Optimization of phosphogypsum conversion into calcium carbonate and lithium sulfate monohydrate

2021 ◽  
Vol 109 (2) ◽  
pp. 202
Author(s):  
Yassine Ennaciri ◽  
Mohammed Bettach
Keyword(s):  
Calcium Carbonate ◽  
Phosphoric Acid ◽  
Environmental Risk ◽  
Lithium Sulfate ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Initial Concentration ◽  
Reaction Duration ◽  
X Ray ◽  
Influential Parameters

Phosphogypsum (PG) is an acidic by-product generated during the production of phosphoric acid. Usually this by-product is stockpiled or dumped into water bodies, which causes several environmental pollution problems. The aim of this work is to reduce this environmental risk by producing CaCO3 and Li2SO4.H2O from the conversion of PG by Li2CO3. To optimize the reaction conditions, four parameters have been investigated such as the initial concentration of the reagents, the reaction duration, the temperature and the gypsum purity. In addition, the nature of the resulting products was proved principally by X-ray diffraction technic. The obtained results show that the initial concentration of the reagents and the reaction duration are the most influential parameters, while the temperature has no significance effect on this reaction. Also, the acidity and the presence of impurities into PG induce its reactivity compared than commercial gypsum. The purity of the formed CaCO3 and Li2SO4.H2O at the optimum conversion of PG is 96.08 and 98.71% respectively.

Surfactant involved in Copper Sulfide Nanocrystallites Synthesis

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Claudia Maria Simonescu ◽  
Valentin Serban Teodorescu ◽  
Camelia Capatina
Keyword(s):  
Copper Sulfide ◽  
X Ray Diffraction ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Shape Of Nanoparticles ◽  
Tem Transmission Electron Microscopy ◽  
Shape And Size

This paper presents the obtaining of copper sulfide CuS (covelite) from Cu(CH3COO)2.H2O and thioacetamide (TAA) system. The reaction was conducted in presence or absence of sodium-bis(2-ethylhexyl) sulfosuccinate (Na-AOT). The effects of various reaction parameters on the size and on the shape of nanoparticles have been examined. CuS obtained was characterized by X ray diffraction, IR spectroscopy, TEM � transmission electron microscopy and SAED selected area electron diffraction. The influence of surfactant to the shape and size of CuS (covellite) nanocrystals was established. The size of the nanocrystals varied from 10-60 nm depending on the reaction conditions such as quantity of surfactant.

scholarly journals UV-Accelerated Photocatalytic Degradation of Pesticide over Magnetite and Cobalt Ferrite Decorated Graphene Oxide Composite

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 6
Author(s):  
Asma Tabasum ◽  
Mousa Alghuthaymi ◽  
Umair Yaqub Qazi ◽  
Imran Shahid ◽  
Qamar Abbas ◽  
...  
Keyword(s):  
Spectroscopic Techniques ◽  
Combined Effects ◽  
X Ray Diffraction ◽  
Contributing Factors ◽  
Reaction Conditions ◽  
X Ray ◽  
Oxidant Concentration ◽  
Optimized Conditions ◽  
High Degradation Rate ◽  
Considerable Loss

Pesticides are one of the main organic pollutants as they are highly toxic and extensively used worldwide. The reclamation of wastewater containing pesticides is of utmost importance. For this purpose, GO-doped metal ferrites (GO-Fe3O4 and GO-CoFe2O4) were prepared and characterized using scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopic techniques. Photocatalytic potentials of catalysts were investigated against acetamiprid’s degradation. A detailed review of the parametric study revealed that efficiency of overall Fenton’s process relies on the combined effects of contributing factors, i.e., pH, initial oxidant concentration, catalyst dose, contact time, and acetamiprid load. ~97 and ~90% degradation of the acetamiprid was achieved by GO-CoFe2O4 and GO-Fe3O4, respectively during the first hour under UV radiations at optimized reaction conditions. At optimized conditions (i.e., pH:3, [H2O2]: 14.5 mM (for Fe3O4, GO-Fe3O4, and GO-CoFe2O4) and 21.75 mM (for CoFe2O4), catalysts: 100 mgL−1, time: 60min) the catalysts exhibited excellent performance, with high degradation rate, magnetic power, easy recovery at the end, and efficient reusability (up to 5 cycles without any considerable loss in catalytic activity). A high magnetic character offers its easy separation from aqueous systems using an external magnet. Moreover, the combined effects of experimental variables were assessed simultaneously and justified using response surface methodology (RSM).

Replacing sulfonate by carboxylate: application of pyridyliminocarboxylato copper(II) complexes in rac-lactide polymerization and Chan–Evans–Lam coupling

2019 ◽  
Vol 97 (3) ◽  
pp. 178-190 ◽  
Author(s):  
Valérie Hardouin Duparc ◽  
Clémentine Dimeck ◽  
Frank Schaper
Keyword(s):  
Molecular Sieves ◽  
Weight Control ◽  
Phenylboronic Acid ◽  
Side Reactions ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Induction Periods ◽  
Lactide Polymerization

Copper(II) complexes carrying pyridylmethyleneaminobenzoate or –propanoate ligands, LCuX, were prepared in one-pot reactions from pyridinecarboxaldehyde, aminobenzoic acid or β-alanine, and CuX2 (X = Cl, NO3, OAc, or OTf). All complexes were characterized by single-crystal X-ray diffraction studies and formed either dimers, tetramers, or coordination polymers. Attempted preparation of the respective alkoxide complexes, LCu(OR), was unsuccessful, but use of LCuX/NaOMe mixtures in rac-lactide polymerization indicated under some conditions coordination–insertion polymerization via a copper alkoxide as the mechanism. The complexes performed poorly in rac-lactide polymerization, showing low activities (12 h to completion at 140 °C), low to moderate heterotacticity (Pr = 0.6–0.8), and poor polymer molecular weight control (intramolecular transesterification). They were competent catalysts for Chan–Evans–Lam couplings with phenylboronic acid, without any indication of side reactions such as deboration or aryl homocoupling. The complexes were active in undried methanol, without addition of base, ligand, or molecular sieves. Aniline, n-octylamine, and cyclohexylamine were coupled quantitatively under identical reaction conditions. There is only little influence of the anion on activities (less than a factor of 2) but a strong influence on induction periods. The complexes were not active in CEL coupling with alcohols, phenols, or alkylboronic acids.

scholarly journals Mineralogical stabilization of Ternesite in Belite Sulfo-Aluminate Clinker elaborated from limestone, shale and phosphogypsum

2018 ◽  
Vol 149 ◽  
pp. 01073
Author(s):  
K. Ben Addi ◽  
A. Diouri ◽  
N. Khachani ◽  
A. Boukhari
Keyword(s):  
Infrared Spectroscopy ◽  
Phosphoric Acid ◽  
Portland Cement ◽  
Stability Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability

This paper investigates the mineralogical evolution of sulfoaluminate clinker elaborated from moroccan prime materials limestone, shale and phosphogypsum as a byproduct from phosphoric acid factories. The advantage of the production of this type of clinker is related to the low clinkerisation temperature which is known around 1250°C, and to less consumption quantity of limestone thus enabling less CO2 emissions during the decarbonation process compared to that of Portland cement. In this study we determine the stability conditions of belite sulfoaluminate clinker containing belite (C2S) ye’elimite (C4A3$) and ternesite (C5S2$). The hydration compounds of this clinker are also investigated. The monitoring of the synthesized and hydrated phases is performed by X-Ray Diffraction and Infrared spectroscopy. The results show the formation of ternesite at 800°C and the stabilization of clinker containing y’elminite, belite and ternesite at temperatures between 1100 and 1250°C.

scholarly journals Lanthanoid Complexes Supported by Retro-Claisen Condensation Products of β-Triketonates

2018 ◽  
Author(s):  
Laura Abad Galán ◽  
Alexandre N. Sobolev ◽  
Eli Zysman-Colman ◽  
Mark Ogden ◽  
Massimiliano Massi
Keyword(s):  
Chelating Ligands ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Claisen Condensation ◽  
X Ray ◽  
Condensation Products ◽  
Complexation Reactions ◽  
The Impact ◽  
Low Solubility

<i>β</i>-Triketonates have been recently used as chelating ligands for lanthanoid ions, presenting unique structures varying from polynuclear assemblies to polymers. In an effort to overcome low solubility of the complexes of tribenzoylmethane, four <i>β</i>-triketones with higher lipophilicity were synthesised. Complexation reactions were performed for each of these molecules using different alkaline bases in alcoholic media. X-ray diffraction studies suggested that the ligands were undergoing decomposition under the reaction conditions. This is proposed to be caused by <i>in situ</i>retro-Claisen condensation reactions, consistent with two examples that have been reported previously. The lability of the lanthanoid cations in the presence of a varying set of potential ligands gave rise to structures where one, two, or three of the molecules involved in the retro-Claisen condensationreaction were linked to the lanthanoid centres. These results, along with measurements of ligand decomposition in the presence of base alone, suggest that using solvents of lower polarity will mimimise the impact of the retro-Claisen condensation in these complexes. <br>

Evolution of Crystalline Phase and Morphology of the Products Formed during the Hydrothermal Synthesis of Y2O3 Powders

2011 ◽  
Vol 189-193 ◽  
pp. 1275-1279
Author(s):  
Ying Wang ◽  
Gao Yang Zhao ◽  
Li Yuan
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Treatment ◽  
Crystalline Phase ◽  
Hydrothermal Reaction ◽  
Yttrium Nitrate ◽  
Temperature Reaction ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Transmission Electron

The crystalline phase and morphology of the products formed during the synthesis of yttrium oxide via the hydrothermal treatment yttrium nitrate were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. Products with high OH/NO3ratios are formed with the increasing of hydrothermal treatment. The crystalline phases are evolved from Y2(OH)5.14(NO3)0.86•H2O toY4O(OH)9(NO3) and finally Y(OH)3. The hydrothermal reaction conditions play an important role in the synthesis of the microstructures. Results show the particle size and final morphology of samples could be controlled by reaction temperature, reaction time, and OH-concentration. Sheets, hexagonal and needle-like Y2O3powders are obtained with the hydrothermal treatment of yittrium nitrate at 180 oC to 200oC for 2-8 hours at pH 9-13.

Effects of Rotation Speeds and Media Density on Ground Calcium Carbonate during Ultrafine Grinding Process in Planetary Mill

2014 ◽  
Vol 997 ◽  
pp. 542-545
Author(s):  
Yan Ru Chen ◽  
Yi Chen Lu ◽  
Xiao Min Lian ◽  
Chao Yang Li ◽  
Shui Lin Zheng
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Rotational Speed ◽  
Planetary Mill ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dry Grinding ◽  
Ultrafine Grinding ◽  
Effects Of Rotation ◽  
Ground Calcium Carbonate

Superfine ground calcium carbonate (GCC) produced by carbonate minerals is a widely used inorganic powder material. In order to get a finer GCC powder with narrow distribution span, the effect of rotational speed and media density on ground GCC were studied by dry grinding GCC in a planetary ball mill under different rotational speed and various media density. The grinding limit-particle size and distribution of grinding calcium carbonate were measured by centrifugal sedimentation granulometer. The structure of GCC was measured by X-ray diffraction. The result shows that low rotational speed and high-density media is conducive to get a product with smaller particle size and narrow size distribution; crystal plane (012) and (122) are more stable than (018) and (116).

Effects of Reaction Conditions on Deposition of Ferrites from Alkaline Metal Hydroxide Gels

1997 ◽  
Vol 495 ◽  
Author(s):  
Karl F. Schoch ◽  
Theodore R. Vasilow
Keyword(s):  
Flow Rate ◽  
Oxygen Flow Rate ◽  
Oxygen Flow ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Metal Hydroxides ◽  
X Ray ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Mg Content

ABSTRACTFormation of ferrites from aqueous solution of metal salts is a well known process involving precipitation of metal hydroxides followed by oxidation of the resulting gel. The purpose of the present work was to determine the effects oxygen flow rate on the progress of the reaction and on the structure and properties of the resulting precipitate. The reaction was carried out at 70°C with pH of 10.5 and oxygen flow rate of 2,4, or 8 standard liters per hour. The progress of the reaction was monitored by following the oxidation-reduction potential of the solution, which changes dramatically after the Fe(II) is consumed. The reaction rate increased with increasing oxygen flow rate. The Mg content of the precipitate was lower than that of the reaction mixture, possibly because of the pH of the reaction mixture. X-ray diffraction and infrared spectroscopy confirmed formation of a ferrite under these conditions.

Synthesis of Precipitate Calcium Carbonate with Variation Morphology from Limestone by Using Solution Mixing Method

2019 ◽  
Vol 966 ◽  
pp. 200-203
Author(s):  
Zaenal Arifin ◽  
Triwikantoro ◽  
Bintoro Anang Subagyo ◽  
Mochamad Zainuri ◽  
Darminto
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Molar Ratio ◽  
Mixing Process ◽  
X Ray Diffraction ◽  
Precipitate Calcium Carbonate ◽  
X Ray ◽  
Mixing Method ◽  
Scanning Electron

Abstract. In this study, the CaCO3 powder has been successfully synthesized by mixing CaCl2 from natural limestone and Na2CO3 in the same molar ratio. The mixing process of solutions was carried out by employing the molar contents of 0.125, 0.25, 0.375 and 0.5M at varying temperatures of 30, 40, 60 and 80ᴼC. The produced CaCO3 microparticles were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The highest content of aragonite phase with morphology rod-like of the samples is around 29 wt%, resulting from the process using solution of 0.125 M at 80 ᴼC. While at 30 ᴼC and 40 ᴼC produced 100 wt% calcite phase.

Synthesis of Novel 2-Alkoxy-5H-benzo[6,7]cyclohepta[1,2-b]pyridine-3-carbonitriles

2003 ◽  
Vol 58 (7) ◽  
pp. 698-703 ◽  
Author(s):  
Adel S. Girgis ◽  
I. S. Ahmed-Farag
Keyword(s):  
Single Crystal ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Independent Synthesis

Reaction of 6-arylmethylene-6,7,8,9-tetrahydro-5H-benzocyclo-hepten-5-ones (1) with malononitrile in the appropriate alcohol in the presence of sodium afforded the corresponding 2-alkoxy-4-aryl- 6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-b]pyridine-3-carbonitriles (2) and not their isomeric forms 2-alkoxy-4-aryl-6,7-dihydro-5H-benzo[3,4]-cyclohepta[1,2-c]pyridine-1-carbonitriles (3). The proposed structure was confirmed via independent synthesis of (2) through the reaction of 6,7,8,9- tetrahydro-5-benzocycloheptenone (4) with the appropriate ylidenemalononitriles 5 under the same reaction conditions. Single crystal X-ray diffraction proves the structures of 2a,b.

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