Experimental Study on De-Fluorinating by Adding Dilute Alkali in Wet Phosphoric Acid Extraction Organic Phase

2014 ◽  
Vol 662 ◽  
pp. 46-50
Author(s):  
Hai Yan Zhang ◽  
Jin Yang ◽  
Da Zeng Ming ◽  
Zhi Xiang Li
Keyword(s):  
Phosphoric Acid ◽  
Organic Phase ◽  
Mass Fraction ◽  
Pure Water ◽  
Acid Extraction ◽  
Experimental Conditions ◽  
Iron Aluminum ◽  
Acid Washing ◽  
Traditional Process ◽  
Optimization Of Experimental Conditions

Possible ways to remove fluoride from phosphoric acid are extraction,but there are always generated a second organic phase ,where still have small amounts of impurities such as fluoride,sulfate,iron,aluminum and heavy metals. The traditional process using pure water or dilute phosphoric acid washing the organic phase to get phosphoric acid ,but the impurities removing rate is not obvious.This study explore a new way to changes the washing detergent,using dilute alkali solution to reduce fluoride content of stripping in phosphoric acid.The optimization of experimental conditions is dilute alkali mass fraction 20%,dosage 0.4%,temperature 45°C,the defluorization rate can be 67.75% and phosphorus pentoxide yield rise to 95.50%.This study provides a new idea to improve defluorination rate in industrial production.

Effect of viscoelasticity on the soft-wall transition and turbulence in a microchannel

2017 ◽  
Vol 812 ◽  
pp. 1076-1118 ◽  
Author(s):  
S. S. Srinivas ◽  
V. Kumaran
Keyword(s):  
Molecular Weight ◽  
Reynolds Number ◽  
Reynolds Stress ◽  
Mass Fraction ◽  
Rectangular Cross Section ◽  
Pure Water ◽  
Polymer Concentration ◽  
Wall Turbulence ◽  
Solution Viscosity ◽  
Soft Wall

The modification of soft-wall turbulence in a microchannel due to small amounts of polymer dissolved in water is experimentally studied. The microchannels are of rectangular cross-section with height ${\sim}$160 $\unicode[STIX]{x03BC}\text{m}$, width ${\sim}$1.5 mm and length ${\sim}$3 cm, with three walls made of hard polydimethylsiloxane (PDMS) gel, and one wall made of soft PDMS gel with an elasticity modulus of ${\sim}$18 kPa. Solutions of polyacrylamide of molecular weight $5\times 10^{6}$ and mass fraction up to 50 ppm, and of molecular weight $4\times 10^{4}$ and mass fraction up to 1500 ppm, are used in the experiments. In all cases, the solutions are in the dilute limit below the critical overlap concentration, and the solution viscosity does not exceed that of water by more than 10 %. Two distinct types of flow modifications are observed below and above a threshold mass fraction for the polymer, $w_{t}$, which is ${\sim}$1 ppm and 500 ppm for the solutions of polyacrylamide with molecular weights $5\times 10^{6}$ and $4\times 10^{4}$, respectively. At or below $w_{t}$, there is no change in the transition Reynolds number, but there is significant turbulence attenuation, by up to a factor of 2 in the root-mean-square velocities and a factor of 4 in the Reynolds stress. When the polymer concentration increases beyond $w_{t}$, there is a decrease in the transition Reynolds number and in the intensity of the turbulent fluctuations. The lowest transition Reynolds number is ${\sim}$35 for the solution of polyacrylamide with molecular weight $5\times 10^{6}$ and mass fraction 50 ppm (in contrast to 260–290 for pure water). The fluctuating velocities in the streamwise and cross-stream directions are lower by a factor of 5, and the Reynolds stress is lower by a factor of 10, in comparison to pure water.

scholarly journals Mechanism of the process of decomposition of apatitis with phosphoric acid

2019 ◽  
Vol 81 (1) ◽  
pp. 294-297
Author(s):  
R. F. Sabirov ◽  
A. F. Makhotkin ◽  
Yu. N. Sakharov ◽  
I. A. Makhotkin ◽  
I. Yu. Sakharov
Keyword(s):  
Phosphoric Acid ◽  
Ph Value ◽  
Batch Reactor ◽  
Experimental Studies ◽  
Hydrogen Ions ◽  
Experimental Conditions ◽  
Monocalcium Phosphate ◽  
Ph Values ◽  
Whole Process ◽  
Proportional Increase

Experimental studies of the kinetics and mechanism of the process, decomposition of apatite by phosphoric acid, in the Apatite-H3PO4-H2O system without the addition of sulfuric acid have been performed. The study of the decomposition process of Kovdorsky apatite with certain particle sizes was carried out in a batch reactor with a volume of 1 dm3 with stirring of the reaction mixture, and an initial concentration of phosphoric acid of 17% by weight, at a temperature of 78–82 °C. Observation of the process was carried out by determining the concentration of phosphoric acid and the concentration of monocalcium phosphate. The acidity of the reaction mixture was determined by the pH meter readings (pH-105 MA with a glass combined-ESC-10603 electrode). It was shown that during the whole process a constant smooth increase in the pH value of the reaction mixture to pH 6 occurs. Comparison of the pH values of the reaction mixture during the actual at the time of determining the concentration of phosphoric acid and pH of phosphoric acid of the corresponding concentration in the aqueous solution shows that the pH value of the reaction mixture is significantly affected by the presence of monocalcium phosphate gel. During the process, during the first thirty minutes, the concentration of phosphoric acid decreases from 17 to 10% by weight, the corresponding quantitative formation of monocalcium phosphate gel and a proportional increase in the pH of the reaction mixture. Then, as the concentration of phosphoric acid decreases, the process slows down and does not proceed to the end under the experimental conditions. The dependence of the concentration of hydrogen ions in the reaction mixture on the time of the process of decomposition of apatite in phosphoric acid, which is presented in logarithmic coordinates, shows that the mechanism of formation of hydrogen ions during the whole process does not change. Thus, it is shown that the process of decomposition of apatite by phosphoric acid in the Apatite-H3PO4-H2O system proceeds with the formation of an intermediate product - monocalcium phosphate gel. When this occurs, a corresponding significant change in the pH values of the reaction mixture occurs. During the whole process there is a constant decrease in the concentration of phosphoric acid.

Utilizing ultrafiltration to remove alkaline phosphatase from clinical analyzer water

2006 ◽  
Vol 44 (5) ◽  
Author(s):  
Julien Bôle ◽  
Stéphane Mabic
Keyword(s):  
Alkaline Phosphatase ◽  
Water Samples ◽  
Bacterial Contamination ◽  
Pure Water ◽  
Experimental Conditions ◽  
Enzyme Immunoassays ◽  
Selection Of

AbstractAlkaline phosphatase (ALP) conjugated to antibodies is often used in enzyme immunoassays (EIAs). These assays are notably sensitive to experimental conditions. A possible source of interference is bacterial ALP, which is released when bacterial contamination occurs in clinical analyzers. Preliminary experiments led to the selection of a detection kit, ALP source, and specific types of tubes for collecting water samples and performing assays. The release of ALP from various strains of bacteria identified in pure water was demonstrated (10–30×10

Pertraction of methylene blue using a mixture of D2EHPA/M2EHPA and sesame oil as a liquid membrane

2013 ◽  
Vol 67 (7) ◽  
Author(s):  
Pezhman Kazemi ◽  
Mohammad Peydayesh ◽  
Alireza Bandegi ◽  
Toraj Mohammadi ◽  
Omid Bakhtiari
Keyword(s):  
Methylene Blue ◽  
Phosphoric Acid ◽  
Liquid Membrane ◽  
Membrane Surface ◽  
Sesame Oil ◽  
Acetic Acid Concentration ◽  
Membrane Phase ◽  
Experimental Conditions ◽  
Feed Phase ◽  
Kinetics Of

AbstractAn experimental study on the pertraction of methylene blue (MB) through a supported liquid membrane (SLM) using a mixture of mono-(2-etylhexyl) ester of phosphoric acid (M2EHPA) and bis-(2-etylhexyl) ester of phosphoric acid (D2EHPA) and sesame oil as the liquid membrane (LM) was performed. Parameters affecting the pertraction of MB such as initial MB concentration, carrier concentration, feed phase pH, and stripping phase concentration were analyzed. Optimal experimental conditions for MB pertraction (permeability of 5.63 × 10−6) were obtained after a 7 h separation with the MB concentration in the feed phase of 80 mg L−1, D2EHPA/M2EHPA concentration in membrane phase of 40 vol. %, feed pH of 6, and acetic acid concentration in the stripping phase of 0.4 mol L−1. Kinetics of transport and stability of the SLM system were also studied and the mass transfer coefficient for this system was evaluated. Scanning electron microscopy (SEM) was used to morphologically characterize the membrane surface.

Laboratory Experiments on the Droplet Shattering Secondary Ice Production Mechanism

2020 ◽  
Author(s):  
Alice Keinert ◽  
Judith Kleinheins ◽  
Dominik Spannagel ◽  
Alexei Kiselev ◽  
Thomas Leisner
Keyword(s):  
High Resolution ◽  
High Speed ◽  
Cloud Model ◽  
Pure Water ◽  
Measuring System ◽  
Striking Difference ◽  
Observation Data ◽  
Experimental Conditions ◽  
Wide Range ◽  
Ice Production

<p>Supercooled drizzle droplets may produce multiple ice particles upon freezing. This mechanism could potentially explain the high ice number concentrations outside of temperature range where the well-known Hallett-Mossop mechanism of ice multiplication would take place. Limited experimental methods in the past prevented direct observations of the shattering droplets, resulting in a wide range of experimental results, unsuitable for the development of a sophisticated cloud model parameterization. Recently, we have revived experiments on secondary ice production by levitating individual drizzle droplets in electrodynamic balance (EDB) and observing the freeze-shattering with high-speed video microscopy and high-resolution infrared thermal measuring system. In this way we have been able to identify three additional SIP mechanisms (cracking, jetting and bubble bursts) associated with the freezing of drizzle droplets (Lauber et al., 2018). <br>Additionally, we have extended the range of experimental conditions to mimick the freezing of continental (pure water) and maritime (aqueous solution of analogue sea salt) drizzle droplets suspended in the updraft of cold moist air. We report a strong enhancement of shattering probability as compared to the previous studies conducted under stagnant air conditions. The high-definition video records of shattering events reveal the coupling between various microphysical processes caused by ice propagation inside the freezing drop and reveal striking difference between freezing of pure water and SSA solution droplets. Application of high-resolution infrared microscopy allowed us to record the evolution of the droplet temperature under realistic flow conditions and thus constrain the thermodynamic parameters controlling the pressure build-up inside the droplet. Based on these new observation data and theoretical model of freezing droplet, we discuss the physical mechanism behind the shattering of drizzle droplets and its implication for mixed-phase cloud modeling.</p><p>Lauber, A., A. Kiselev, T. Pander, P. Handmann, and T Leisner (2018). “Secondary Ice Formation during Freezing of Levitated Droplets”, Journal of the Atmospheric Sciences 75, pp. 2815–2826.</p>

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