XAS Evidence of As(V) Association with Iron Oxyhydroxides in a Contaminated Soil at a Former Arsenical Pesticide Processing Plant

2005 ◽  
Vol 39 (24) ◽  
pp. 9398-9405 ◽  
Author(s):  
B. Cancès ◽  
F. Juillot ◽  
G. Morin ◽  
V. Laperche ◽  
L. Alvarez ◽  
...  
2002 ◽  
Vol 2 ◽  
pp. 308-319 ◽  
Author(s):  
D. Craw ◽  
L. Pacheco

Arsenopyrite (FeAsS) is the principal arsenic (As) mineral in mineralised mesothermal veins (typically 5,000 mg/kg As) in southeastern New Zealand. Groundwater in contact with arsenopyrite-bearing rocks has elevated As concentrations (up to 0.1 mg/l). The arsenopyrite decomposes slowly on oxidation in soils and historic mine workings in a cool semiarid climate. Dissolved As is predominantly As(III) in association with arsenopyrite, but this is rapidly oxidised over days to weeks to As(V) in the vadose zone. Oxidation is facilitated by particulate Fe and/or Mn oxyhydroxides, and by bacteria in surface waters. Evaporative concentration of dissolved As(V) in the vadose zone causes precipitation of scorodite (Fe(III)As(V)O4.2H2O). Adsorption of As(V) to Fe oxyhydroxides in soils and groundwater pathways lowers dissolved As concentrations. Soils over mineralised veins typically have <200 mg/kg As, as most As is removed in solution on geological time scales. Most plants on the mineralised rocks and soils do not take up As, although some inedible species can fix up to 18 mg/kg As. Hence, bioavailability of As(V) is low in this environment, despite the substantial As flux.Similar As mobility is seen in an active gold mine processing plant and tailings. Arsenopyrite dissolves more rapidly on agitation, and mine waters can have dissolved As >200 mg/l, predominantly as As(V). This dissolved As decreases in tailings waters to near 2 mg/l, mainly as As(III) when in contact with arsenopyrite. Weak oxidation of evaporatively dried tailings causes cementation with scorodite and iron oxyhydroxides, and scorodite precipitation exerts some control on dissolved As(V) concentrations. High dissolved As in mine waters is lowered by adsorption to iron oxyhydroxides, and waters discharged from the mine site have negligible dissolved As.


2012 ◽  
Vol 76 (7) ◽  
pp. 2693-2707 ◽  
Author(s):  
A. A. Bogush ◽  
O. G. Galkova ◽  
N. V. Ishuk

AbstractThis study describes geochemical barriers that have developed at three different localities in sulfiderich tailings in the Kemerovo region of Western Siberia, Russia. Iron oxyhydroxides, gypsum, malachite, chalcanthite, goslarite, bianchite, gunningite and copper and zinc chlorides crystallized in the sequence specified at an evaporative barrier around glassy slag produced by the Belovo zinc processing plant. A complex cemented barrier that has developed within the old Salair sulfide tailings contains two well defined layers: an upper layer containing Fe(III) minerals and gypsum as cements in which Pb, As, Mo, Ni and Co have been deposited; and (2) a lower calcite- and gypsum-bearing layer, in which phases containing Zn, Cd and Cu have been deposited. A complex organic-mineral barrier below the Ursk sulfide tailings consists of peaty organic matter, clay minerals and iron oxyhydroxides cemented by gypsum. Elements that have leached from the tailings are present in this barrier in a variety of different forms: Ca and Mn are present as water-soluble species; Cu, Fe and Zn are present as species produced by interaction with organic matter via ion-exchange, metal humate formation and cation bridging in organic-mineral complexes; Pb and As are co-precipitated with and/or adsorbed onto iron oxyhydroxides; gold has been deposited as minute particles of native metal. The mechanisms for the formation of the different geochemical barriers are discussed.


Author(s):  
Cácio Luiz Boechat ◽  
Filipe Selau Carlos ◽  
Clístenes Williams Araújo do Nascimento ◽  
Patricia Dorr de Quadros ◽  
Enilson Luiz Saccol de Sá ◽  
...  

Author(s):  
P.I. Loboda ◽  
Younes Razaz ◽  
S. Grishchenko

Purpose. To substantiate the efficiency of processing hematite raw materials at the Krivoy Rog Mining and Processing Plant of Oxidized Ores using the direct reduction technology itmk3®. Metodology. Analysis of the results of the itmk3® direct restoration technology developed by Kobe Steel Ltd., Japan and Hares Engineering GmbX, Austria, with a view to using it to process Krivbass hematite ores into granulated iron (so-called “nuggets”). Findings. The involvement in the production of hematite ores (oxidized quartzite) of Krivbass with high iron content, but with low magnetic properties for their processing into granular cast iron is grounded. Originality. The use of itmk3® direct reduction technology from Kobe Steel Ltd., Japan and Hares Engineering GmbH, Austria for the processing of Krivbass hematite ores into granular cast iron is justified for the first time. Practical value. The efficiency of the use of hematite ores (oxidized quartzite) has been substantiated, which can significantly reduce the costs in the mining cycle for the economical production of metallurgical products.


2019 ◽  
Vol 10 (3) ◽  
pp. 148
Author(s):  
Nesreen Kurdy Al-Obaidy ◽  
Assad Al-Shueli ◽  
Hawraa Sattar ◽  
Zainab Majeed ◽  
Noor Al Huda Hamid

Author(s):  
A.I. Barbashev ◽  
◽  
S.N. Sushkova ◽  
T.M. Minkina ◽  
T.S. Dudnikova ◽  
...  

The effect of diatomite and tripoli added into the soil artificially contaminated with benzo[a]pyrene was studied. A decrease in the toxic effect of BaP on barley plants was established when diatomite and tripoli were added as ameliorants to contaminated soil. The improvement of plants grown сharacteristics on soils contaminated with BaP with the addition of diatomite and tripoli was shown up to 2-4 times compare to contaminated samples.


Author(s):  
V.V. Zinchenko ◽  
◽  
E.S Fedorenko ◽  
A.V Gorovtsov ◽  
T.M Minkina ◽  
...  

As a result of the model experiment, an increase in the enzymatic activity of meadow chernozem of the impact zone of Ataman Lake with the introduction of a strains mixture of metal-resistant microorganisms into the soil was established. The experiment has shown that the application of bacterial strains increases the dehydrogenase activity of contaminated soil by 51.8% compared to the variant without remediation


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