scholarly journals Experimental Study on the Dissolution Behavior of Calcium Fluoride

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 988
Author(s):  
Suchandra Sar ◽  
Caisa Samuelsson ◽  
Fredrik Engström ◽  
Lena Sundqvist Ökvist
Keyword(s):  
Calcium Fluoride ◽  
Raw Materials ◽  
Extraction Process ◽  
Thermodynamic Calculations ◽  
Dissolution Behavior ◽  
Zinc Extraction ◽  
Solubility Behavior ◽  
Dissolution Tests ◽  
Waelz Oxide ◽  
Co Precipitation

The presence of halogens has an adverse effect on the zinc extraction process through electrowinning, the last phase of the RLE (Roasting, Leaching and Electrowinning) zinc extraction route. Fluoride (F−) may be present as calcium fluoride (CaF2) and this is, for example, the case in double leached Waelz oxide (DLWO). Efficient removal of F− from primary and secondary raw materials for zinc extraction results in a simplified process and increases flexibility in the selection of raw materials. Understanding of the solubility behavior of pure CaF2 can give valuable information on treatment for maximized halogen removal. Dissolution of CaF2 was studied with the addition of sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3). Dissolution studies were combined with thermodynamic calculations to understand the solubility behavior of CaF2 under different conditions. Results from the experiments and the thermodynamic calculations show that Na2CO3 and NaHCO3 have similar behavior if the pH is controlled at the same value. The available carbonate (CO32−) ion in the system limits the concentration of calcium (Ca2+) ion by precipitation of CaCO3, which enhances the dissolution of CaF2. At higher temperatures and pH, calcite, vaterite, and aragonite were formed and co-precipitation of CaF2 along with calcium carbonate (CaCO3) was observed. At lower temperatures and lower pH levels, only calcite and vaterite were formed and a coating by CaCO3 on CaF2 was found to hinder complete dissolution reaction. The results of this study indicate that the temperature along with the reagents used for the dissolution tests have a significant impact on the CaCO3 polymorph mixture (calcite, vaterite and aragonite) formation.

scholarly journals Preparation of composite coagulant of PFM-PDMDAAC and its coagulation performance in treatment of landfill leachate

2015 ◽  
Vol 5 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Simin Li ◽  
Yongkang Lv ◽  
Zhanmeng Liu
Keyword(s):  
Landfill Leachate ◽  
Raw Materials ◽  
Oxygen Demand ◽  
X Ray Diffraction ◽  
Mechanical Mixing ◽  
Coagulation Performance ◽  
Coagulation Mechanism ◽  
As Adsorption ◽  
Co Precipitation ◽  
Composite Coagulant

A novel inorganic–organic composite coagulant, poly-ferric-magnesium (PFM) polydimethyldiallylammonium chloride (PDMDAAC), was prepared using FeSO4, MgSO4 and PDMDAAC as raw materials and was introduced to treat landfill leachate. The coagulation performance of the new reagent was evaluated and compared with those of other coagulants. The new reagent was characterized in terms of the analysis of ferron-timed spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The coagulation mechanism was investigated by measuring the ζ-potential reduction and chemical oxygen demand removal at different dosages. Coagulation experiments revealed that the new reagent exhibited better coagulation performance compared with the simple PFM and the PFM + PDMDAAC. Ferron-timed spectroscopy showed that the new reagent exhibited increased effective polymer species concentration. XRD and FTIR spectroscopy showed that the new reagent was not a simple mechanical mixing of PFM and PDMDAAC, but a composite system with inorganic–organic complex interpenetration networks. The predominant coagulation mechanism of the new reagent was charge neutralization at low dosages, as well as adsorption bridging and co-precipitation netting at high dosages, when treating landfill leachate.

scholarly journals Pre-treatment of desalination feed seawater by Jordanian Tripoli, Pozzolana, and Feldspar: Batch experiments

2011 ◽  
Vol 17 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Aiman Al-Rawajfeh ◽  
Khaldoon Al-Whoosh ◽  
Dwairi Al ◽  
Ahmad Al-Maaberah ◽  
Amer Tarawneh
Keyword(s):  
Layered Double Hydroxide ◽  
Metal Ion ◽  
Raw Materials ◽  
Batch Experiments ◽  
Initial Concentration ◽  
Considerable Potential ◽  
Ion Concentrations ◽  
Pre Treatment ◽  
Co Precipitation ◽  
Double Hydroxide

In this research, composites of layered double hydroxide (LDH) with three Jordanian natural raw materials; Tripoli (T), Pozzolana (P) and Feldspar (F) were prepared by co-precipitation and have been used for feed seawater pre-treatment. The data reveals that percent adsorption decreased with increase in initial concentration, but the actual amount of adsorbed ions per unit mass of LDH/T-P-F increased with increase in metal ion concentrations. The values of ?Go were negative and within 21 to 26 KJ/mol, while the values of ?Ho and ?So were positive and within the range of 0.1 to 25 KJ/mol. The values of ?H?, ?S?, and ?G? indicate the favorability of physisorption and show that the LDH/T-P-F composites have a considerable potential as adsorbents for the removal of ions from seawater.

Extraction Process of Amaranthine Pigment Keeping the Water Wax Fuit Biological Active

2013 ◽  
Vol 295-298 ◽  
pp. 150-154
Author(s):  
Feng Jie Wang ◽  
Xin Qiao Dong ◽  
Xiao Liu
Keyword(s):  
Citric Acid ◽  
Extraction Method ◽  
Raw Materials ◽  
Extraction Process ◽  
Extraction Yield ◽  
Extraction Temperature ◽  
Natural Pigment ◽  
Pigment Extraction ◽  
Acid Aqueous Solution ◽  
The Stability

Development natural pigment retained a variety of nutrition composition is extremely research value.Water Wax Trees Fruit was as raw materials,citric acid aqueous solution was as extracting agent.Amaranthine pigment extraction method were studied on fully grasping the stability of the natural amaranthine pigment and no damage to the water wax fruit biological activity.The effect of extraction yield were studied on Water Wax Trees Fruit natural amaranthine pigment.The results show that the better extraction conditions are extraction temperature at 70 °C, extraction time for 3h,citric acid concentration1.0 % , the material/liquid ration(g/ml) 1:5.The extraction yield is 2.95%.Ultraviolet absorption maximum wavelength is 280 nm.

scholarly journals Intensification of the extraction process of phenolic compounds from Acorus calamus leaves

2021 ◽  
pp. 4-10
Author(s):  
Oleksiy Andryushayev ◽  
Olena Ruban ◽  
Yuliia Maslii ◽  
Inna Rusak
Keyword(s):  
Phenolic Compounds ◽  
Raw Materials ◽  
Extraction Process ◽  
Raw Material ◽  
Acorus Calamus ◽  
Optimal Conditions ◽  
Ultrasonic Action ◽  
Different Temperatures ◽  
Method Of Extraction ◽  
Temperature Time

The aim. To determine the intensified method of extraction of phenolic compounds from Acorus calamus leaves and optimal conditions for the process. Materials and methods. In order to develop the optimal intensified method of extraction samples were prepared in different conditions of raw materials-extractant ratio, temperature, time and multiplicity. As a raw materials spectrophotometrically pre-standardized Acorus calamus leaves were used. The extraction was carried out in a hermetically sealed ultrasonic extraction reactor PEX 1 (REUS, Contes, France). As the criteria of extraction efficiency were indicators of dry residue and total amount of flavonoids determined using methods described in State Pharmacopoeia of Ukraine. The amount of flavonoids was determined spectrophotometrically on a certified device Specord 200 (Analytik Jena, Germany). Results. According to our research results it was found that ultrasonic action and addition of surfactant significantly improves the efficiency of the extraction process. The optimal conditions for the process were determined. Experimentally proved that the rational raw material-extractant ratio is 1:15. Comparative study of the extraction process with different temperatures showed that the highest amount of extractives is achieved at temperature 70 °C and 45 min of duration. The optimal extraction multiplicity is 3. Conclusions. As a result of the study, the intensified extraction method for Acorus calamus leaves – re-maceration with ultrasound – was established. The conducted researches allowed to develop the method of extraction, expedient in the conditions of the modern pharmaceutical industry.

scholarly journals PRODUCTION OF EXTRACTS FROM VEGETABLE RAW MATERIALS BY CARBON DIOXIDE

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
K. Gafurov ◽  
B. Muhammadiev ◽  
Sh. Mirzaeva ◽  
F. Kuldosheva
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Co2 ◽  
Raw Materials ◽  
Maximum Yield ◽  
Volumetric Flow Rate ◽  
Extraction Process ◽  
Raw Material ◽  
Critical Conditions ◽  
Plant Materials ◽  
Laboratory Setup

The unique properties of supercritical carbon dioxide as a solvent are widely used for extraction. In supercritical media, the dissolution of molecules of various chemical nature is possible. The purpose of this investigation was to study the extraction process and obtain extracts from valuable regional plant materials by applying CO2 extraction under pre- and supercritical conditions. The objects of research were: ground seeds of melon, pumpkin and licorice roots, as well as mint leaves, mulberry and jida flowers. For extraction, a laboratory setup was used that allows extraction when the CO2 is supplied by a high-pressure plunger pump in the sub- and supercritical state using a heat pump. The pressure range is 3-15 MPa, temperatures 295–330 K, and the volumetric flow rate above the critical CO2 is 800–900 g. Experiments with ground seeds of melon and pumpkin showed that as a result of 4 sequentially performed extraction cycles on a single load with supercritical CO2 parameters ( 315–330 K; 3–7.5 MPa) the decrease in the mass of melon seeds was 90 g (pumpkins 80 g). During the total extraction time (2.5 hours), 20 kg of CO2 were pumped through the reactor (25 l at 290 K and 6.8 MPa), while the average oil content in the extract was 4 g per 1 kg of CO2 (3.0 g per 1 l of SС-CO2) In experiments with jida flowers, the maximum amount of solid extractable substance (2% by weight of the raw material) was obtained at a temperature in the extractor of 308 K and a pressure of 7.5 MPa. Upon extraction under critical conditions in collection 2, the liquid phase was absent; only a yellow-green paste was released in it. According to the results of experiments with mint leaves, the maximum yield of a greenish liquid was observed at T = 315 K and P = 4 MPa., Mulberry - at T = 306 K and P = 6.0 MPa. The results of the extraction of oils and extracts from ground seeds of melon, pumpkin and licorice roots, as well as mint leaves, mulberries and jida flowers confirm that the maximum yield of the extracted substance is achieved with supercritical CO2 parameters in the extractor (310 K, 7.5 MPa). When liquid CO2 is extracted (300 K and 6-8 MPa), up to 2% of a yellow substance is extracted, which does not differ in appearance from a supercritical extract.

scholarly journals CONCOMITANT EXTRACTION PROCESS OF NIOBIUM AT THE TITANIUM TETRACHLORIDE PRODUCTION

2020 ◽  
pp. 173-177
Author(s):  
Т.К. Sarsembekov ◽  
Т.B. Yanko ◽  
S.A. Sidorenko ◽  
M.M. Pylypenko
Keyword(s):  
Phase Transformations ◽  
Nuclear Power ◽  
Titanium Tetrachloride ◽  
Raw Materials ◽  
Extraction Process ◽  
By Products ◽  
Titanium Raw Materials

Development of the fundamentals of a technology for producing niobium by the concomitant extraction in the process of production of titanium tetrachloride from titanium raw materials. The paper provides data on the amount of niobium contained in the feedstock to produce titanium tetrachloride, the distribution of niobium during processing by products and waste. The forms of phase transformations and transitions of niobium during processing are considered. Schemes for processing niobium-containing chloride materials and technologies for their further application for producing alloys for nuclear power are proposed.

scholarly journals Emulsion Liquid Membrane Extraction of Turquoise Blue Reactive Dye–Study on Membrane Breakage and Swelling

2017 ◽  
Vol 11 (1) ◽  
Author(s):  
N. Othman ◽  
S. N. Zailani ◽  
N. Mili
Keyword(s):  
Liquid Membrane ◽  
Raw Materials ◽  
Extraction Process ◽  
Reactive Dye ◽  
Point Of View ◽  
Membrane Extraction ◽  
Hydrodynamic Condition ◽  
Emulsion Liquid Membrane ◽  
Liquid Membrane Extraction ◽  
Span 80

Reactive dyes are the principal dyes used in batik industry in Malaysia. From the environmental point of view the dyes should be removed from wastewater because they are toxic in nature. Therefore, the removal and recovery of dyes from batik industry wastewater is absolute necessity in order to save raw materials and to protect environment from hazardous compounds. An experiment was carried out using emulsion liquid membrane (ELM) process in batch system to study the extraction behaviour of Turquoise Blue which is commonly used in batik industry. Several parameters have been studied such as carrier and surfactant/emulsifier concentrations, stripping agent and extraction time. The liquid membrane was formulated using kerosene as diluent, SPAN 80 as emulsifier and tri-dodecylamine (TDA) as a carrier. Hydrodynamic condition to generate extraction process was at 1:3 treat ratio and 250 rpm stirring speed for 10 minutes while the emulsification was done at 12000 rpm for 5 minutes using homogenizer. The result obtained shows that, more than 70% of Turquoise Blue was extracted at favourable condition of 0.07 M TDA, 7% (w/v) SPAN 80 and 0.5 M Thiourea in 1 M NaOH.

Optimization of Extraction Conditions of Essential Oil from Latifolia miq Roots and Stems with Supercritical CO2 Fluid

2013 ◽  
Vol 726-731 ◽  
pp. 4512-4516
Author(s):  
Ren Yong Gu ◽  
Zhi Ping Li
Keyword(s):  
Essential Oil ◽  
Optimum Condition ◽  
Raw Materials ◽  
Extraction Process ◽  
Orthogonal Test ◽  
Single Factor ◽  
Extraction Condition ◽  
Optimum Extraction ◽  
Optimum Extraction Condition

Studying on the extraction process of essential oil from Latifolia Miq roots and stems by Supercritical CO2 extraction. The effects on extracting ratio were investigated by using single factor test, adding content of grinding fineness of raw materials,extracting temperature, extracting pressure and extracting time. The optimum extraction condition was determined by orthogonal test. The results showed that the optimum condition of the extraction was as follows: grinding fineness 90 mesh, extracting temperature 45 °C, extracting pressure 20 MPa and extracting time 2.5 h.

Preparation and Electrochemical Performance of Mn3O4/GR Composites Electrode Material in Supercapacitors

2019 ◽  
Vol 807 ◽  
pp. 50-56
Author(s):  
Yun Long Zhou ◽  
Zhi Biao Hu ◽  
Li Mei Wu ◽  
Jiao Hao Wu
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Precipitation Method ◽  
Electrochemical Performances ◽  
Manganese Sulfate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
A Current ◽  
Discharge Test

Using hydrated manganese sulfate and general type graphene (GR) as raw materials, Mn3O4/GR composite has been successfully prepared by the liquid phase chemical co-precipitation method at room temperature. X-ray diffraction (XRD) was used to investigate the phase structure of Mn3O4powder and Mn3O4/GR composite; The electrochemical performances of the samples were elucidated by cyclic voltammetry and galvanostatic charge-discharge test in 0.5 mol/L Na2SO4electrolyte. The results show that the Mn3O4/GR composite possesses graphene phase and good reversibility; the composite also displays a specific capacitance of 318.8 F/g at a current density of 1 A/g.

Study on the Characterization of Zinc Ferrite High-Temperature Coal Gas Desulfurization Agent

2010 ◽  
Vol 129-131 ◽  
pp. 1233-1237
Author(s):  
Hong Yan Xu ◽  
Mei Sheng Liang ◽  
Chun Hu Li
Keyword(s):  
Zinc Ferrite ◽  
Raw Materials ◽  
Particle Diameter ◽  
Textural Properties ◽  
Zinc Nitrate ◽  
Gas Absorption ◽  
Precipitation Method ◽  
Ferric Nitrate ◽  
The One ◽  
Co Precipitation

Using ferric nitrate, zinc nitrate, ammonia liquor and binder as main raw materials, five kinds of zinc ferrite sorbents were prepared by the co-precipitation method. The effects of the different binders on the structure and texture of zinc ferrite sorbents were investigated. The morphology, composite structure, pore properties, and mechanical strength were studied by using modern several physicochemical techniques such as powder X-ray diffraction (XRD), scanning electronic microscopy (SEM), strength tester and gas absorption meter. It is showed that spinel structure ZnFe2O4 is not affected by different binders，and its particle diameter is in micron leve1. The spinel structures are present in the sorbents that have been calcined at 750 0C.. The sorbent employed kaolinite as binder is the best one of the five types of sorbents for desulfurization, while the one employed diatomite is the worst.Different binders modify the textural properties, modifying consequently the sorbent reactivity. Furthermore, the reactivity and sulfur capacity of sorbents are increasing with an increase in the pore volume.

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