Role of water contents on microwave roasting of gold bearing high arsenic sulphide concentrate

2017 ◽  
Vol 161 ◽  
pp. 72-77 ◽  
Author(s):  
Nan Hu ◽  
Wei Chen ◽  
De-xin Ding ◽  
Feng Li ◽  
Zhong-ran Dai ◽  
...  
Keyword(s):  
Microwave Roasting ◽  
Water Contents ◽  
High Arsenic ◽  
Gold Bearing

Formation of tooeleite and the role of direct removal of As(III) from high-arsenic acid wastewater

2016 ◽  
Vol 320 ◽  
pp. 620-627 ◽  
Author(s):  
Liyuan Chai ◽  
Mengqing Yue ◽  
Jinqin Yang ◽  
Qingwei Wang ◽  
Qingzhu Li ◽  
...  
Keyword(s):  
Arsenic Acid ◽  
High Arsenic

scholarly journals Bio-oxidation of a refractory gold bearing high arsenic sulphide concentrate: A pilot study

1993 ◽  
Vol 11 (1-3) ◽  
pp. 243-252 ◽  
Author(s):  
J.T. Chapman ◽  
P.B. Marchant ◽  
R.W. Lawrence ◽  
R. Knopp
Keyword(s):  
Pilot Study ◽  
Refractory Gold ◽  
High Arsenic ◽  
Gold Bearing

scholarly journals Role of the Environment in the Placement of Apocarbonate Gold Mineralization Chakylkalyan Megablock (Southern Uzbekistan)

2021 ◽  
Vol 7 (6) ◽  
Author(s):  
T. Yarboboev ◽  
Sh. Sultanov ◽  
I. Ochilov
Keyword(s):  
Carbonate Rocks ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Gold Deposition ◽  
Sufficient Detail ◽  
Available Information ◽  
Gold Bearing ◽  
Geochemical Specialization

Analysis of the available information and the results of many years of research on gold deposits in Uzbekistan made it possible to identify the main unconventional types of deposits. Among them, the most interesting are apocarbonate, crustal, sulfide-carbonaceous and apovolcanogenic quartzite (Upper-Kattakashkasai ore occurrence). The apocarbonate type is widespread in Uzbekistan, has been studied in sufficient detail and information is provided on it in this article. The article examines the existence, distribution and genesis of ores of Karlin type gold deposits. The generalizing characteristics of the Karlin type gold mineralization are given. The issues of geochemical specialization of the Paleozoic strata of the Chakylkalyan megablock are considered, the most favorable stratolevel for the localization of mineralized zones is determined, and the features of carbonate rocks in the process of gold deposition during reactions with silicic solutions are characterized. Based on the materials of regional geochemical profiling, the behavior of the main ore-forming elements in the rocks of both carbonate and volcanogenic-terrigenous strata is analyzed. As a result of the analysis, subclarkic contents of the main ore-forming elements (As, Co, Ni, Pb, Cu, Ag, V, Cr, Sc) were revealed, which create increased concentrations in gold-bearing pyrites of both apocarbonate gold mineralization and related formations.

scholarly journals Influence of chemical fertilizers on arsenic mobilization in the alluvial Bengal delta plain: a critical review

2021 ◽  
Author(s):  
Md. Shajedul Islam ◽  
M. G. Mostafa
Keyword(s):  
Microbial Community ◽  
Strong Positive Correlation ◽  
Chemical Fertilizers ◽  
Arsenic Mobilization ◽  
Bengal Delta ◽  
Delta Plain ◽  
Arsenic In Groundwater ◽  
Guideline Value ◽  
High Arsenic

Abstract Arsenic contamination of alluvial aquifers of the Bengal delta plain causes a serious threat to human health for over 75 million people. The study aimed to explore the impacts of chemical fertilizer on arsenic mobilization in the sedimentary deposition of the alluvial Bengal delta plain. It selected ten comparatively higher affected Districts and the least affected two Divisions as a referral study site. The countrywide pooled concentration of arsenic in groundwater was 109.75 μg/L (52.59, 166.91) at a 95% confidence interval, which was double the national guideline value (50 μg/L). The analysis results showed a strong positive correlation (r ≥ 0.5) of arsenic with NO3, NH4, PO4, SO4, Ca, and K, where a portion of those species originated from fertilizer leaching into groundwater. The results showed that PO4 played a significant influence in arsenic mobilization, but the role of NO3, SO4, and NH4 was not clear at certain lithological conditions. It also showed that clay, peat, silt-clay, and rich microbial community with sufficiently organic carbon loaded soils could lead to an increase in arsenic mobilization. Finally, the study observed that the overall lithological conditions are the main reason for the high arsenic load in the study area.

scholarly journals Understanding Stress Response to High-Arsenic Gold-Bearing Sulfide Concentrate in Extremely Metal-Resistant Acidophile Sulfobacillus thermotolerans

2020 ◽  
Vol 8 (7) ◽  
pp. 1076 ◽  
Author(s):  
Anna Panyushkina ◽  
Daria Matyushkina ◽  
Olga Pobeguts
Keyword(s):  
Stress Response ◽  
Microbial Communities ◽  
Molecular Mechanisms ◽  
Raw Materials ◽  
Metal Resistance ◽  
Sulfide Ore ◽  
Microbial Responses ◽  
Sulfide Concentrate ◽  
High Arsenic ◽  
Gold Bearing

Biooxidation of gold-bearing arsenopyrite concentrates, using acidophilic microbial communities, is among the largest commercial biohydrometallurgical processes. However, molecular mechanisms of microbial responses to sulfide raw materials have not been widely studied. The goal of this research was to gain insight into the defense strategies of the acidophilic bacterium Sulfobacillus thermotolerans, which dominates microbial communities functioning in industrial biooxidation processes at >35 °C, against the toxic effect of the high-arsenic gold-bearing sulfide concentrate. In addition to extreme metal resistance, this acidophile proved to be one of the most As-tolerant microorganisms. Comparative proteomic analysis indicated that 30 out of 33 differentially expressed proteins were upregulated in response to the ore concentrate, while the synthesis level of the functional proteins required for cell survival was not negatively affected. Despite a high level of cellular metal(loid) accumulation, no specific metal(loid)-resistant systems were regulated. Instead, several proteins involved in the metabolic pathways and stress response, including MBL fold metallo-hydrolase, sulfide:quinone oxidoreductase, and GroEL chaperonin, may play crucial roles in resistance to the sulfide ore concentrate and arsenic, in particular. This study provides the first data on the microbial responses to sulfide ore concentrates and advances our understanding of defense mechanisms against toxic compounds in acidophiles.

Some Considerations on the Role of Water in Thin Layer Chromatography of Inorganic Anions

1984 ◽  
Vol 39 (2) ◽  
pp. 186-189
Author(s):  
Takaya Iida ◽  
Kaname Ito
Keyword(s):  
Thin Layer ◽  
Partition Coefficient ◽  
Thin Layer Chromatography ◽  
Partition Coefficients ◽  
Ionic Radius ◽  
Stationary Phases ◽  
Partial Charge ◽  
Layer Chromatography ◽  
Water Contents

The volume ratios of the mobile and stationary phases in thin layer chromatography, and the partition coefficients of halide and halate anions and some other anions between these phases were obtained by developing the ions simultaneously with a series of metaphosphates. The water contents of the developing solvents influenced the volume ratios very much, but not so much the partition coefficients. The logarithm of the partition coefficient of the halide anions is proportional to the reciprocal of their ionic radius, and that of the halate anions and oxoanions to the partial charge on the oxygens of them.

scholarly journals Unraveling the Central Role of Sulfur-Oxidizing Acidiphilium multivorum LMS in Industrial Bioprocessing of Gold-Bearing Sulfide Concentrates

2021 ◽  
Vol 9 (5) ◽  
pp. 984
Author(s):  
Anna Panyushkina ◽  
Aleksandr Bulaev ◽  
Aleksandr V. Belyi
Keyword(s):  
Sulfur Metabolism ◽  
Draft Genome ◽  
Microbial Consortia ◽  
Reduced Sulfur Compounds ◽  
Sulfur Oxidizer ◽  
Sulfur Oxidizing ◽  
Unique Strain ◽  
Sulfide Concentrates ◽  
Gold Bearing

Acidiphilium multivorum LMS is an acidophile isolated from industrial bioreactors during the processing of the gold-bearing pyrite-arsenopyrite concentrate at 38–42 °C. Most strains of this species are obligate organoheterotrophs that do not use ferrous iron or reduced sulfur compounds as energy sources. However, the LMS strain was identified as one of the predominant sulfur oxidizers in acidophilic microbial consortia. In addition to efficient growth under strictly heterotrophic conditions, the LMS strain proved to be an active sulfur oxidizer both in the presence or absence of organic compounds. Interestingly, Ac. multivorum LMS was able to succeed more common sulfur oxidizers in microbial populations, which indicated a previously underestimated role of this bacterium in industrial bioleaching operations. In this study, the first draft genome of the sulfur-oxidizing Ac. multivorum was sequenced and annotated. Based on the functional genome characterization, sulfur metabolism pathways were reconstructed. The LMS strain possessed a complicated multi-enzyme system to oxidize elemental sulfur, thiosulfate, sulfide, and sulfite to sulfate as the final product. Altogether, the phenotypic description and genome analysis unraveled a crucial role of Ac. multivorum in some biomining processes and revealed unique strain-specific characteristics, including the ars genes conferring arsenic resistance, which are similar to those of phylogenetically distinct microorganisms.

The influence of degree of saturation on the coefficient of aqueous diffusion

1998 ◽  
Vol 35 (5) ◽  
pp. 811-827 ◽  
Author(s):  
P C Lim ◽  
S L Barbour ◽  
D G Fredlund
Keyword(s):  
Diffusion Coefficient ◽  
Effective Diffusion ◽  
Theoretical Models ◽  
Chloride Ions ◽  
Model Verification ◽  
Degree Of Saturation ◽  
Best Fit ◽  
Coefficient Of Diffusion ◽  
Water Contents

The role of degree of saturation on the coefficient of diffusion of contaminants in the aqueous phase is presented and theoretical models for predicting the coefficient of diffusion at any degree of saturation are described. Three predictive models were developed based on three different diffusion modes: diffusion in parallel and series arrangements and combination of both. Diffusion tests were conducted on a sand at various water contents ranging from saturation to the residual degree of saturation using potassium and chloride ions as tracers to verify the applicability of the models. Results from the diffusion tests showed a decrease in effective diffusion coefficient of potassium with a decrease in degree of saturation. The functional relationship between the normalized diffusion coefficient for potassium and the degree of saturation is slightly nonlinear. The results for chloride also showed a decreasing trend, although the data were quite scattered and further verification is needed. Model verification based on the results for potassium showed that among the three models proposed, the model which combines the diffusion pathways in parallel and series arrangements provides the best fit to the experimental data.Key words: unsaturated, contaminant transport, aqueous diffusion, degree of saturation.

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