scholarly journals Reactivity of calcium carbonate prepared from flue gas desulfurization gypsum

2019 ◽  
Vol 12 (1) ◽  
pp. 14-21
Author(s):  
Jana Jurišová ◽  
Vladimír Danielik ◽  
Pavel Fellner ◽  
Milan Králik ◽  
Tomáš Foltinovič
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Flue Gas ◽  
Average Particle Size ◽  
Initial Reaction Rate ◽  
Flue Gas Desulfurization ◽  
Initial Reaction ◽  
Average Particle ◽  
Precipitated Calcium Carbonate ◽  
Compact Structure

Abstract Reactivity of various calcium carbonate samples for flue gas desulfurization was tested. Two groups of CaCO3 samples were considered; natural limestone containing calcite phase dominantly and samples prepared by the conversion of gypsum with ammonium and carbon dioxide (precipitated CaCO3) containing different amounts of calcite, aragonite and vaterite. Reactivity of precipitated calcium carbonate depends primarily on the particle size, similarly as in case of industrial samples. The initial reaction rate was comparable with the industrial limestones for samples with the average particle size lower than 15 μm. However, the conversion of laboratory samples was significantly higher after 5 min of the reaction. Phase composition of the precipitated calcium carbonate has a minor but noticeable impact on the reactivity. The presence of vaterite slightly increased the reactivity, which is in accordance with its lower compact structure in comparison with calcite and aragonite. Unexpected effect of the increased content of aragonite, which is the most compact phase in comparison with calcite and vaterite, was observed. If calcium carbonate contains up to approximately 30 % of aragonite the reactivity increases, which can be explained by the SEM pictures showing agglomerate composition with relatively high specific surface. At higher contents of aragonite, the reactivity decreases. All the obtained results proved the suitability of precipitated CaCO3 prepared from flue gas desulfurization gypsum to be recycled in the flue gas desulfurization process.

The Performance of Precipitated Calcium Carbonate Fillers in Fine Quality Printing and Writing Papers

1990 ◽  
Vol 197 ◽  
Author(s):  
Robert A. Gill
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Surface Area ◽  
Average Particle Size ◽  
Filler Materials ◽  
Average Particle ◽  
Strong Correlations ◽  
Precipitated Calcium Carbonate ◽  
Paper Properties ◽  
Custom Made

ABSTRACTThe trend toward alkaline papermaking has accelerated over the past four years due to the availability of inexpensive, high quality precipitated calcium carbonate. This movement has been largely brought about through on-site production of precipitated calcium carbonate (PCC). Over ten facilities exist in North America providing the host mills with custom-made PCC products to provide specific properties for the paper grades being manufactured.Laboratory studies were recently conducted to investigate the performance of paper-grade PCC fillers in fine quality printing papers. This investigation focused on the effect of changes in PCC particle size, size distribution, surface area, and morphology on paper properties. The PCC fillers were also compared to other filler materials such as ground limestone and kaolin.In general, the results show that sheet properties are greatly influenced by the size and shape of the PCC product used. The data reveal strong correlations between average particle size and/or surface area, and sheet properties such as opacity, porosity, tensile strength, bulk, and sizing within certain filler morphologies.

Effect of Several Factors on the Synthesis of Calcium Hydroxide Prepared by Spray Drying Method Using Limestone

2007 ◽  
Vol 544-545 ◽  
pp. 733-736
Author(s):  
Moon Kwan Choi ◽  
Jin Sang Cho ◽  
Sung Min Joo ◽  
Jin Koo Park ◽  
Ji Whan Ahn ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Spray Drying ◽  
Feeding Rate ◽  
Spherical Shape ◽  
Initial Reaction ◽  
Outlet Temperature ◽  
Drying Method ◽  
Precipitated Calcium Carbonate ◽  
Carbonation Process

The purpose of this work is to influence of CaO concentrations of 5.0 wt.% and 10.0 wt.%, slurry feeding rate of 200~400 /min, rotating rate of drum of 5,000 and 10,000 rpm, inlet and outlet temperature on the synthesis of Ca(OH)2 powder, and the synthesis of precipitated calcium carbonate by carbonation process using Ca(OH)2 prepared by spray drying method. As the feeding rate of slurry was increased, the particle size of Ca(OH)2 was decreased. Regardless of rotating rate of drum, when the concentration of CaO was 5.0 wt.% and 10.0 wt.%, the morphology of Ca(OH)2 showed spherical shape of 10~30 μm and 20~60 μm, respectively. The specific surface area of synthesized Ca(OH)2 was 27~30 m2/g. When the initial reaction temperature was 11 °C and 30 °C, the shape and particle size of precipitated calcium carbonate synthesized in the carbonation process showed the rectangular shape of 0.1~0.4 μm and the spindle shape of 0.5~1.0 μm, respectively.

Morphology-Controlled CaCO3 Nanostructures by Modified Co-Precipitation in Pulsed Mode

2015 ◽  
Vol 752-753 ◽  
pp. 148-153
Author(s):  
M.M. Nassar ◽  
Taha Ebrahiem Farrag ◽  
M.S. Mahmoud ◽  
Sayed Abdelmonem
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Rotation Speed ◽  
Average Particle Size ◽  
Calcium Nitrate ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray ◽  
Co Precipitation ◽  
Pulsed Mixing

Calcium carbonate nanoparticles and nanorods were synthesized by precipitation from saturated sodium carbonate and calcium nitrate aqueous solutions through co precipitation method. A new rout of synthesis was done by both using pulsed mixing method and controlling the addition of calcium nitrate. The effect of the agitation speed, and the temperature on particle size and morphology were investigated. Particles were characterized using X-ray Microanalysis, X-ray analysis (XRD) and scanning electron microscopy (SEM). The results indicated that increasing the mixer rotation speed from 3425 to 15900 (rpm) decreases the average particle size to 64±7 nm. A rapid nucleation then aggregation induced by excessive shear force phenomena could explain this observation. Moreover, by increasing the reaction temperature, the products were converted from nanoparticle to nanorods. The maximum attainable aspect ratio was 6.23 at temperature of 75°C and rotation speed of 3425. Generally, temperature raise promoted a significant homoepitaxial growth in one direction toward the formation of calcite nanorods. Overall, this study can open new avenues to control the morphology of the calcium carbonate nanostructures.

Effect of silicon on properties of causticized calcium carbonate produced in wheat straw soda pulping

TAPPI Journal ◽  
2014 ◽  
Vol 13 (7) ◽  
pp. 41-46 ◽  
Author(s):  
XINXING XIA ◽  
XING WANG ◽  
MINGZHU DU ◽  
ZHAOQING LU
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Wheat Straw ◽  
Silicon Content ◽  
Average Particle Size ◽  
Recovery Process ◽  
Crystal Form ◽  
Silica Content ◽  
Chemical Recovery ◽  
Average Particle

Green liquor in the chemical recovery process of wheat straw pulping was treated with carbon dioxide to precipitate silicon. We report on the properties of causticized calcium carbonate (CCC) with different silicon contents, as well as its impact on paper quality when used as filler. The research results showed that silicon content had no significant effect on the crystal form of CCC, and all crystals were formed as calcite. Calcium silicate itself did not polymerize to form crystal in the course of causticization. Instead, silicon existed as a solid solution in CCC. The morphology of CCC changed gradually from amorphous to square with the decrease of silicon content. The brightness of CCC increased slightly and the average particle size tended to grow after removal of silicon. When 97% of silicon was removed and the average particle size reached 6.84 μm, the specific surface area and sedimentation volume decreased gradually as the desilication rate increased. When CCC was used as filler and silicon in CCC decreased, opacity remained nearly the same and brightness increased slightly; however, the Cobb value decreased significantly and the sizing efficiency obviously improved. When the silica content decreased to 3.2% the Cobb value was 27.7 g/m2, which reached the standard for fine paper sizing. The tear strength increased gradually, while the tensile strength decreased with the reduction of silicon.

Characterization of Precipitated Calcium Carbonate from Eggshell Powder

2011 ◽  
Vol 410 ◽  
pp. 228-231
Author(s):  
Wimonlak Sutapun ◽  
Yupaporn Ruksakulpiwat ◽  
Nitinat Suppakarn ◽  
Rachasit Jeencham ◽  
Ajcharaporn Aontee
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Average Diameter ◽  
Single Step ◽  
Average Particle ◽  
Precipitated Calcium Carbonate

In this work, PCC was prepared from chicken eggshell powder (ESP) by dissolving 100 g ESP in 1 M hydrochloric acid at room temperature. Under vigorous stirring, PCC was precipitated from the ESP-dissolved solution using 1 M sodium carbonate solution. The dried PESP (precipitated eggshell powder) was then characterized by particle size analyzer, X-ray diffractometer, Brunauer-Emmett-Teller surface analyzer and thermogravimetric analyzer. The particle shape of the PESP was revealed using scanning electron microscope. It was found that PESP was a binary mixer of calcite and vaterite. The particles were in cubic and spherical shape. In addition, PESP had a volume average diameter of 8.16 μm, D[V, 0.5] of 7.22 μm, D[V,0.9] of 16.57 μm, and the specific surface area of 4.38 m2/g. The average particle size was lower than and the specific surface area was higher than that of ESP. The decomposition process of PESP occured in a single step between 610 and 770 °C, with 44.43% weight loss.

Synthesis and Characterization of Calcium Carbonate Nanoparticles via Bacterial Mineralization in Steel Slag Comprising Cementitious Materials

2020 ◽  
Vol 12 (5) ◽  
pp. 760-768 ◽  
Author(s):  
Haihe Yi ◽  
Chun-Xiang Qian
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Compressive Strength ◽  
Calcium Carbonate ◽  
Building Materials ◽  
Average Particle Size ◽  
Steel Slag ◽  
Average Particle ◽  
Calcium Carbonate Precipitate ◽  
X Ray

Bacteria-induced mineralization is a new technique to produce calcium carbonate in steel slag for the preparation of building materials. Calcium carbonate nanoparticles were precipitated as a result of the enzymatic activity of Bacillus mucilaginous subtilis in steel slag. The crystal structure and morphology of the calcium carbonate precipitate were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), atomic force microscopy (AFM), while thermal properties were studied by thermogravimetric-differential scanning calorimetry (TG-DSC) analysis. The experimental results showed that the microstructure of calcium carbonate precipitate induced by the reproductive enzymes of Bacillus mucilaginous differs from the chemical precipitation in simulated pore solution of steel slag. Powder XRD patterns confirmed the formation of Bacillus mucilaginous subtilis-induced calcium carbonate with an average particle size of 42.1 nm, while the average particle size of the chemically synthesized calcium carbonate was 59.3 nm. Compared with the chemical synthesis, we found that the decomposition temperature of calcite by bacterial precipitation was higher than that for the chemically-precipitated calcite. The compressive strength improved with the amount of bacterial content. Bacterial mineralization could accelerate the rate of carbon sequestration in the mineralization process. The content of calcium carbonate in microbial mineralized steel slag increased obviously. The compressive strength of steel slag mortar with 1.5% bacterial reached up to 51.5 MPa, the compressive strength increased over 50% compared with the carbonized steel slag mortar. The micron-size calcite by bacterial mineralization resulted in a more compact structure. Our study suggests that microbial mineralization technology is a good method to utilize steel slag for building materials.

Determination of grinding parameters of fenugreek seed

1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh
Keyword(s):  
Particle Size ◽  
Energy Consumption ◽  
Moisture Content ◽  
Specific Energy ◽  
Feed Rate ◽  
Average Particle Size ◽  
Specific Energy Consumption ◽  
Average Particle ◽  
Fenugreek Seeds ◽  
Fenugreek Seed

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  

Formulating SLN and NLC as Innovative Drug Delivery Systems for Non-Invasive Routes of Drug Administration

2020 ◽  
Vol 27 (22) ◽  
pp. 3623-3656 ◽  
Author(s):  
Bruno Fonseca-Santos ◽  
Patrícia Bento Silva ◽  
Roberta Balansin Rigon ◽  
Mariana Rillo Sato ◽  
Marlus Chorilli
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Drug Release ◽  
Drug Loading ◽  
Average Particle Size ◽  
Delivery Systems ◽  
Average Particle ◽  
Minor Importance ◽  
Routes Of Administration ◽  
Non Invasive

Colloidal carriers diverge depending on their composition, ability to incorporate drugs and applicability, but the common feature is the small average particle size. Among the carriers with the potential nanostructured drug delivery application there are SLN and NLC. These nanostructured systems consist of complex lipids and highly purified mixtures of glycerides having varying particle size. Also, these systems have shown physical stability, protection capacity of unstable drugs, release control ability, excellent tolerability, possibility of vectorization, and no reported production problems related to large-scale. Several production procedures can be applied to achieve high association efficiency between the bioactive and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes Lipid-based nanocarriers (LNCs) versatile delivery system for various routes of administration. The route of administration has a significant impact on the therapeutic outcome of a drug. Thus, the non-invasive routes, which were of minor importance as parts of drug delivery in the past, have assumed added importance drugs, proteins, peptides and biopharmaceuticals drug delivery and these include nasal, buccal, vaginal and transdermal routes. The objective of this paper is to present the state of the art concerning the application of the lipid nanocarriers designated for non-invasive routes of administration. In this manner, this review presents an innovative technological platform to develop nanostructured delivery systems with great versatility of application in non-invasive routes of administration and targeting drug release.

Azithromycin nanosuspension preparation using evaporative precipitation into aqueous solution (EPAS) method and its comparative dissolution study

2020 ◽  
Vol 17 ◽  
Author(s):  
Mohammad Hossain Shariare ◽  
Tonmoy Kumar Mondal ◽  
Hani Alothaid ◽  
Md. Didaruzzaman Sohel ◽  
MD Wadud ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Dissolution Rate ◽  
Average Particle Size ◽  
Scale Up ◽  
Average Particle ◽  
Total Drug ◽  
Residual Solvent ◽  
Dissolution Study ◽  
Drug Content

Aim: EPAS (evaporative precipitation into aqueous solution) was used in the current studies to prepare azithromycin nanosuspensions and investigate the physicochemical characteristics for the nanosuspension batches with the aim of enhancing the dissolution rate of the nanopreparation to improve bioavailability. Methods: EPAS method used in this study for preparing azithromycin nanosuspension was achieved through developing an in-house instrumentation method. Particle size distribution was measured using Zetasizer Nano S without sample dilution. Dissolved azithromycin nanosuspensions were also compared with raw azithromycin powder and commercially available products. Total drug content of nanosuspension batches were measured using an Ultra-Performance Liquid Chromatography (UPLC) system with Photodiode Array (PDA) detector while residual solvent was measured using gas chromatography (GC). Results: The average particle size of azithromycin nanosuspension was 447.2 nm and total drug content was measured to be 97.81% upon recovery. Dissolution study data showed significant increase in dissolution rate for nanosuspension batch when compared to raw azithromycin and commercial version (microsuspension). The residual solvent found for azithromycin nanosuspension is 0.000098023 mg/ mL or 98.023 ppb. Conclusion: EPAS was successfully used to prepare azithromycin nanoparticles that exhibited significantly enhanced dissolution rate. Further studies are required to scale up the process and determine long term stability of the nanoparticles.

scholarly journals Evaluation of the Effects of Filler Fineness on the Properties of an Epoxy Asphalt Mixture

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2003
Author(s):  
Wei Xu ◽  
Jintao Wei ◽  
Zhengxiong Chen ◽  
Feng Wang ◽  
Jian Zhao
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Asphalt Mixture ◽  
Average Particle ◽  
Fine Dust ◽  
Bonding Structure ◽  
Epoxy Asphalt ◽  
Mineral Powder ◽  
Marshall Stability ◽  
Mixture Sample

The type and fineness of a filler significantly affect the performance of an asphalt mixture. There is a lack of specific research on the effects of filler fineness and dust from aggregates on the properties of epoxy asphalt (EA) mixtures. The effects of aggregate dust and mineral powder on the properties of an EA mixture were evaluated. These filler were tested to determine their fineness, specific surface area and mineral composition. The effects of these fillers on the EA mastic sample and mixture were evaluated. The morphology of the EA mastic samples was analyzed using scanning electron microscopy (SEM). The effects of the fillers on the Marshall stability, tensile strength and fatigue performance of the EA mixture were evaluated. The dust from the aggregates exhibited an even particle size distribution, and its average particle size was approximately 20% of that of the mineral powder. The SEM microanalysis showed that the EA mastic sample containing relatively fine dust formed a tight and dense interfacial bonding structure with the aggregate. The EA mixture sample containing filler composed of dust from aggregate had a significantly higher strength and longer fatigue life than that of the EA sample containing filler composed of mineral powder.

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