scholarly journals Study on the mechanism and kinetics of manganese release from waste manganese ore waste rock under rainfall leaching

Author(s):  
Xin Wang ◽  
Bozhi Ren ◽  
Yingying Zhou ◽  
Xiyang Shi
2021 ◽  
Author(s):  
Xin Wang ◽  
Bozhi Ren ◽  
Yingying Zhou ◽  
Xiyang Shi

Abstract Manganese released from manganese ore wastes under leaching poses a serious threat to the local ecosystem and human health. The mechanism and dynamic characteristics of manganese release under the leaching of manganese ore waste rock are studied based on static and dynamic experiment. The concentration of manganese in the leaching solution under the disturbance state is twice as much as that in the static state; the manganese release from the waste rock increases with the increase of the solid-liquid ratio, and the manganese release is 922.35mg/l when the solid-liquid ratio is 1:5; when the particle size of waste rock is greater than 80 mesh, the precipitation amount of manganese is the largest, and the precipitation concentration is 491.3mg/l; at pH = 7, rainfall intensity is 80 With the increase of leaching time, the amount of manganese released rapidly decreased and gradually reached equilibrium; the cumulative release of manganese increased with the increase of rainfall duration. In the dynamic leaching process, the change of pH and EC of leachate has nothing to do with the initial pH of leachate, but has a close relationship with the hydrolysis of minerals in waste; through the fitting results of kinetic model, it is found that the double constant equation model can better fit the kinetic process of release process. The purpose of this study is to provide a scientific basis for the assessment and control of manganese pollution in soil and groundwater in manganese mining area.


2020 ◽  
Vol 3 (1) ◽  
pp. 155-160
Author(s):  
Ye. M. Semenyshyn ◽  
◽  
V. M. Atamanyuk ◽  
O. Ya. Dobrovetska ◽  
T. I. Rymar ◽  
...  

2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.


2020 ◽  
Vol 2020 (10) ◽  
pp. 1102-1115
Author(s):  
M. A. Korzhuev ◽  
I. V. Katin ◽  
M. A. Kretova ◽  
E. S. Avilov

1987 ◽  
Vol 52 (6) ◽  
pp. 1386-1396 ◽  
Author(s):  
Ján Mocák ◽  
Michal Németh ◽  
Mieczyslaw Lapkowski ◽  
Jerzy W. Strojek

A spectrocoulometric macrocell with a direct-view optical probe was designed and constructed, where the optical signal is transferred by light-conducting glass or quartz fibres permitting to work at wavelengths above 410 or 300 nm. The method of measurement on the proposed equipment is described; it was tested in the study of the mechanism and kinetics of oxidation of Fe(bipy)32+ ions (bipy = 2,2'-bipyridyl) with the use of potentiostatic coulometric electrolysis with open-circuit relaxation at a suitable time. The primary product of electrolysis, Fe(bipy)33+, undergoes a follow-up hydrolytic reaction with the formation of a binuclear complex. The rate constant of the reaction of the first order involves the contributions, kBi, from all bases present in solution; the corresponding values for H2O, OH-, bipy, and CH3COO- ions at a ionic strength 0·5 mol dm-3 and 25 °C were determined as kOH = (5·0 ± 0·6) . 105 mol-1 dm3 s-1, kbipy = (1·3 ± 0·2) . 10-1 mol-1 dm3 s-1, kAc = (5·8 ± 1·0) . 10-2 mol-1 dm3 s-1, and kH2O is not significant with respect to experimental errors.


1986 ◽  
Vol 51 (3) ◽  
pp. 636-642
Author(s):  
Michal Németh ◽  
Ján Mocák

A highly efficient coulometric cell was designed and constructed, ensuring a constant potential over the whole surface of the working electrode and suitable for very rapid electrolysis. It consists of concentric cylindrical Teflon parts; also the working and auxiliary electrodes are cylindrical and concentric. Electrolysis can be carried out under anaerobic conditions. Functioning of the cell was tested on the oxidation of hexacyanoferrate(II) and chlorpromazine and reduction of hexacyanoferrate(III). The new cell is suitable for routine quantitative analyses and in studying the mechanism and kinetics of moderately rapid chemical reactions.


2021 ◽  
pp. 2100158
Author(s):  
Dominik Söder ◽  
Manuela Garay‐Sarmiento ◽  
Khosrow Rahimi ◽  
Fabian Obstals ◽  
Sarah Dedisch ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document