Leaching of Indium from Indium-and Iron-Bearing Sphalerite Concentrate in Sulfuric Acid–Ferric Sulfate Solution

2019 ◽  
Vol 17 (10) ◽  
Author(s):  
Huang Hui ◽  
Zhang Fan ◽  
Deng Zhigan ◽  
Wei Chang ◽  
Li Xingbin ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Elemental Sulfur ◽  
Control Process ◽  
Dissolution Kinetics ◽  
Sulfate Solution ◽  
Ferric Sulfate ◽  
Ferric Ion ◽  
X Ray ◽  
Mixed Control ◽  
Iron Bearing

Abstract Leaching of indium from an indium-and iron-bearing sphalerite concentrate in sulfuric acid– ferric sulfate solution was examined. The effects of various parameters were studied. Increases in the stirring speed, temperature, ferric ion and sulfuric acid concentrations, and decreases in the particle size, enhanced the indium leaching rate. Scanning electron microscopy/energy-dispersive X-ray spectroscopy and X-ray diffraction analyses of the unreacted and reacted sphalerite concentrate particles showed that elemental sulfur was formed and precipitated at the particle surfaces. The results show that dissolution was controlled by a mixed-control process. In the initial stage, the dissolution kinetics was chemically controlled. When more elemental sulfur was present on the particle surfaces, the dissolution kinetics was controlled by mass transfer though the sulfur layer. The activation energy of the chemically controlled step was 33.9 kJ/mol. The reaction orders with respect to the initial sulfuric acid and ferric ion concentrations were approximately 0.74 and 0.60, respectively.

Physical Peeling of Passivating Layers on Chalcopyrite Leached with Ferric Ion Using Small Alumina Balls

2015 ◽  
Vol 1130 ◽  
pp. 304-307
Author(s):  
Seongjin Joe ◽  
Chihiro Inoue ◽  
Tadashi Chida
Keyword(s):  
Elemental Sulfur ◽  
Control Experiment ◽  
Dissolution Kinetics ◽  
Physical Method ◽  
Sulfate Solution ◽  
Copper Extraction ◽  
Solution Ph ◽  
Copper Dissolution ◽  
Leaching Experiments ◽  
Alumina Ball

Chalcopyrite is the most abundant copper mineral but notorious as its slow dissolution kinetics in hydrometallurgical processes due to the formation of passivating layers on the surface of the mineral. We tried to improve chalcopyrite leaching rate through adding small alumina balls in a shaking flask to peel off physically the passivating layers. Leaching experiments were carried out in shaking flasks at 333 K in anaerobic condition. Each flask contained ferric sulfate solution (pH 0.7), chalcopyrite concentrate, and alumina balls (5-mm diameter). The effects of the alumina ball addition on the chalcopyrite leaching were outstanding. About 97 % copper dissolution was achieved after 30 hours leaching period, while only 12 % of copper was dissolved from the control experiment. In former case, elemental sulfur was detected clearly as a reaction product. These facts indicate that elemental sulfur formed by ferric leaching did not obstruct copper dissolution in case of alumina ball addition in leaching system. Our findings show that the passivating layers on chalcopyrite surface can be peeled off effectively by physical method and high copper extraction can be achieved.

Effect of inoculation of iron oxidizing bacteria on elution of copper from anaerobically digested sewage sludge

1998 ◽  
Vol 38 (2) ◽  
pp. 63-70 ◽  
Author(s):  
Ayumi Ito ◽  
Teruyuki Umita ◽  
Jiro Aizawa ◽  
Kumiko Kitada
Keyword(s):  
Sulfuric Acid ◽  
Sewage Sludge ◽  
Ferrous Sulfate ◽  
Ferric Sulfate ◽  
Ferrous Ion ◽  
Ferric Ion ◽  
Biological Oxidation ◽  
Iron Oxidizing Bacteria ◽  
Elution Rate ◽  
Digested Sewage Sludge

The effect of inoculation of iron oxidizing bacteria on elution of Cu from anaerobically digested sewage sludge was investigated without adding ferrous sulfate as a substrate. The inoculation of iron oxidizing bacteria to the sludge brought about the effective elution of Cu at pH 2 and 3. Ferric ion produced by the biological oxidation of ferrous ion which was eluted from the sludge or ferric ion eluted directly from the sludge and iron oxidizing bacteria caused the elution of Cu. Furthermore, both chemical and biological leachings of Cu from CuS were studied at pH 2, 3 and 4. It was found that both ferric ion and iron oxidizing bacteria could elute Cu. The elution rate of Cu with ferric ion decreased as the pH increased and two moles of Fe(III) eluted 1 mole of Cu. The biological leaching by iron oxidizing bacteria eluted Cu more effectively than the chemical one with sulfuric acid or ferric sulfate at pH 2, 3 and 4.

scholarly journals pH-dependent leaching mechanism of carbonatitic chalcopyrite in ferric sulfate solution

2021 ◽  
Vol 31 (7) ◽  
pp. 2139-2152
Author(s):  
Kolela J NYEMBWE ◽  
Elvis FOSSO-KANKEU ◽  
Frans WAANDERS ◽  
Martin MKANDAWIRE
Keyword(s):  
Sulfate Solution ◽  
Ferric Sulfate ◽  
Ph Dependent ◽  
Leaching Mechanism

DEPOSITION OF SINGLE-PHASE CuInSe2 THIN FILMS UNDER LOW VACUUM LEVEL BY A TWO-STAGE GROWTH TECHNIQUE

2009 ◽  
Vol 16 (03) ◽  
pp. 381-386 ◽  
Author(s):  
J. B. CHU ◽  
H. B. ZHU ◽  
Z. A. WANG ◽  
Z. Q. BIAN ◽  
Z. SUN ◽  
...  
Keyword(s):  
Solar Cells ◽  
Single Phase ◽  
Low Cost ◽  
Control Process ◽  
Rf Magnetron Sputtering ◽  
Chalcopyrite Structure ◽  
Sputtering Deposition ◽  
Vacuum Level ◽  
X Ray ◽  
High Efficient

Single-phase CuInSe 2 films were grown by high vapor selenization of CuIn alloy precursors within a partially closed graphite box. The CuIn precursors were prepared using Cu x In y alloy targets with different composition rates under low vacuum level by a homemade sputtering system. The Cu and In composition rates of the used targets are 11:9, 10:10, and 9:11, respectively. The metallic precursor films were selenized using a two-step temperature profile, i.e. at 250°C and 400–500°C, respectively. The influence of the temperature at the second selenization step on the quality of the CIS absorbing layers was investigated. The CIS films were characterized by X-ray diffractometry, scanning electron microscopy, energy dispersive X-ray analysis, and Raman spectroscopy. The deposited CIS absorbers selenized at a high temperature of 500°C for 30 min exhibited a single-phase chalcopyrite structure with a preferential orientation in the (112) direction. These layers display uniform, large, and densely packed crystals with a grain size of about 3–5 μm. Cadmium sulfide buffer layer was manufactured by chemical bath deposition method. Bilayers ZnO / ZnO : Al were prepared by RF magnetron sputtering deposition. CIS solar cells with an efficiency of about 6.5% were produced without antireflective films. The method to fabricate CIS solar cells by a combination of the low vacuum sputtering deposition and the graphite box selenization process has provided a simple control process and shown a promising potential for developing high efficient and low-cost CuInSe 2 solar cells.

Microwave-Assisted Leaching Vanadium from Stone Coal

2011 ◽  
Vol 189-193 ◽  
pp. 3916-3919 ◽  
Author(s):  
Hong Zhou Ma ◽  
Xin Zhe Lan ◽  
Yao Ning Wang ◽  
Yu Hong Tian
Keyword(s):  
Sulfuric Acid ◽  
Microwave Power ◽  
Orthogonal Design ◽  
Chemical Constituents ◽  
Influence Factors ◽  
Sulfate Solution ◽  
Leaching Rate ◽  
Stone Coal ◽  
Microwave Assisted ◽  
Design Experiments

Technological process of microwave-assisted leaching of vanadium with sulfate solution has been defined on the base of phase and chemical constituents of stone coal. The influence factors such as content of sulfuric acid, microwave power, and leaching time were studied on leaching rate of vanadium from the stone coal. One element experiments and orthogonal design experiments are carried out to achieve optimized parameters. The experimental results showed that the leaching rate of vanadium was improved by the change of influence factors at some range. The single leaching rate of vanadium reached 80.9% under the optimal conditions of sulfuric acid content of 12%, microwave power 539w,leaching time of 2h.

scholarly journals Effect of X-ray irradiation on the F1 generation of Sitophilus zeamais Motschulsky and the germination rate of maize grain

2021 ◽  
Vol 82 (1) ◽  
Author(s):  
Sobifagha Princess Bell-Gam ◽  
Luke Chinaru Nwosu ◽  
Kayode David Ileke ◽  
Uwaoma Otuodichinma Aguwa
Keyword(s):  
Germination Rate ◽  
Seed Viability ◽  
Control Process ◽  
Progressive Increase ◽  
Sitophilus Zeamais ◽  
Maize Weevil ◽  
Maize Production ◽  
X Ray ◽  
Significant Difference ◽  
Flour Production

Abstract Background The use of X-ray irradiation in the control of the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) infesting stored maize was tested at 60, 70 and 80 KeV as part of the international concerted efforts to save maize production and enhance food security. Investigations were done in the laboratory at mean temperature and relative humidity of 29.2 °C and 75.7%, respectively using three varieties of maize. The possibility that X-ray irradiation can affect the viability of maize grains when planted after weevil control process was also evaluated in the laboratory. Standard methods were used to achieve the specific objectives, and X-ray machine snap constituted the exposure time for each dose. Results The results revealed 10% mortality of adult weevils after 24 h and 40% mortality after a period of 7 days. The result indicates moderate effect on mortality. Progressive increase in mortality was recorded as dose increased from 60 to 80 KeV. X-ray irradiation at the doses tested did not significantly (P > 0.05) restrict S. zeamais emergence from maize grains and did not also significantly protect grains against damage and flour production. There was no difference in the pattern of daily emergence of new progenies and pattern of accumulated emergence. The relationship between X-ray irradiation doses and weight of emerging progenies require more specific analysis. Absence of significant difference between the viability of irradiated grains and un-irradiated grains strongly suggests that X-ray irradiation did not adversely affect seed viability, and this gives irradiation technique an opportunity of higher acceptability in agriculture. Conclusions We recommend > 80 KeV of X-ray irradiation or its incorporation into integrated pest management system in order to achieve effective post-harvest control of the pest.

Corrosion of a chrome-moly pipe transporting sulfuric acid in a demineralization section: a failure analysis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Andres Marquez ◽  
Chris Maharaj
Keyword(s):  
Sulfuric Acid ◽  
Material Selection ◽  
Real Life ◽  
Main Idea ◽  
Petrochemical Plant ◽  
Material Loss ◽  
Corrosion Failure ◽  
Content Type ◽  
Characterization Methods ◽  
X Ray

Purpose The purpose of this study was to carry out an analysis of the corrosion failure on a chrome-moly pipeline transporting highly concentrated sulfuric acid in a demineralization section at a petrochemical plant, along with the feasibility of using inhibitors to minimize the corrosive effects of sulfuric acid. Design/methodology/approach X-ray fluorescence spectroscopy, high-resolution optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and accelerated corrosion experiments (ACE) were performed. Findings Erosion-corrosion failure was confirmed by the significant reduction in thickness of the internal surface of the material exposed to sulfuric acid, as well as the formation of an oxide scale/layer. ACE accurately predicted high material loss from exposure to sulfuric acid. Moreover, adding ascorbic acid as a corrosion inhibitor (even at low concentrations) was found to reduce the oxidation by more than 50% in the presence of sulfuric acid. Originality/value The main idea/purpose of this work relies on the analysis of recurrent real-life corrosion-attributed failures that are common in industry but are not properly addressed for a variety of reasons, poor management and lack of corrosion preventive strategies being the main ones. This study once again highlights readily available solutions/implementations that are capable of not only addressing technically the issue investigated but also, and as important, economically. By using microscopic imaging, reliable well-tested and widely used characterization methods, all combined with basic experiments and tests, the nature of the repetitive failure investigated was clearly demonstrated as well as readily available alternatives to minimize it in the short term. Nevertheless, implementing material selection techniques appropriately as effective corrosion prevention/control and cost-saving strategies must be enforced in any process.

Deterioration of concrete containing limestone powder exposed to sulfate attack at ambient temperature

2021 ◽  
Vol 11 (5) ◽  
pp. 724-731
Author(s):  
Hemin Liu ◽  
Qian Huang ◽  
Liang Zhao
Keyword(s):  
Ambient Temperature ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
Adverse Influence ◽  
Powder Content ◽  
Scanning Electron

This study investigates the deterioration of concrete containing limestone powder exposed to sulfate solution under ambient temperature (20~25 °C). Microstructure and mineral phases within the attacked concrete were measured by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). It was found that the addition of limestone powder increased the initial porosity of concrete. Consequently, a larger amount of SO2–4 ions diffused into the concrete containing limestone powder, and their degree of deterioration caused by sulfate attack increased with the increase in limestone powder content. At ambient temperature, gypsum and ettringite were the major attack products, respectively within the surface and nearsurface portions of concrete containing limestone powder, which was consistent with the products of sulfate attack within concrete without limestone powder. Therefore, the type and distribution of the attack products in concrete had not been revised due to the addition of limestone powder. Nevertheless, the adverse influence of limestone powder on the sulfate resistance of concrete, even at ambient temperature, should be considered. Furthermore, effective measures should be implemented to improve the durability of concrete containing limestone powder in this environment.

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