution patterns of calcium carbonate, including contact cementing, bridging, and grain coating. The effect of calcium carbonate content (CCC) on the deformation and failure mechanism is studied at macroscopic and granular scales. The findings show that a small amount of calcium carbonate can quickly increase the strength of sand. The strength improvement and deformation control of MICP technology are better than those of traditional compaction treatment. As the calcium carbonate content increases, the mechanical coordination number of the sand also increases, indicating a more stable microstructure of the sand phase. In the contact bonding mode, initial failure occurs as shear failure between sand and calcium carbonate. In the bridge mode, initial failure manifests as shear failure between calcium carbonate particles. In the coating mode, initial failure occurs as tensile failure between sand and calcium carbonate. Calcium carbonate contributes to a reduction in both sliding and rolling movements among sand particles.

Visualization experiment on dynamic migration and sealing mechanism of irregular materials in rough fractures

Lost circulation is one of the main problems causing low drilling efficiency and high drilling costs in the oil and gas industry. Due to an insufficient understanding of the migration and sealing mechanism of lost circulation materials (LCMs) in rough fractures, the success of fracture sealing is highly unpredictable. This study conducted visualization experiments using four types of LCMs to observe the entire dynamic sealing process of rough fractures. Adaptive fracture sealing experiments were designed to improve the sealing performance of LCMs at low concentrations. The results indicated that the key to sealing rough fractures is forming an effective sealing zone inside the fracture space rather than in the inlet buffer zone. The dynamic sealing process has experienced four typical stages: sporadic bridging, bridging structure expansion, sealing front formation, and sealing layer thickening. The first three typical stages correspond to flow from plate flow to trench flow and seepage. The formation of an effective sealing zone within fractures depends on forming a practical sealing front and subsequent particle accumulation of LCMs that thicken the sealing layer. Compared with regular particles, the sealing front of irregular particles is an area with a specific aperture range. The increase in irregular particle concentration makes the sealing front migrate to the fracture entrance, which is more likely to lead to inlet blockage. The distribution of a sealing zone depends upon the surface morphology of rough fracture. Increasing the particle size distribution improves the favorable bridging area and enhances the sealing performance. The adaptive sealing strategy uses low-concentration granular materials to form multi-point bridging within rough fractures and low-concentration flaky materials to adaptively and quickly extend and connect dispersed bridging structures. Mica flakes are more conducive to extending along the contour of fracture aperture than calcium carbonate particles. Adding mica flakes promotes the expansion of the bridging structures, forming a sealing front and a robust sealing layer in advance. This study delves into irregular materials' migration and sealing mechanisms in rough fractures, enriching theoretical understanding and providing guidance for on-site sealing operations.

Stress and flow inhomogeneity in shear-thickening suspensions

HypothesisThe viscosity of dense suspensions surges when the applied stress surpasses a material-specific critical threshold. There is growing evidence that the thickening transition involves non-uniform flow and stress with considerable spatiotemporal complexity. Nevertheless, it is anticipated that dense suspensions of calcium carbonate particles with purely repulsive interactions may not conform to this scenario, as indicated by local pressure measurements with millimeter spatial resolution. ExperimentHere we utilize Boundary Stress Microscopy (BSM), a technique capable of resolving stresses down to the micron scale, to search for evidence of stress heterogeneity. In addition, we measure the flow field at the lower boundary of the suspension where the boundary stress is measured. FindingsWe find localized regions of high-stresses that are extended in the vorticity direction and propagate in the flow direction at a speed approximately half that of the rheometer's top plate. These high-stress regions proliferate with the applied stress accounting for the increased viscosity. Furthermore, the velocity of particles at the lower boundary of the suspension shows a significant and complex nonaffine flow that accompanies regions of high-stresses. Hence, our findings demonstrate that stress and flow inhomogeneity are intrinsic characteristics of shear-thickening suspensions, regardless of the nature of interparticle interactions.

Influence of the Crystal Forms of Calcium Carbonate on the Preparation and Characteristics of Indigo Carmine-Calcium Carbonate Lake

In this study, indigo carmine (IC)-calcium carbonate lakes with different crystalline forms of calcium carbonate were prepared through co-precipitation methods, and the properties of these lakes and their formation mechanisms were investigated. The results showed that amorphous calcium carbonate (ACC) exhibited the smallest particle size and the largest specific surface area, resulting in the highest adsorption efficiency. Vaterite, calcite, and aragonite followed after ACC in decreasing order of adsorption efficiency. Kinetic analysis and isothermal analysis revealed the occurrence of chemisorption and multilayer adsorption during formation of the lakes. The FTIR and Raman spectra suggested participation of sulfonic acid groups in chemisorption. Appearance of IC significantly altered TGA curves by changing weight loss rate before decomposition of calcium carbonate. EDS analysis revealed the adsorption of IC predominantly happened on the surface of calcium carbonate particles rather than the interior.

Preparation of antibacterial composite aerogel for biomedical purposes based on alginate-chitosan complex and calcium carbonate

Aerogel composites were synthesized on the basis of the sodium alginate-chitosan interpolymer complex with the inclusion of calcium carbonate microparticles and supercritical drying. It is shown that the textural characteristics of materials do not depend on the morphology of calcium carbonate particles: the specific surface area of aerogels is almost the same for all materials and amounts to 380–400 m2/g. The developed porous structure of composites along with the polyelectrolyte nature determines their high water absorption— up to 110 g/g. To impart antimicrobial properties, the materials were impregnated with atranorin isolated from the lichen Hypogymnia physodes, which has a pronounced inhibitory effect on the bacterium Proteus mirabilis, which is the main causative agent of wound infections. The minimum suppressive concentration of atranorine is 1 mg/ml. The release of the main amount of atranorine aerosol material included in the matrix occurs within 4 hours and amounts to 50%.

Preparation of eggshell-based materials and their adsorption performance on Fe(III) in water*

Abstract If there is too much trivalent iron in the body, it will disrupt the balance of osmotic pressure inside the body, and its heavy metal properties will denature proteins. Therefore, effective management of industrial pollution source wastewater is very important for environmental protection and human’s health. Calcium carbonate particles have a good ability to adsorb trivalent iron in wastewater. The aim is to prepare porous calcium carbonate by a template method using eggshell powder, hydrochloric acid, sodium stearate, and anhydrous sodium carbonate solution as the raw materials and research the adsorption properties of porous calcium carbonate to trivalent iron. Porous calcium carbonate was prepared by a template method using eggshell powder, hydrochloric acid, sodium stearate, and anhydrous sodium carbonate solution as the raw materials. The morphology and adsorptive properties of Fe (III) of the porous calcium carbonate were analyzed by scanning electron microscope (SEM) and UV-visible spectrophotometer (UV). The best value was found between different temperatures, time, and pH. The results verified that the maximum amount of adsorption was obtained when calcination was 400°C, pH was 5, time was 60 min, and the input amount was 20 mg. The adsorption of porous calcium carbonate to Fe (III) is chemical and has a better adsorption effect.

Cytostatic drug mitoxantrone delivery platform based on porous vaterite particles: Synthesis, characterization and release

Malignant neoplasms remain a serious problem worldwide, requiring improved approaches to chemotherapy. Cytostatic drug delivery platforms offer a number of advantages, such as controlling the rate of drug release and the ability to increase drug concentration in the pathologic area. The high biocompatibility and physicochemical features of porous calcium carbonate particles (vaterite) make them an ideal candidate for drug delivery. Vaterite of two sizes (micron and sub-micron) have been considered as a delivery platform for cytostatic drug mitoxantrone (MTX). We used freezing-induced loading of MTX into calcium carbonate particles, and MTX loading capacity and efficacy were independent of particle size (0.09 ± 0.01 wt% and 70 ± 9 % for micron, and 0.07 ± 0.03 wt% and 65 ± 14 % for sub-micron particles). The release profile of MTX for particles of two sizes differed, with release accompanied by recrystallization of vaterite. The MTX release was faster for micron-sized particles. We have proposed a completely new approach to visualize the process of MTX release from calcium carbonate particles, based on the quenching the fluorescence of gel, contained semiconductor quantum dots (FluoGel). A cytotoxicity study of two sizes of calcium carbonate particles with MTX demonstrated the preservation of anti-cancer efficacy, with better results for micron-sized particles. Thus, the proposed cytostatic drug mitoxantrone delivery platform may be promising for drug delivery.

Effects of calcium carbide slag on properties and carbon sequestration efficiency of cement pastes mixed under direct CO2 injection conditions

CO2-mixing by directly injecting CO2 into fresh cement-based materials is a burgeoning technology to produce low-carbon cement products. The objective of this study is to investigate the influence of the calcium carbide slag (CCS) content on the properties and carbon sequestration efficiency of cement pastes mixed under direct CO2 injection conditions. The results indicate that the addition of CCS reduced the fluidity of the cement pastes, accelerated the setting process, increased volume shrinkage, and reduced compressive strength. Following the injection of CO2 into the cement pastes, calcium hydroxide (CH) was carbonated to form calcium carbonate (CC) particles which fill the voids in the cement pastes, thereby reducing volume shrinkage and increasing compressive strength. A lower CO2 inflow rate (2 L/min) was more beneficial to the workability of the cement pastes, while a high inflow rate (6 L/min) can lead to insufficient hydration and affect the development of strength. However, a higher CO2 inflow rate was favorable for improving carbon sequestration efficiency. The highest amountof carbon sequestration can be reached at 6.93 %, when the CCS content is 10 % and the CO2 inflow rate is 6 L/min.

Silica extraction from sodium silicate for wollastonite synthesis at low temperatures

In this study, ceramic wollastonite was prepared at low temperatures by using amorphous silica and calcium oxide powders. The amorphous silica was extracted from sodium silicate, while calcium oxide (CaO) was obtained through the calcination of calcium carbonate (CaCO3) particles. The effect of reaction temperature on the formation of wollastonite was systematically investigated. The synthesized powders were analyzed using various characterization techniques, including X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results indicate that the synthesized silica nanopowders exhibit a notable surface area, with specific surface area (SSA) values reaching 148 m²/g for samples subjected to calcination at 600°C. Furthermore, based on XRD and differential scanning calorimetry (DSC) analyses, it is evident that β-CaSiO3 forms at approximately 780°C and subsequently undergoes complete transformation into α-CaSiO3 at 1200°C. Notably, this study underscores that the utilization of amorphous silica expedites wollastonite formation at lower temperatures compared to those reported in existing literature.

Effect of Calcium Carbonate as Filler on the Physicomechanical Properties of Polypropylene Random

To minimize the cost of production and enhancement pipe quality, this research aims to gain insights into the physical and mechanical characteristics of high-performance polypropylene random filled with rigid inorganic calcium carbonate particles at various content levels, with a specific focus on how the toughness of PPR changes. Virgin Polypropylene Random PPR, a new material extracted from a homopolymer polypropylene, is used as a matrix with 10, 20, 30, 40, and 50 wt. % of CaCO3. The density, melt flow rate, tensile strength, tensile strain, modulus of elasticity, and hardness are used to evaluate the quality of the material. The results showed that the density, the modulus of elasticity, and the hardness increased with increasing the percentage of CaCO3. As the percentage of CaCO3 increased, the melt flow rate decreased. The tensile strength and strain increased to 28.7 MPa and 533.25%, respectively at 20 wt.% of CaCO3, with 14.8% and 6.65% reaching gains compared to the virgin PPR (25 MPa and 500%). The enhancement of the mechanical properties is thanks to the presence of stiffer and rigid particles of CaCO3 that act as a reinforcing agent. Moreover, when CaCO3 is well dispersed, it forms a strong bond with the polypropylene matrix, and facilitates the transfer of stress from the matrix to the fillers, resulting in increased stiffness. The optimum percentage of CaCO3 to add into the inner layer of extruded PPR pipes is at a composition of the filler of 20 wt. %.

Heavy metal immobilization and radish growth improvement using Ca(OH)2-treated cypress biochar in contaminated soil

Heavy metal contamination poses a significant threat to soil quality, plant growth, and food safety, and directly affects multiple UN SDGs. Addressing this issue and offering a remediation solution are vital for human health. One effective approach for immobilizing heavy metals involves impregnating cypress chips with calcium hydroxide (Ca(OH)2) to enhance the chemical adsorption capacity of the resulting woody charcoal. In the present study, un-treated cypress biochar (UCBC) and calcium-treated cypress biochar (TCBC), were introduced into pristine and contaminated soil, at rates of 3, 6, and 9% (w/w). Both BCs were alkaline (UCBC pH: 8.9, TCBC pH: 9.7) with high specific surface area, which improved the soil properties (pH, EC, and OM). Radish (Raphanus sativus) cultivated in pots revealed that both UCBC and TCBC demonstrated significant improvements in growth attributes and heavy metal immobilization compared to the control, with TCBC exhibiting superior effects. The TCBC surface showed highly active nanosized precipitated calcium carbonate particles that were active in immobilizing heavy metals. The application of TCBC at a rate of 9% resulted in a substantial reduction in Zn and Cu uptake by radish roots and shoots. In contaminated soil, Zn uptake by radish roots decreased by 55% (68.3–31.0 mg kg−1), and shoots by 37% (49.3–31.0 mg kg−1); Cu uptake decreased by 40% (38.6–23.2 mg kg−1) in roots and 39% (58.2–35.2 mg kg−1) in shoots. Uptake of Pb was undetectable after TCBC application. Principal component analysis (PCA) highlighted the potential of TCBC over UCBC in reducing heavy metal concentrations and promoting radish growth. Future research should consider the long-term effects and microbial interactions of TCBC application.

Preparation of inorganic salt particles by reactive crystallization in an annular swirling flow reactor

This study investigates the performance of an annular conical swirling flow reactor in liquid–liquid reactions for the preparation of inorganic salt particles. Utilizing Particle Image Velocimetry (PIV) measurements and Computational Fluid Dynamics (CFD) simulations, it was observed that the conical design effectively inhibited the attenuation of swirling flow intensity along the axial direction, with the primary mass transfer region close to the central conical wall. In comparison to a stirred reactor, calcium carbonate particles synthesized in the swirling flow reactor exhibited more uniform morphology, smoother and defect-free surface. Notably, the average particle size remained consistently within 5–6 μm (excluding the 0.3 M feedstock), whereas stirring led to particles with an average size ranging from 8-11 μm. Analysis of the residence time distribution curve revealed minimal back mixing in the swirling flow reactor, ensuring nearly equal growth time for salt particles, thus yielding particles with a uniform size distribution. As a result, the swirling flow reactor presents compelling prospects for applications in reactive crystallization.

Discontinuous Shear Thickening of Suspensions of Magnetic Particles in Relation to the Polymer Coating on Their Surfaces

The phenomenon of discontinuous shear thickening (DST) is observed in suspensions of solid particles with a very high-volume fraction. It is characterized by an abrupt decrease in the shear rate for critical stress during a ramp of stress. This behavior can be reproduced in numerical simulations by introducing a local friction between two particles above a given local force. We present experimental results showing this DST behavior obtained with suspensions of magnetic (iron) and nonmagnetic (calcium carbonate) particles and different amounts of a superplasticizer molecule used in the cement industry. For both types of particles, the same behavior was observed with first an increase in critical stress with the amount of plasticizer followed by a decrease at higher concentrations but with a larger viscosity before critical stress was reached. At a low concentration of plasticizer, the low critical stress is interpreted by the local sliding of plasticizer molecules on the surface of particles. At higher concentrations, when total coverage is achieved, the critical stress is higher since it has to remove the molecules out of the surface. At still higher concentrations, the increase in viscosity is explained by the formation of multilayers of molecules on the surface of the particles. This interpretation is supported by the measurement of the adsorption isotherm of the plasticizer on the surface of the particles.

Acoustofluidics enables direct ink writing of vascular scaffolds with intrinsically patterned porous microstructures

Vascular scaffolds with well-organized pore characteristics are crucial for promoting infiltration, adhesion, growth, tissue-specific arrangement, and substance-exchanges of biological cells. However, their controllable fabrication is extremely challenging, especially for those with specially designed three-dimensional (3D) tubular and porous microstructures. In this paper, a new methodology based on acoustofluidics-assisted direct ink writing (DIW) technique is developed to fabricate vascular scaffolds with controlled porosity distributions and well-defined porous microstructures. Calcium carbonate (CaCO3) particles and alginate are uniformly mixed as the printing ink, which is printed along a rotating rod to form a vessel-like structure. Distributions of these CaCO3 particles in the printed structure are precisely controlled using bulk acoustic waves. The particles within the vessel-like structure are dissolved in situ using hydrochloric acid, resulting in the formation of 3D vascular scaffolds with intrinsically patterned porous microstructures. The scaffolds printed by the acoustofluidics-assisted DIW method exhibit a 69% improvement in pore connectivity compared to conventional 3D-printed scaffolds. Fibroblast cells are successfully seeded onto these scaffolds, achieving distinctive distributions along the patterned porous microstructures. This innovative methodology, with its excellent microfabrication capabilities, holds great promise for applications in tissue engineering, drug release, composite formation, microfluidic chips, and biosensors.

The Compressive Strength of Unsaturated polyester reinforced by natural and synthetic Calcium Carbonate

A modifications on the ultimate compression strength of unsaturated polyester (UPE) carrying out, by adding nano Chicken eggshells fibers (E.S) as a natural source of calcium carbonate or synthetic nano calcium carbonate particles (CaCO3) in different weight percentages ranging from (1-5%). The ratio (1% eggshell fibers) and (3% CaCO3) are the best weight ratios that selected according to ultimate compressive strength of Unsaturated Polyester composites. Ultamite compressive strength was improved from (73.84 N/mm2) for UPE to (85.54 N/mm2) for (UPE/1% E.S) composite and to higher value (87.88 N/mm2) for (UPE/3%CaCO3) composite. The partictes with nano-sized of titanium dioxide (TiO2) was used to reinforce the two best composites, to get more improvement in there ultamite compressive strength to reach to (94.27 N/mm2) for (UPE/1%E.S) and to (100.18 N/mm2) for (UPE/3%CaCO3) composites.

Fast-dissolving calcium carbonate particles as a high-performance lime for amelioration of agricultural acidic soils

Effective soil management is essential for maximizing crop yields, as soil fertility plays a pivotal role in this process. Unfortunately, liming and fertilization practices are frequently ineffective, leading to overdoses and unnecessary product waste. Liming is essential for correcting soil acidity, mitigating aluminum toxicity, and promoting nutrient bioavailability before fertilizer application. This study explores the potential of vaterite, a highly soluble CaCO3 polymorph, as a sustainable liming agent. Vaterite particle synthesis is challenging because of its poor stability and rapid phase transformation into calcite, therefore, we analyze the effects of precursor concentration, Ca2+/CO32- ratio, and stirring rate on vaterite morphology and content in a reactive precipitation process through screening and D-optimal experimental designs, resulting in a design space to tailor the conditions that promote vaterite particles with a high dissolution profile at the lowest possible cost. To assess the efficacy of fast-dissolving CaCO3 particles, a comparative incubation test was conducted in andisol-type soil with a high buffering capacity. The results demonstrated that vaterite particles were capable of quickly adjusting the soil pH in the first few days using 360% fewer conventional liming agents. This innovative strategy aligns with Precision Agriculture principles, enabling efficient crop production while minimizing the environmental impact.

Real-time application and modelling of the NOx-sorption reaction on a particulate calcium carbonate surface-flow filter exposed to combustion exhaust.

Of major interest, especially in city environments, and increasingly inside vehicles or industrial plants, is the drive to reduce human exposure to nitrogen oxides (NOx). This trend has drawn increasing attention to filtration, which has developed remarkably owing to the capabilities of recently developed mathematical models and novel filter concepts. This paper reports on the study of the kinetic modelling of adsorption of nitrogen dioxide (NO2), collected from the tailpipe of a diesel engine, reacting to calcium nitrate salt (Ca(NO3)2) on a surface flow filter consisting of a coating of fine ground limestone or marble (CaCO3) in combination with micro-nanofibrillated cellulose (MNFC) acting as binder and humectant applied onto a multiply recycled newsprint substrate. The coating and substrate are both porous, but on different pore size scales, with the coating having significantly lower permeability. To maximise gas-coating contact, therefore, the coating deposition is pixelated, achieved by pin coating. An axially dispersed gaseous plug flow model (dispersion model) was used to simulate the transport within the coating pore network structure, following earlier flow modelling studies, and a kinetic reaction model was used to examine NO2 to NO3- conversion in correlation with experimental results. Modelling results indicate a 60.38% conversion of exposed NO2 gas to Ca(NO3)2 under the specific conditions applied, with an absolute relative error between the predicted and experimentally estimated value being 0.81%. The model additionally enabled a prediction of effects of changing parameters over a limited perturbation range, thus assisting in predicting filter element consumption, with attention given to the active component CaCO3 surface as a function of particle size in relation to the gas contact exchange, promoting the reaction over time. It is intended that the Ca(NO3)2 formed from the reaction can go on to be used as a value-added fertiliser, thus contributing to circular economy.