Monocalcium phosphate monohydrate (MCPM) powder with nano-size particles was synthesized by a low-cost powder precursor of green mussel shells in a laboratory magnetic stirrer. In the present study, ...powder processing procedures included stages of preparing the raw mussel shells into the high-quality precipitated calcium carbonate (PCC) through washing, size reducing, ball milling, intensive calcination, and carbonation in the nitric acid solution. Moreover, the MCPM powder was synthesized by reacting PCC powder with the phosphoric acid in aqueous-water media at the 90 °C with four stirring time durations (30, 60, 90, and 120 min). Additionally, analytical methods such as X-ray powder diffraction (XRD), FTIR spectroscopy, and scanning electron microscopy (SEM/EDX) were applied for examining the raw- and synthesized powders. The resulting PCC product contained vaterite (91.26 wt%), and calcite (8.74 wt%). The use of PCC polymorph for the synthesis provided the high purity of MCPM nanoparticles in stirring time durations (from 30 to 90 min). However, the increased stirring time duration of 120 min yielded the second phase of monocalcium phosphate anhydrous (MCPA). Instead, more homogenous particle size was further obtained with increasing stirring time. This reproducible and low-cost approach would be a promising strategy for recycling green mussel shells into large-scale MCPM products.
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•The experimental approach of converting green mussel shells into value-added ceramics.•Powder processing of shells yielded for the synthetic biomaterials of calcium phosphates.•Green mussel shells have an important component of bio-minerals.•High grade monocalcium phosphate monohydrate with homogenous nanoparticles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study explores the use of precipitated calcium carbonate (PCC), an industrial by-product from the carbon sequestration process for emitted CO2 from factories, in the cementless CaO-activated ...ground-granulated blast-furnace slag (GGBFS) system in an aim not only to improve the strength but also to develop more sustainable structural binder for concrete. The 28-day strength improved with increasing PCC content up to 20 wt%, and its highest strength showed an ∼23% increase from the original strength of the sample without PCC. The analysis revealed that the PCC was not a simple inert filler, but it might promote more dissolution of GGBFS, resulting in a higher strength from additional formation of reaction products. In particular, even the sample with 50 wt% PCC yielded a very similar strength compared to the sample without PCC at 28 days. Thus, this binder system could be a decent solution that can store a large amount of PCC without a significant strength reduction.
•The PCC from CO2 uptake process was used in CaSO4-blended CaO-activated GGBFS.•This study discussed characteristics of strength and microstructure of the pastes.•The 28-day strength increased ∼23% at 20 wt% of the PCC content.•There was no significant strength reduction even at 50 wt% of PCC usage.•The PCC was not a simple inert filler, but it might promote dissolution of GGBFS.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Polymer composite materials find application in various life sectors such as packaging, lightweight construction and the fabrication of medical devices. Functional fillers like mineral colloids, ...synthetic and natural fibres enable a precise tailoring of the mechanical properties of the resulting compounds. Precipitated calcium carbonate (CaCO
3
, PCC) has proven to be a special popular mineral polymer filler. From economic and ecologic reasons, it is desirable to increase filler contents in polymers while maintaining material strength. To achieve this, the present work has developed a hybrid filler system which is based on carboxymethylated, fibrillated cellulose fibres. CaCO
3
is precipitated onto the fibres in a single step twin-screw extrusion process by the co-precipitation method. This process ensures a strong, permanent interaction between the fibres and the mineral particles, which enables CaCO
3
contents in the filler of up to 68 wt.-%. The resulting hybrid fillers were compounded with polypropylene (PP) in a powder or paste state with filler contents between 5 wt.-% and 20 wt.-%. The resulting composites show an increase in the zero-shear viscosity and, in the event of sufficient network formation, a marked increase in stiffness was observed.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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•Calcium extraction efficiency was improved from slag by ball milling.•Vaterite-phase round PCC particles could be changed by increasing temperature.•Initial rate of PCC production is ...improved with increasing CO2 injection velocity.•Initial rate of PCC production is improved with increasing solvent concentrations.
We investigate the effect of ball milling and heat treatment on slag particle size, revealing that this parameter significantly influences the efficiency of calcium extraction. The efficiency and morphological properties of precipitated calcium carbonate (PCC) produced from calcium oxide were investigated for different extraction solvent, temperatures, CO2 injection rate and solvent concentration. As a result, ammonium chloride was determined to be the best extraction solvent for PCC production. Initial rate of PCC production is improved with increasing solvent concentrations and CO2 injection rate. The precipitated CaCO3 could be obtained in three different polymorphic forms, depending on the Gibbs free energy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Carbon dioxide capture by ammonia is considered one of the promising technologies for emission control in cement plants. This paper focuses on the experimental investigation of the factors affecting ...the chemical absorption process of carbon dioxide by ammonium hydroxide solution. The factors include ammonia concentration below 14%, reaction temperature below 20 °C and reaction time 30 min as the optimum parameters. The paper also highlights the economic and practical aspects to be taken into consideration when applying this technology to cement plants.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Biological soil stabilization through Microbial-Induced Calcite Precipitation (MICP) demonstrates the potential to be an eco-friendly and sustainable approach to enhance the strength properties of ...cohesionless granular soils. In this study, based on a comprehensive set of experimental data compiled from literature, the amounts of Precipitated Calcium Carbonate (PCC) and Unconfined Compressive Strength (UCS) of MICP-treated sands are estimated through hybridizing Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) models with metaheuristic algorithms. During the data extraction procedure, a total of 70 and 115 datasets are used to predict the PCC and UCS, respectively. Accordingly, five key features of urea concentration (Mu), calcium chloride (Mcc), optical density of bacterial suspension (OD600), pH and total volume of injection per volume of sample (Vt), are first selected as the inputs of the hybrid models to estimate the amount of calcium carbonate precipitation within the porous structure of MICP-treated granular medium. The experimental data on the PCC along with the basic characteristics of the host sand including mean grain size (D50), uniformity coefficient (Cu) and void ratio (e), are then adopted as the inputs of the numerical models in the second phase whilst the UCS of bio-mediated sands is set as the output. The performance and accuracy of implemented models are rigorously assessed through analyzing various statistical indices and performance criteria. According to the numerical analysis, the ANN-PSO and ANFIS-PSO hybrid models show the best performance in predicting PCC and UCS of bio-mediated sands, respectively. Using the well-established Gene Expression Programming (GEP) algorithm, practical correlations are developed to predict the PCC and UCS values of MICP-mediated soils based on the characteristics of biological binding agents as well as the host material. The Machine Learning (ML)-based models presented in this study provide engineers with a fruitful framework for the rough and preliminary estimation of the amount of calcite precipitation as well as the UCS of bio-mediated sands in the field prior to stabilization and performing complementary tests.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Calcium in the slag is selectively extracted by an aqueous solution of NH4Cl.•96% of the calcium in the slag were extracted by ultrasonic agitation.•Sonication enhances the calcium extraction ...efficiency from steel slag.•A weak surface of impurities in the slag is removed by the physical effects of sonication.
Ultrasound is considered to be an effective agitation technique to enhance the rates of reaction and mass transfer for various chemical processes. The literature reports several successful ultrasonic application cases, including extractive metallurgy. The present study investigates the effect of sonication (referring to the application of ultrasound) on the dissolution of calcium from steel slag to maximize the amount of CO2 sequestrated. The results are compared with results from similar tests with mechanical agitation.
When calcium bearing phases liberate their calcium, the remaining silica and other common impurity species in the slag form a porous layer on top of the calcium-liberating surface. This porous layer and in some cases, mechanically weak surface can be removed effectively by sonication. Hence, 96% of the calcium in the smallest particles (50–74μm) of the slag was extracted by ultrasonic, and 65% by mechanical agitation. While from the largest particles (500–1000μm), 38% of the calcium were extracted by ultrasonic and 18% by mechanical agitation. Thus, sonication significantly enhances the extraction of calcium from both small and large particles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this study, the influence of acid solutions on the production of precipitated calcium carbonate (PCC) using seashells was investigated. In terms of the Ca dissolution efficiency and atmosphere for ...dissolving CO32−, the results indicate that HCl, HNO3, CH3COOH, and HCOOH at 1.0 M were the most ideal among the acid solutions. The use of weak acids resulted in the low degree of dissolution of Al and Fe. These impurities could be mostly removed through the pH adjustment process, leading to PCC with a purity of 99% or more. Further, CH3COOH and HCOOH exhibited low CaCO3 carbonation efficiency owing to the hydrogen bonding of the carboxyl group and its hindering effect on the growth of CaCO3 particles. In addition, in the presence of the carboxyl group, the morphology tended to be oval, and the particle size was small. Particularly, when CH3COOH was used, the combined effect of the low initial Ca ion concentration and slow CO2 dissolution rate resulted in minimal changes during the carbonation time and the smallest particle size. However, variations in the degree of Ca concentration with a change in the acid solution concentration influenced the dominance of nucleation and particle growth, leading to variations in the particle size. The results of this study revealed that when manufacturing PCC using seashells, the appropriate acid solution must be selected to obtain the required PCC properties.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Carboxymethyl cellulose and alum were used in the modification of precipitated calcium carbonate filler, and the use of modified fillers in papermaking was investigated. The alum dosage was found to ...be much critical to the effective precipitation and encapsulation of carboxymethyl cellulose on filler surfaces. When the dosages of carboxymethyl cellulose and alum were 4% and 12% (based on the dry weight of precipitated calcium carbonate), respectively, filler modification significantly improved filler retention by as much as 71.5%, and the brightness and opacity of the filled paper were strikingly enhanced; however, paper strength was practically unchanged, indicating improved affinity of filler particles to fibers in the aqueous papermaking wet end system. XPS analysis and SEM observations of the fillers confirmed the surface encapsulating effect of the modifiers on the filler. SEM images of the paper-sheets indicated that modified filler particles were more effectively adhered and bonded to the pulp fibers, in comparison to unmodified filler particles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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