scholarly journals Prospects for selective-and-advanced recovery of rhenium from pregnant solutions of in-situ leaching of uranium ores at Dobrovolnoye deposit

2021 ◽  
Vol 6 (3) ◽  
pp. 158-169
Author(s):  
A. A. Rudenko ◽  
I. D. Troshkina ◽  
V. V. Danileyko ◽  
O. S. Barabanov ◽  
F. Ya. Vatsura
Keyword(s):  
Uranium Deposit ◽  
English Literature ◽  
Selective Extraction ◽  
Ammonia Solution ◽  
Product Recovery ◽  
Advanced Technology ◽  
Measuring Instruments ◽  
Ammonium Perrhenate ◽  
A Chain

Analysis of exploration materials and market conditions showed that by-product recovery of rhenium, one of the rarest strategic elements of the periodic system, was not always effective in processing the whole volume of pregnant uranium-bearing solutions. The main goal of the research was to develop an effective method for recovery rhenium from pregnant solutions in in-situ uranium leaching. The objectives of the research were as follows: evaluation of the possibility of selective-and-advanced recovery of rhenium from ores by in-situ leaching method and comparison of the technological advantages of the new proposed method with the known ones. The study involved the analysis of historical geological, mineralogical and geochemical information on the Dobrovolnoye deposit and analysis of technological aspects of by-product recovery of rhenium in the world practice. A selective-and-advanced scheme of rhenium recovery from pregnant uranium-bearing sulfate (sulfuric acid) solutions of the Dobrovolnoye deposit ISL (Russia) using mobile installations was proposed. The process has the following features: zoning of production blocks when constructing injection and extraction (pumping) wells; piping of selective extraction wells into a separate collecting pipe; implementation of advanced rhenium sorption. The process implementation makes it possible to obtain rhenium from economically viable areas of the uranium deposit. The mobile installation includes the following main units: a filter for purification (aftertreatment) to remove suspension, a chain of sorption apparatuses (sorption filters or columns), connecting fittings, control and measuring instruments. The sorption apparatuses are filled with rhenium-selective ionite (ion exchanger). As a selective sorbent for the primary concentration of rhenium from sulfate solutions (pH 2), weakly basic nitrogen-bearing ionites containing amine functional groups of various types can be used. If further concentration of rhenium is required, in order to unify the equipment used, materials with a mobile extractant phase (so-called TVEXs (solid extractants or Levextrel resins in English literature) and so-called “impregnated” or “impregnates”), such as TVEX-DIDA containing diisododecyl amine, or TAA-impregnate containing trialkylamine, can be used. Rhenium desorption from these materials is carried out by an ammonia solution, which allows producing rough ammonium perrhenate from the eluate. Economic aspects of the rhenium selective-andadvanced technology were evaluated. Implementation of the recovery selective-and-advanced technology allows obtaining rhenium from economically-viable areas of the uranium deposit.

scholarly journals In-situ Isotopic and Chemical Study of Pyrite from Chu-Sarysu (Kazakhstan) Roll-front Uranium Deposit

2015 ◽  
Vol 13 ◽  
pp. 207-210 ◽  
Author(s):  
Philippe Lach ◽  
Michel Cathelineau ◽  
Marc Brouand ◽  
Nicolas Fiet
Keyword(s):  
Uranium Deposit ◽  
Chemical Study

Two-stage in situ gas stripping for enhanced butanol fermentation and energy-saving product recovery

2013 ◽  
Vol 135 ◽  
pp. 396-402 ◽  
Author(s):  
Chuang Xue ◽  
Jingbo Zhao ◽  
Fangfang Liu ◽  
Congcong Lu ◽  
Shang-Tian Yang ◽  
...  
Keyword(s):  
Energy Saving ◽  
Product Recovery ◽  
Gas Stripping ◽  
Two Stage ◽  
Butanol Fermentation

scholarly journals Intercomparison of four different in-situ techniques for ambient formaldehyde measurements in urban air

2005 ◽  
Vol 5 (3) ◽  
pp. 2897-2945 ◽  
Author(s):  
C. Hak ◽  
I. Pundt ◽  
C. Kern ◽  
U. Platt ◽  
J. Dommen ◽  
...  
Keyword(s):  
Regression Line ◽  
Ambient Air ◽  
Urban Site ◽  
Optical Absorption Spectroscopy ◽  
Measuring Instruments ◽  
Chromatographic Technique ◽  
In Situ Techniques ◽  
Time Period ◽  
The Individual

Abstract. Results from an intercomparison of several currently used in-situ techniques for the measurement of atmospheric formaldehyde (CH2O) are presented. The measurements were carried out at Bresso, an urban site in the periphery of Milan (Italy) as part of the FORMAT-I field campaign. Eight instruments were employed by six independent research groups using four different techniques: Differential Optical Absorption Spectroscopy (DOAS), Fourier Transform Infra Red (FTIR) interferometry, the fluorimetric Hantzsch reaction technique (five instruments) and a chromatographic technique employing C18-DNPH-cartridges (2,4-dinitrophenylhydrazine). White type multi-reflection systems were employed for the optical techniques in order to avoid spatial CH2O gradients and ensure the sampling of nearly the same air mass by all instruments. Between 23 and 31 July 2002, up to 13 ppbv of CH2O were observed. The concentrations lay well above the detection limits of all instruments. The formaldehyde concentrations determined with DOAS, FTIR and the Hantzsch instruments were found to agree within ±11%, with the exception of one Hantzsch instrument, which gave systematically higher values. The two hour integrated samples by DNPH yielded up to 25% lower concentrations than the data of the continuously measuring instruments averaged over the same time period. The consistency between the DOAS and the Hantzsch method was better than during previous intercomparisons in ambient air with slopes of the regression line not significantly differing from one. The differences between the individual Hantzsch instruments could be attributed in part to the calibration standards used. Possible systematic errors of the methods are discussed.

scholarly journals A comparison of the energy use of in situ product recovery techniques for the Acetone Butanol Ethanol fermentation

2016 ◽  
Vol 220 ◽  
pp. 590-600 ◽  
Author(s):  
Victoria Outram ◽  
Carl-Axel Lalander ◽  
Jonathan G.M. Lee ◽  
E. Timothy Davis ◽  
Adam P. Harvey
Keyword(s):  
Ethanol Fermentation ◽  
Energy Use ◽  
Product Recovery ◽  
In Situ Product Recovery ◽  
Recovery Techniques ◽  
Acetone Butanol Ethanol

Debris cover and the thinning of Kennicott Glacier, Alaska

2021 ◽  
Author(s):  
Leif S. Anderson ◽  
William H. Armstrong ◽  
Robert S. Anderson ◽  
Dirk Scherler
Keyword(s):  
Satellite Imagery ◽  
Hot Spots ◽  
High Mountain ◽  
Threshold Method ◽  
Ice Dynamics ◽  
Ice Flow ◽  
Debris Cover ◽  
A Chain ◽  
The Relationship

<p>Many glaciers in High Mountain Asia are experiencing the debris-cover anomaly. The Kennicott Glacier, a large Alaskan Glacier, is also thinning most rapidly under debris cover. This contradiction has been explained by melt hotspots, such as ice cliffs, streams, or ponds scattered within the debris cover or by declining ice flow in time. We collected abundant in situ measurements of debris thickness, sub-debris melt, and ice cliff backwasting, allowing for extrapolation across the debris-covered tongue. A newly developed automatic ice cliff delineation method is the first to use only optical satellite imagery. The adaptive binary threshold method accurately estimates ice cliff coverage even where ice cliffs are small and debris color varies. We also develop additional remotely-sensed datasets of ice dynamical variables, other melt hot spots, and glacier thinning.</p><p>Kennicott Glacier exhibits the highest fractional area of ice cliffs (11.7 %) documented to date. Ice cliffs contribute 26 % of total melt across the glacier tongue. Although the <em>relative</em> importance of ice cliffs to area-average melt is significant, the<em> absolute</em> area-averaged melt is dominated by debris. At Kennicott Glacier, glacier-wide melt rates are not maximized in the zone of maximum thinning. Declining ice discharge through time therefore explains the rapid thinning. Through this study, Kennicott Glacier is the first glacier in Alaska, and the largest glacier globally, where melt across its debris-covered tongue has been rigorously quantified.</p><p>We also carefully explore the relationship between debris, melt hotspots, ice dynamics, and thinning across the debris-covered tongue. In doing so we reveal a chain of linked processes that can explain the striking patterns expressed on the debris-covered tongue of Kennicott Glacier.</p>

scholarly journals Quantitative Analysis of Sulpiride and Impurities of 2-Aminomethyl-1-Ethylpyrrolidine and Methyl-5-Sulphamoyl-2-Methoxybenzoate in Pharmaceuticals by High-Performance Thin-Layer Chromatography and Scanning Densitometry

1999 ◽  
Vol 82 (4) ◽  
pp. 825-829 ◽  
Author(s):  
Danica Agbaba ◽  
Tatjana Miljkovic ◽  
Valentina Marinkovic ◽  
Dobrila Zivanov-Stakic ◽  
Sote Vladimirov
Keyword(s):  
Quantitative Analysis ◽  
Thin Layer ◽  
High Performance ◽  
Methylene Chloride ◽  
Solvent System ◽  
Ammonia Solution ◽  
Dosage Forms ◽  
Raw Material ◽  
Layer Chromatography

Abstract A simple and reliable thin-layer chromatographic method for determining sulpiride and impurities of 2-aminomethyl-1-ethylpyrrolidine and methyl-5-sulphamoyl-2-methoxybenzoate was developed and validated. A methylene chloride–methanol–ammonia solution (25%; 18 + 2.8 + 0.4, v/v) solvent system is used for separation and quantitative evaluation of chromatograms. The chromatographic plate is first scanned at 240 nm to locate chromatographic zones corresponding to sulpiride and methyl-5-sulphamoyl-2-methoxybenzoate. Then 2-aminomethyl-1-ethylpyrrolidine is derivatized in situ with ninhydrin, and resulting colored spots are measured at 500 nm. The method is reproducible and convenient for quantitative analysis and purity control of sulpiride in its raw material and in its dosage forms.

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