scholarly journals Analyzing changes in a leach solution oxygenation in the process of uranium ore borehole mining

2021 ◽  
Vol 15 (3) ◽  
pp. 39-44
Author(s):  
Erbolat Aben ◽  
Bakytzhan Toktaruly ◽  
Nursultan Khairullayev ◽  
Mukhtar Yeluzakh
Keyword(s):  
Sulfuric Acid ◽  
Flow Velocity ◽  
Oxygen Concentration ◽  
Acid Concentration ◽  
Reduction Potential ◽  
Sulfuric Acid Concentration ◽  
Leach Solution ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Solution Volume

Purpose is to increase uranium content in a PR solution while developing a technique varying oxidation-reduction potential of a leach solution with its oxygenation and identify changes in the oxygenation depending upon sulfuric acid concentration as well as transportation distance of the solution. Methods. A laboratory facility, involving solution tank, pump, Venturi tube, tank to install oxygen analyzer, and a dump tank, has been manufactured under the lab conditions to determine a leach solution oxygenation taking into consideration its delivery rate, sulfuric acid concentration, and temporal preservation of the concentration. Solution flow velocity; the deli-vered solution volume; sulfuric acid concentration; and distance from oxygenation point to a seam changed and varied during the study. Oxygenation was measured with the help of AZ 8403 oximeter; IT-1101 device was used to measure pH value as well as oxidation-reduction potential (ORP). Findings. A technique for a leach solution oxygenation and results of laboratory tests to identify influence of a sulfuric acid as well as transportation distance of a solution on oxygen concentration in the solution have been represented. It has been determined that Venturi tube helps oxygenize a leach solution; in this context, maximum oxygen concentration is achieved if a flow velocity is optimum one. It has been specified that a solution oxygenating depends upon a sulfuric acid concentration decreasing moderately with the increasing distance of the solution transportation. Originality.Following new dependencies have been determined: oxygen concentration in a solution upon a flow velocity and solution volume; and oxygen concentration in a solution upon distance from concentration place and sulfuric acid concentration. Practical implications.A leach solution oxygenation results in the increased oxidation-reduction potential and in the increased content of a useful component in the pregnant solution respectively. The proposed technique is notable for its low capital spending. Moreover, it is integrated easily into the available system being absolutely environmentally friendly.

scholarly journals The Effect of Anaerobic Conditions on Two Heterotrich Ciliate Protozoa from Papyrus Swamps

1959 ◽  
Vol 36 (4) ◽  
pp. 583-589
Author(s):  
L. C. BEADLE ◽  
J. R. NILSSON
Keyword(s):  
Oxygen Concentration ◽  
Reduction Potential ◽  
Red Pigment ◽  
Low Oxygen ◽  
Anaerobic Conditions ◽  
Simultaneous Measurements ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Low Oxygen Concentration ◽  
Ciliate Protozoa

1. Under conditions of decreasing oxygen concentration in sealed bottles of swamp water Bursaria sp. always died as soon as the oxygen was exhausted, but Blepharisma undulans invariably survived 1-3 days of anaerobic conditions. 2. Simultaneous measurements of oxygen, pH and oxidation-reduction potential suggested that the oxygen concentration is the most important factor for survival. 3. The red pigment of B. undulans plays no part in the resistance to low oxygen concentration. 4. It is suggested as a hypothesis that B. undulans can live without oxygen until it has exhausted its reserves of carbohydrate, which can only be renewed in presence of oxygen.

Study on M5640 Extraction Copper from Ammoniac Leach Solution of Copper Oxidized Ore

2014 ◽  
Vol 968 ◽  
pp. 190-193 ◽  
Author(s):  
Ying Bo Mao ◽  
Zhi Cong Wei ◽  
Jian Jun Fang ◽  
Tie Min Zhang ◽  
Tai Guo Jiang
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Leach Solution ◽  
Extraction Time ◽  
Phase Ratio ◽  
Maximum Extraction ◽  
Laboratory Investigations ◽  
Extraction Agent

The extractant M5640 that extracted and stripped copper in the ammonia leach solution of copper oxidized ores solution of were mainly studied for the experimentation examined the M5640 concentration, phase ratio, extraction time, and liquid pH. Laboratory Investigations indicated that M5640 is really an efficient copper extractant with a maximum extraction of as high as 99.64% under the conditions of 6.48g/L Cu in leach solution, the extraction agent concentration is 10%, phase ratio is 1:1, extraction time is 2 min and liquid pH was 9.58. The stripping can be conducted with the barren electrolyte as a stripping agent in which the sulfuric acid concentration remains about 150g/L, and a stripping rate of 99.80% is obtained.

A Study on LIX84-I Extraction Copper from Ammoniac Leach Solution of Copper Oxidized Ore

2013 ◽  
Vol 281 ◽  
pp. 457-460
Author(s):  
Ying Bo Mao ◽  
Jian Jun Fang ◽  
Ya Wen ◽  
Shan Wang ◽  
Tie Min Zhang ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Leach Solution ◽  
Extraction Time ◽  
Phase Ratio ◽  
Maximum Extraction ◽  
Laboratory Investigations

Abstract: The extractant LIX84-I that extracted and stripped copper in the ammonia leach solution of copper oxidized ores solution of were mainly studied for the experimentation examined the influence of the LIX84-I concentration, the extraction time, the phase ratio, the pH , the stripping sulfuric acid concentration and the stripping time. Laboratory Investigations indicated that LIX84-I is really an efficient copper extractant with a maximum extraction of as high as 99.91% under the conditions of 5.23g/L Cu in leach solution, LIX84-I concentration 7%, 3 min mixtures, phase ratio 1/1and pH﹥4.5. The stripping can be conducted with the barren electrolyte as a stripping agent in which the sulfuric acid concentration remains about 150g/L, and a stripping rate of 99.92% is obtained.

scholarly journals In situ measurements of oxidation–reduction potential and hydrogen peroxide concentration as tools for revealing LPMO inactivation during enzymatic saccharification of cellulose

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Adnan Kadić ◽  
Anikó Várnai ◽  
Vincent G. H. Eijsink ◽  
Svein Jarle Horn ◽  
Gunnar Lidén
Keyword(s):  
Reduction Potential ◽  
Enzymatic Saccharification ◽  
The State ◽  
Enzyme Inactivation ◽  
Ex Situ ◽  
Process Economics ◽  
Complete Inactivation ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential

Abstract Background Biochemical conversion of lignocellulosic biomass to simple sugars at commercial scale is hampered by the high cost of saccharifying enzymes. Lytic polysaccharide monooxygenases (LPMOs) may hold the key to overcome economic barriers. Recent studies have shown that controlled activation of LPMOs by a continuous H2O2 supply can boost saccharification yields, while overdosing H2O2 may lead to enzyme inactivation and reduce overall sugar yields. While following LPMO action by ex situ analysis of LPMO products confirms enzyme inactivation, currently no preventive measures are available to intervene before complete inactivation. Results Here, we carried out enzymatic saccharification of the model cellulose Avicel with an LPMO-containing enzyme preparation (Cellic CTec3) and H2O2 feed at 1 L bioreactor scale and followed the oxidation–reduction potential and H2O2 concentration in situ with corresponding electrode probes. The rate of oxidation of the reductant as well as the estimation of the amount of H2O2 consumed by LPMOs indicate that, in addition to oxidative depolymerization of cellulose, LPMOs consume H2O2 in a futile non-catalytic cycle, and that inactivation of LPMOs happens gradually and starts long before the accumulation of LPMO-generated oxidative products comes to a halt. Conclusion Our results indicate that, in this model system, the collapse of the LPMO-catalyzed reaction may be predicted by the rate of oxidation of the reductant, the accumulation of H2O2 in the reactor or, indirectly, by a clear increase in the oxidation–reduction potential. Being able to monitor the state of the LPMO activity in situ may help maximizing the benefit of LPMO action during saccharification. Overcoming enzyme inactivation could allow improving overall saccharification yields beyond the state of the art while lowering LPMO and, potentially, cellulase loads, both of which would have beneficial consequences on process economics.

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