Comparison of Bioleaching High Arsenic-Bearing Copper Sulphide Concentrate Using Thiobacillus Ferrooxidans and Sulfobacillus Thermosulfidooxidans

2012 ◽  
Vol 524-527 ◽  
pp. 1997-2003
Author(s):  
Hai Yun Xie ◽  
Zhuo Yue Lan ◽  
Shu Ming He ◽  
Li Kun Gao ◽  
Xiong Tong

The usage of high-arsenic sulfide copper concentrate were limited because the arsenic in the concentrate harms the qualities of copper product and pollutes the environment. In this paper an innovative process for high-arsenic copper sulfide concentrate with with bio-oxidation respectively Thiobacillus ferrooxidans and moderate thermophile Sulfobacillus thermosulfidooxidans has been studied out, and the influencing factors have been comparative studied during the leaching process, such as concentration particle size, leaching methods, pulp concentration, leaching time and the initial concentration of Fe3+, etc. Under the suitable leaching conditions, the experiments results show that the concentrate is leached 47.13% of Cu,50.09% of As and 52.46% of Fe by Thiobacillus ferrooxidans and 82.39% of Cu,78.21% of As and 40.38% of Fe by moderate thermophile Sulfobacillus thermosulfidooxidans. The high concentration initial Fe3+ has speeded leaching process up in the presence of moderate thermophile Sulfobacillus thermosulfidooxidans, and when the pulp initial concentration of Fe3+ is in the range of 0.08~0.32mol/L, the leaching rate of Cu is 86.34~97.06%, As 89.22~94.13%. It is concluded that Sulfobacillus thermosulfidooxidans have a better effect on bioleaching high-arsenic sulfide copper concentrate than Thiobacillus ferrooxidans.

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 583
Author(s):  
Dongdong He ◽  
Yuming Xiong ◽  
Li Wang ◽  
Wei Sun ◽  
Runqing Liu ◽  
...  

Arsenic (As) is considered one of the most serious inorganic pollutants, and the wastewater produced in some smelters contains a high concentration of arsenic. In this paper, we purified the high-concentration arsenic solution with red mud and Fe3+ synergistically. In this system, arsenite anions reacted with Fe(III) ions to form ferric arsenite, which attached on the surface of red mud particles. The generated red mud/Fe1−x(As)x(OH)3 showed a better sedimentation performance than the pure ferric arsenite, which is beneficial to the separation of arsenic from the solution. The red mud not only served as the carrier, but also as the alkaline agent and adsorbent for arsenic treatment. The effects of red mud dosage, dosing order, pH, and molar ratio of Fe/As on arsenic removal were investigated. The efficiency of arsenic removal increased from a pH of 2 to 6 and reached equilibrium at a pH of 7. At the Fe/As molar ratio of 3, the removal efficiency of arsenic ions with an initial concentration of 500 mg/L reached 98%. In addition, the crystal structure, chemical composition, and morphological properties of red mud and arsenic removal residues (red mud/Fe1−x(As)x(OH)3) were characterized by XRD, XPS, X-ray fluorescence (XRF), SEM-EDS, and Raman spectroscopy to study the mechanism of arsenic removal. The results indicated that most of the arsenic was removed from the solution by forming Fe1−x(As)x(OH)3 precipitates on the red mud surface, while the remaining arsenic was adsorbed by the red mud and ferric hydroxide.


1996 ◽  
Vol 16 (3) ◽  
pp. 249-263 ◽  
Author(s):  
Hai-Lan Chen ◽  
Philip S. Rudland ◽  
John A. Smith ◽  
David G. Fernig

Maximal stimulation of DNA synthesis in quiescent rat mammary (Rama) 27 fibroblasts is elicited by epidermal growth factor (EGF) or basic fibroblast growth factor (bFGF) 18 h after the initial addition of the growth factors-the ‘lag’ period. At maximally-stimulating concentrations, EGF and bFGF are interchangeable 9 h after their initial addition. When the initial concentration of growth factor is below that required to elicit a maximal response, it is possible to increase the level of DNA synthesis by increasing the concentration of growth factor 9 h after its initial addition. When the initial concentration of growth factor is high, substitution by a lower concentration of growth factor after 9 h allows a greater proportion of cells to synthesize DNA than would be expected from a continuous low dose of growth factor. Similar results are obtained when both the growth factor and its concentration are changed 9 h after the initial addition of growth factor. However, when EGF at a low concentration is substituted for a high concentration of EGF or bFGF the resulting increase in the levels of DNA synthesis is greater when EGF rather than bFGF is added for a second time. The half-life of the growth-stimulatory signals delivered by EGF and by bFGF 9 h after their initial addition is 1–2 h. These results suggest that to stimulate DNA synthesis: (i) EGF or bFGF must deliver a signal(s) continuously; (ii) the initial signals produced by EGF and bFGF are equivalent; (iii) the signals produced between 9–18 h by EGF may be different to those produced by bFGF.


Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 518 ◽  
Author(s):  
César I. Castellón ◽  
Pía C. Hernández ◽  
Lilian Velásquez-Yévenes ◽  
María E. Taboada

An alternative copper concentrate leaching process using sodium nitrate and sulfuric acid diluted in seawater followed by gas scrubbing to recover the sodium nitrate has been evaluated. The work involved leaching test carried out under various condition by varying temperature, leaching time, particle size, and concentrations of NaNO3 and H2SO4. The amount of copper extracted from the chalcopyrite concentrate leached with seawater, 0.5 M of H2SO4 and 0.5 M of NaNO3 increased from 78% at room temperature to 91% at 45 °C in 96 h and 46 h of leaching, respectively. Gas scrubbing with the alkaline solution of NaOH was explored to recover part of the sodium nitrate. The dissolved salts were recovered by evaporation as sodium nitrate and sodium nitrite crystals.


2015 ◽  
Vol 814 ◽  
pp. 273-277
Author(s):  
Ping Tang ◽  
Jing Liu ◽  
Min Wei Song ◽  
Hai Ping Yu ◽  
Xu Zhang

The traditional gold leaching method is cyanidation, which carries serious security and environmental problems. More and more attention is paid to the research on non-cyanide process. A high-arsenic-and-sulphur refractory gold concentrate in Sichuan was taken as the object of study. After the roasting-oxidation pretreatment of the sample, potassium ferricyanide was adopted to carry on the process experiment on gold-leaching. The leaching results as well as correlative process conditions were both investigated. The results showed that good leaching effects could be achieved by potassium ferricyanide. When the amount of potassium ferricyanide was 60g/L, the concentration of NaOH 0.2mol/L, the liquid-solid ratio 6:1 and the leaching process at room temperature lasted for 20h, the gold leaching rate reached 88.1%. If the leaching aid CaO2 is added simultaneously, it can contribute to the gold leaching. When the amount of CaO2 was 3g/L, the gold leaching rate increased to more than 94%, the amount of potassium ferricyanide decreased to 50g/L and the leaching time reduced to 14h.


2019 ◽  
Vol 72 (5) ◽  
Author(s):  
Élise D’Huart ◽  
Jean Vigneron ◽  
Alexandre Charmillon ◽  
Igor Clarot ◽  
Béatrice Demoré

ABSTRACTBackground: In severe infections, high-concentration vancomycin may be administered by continuous infusion. The dosage of vancomycin may reach 60 mg/kg per day. Objectives: To study the feasibility of preparing high-concentration vancomycin solutions (40 to 83.3 mg/mL), to study the effect of an electric syringe pump on the physical stability of high-concentration vancomycin, and to study the stability of vancomycin 62.5 and 83.3 mg/mL in 0.9% sodium chloride (0.9% NaCl) or 5% dextrose in water (D5W) with storage up to 48 h at room temperature. Methods: The following sets of syringes were prepared: (1) 4 syringes of vancomycin in 0.9% NaCl for each of 5 concentrations between 40 and 83.3 mg/mL (total 20 syringes); (2) 6 syringes at 83.3 mg/mL in 0.9%NaCl and 6 syringes at 83.3 mg/mL in D5W; and (3) 30 syringes at 83.3 mg/mL in D5W. Visual inspection was performed for all 3 syringe sets, and subvisual inspection for sets 1 and 2 (for periods of 24 h for set 1 and 48 h for sets 2 and 3). One syringe of vancomycin 83.3 mg/mL with each solvent was inserted into an electric syringe pump, and samples from the infusion line and collected after transit through the pump were inspected visually. Chemical stability was evaluated by high-performance liquid chromatography, and physical stability, pH, and osmolality were investigated. Results: For all sets of syringes, no physical modification was observed over time, nor were any changes observed after transit through the electric syringe pump. In 0.9% NaCl, vancomycin 62.5 and 83.3 mg/mL retained more than 90% of the initial concentration after 48 and 24 h, respectively; however, for the 83.3 mg/mL solution, precipitate was visible after 48 h. In D5W, vancomycin at 62.5 and 83.3 mg/mL retained more than 90%of the initial concentration after 48 h. Conclusion: It was feasible to prepare high-concentration solutions of vancomycin. The electric syringe pump did not cause any precipitation. Vancomycin in D5W at 62.5 and 83.3 mg/mL was stable over 48 h at room temperature. Precipitation occurred in 0.9% NaCl. D5W is therefore recommended as the solvent for this drug.RÉSUMÉContexte : En cas d’infection grave, de la vancomycine à forte concentration peut être administrée par perfusion continue à une dose pouvant atteindre 60 mg/kg par jour. Objectifs : Mener une étude de faisabilité portant sur la préparation de solutions de vancomycine à forte concentration (de 40 à 83,3 mg/mL); étudier l’effet d’un pousse-seringue électrique sur la stabilité physique de la vancomycine à forte concentration; et étudier la stabilité de la vancomycine (62,5 et 83,3 mg/mL) dans une solution de chlorure de sodium à 0,9 % (NaCl à 0,9 %) ou dans une solution aqueuse de dextrose à 5 % (D5W) après 48 h à la température ambiante.Méthodes : Trois ensembles de seringues ont été préparés : (1) quatre seringues de vancomycine dans une solution de NaCl à 0,9 %, à chacune des cinq concentrations comprises entre 40 et 83,3 mg/mL (20 seringues au total); (2) six seringues à 83,3 mg/mL dans une solution de NaCl à 0,9 % et six seringues à 83,3 mg/mL dans une solution de D5W; et (3) 30 seringues à 83,3 mg/mL dans une solution de D5W. Une inspection visuelle des trois ensembles de seringues et une inspection « sous-visuelle » des ensembles 1 et 2 ont eu lieu (période de 24 h pour l’ensemble 1 et de 48 h pour les ensembles 2 et 3). Une seringue contenant de la vancomycine à 83,3 mg/mL mélangée à chaque solvant a été insérée dans un pousse-seringue électrique, et les échantillons prélevés dans le tube de perfusion et ceux recueillis après leur passage dans la pompe ont été inspectés visuellement. La stabilité chimique a été évaluée par chromatographie liquide à haute performance et la stabilité physique, le pH ainsi que l’osmolalité ont eux aussi été étudiés. Résultats : Les trois ensembles de seringues n’ont présenté aucune modification physique avec le temps. Aucun changement n’a non plus été observé après le passage dans le pousse-seringue électrique. Dans la solution de NaCl à 0,9 %, la vancomycine à 62,5 et à 83,3 mg/mL a conservé plus de 90 % de sa concentration initiale respectivement après 48 et 24 h. Cependant, le précipité de la solution à 83,3 mg/mL était visible après 48 h. Dans la solution de D5W, la vancomycine à 62,5 et à 83,3 mg/mL a conservé plus de 90 % de sa concentration initiale après 48 h. Conclusion : La préparation de solutions de vancomycine à forte concentration est faisable. Le pousse-seringue électrique n’a pas causé de précipitation. La vancomycine dans la solution de D5W à 62,5 et à 83,3 mg/mL est restée stable pendant plus de 48 h à la température ambiante. Les précipitations se sont produites dans les solutions de NaCl à 0,9 %. On recommande donc la solution de D5W comme solvant pour ce médicament.


2012 ◽  
Vol 29 (2) ◽  
pp. 121-128
Author(s):  
M. Devia ◽  
I. Wilkomirsky ◽  
R. Parra

2014 ◽  
Vol 881-883 ◽  
pp. 1549-1553
Author(s):  
Hai Yun Xie ◽  
Qun Jie Ye ◽  
Xiong Tong ◽  
Li Kun Gao ◽  
Ji Xing Liu

In the bacterial leaching, the oxidation of Fe2+ is very important process. According to the results of this paper, Fe2+ and Fe3+ concentration effect on the growth of moderate thermophile. The optimum conditions for growth of moderate thermophile are the initial concentration of Fe2+ at 0.16mol/l. It indicates the existence of the optimum conditions including initial concentrations of Fe2+ and Fe3+ for the bio-oxidation Fe2+. To increase the initial concentration of Fe3+ can enhance the oxidation rate of Fe2+. The dynamic model of the moderate thermophile oxidation Fe2+ has been established by analyzing and calculating test data with the Matlab software.


Sign in / Sign up

Export Citation Format

Share Document