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Huang S.H.,Hunan Research Institute of Nonferrous Metals | Yang Y.,Huazhong Agricultural University | Yuan C.Y.,Hunan Research Institute of Nonferrous Metals | Li Q.,Hunan Research Institute of Nonferrous Metals | And 3 more authors.
IOP Conference Series: Earth and Environmental Science | Year: 2017

In order to investigate the heavy metal pollution conditions of soil of smelting area in Zijiang of Chenzhou, Hunan province, 42 samples were studied. The concentrations of heavy metals As, Pb, Cd, Zn and Cu in the soil were determined by using atomic absorption spectrometry(AAS) and atomic fluorescence spectrometry(AFS). Then the potential pollution risks of heavy metal in the soil were evaluated by method of geological acumination index (Igeo). The results indicated that the average concentrations of As, Pb, Cd, Zn and Cu were 187.79, 2074.52, 15.72, 2178.89, 39.69 mg/kg respectively. The geological evaluation of the cumulative index results showed that the contamination degree of 5 heavy metals follow the sequence of Cd> Zn >Pb > As >Cu. The results show that Cd reached extremely pollution degree, Zn reached strong pollution-extremely pollution levels, the pollution of Pb in the soil is classified as strong pollution degree, Cu and As of no pollution according to the results of Igeo based on the background value of heavy metals in the soil of Hunan Province. © Published under licence by IOP Publishing Ltd.

Huang S.H.,Hunan Research Institute of Nonferrous Metals | Li Q.,Hunan Research Institute of Nonferrous Metals | Yang Y.,Huazhong Agricultural University | Yuan C.Y.,Hunan Research Institute of Nonferrous Metals | And 3 more authors.
Kemija u industriji/Journal of Chemists and Chemical Engineers | Year: 2017

An exploratory study on soil contamination of Cd, Zn, Pb was carried out in the surroundings of a historical, abandoned Pb-Zn mining area in Hunan Province, China. The accumulation in soils and representative plants of Cd, Zn, Pb and their chemical speciation were investigated. The obtained results indicated that Cd, Zn and Pb presented a significant contamination compared with Environmental Quality Standards for Soils in China (GB 15618-1995). The geoaccumulation index suggested the degree of contamination: Pb > Cd > Zn. The modified BCR sequential extraction results showed that Cd, Zn, and Pb exist in soil in a relatively unstable form, and will exert a bad effect on the plants grown in the soil. Heavy metals in oranges collected in the sampling area were tested to identify the extent of pollution. The results confirmed that the sampled oranges were polluted with Pb, which exceeded the national food safety standard by 3.4 - 6.3 times. Heavy metals in branches and leaves showed different accumulation characteristics than the fruits.

Huang S.-H.,Hunan Research Institute of Nonferrous Metals | Huang S.-H.,Central South University
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2011

Based on the optimization of culture medium composition, the growth conditions and ability of Cr(VI) reduction, the in-situ remediation of Cr-contaminated soil can be achieved by adding culture medium in soils to stimulate the activity of indigenous microorganism. The results show that the optimal conditions for the Cr(VI) reduction by indigenous microorganism are 5 g glucose and 5 g nitrogenous compounds A per kilogram soil at 30°C and the mass ratio of soil to water is 1: 1. Under the optimal condition, the water soluble Cr(VI) in the soil contaminated by chromium-containing slag heap is completely removed in the fourth day. The initial pH value of culture medium do not affect Cr(VI) reduction. The inorganic salt does not need to be added into the culture medium when the in-situ remediation of Cr(VI) is carried out by the indigenous microorganism.

Li Q.,Central South University | Li Q.,Hunan Research Institute of Nonferrous Metals | Yang Z.-H.,Central South University | Chai L.-Y.,Central South University | And 4 more authors.
Journal of Central South University | Year: 2013

Bench-scale soil column experiments were carried out to evaluate the effectiveness of Cr(VI) bioremediation process in soils by using indigenous bacteria with the addition of bacteria nutrient media. Effects of particle size, spray intensity, initial Cr(VI) concentration, circulation mode and soil depth on Cr(VI) remediation were studied. Results show that soils after 6 d remediation with spray intensity controlled in the range of 29.6-59.2 mL/min could well fulfill the requirement of concrete aggregate and roadbed material usage, for the leaching toxicity concentration of the Cr(VI) in treated soils under the chosen condition is far less than 5 mg/L. The leaching toxicity and fractions of both hexavalent chromium and trivalent chromium from remediated soils were determined and compared with that of untreated soil. The results show that water soluble Cr(VI) declines from 1520.54 mg/kg to 0.68 mg/kg, exchangeable Cr(VI) decreases from 34.83 mg/kg to 0.01 mg/kg and carbonates-bonded Cr(VI) falls from 13.55 mg/kg to 0.68 mg/kg. Meanwhile, a corresponding increase in carbonate-bonded Cr(III), Fe and Mn oxides-bonded Cr(III) and organic matter-bonded Cr(III) are found. It reveals that indigenous bacteria can leach out water soluble Cr(VI), exchangeable Cr(VI) and carbonates-bonded Cr(VI) from contaminated soil followed by converting into carbonate-bonded Cr(III), Fe and Mn oxides-bonded Cr(III), organic matter-bonded Cr(III) and residual Cr(III). © 2013 Central South University Press and Springer-Verlag Berlin Heidelberg.

Chen D.,Hunan Research Institute of Nonferrous Metals | Yang J.,Hunan Research Institute of Nonferrous Metals | Zeng H.,Hunan Research Institute of Nonferrous Metals
XXV International Mineral Processing Congress 2010, IMPC 2010 | Year: 2010

The mine samples for this experimental study taken from Mozhugongka in Tibet, are typical complex lead-zinc copper multi-metallic sulfide ore which are difficult to process. Based on the characteristics of the ore, we identify the flotation tests of copper, lead and zinc as a mixed Cu-Pb flotation, separate copper and lead, finally float zinc from the copper and lead tailings. The key technology of the process is as follows: (1) Regrinding the middling, which can highly liberate copper and lead from the mixed Cu-Pb ore, thus increase copper and lead recovery. (2) Using activated carbon to absorb the collectors which was used in Cu-Pb separation processing. (3) Adopting the combination of CMC, Na2SO3 and Na2SiO3 which were environment-friendly as the depressant of galena instead of toxic sodium dichromate. Through this technology, the difficult technical problem of copper and lead separation had been s uccessfully solved and a refined beneficiation test indicator had been obtained. This process first got its successful application in two concentrators in Tibet. At present, these two concentrators are running well and have a choiceness beneficiation test indicator.

Wang Z.-X.,Central South University | Chen J.-Q.,Central South University | Chai L.-Y.,Central South University | Yang Z.-H.,Central South University | And 3 more authors.
Journal of Hazardous Materials | Year: 2011

Previous studies often neglected the direct exposure to soil heavy metals in human health risk assessment. The purpose of this study was to assess the environmental impact and site-specific health risks of chromium (Cr) by both direct and indirect exposure assessment method. Results suggested that total Cr was shown a substantial buildup with a significant increase in the industrial and cultivated soils (averaged 1910 and 986mgkg-1, respectively). The Cr contents of vegetables exceeded the maximum permissible concentration by more than four times in every case. Human exposure to Cr was mainly due to dietary food intake in farming locations and due to soil ingestion in both industrial and residential sites. Soil ingestion was the main contributor pathway for direct exposure, followed by inhalation, and then dermal contact. The highest risks of vegetable ingestion were associated with consumption of Chinese cabbage. The results also indicated that plant tissues are able to convert the potentially toxic Cr (VI) species into the non-toxic Cr (III) species. The analyses of human health risks indicated that an important portion of the population is at risk, especially in the industrial site. © 2011 Elsevier B.V.

Guang C.,Central South University | Zhao S.-J.,Hunan Research Institute of Nonferrous Metals | Yang T.-Z.,Central South University
Journal of Central South University of Technology (English Edition) | Year: 2012

The recovery of nickel from molybdenum leach residue by the process of segregation roasting-sulfuric acid leaching-solvent extraction was investigated. The residue was characterized by microscopic investigations, using X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD) techniques and the residue after segregation roasting was characterized by chemical phase analysis method. A series of experiments were conducted to examine the mass ratio of activated carbon (AC) to the residue, segregation roasting time and temperature, sulfuric acid concentration, liquid-to-solid ratio, leaching time, leaching temperature, addition amount of 30% H2O2, stirring speed (a constant) on the leaching efficiency of nickel. A maximum nickel leaching efficiency of 90.5% is achieved with the mass ratio of AC to the residue of 1:2.5, segregation roasting time of 2 h, segregation roasting temperature of 850 °C, sulfuric acid concentration of 4.5 mol/L, liquid-to-solid ratio of 6:1, leaching time of 5 h, leaching temperature of 80 °C, addition of 30% H2O2 of 0.6 mL for 1 g dry residue. Under these optimized conditions, the average leaching efficiency of nickel is 89.3%. The nickel extraction efficiency in the examined conditions is about 99.6%, and the nickel stripping efficiency in the examined conditions is about 99.2%. © Central South University Press and Springer-Verlag Berlin Heidelberg 2012.

Huang S.-H.,Hunan Research Institute of Nonferrous Metals | Huang S.-H.,Key Laboratory for Environmental Protection of Nonferrous Industry
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2014

The pollution characteristics of Pb, Cd, Zn, Cu and Ni in soil of lead-zinc mining area were studied. The results indicate that the contamination degree followed the sequence of Cd>Pb>Zn>Ni>Cu and concentrations of Pb, Cd and Zn exceeded corresponding limits of the Chinese National Soil Environmental Quality Standard III. The soil was extremely polluted by Cd (Iego=5.26), moderately to heavily polluted by Zn (Iego=2.38), heavily to extremely polluted by Pb (Iego=4.13). The results of BCR three-step sequential extraction procedure show that the active Cd, Pb and Zn were relatively high and might exert adverse effects on the plants grown in the soil, while Cu and Ni existed in soil with a relatively stable form. Potential ecological risk results indicate that soils were engaging in a high potential ecological risk by pollution of Cd and should be given rise to concern.

Gu G.-H.,Central South University | Guo Y.-W.,Central South University | Guo Y.-W.,Hunan Research Institute of Nonferrous Metals
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2011

The impact of A.ferrooxidans on dissolution of chalcopyrite in the microbe-mineral contact/uncontact model was studied by employing dialysis bag to insulate the bacteria from chalcopyrite, and the preliminary analysis of surface passivation in leaching process was also investigated. The results show that the behaviors of chalcopyrite leaching include the oxidation of bacteria on elemental sulfur as well as the oxidation of ferric ion, the oxidation product of ferrous ion, on chalcopyrite dissolution in the microbe-mineral contact model; however, the dissolution of chalcopyrite is determined by the oxidation of ferric ion in the microbe-mineral uncontact model. The leaching rate of chalcopyrite is controlled mainly by potentials of leaching system, and high potential is more conductive to chalcopyrite leaching. The microbe-mineral contact model is more conductive to the increase of potentials than microbe-mineral uncontact model, and can eliminate the sulfur film on chalcopyrite surface. Therefore, it is more profitable for leaching of chalcopyrite than uncontact model. The jarosite easily generated on chalcopyrite surface at high potentials is the main cause of surface passivation of chalcopyrite in both microbe-mineral contact and uncontact model.

PubMed | Huazhong Agricultural University and Hunan Research Institute of Nonferrous Metals
Type: | Journal: Bulletin of environmental contamination and toxicology | Year: 2016

The effects of amendments, such as lime, bassanite, sodium phosphate, steel slag and charcoal, and their compounds on the immobilization of cadmium (Cd) are investigated. The lime-bassanite-charcoal compound shows the best remediation performance compared to other agents in conducted experiments. The optimum condition for lime-bassanite-charcoal application in contaminated soil is lime-bassanite-charcoal with a mass ratio of 1:1/3:2/3, a dose of 2% of the soil weight, and a liquid-to-solid ratio of 35%-40%; additionally, the agents should be added before water addition. The highest Cd removal rate was 58.94% (1.19%) with a pH of 0.23, which is much higher than the rates reported in previous studies. The compound amendment was used in a field experiment, demonstrating a Cd removal efficiency of 48.78% (4.23), further confirming its effectiveness.

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