Influence of particle size on copper recovery from sulfide ore by the moderately thermophilic microorganisms

2019 ◽  
Vol 116 (1) ◽  
pp. 119
Author(s):  
Wen-bo Zhou ◽  
Kai Li ◽  
Yu-guang Wang ◽  
Li-juan Zhang ◽  
Hai-na Cheng ◽  
...  
Keyword(s):  
Particle Size ◽  
Xrd Analysis ◽  
Microbial Interactions ◽  
Copper Recovery ◽  
Mineral Particle ◽  
Copper Ore ◽  
Thermophilic Microorganisms ◽  
Moderately Thermophilic ◽  
Before And After ◽  
Leaching Condition

The bioleaching of copper ore by the defined moderately thermophilic consortium containing Leptospirillum ferriphilum and Acidithiobacillus caldus was carried out in the bench-scale column. Bioleaching experiments showed that the leaching rate was 25% higher than that of a conventional leaching and the acid consumption was reduced by 33% at the optimal leaching condition. Meanwhile, the effect of different particle sizes on the rate of the copper leaching was also investigated, and it was shown that the particle size affects the bioleaching rate significantly in the range of 5–25 mm, in which approximately 89.27% of copper was extracted at 5–10 mm, while only 57.08% at 15–25 mm. The results obtained by X-ray diffraction (XRD) analysis of the mineral samples before and after microbial and chemical leaching revealed that the decrease in particle size of the minerals resulted in an enhancement of complex microbial interactions. Especially for the particle size of 5–10 mm, a significant amount of elemental sulfur and jarosite formed on the surface of the mineral, while it was further confirmed that critical microbe-mineral interactions have taken place on the mineral surface. The results indicated that mineral particle size is an integral factor to improve the copper recovery from ore in heap leaching operation. This will provide a reference to the heap construction for the bioleaching.

Effect of Particle Size on the Column Bioleaching of Tibet Yulong Copper Ore

2015 ◽  
Vol 1130 ◽  
pp. 375-378 ◽  
Author(s):  
Li Kai ◽  
Yu Guang Wang ◽  
Li Juan Zhang ◽  
Chen Zhu ◽  
Mao Feng ◽  
...  
Keyword(s):  
Particle Size ◽  
Acid Leaching ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Particle Sizes ◽  
Control Test ◽  
Copper Ore ◽  
Thermophilic Microorganisms ◽  
Column Reactor ◽  
Moderately Thermophilic

This study aimed to investigate the effect of ore particle size on the bioleaching of Yulong copper ore in the bench-scale columns using the mixed culture of moderately thermophilic microorganisms. Bioleaching experiments were carried out on particle sizes of 5-10, 10-15 and 15-25mm in the same kind of column reactors. In the control test of acid leaching, the column reactor was charged with the middle particle size (10-15mm). The results indicated that copper extraction in the column reactor with particle size of 5-10 mm was highest among the three particle sizes. After 110-days leaching, 89% of copper was leached at 5-10 mm particle size while 57% was extracted at 15-25 mm particle size and 80% at 10-15 mm. Under the same particle size (10-15 mm), copper recovery in the column reactor with inoculation of microorganisms was 25% higher in comparison to the control test of acid leaching, while sulfuric acid consumption was 33% less than that.

Particle Size Reduction of Biomaterials Using Cryogenic Milling Process

2005 ◽  
Vol 475-479 ◽  
pp. 2403-2406 ◽  
Author(s):  
Sang Mok Lee ◽  
Hoon Jae Park ◽  
Seung Soo Kim ◽  
Tae Hoon Choi ◽  
E.Z. Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
Xrd Analysis ◽  
Milling Process ◽  
Degree Of Crystallinity ◽  
Particle Size Reduction ◽  
Cryogenic Milling ◽  
Ball Milling Process ◽  
Before And After ◽  
The Degree Of Crystallinity

Reducing the particle size of drug materials down to submicron is an important matter in pharmaceutical industry. Cryogenic milling technology is one of the mechanical milling processes, which is mostly utilized in refining grain size of metal and ceramics at extremely low temperature environment. This technique has not been readily studied in application to medical and biotechnology. This paper, therefore, describes the application of cryogenic milling process to reduce particle size of Ibuprofen. The shape and size of the Ibuprofen particle before and after the cryogenic ball milling process were analyzed. XRD analysis was performed to examine a change in crystallinity of Ibuprofen by the cryogenic ball milling process. The results showed that the size of Ibuprofen particles was reduced to 1/10 or less of its initial size. The results also showed that the degree of crystallinity of Ibuprofen was slightly reduced after cryogenic ball milling with nitrogen.

EIS Studies of Chalcopyrite Involving Iron(II) Ions

2017 ◽  
Vol 262 ◽  
pp. 496-500
Author(s):  
Fabiana Antonia Arena Delfino ◽  
Denise Bevilaqua ◽  
Assis Vicente Benedetti
Keyword(s):  
Particle Size ◽  
Electrochemical Impedance ◽  
Copper Recovery ◽  
Mineral Particle ◽  
Carbon Paste ◽  
Ferrous Ions ◽  
Solution Interface ◽  
Charge Transfer Reactions ◽  
And Diffusion ◽  
Paste Electrode

In this work, we present an Electrochemical Impedance Spectroscopy (EIS) study using a carbon paste electrode modified with chalcopyrite (CuFeS2) containing 50 wt% of the mineral (particle size < 38 μm) and graphite (particle size < 20 μm) in naturally aerated salt acid solutions (pH 1.8) without and with the addition of 0.100 mol L-1 of ferrous ions. The aim was to evaluate the influence of the solution potential on the behavior of chalcopyrite electrode in the presence and absence of iron (II) ions. Additionally, we evaluated the influence of the bacteria Acidithiobacillus ferrooxidans in the system containing iron (II) ions without applying potential. Therefore, EIS was used to investigate the processes occurring at the electrode/solution interface in the different systems, considering the charge transfer reactions involving chalcopyrite and ferrous ions, the presence of a multicomponent layer, and diffusion. The results showed that the combination of iron (II) ions with the imposition of low potential values (0.100 Fe2+ ions with +0.300 V/Ag|AgCl|KCl3mol/L) activates the chalcopyrite surface and enhances the copper recovery.

Bioprocess for Leaching of Copper Concentrate

2015 ◽  
Vol 1130 ◽  
pp. 359-362 ◽  
Author(s):  
Maxim I. Muravyov ◽  
Natalya V. Fomchenko ◽  
Tamara F. Kondrat'eva
Keyword(s):  
Ferrous Iron ◽  
Acid Leaching ◽  
Copper Recovery ◽  
Leach Residue ◽  
Thermophilic Microorganisms ◽  
Acidophilic Microorganisms ◽  
Moderately Thermophilic ◽  
Total Copper ◽  
Acid Leach ◽  
Ferric Leaching

A bioprocess for oxide-sulfide copper flotation concentrates has been proposed. It includes: i) chemical step – leaching with sulfuric acid solution and subsequent high temperature ferric leaching with microbially produced Fe3+-containing solution, and ii) biological step – bioregeneration of ferric iron along with additional biooxidation of the sulfide minerals using moderately thermophilic acidophilic microorganisms. The flotation copper concentrates contained 27.0–37.4% copper as sulfide (digenite, bornite, etc.) and oxide (malachite, azurite, tenorite, etc.) minerals. The acid leaching under batch conditions at 50°C and pH 1.2 during 22 hours led to 40.6% of copper recovery from the concentrate. Subsequent ferric leaching of the acid leach residue at 80°C, pulp density 9%, initial concentration of Fe3+ 30.7 g/L, and pH 1.2–1.3 during 7 hours increased the total copper recovery to 94.5%. Bioregeneration of the Fe3+ was conducted using moderately thermophilic microorganisms including bacteria of the genus Sulfobacillus at 40°C in the presence of 3% leach residue. The average ferrous iron biooxidation rate and total copper recovery within 2 days were 1.0 g/L∙h and 97%, respectively.Leaching of copper under semi-continuous conditions with bioregeneration of Fe3+ at 40°C was studied. It was found that copper recovery achieved 90% within 22 hours and the average oxidation rate of ferrous iron was up to 0.95 g/L·h.

Measurements of Mineral Particle Size Distributions by a Buoyancy Weighing Method

2010 ◽  
Vol 126 (10/11) ◽  
pp. 577-582 ◽  
Author(s):  
Katsuhiko FURUKAWA ◽  
Yuichi OHIRA ◽  
Eiji OBATA ◽  
Yutaka YOSHIDA
Keyword(s):  
Particle Size ◽  
Mineral Particle ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Weighing Method

Effect of particle size and delignification on the rate of digestion of hemicellulose and cellulose by cellulase in mature pangola grass stems

1983 ◽  
Vol 34 (3) ◽  
pp. 241 ◽  
Author(s):  
CW Ford
Keyword(s):  
Particle Size ◽  
Cell Walls ◽  
Trichoderma Viride ◽  
Structural Features ◽  
Cell Wall Polysaccharides ◽  
Particle Size Reduction ◽  
Digitaria Decumbens ◽  
Hemicellulose Degradation ◽  
Before And After ◽  
The Difference

Stem cell walls of pangola grass (Digitaria decumbens) were ground to two particle sizes (c. 1 and 0.1 mm diameter), and incubated with cellulase (ex. Trichoderma viride) for varying times before and after delignification. Total cell walls finely ground (0.1 mm) with a Spex Shatterbox mill were initially degraded more rapidly (to 24 h) than delignified 1 mm particles. Thereafter the delignified material was solubilized to a greater extent. Subsequent specific determinations of cell wall polysaccharides indicated that delignification increased the rate of hemicellulose degradation to a greater extent than did particle size reduction, whereas the opposite was found for cellulose. The difference between delignified and Spex-ground residues, in terms of the amount of polysaccharide digested, was much greater for cellulose than hemicellulose. It is concluded that structural features play a more important role in limiting cellulase degradation of cellulose than does association with lignin, the reverse being so for hemicellulose.

Effect of pH of coating solution on the adhesion strength and corrosion resistance of hydroxyapatite and octacalcium phosphate coated WE43 alloy

2021 ◽  
pp. 088532822110125
Author(s):  
Tuyet Thi Anh Ngo ◽  
Sachiko Hiromoto ◽  
Linh Chi Do ◽  
Hanh Hong Pham ◽  
Le Hanh
Keyword(s):  
Corrosion Resistance ◽  
Adhesion Strength ◽  
Corrosion Current ◽  
Xrd Analysis ◽  
Octacalcium Phosphate ◽  
Solution Deposition ◽  
Chemical Solution Deposition Method ◽  
Before And After ◽  
Coating Layers ◽  
We43 Alloy

Hydroxyapatite (HAp) and octacalcium phosphate (OCP) layers were formed on Mg- 4mass% Y- 3mass% rare earth (WE43) alloy by a chemical solution deposition method at various pH values of pH 5.5, 6.2, 7.5, and 8.6. Adhesion strength of HAp and OCP layers was evaluated before and after immersing in a medium for 14 days by a pull-off test. The corrosion resistance of these coatings was measured by polarization tests performed in a simulated body fluid (SBF). XRD analysis demonstrated that HAp coating layers were formed at pH 7.5 and 8.6, while OCP coating layers were formed at pH 5.5 and 6.2. Adhesion test results showed that the as-coated pH7.5-HAp layer had the highest adhesion strength of 8.6 MPa, which was attributed to the very dense structure of the coating layer. The as-coated pH8.6-HAp layer showed the adhesion strength of 6.5 MPa. The adhesion strength of the as-coated pH5.5- and pH6.2-OCP layers was 3.9 and 7.1 MPa, respectively, that was governed by the thick and fragile property of the layers. After immersing in the medium for 14 days, the adhesion strength of pH7.5- and pH8.6-specimens decreased to 5.8 and 5.6 MPa, respectively. The pitting corrosion and formation of Mg(OH)2 under the HAp layers were responsible for the decrease of adhesion strength. The polarization tests in SBF at 37 °C showed that the corrosion current density decreased with the HAp and OCP coatings, indicating the improvement of the corrosion resistance of WE43 alloy. The HAp coatings improved the corrosion resistance more efficiently than the OCP coatings.

scholarly journals Importance of Initial Interfacial Steps during Chalcopyrite Bioleaching by a Thermoacidophilic Archaeon

2020 ◽  
Vol 8 (7) ◽  
pp. 1009
Author(s):  
Camila Safar ◽  
Camila Castro ◽  
Edgardo Donati
Keyword(s):  
High Temperatures ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Copper Recovery ◽  
Confocal Laser ◽  
Mineral Surface ◽  
Thermophilic Microorganisms ◽  
Valuable Metals ◽  
Refractory Mineral ◽  
Biofilm Development

Studies of thermophilic microorganisms have shown that they have a considerable biotechnological potential due to their optimum growth and metabolism at high temperatures. Thermophilic archaea have unique characteristics with important biotechnological applications; many of these species could be used in bioleaching processes to recover valuable metals from mineral ores. Particularly, bioleaching at high temperatures using thermoacidophilic microorganisms can greatly improve metal solubilization from refractory mineral species such as chalcopyrite (CuFeS2), one of the most abundant and widespread copper-bearing minerals. Interfacial processes such as early cell adhesion, biofilm development, and the formation of passive layers on the mineral surface play important roles in the initial steps of bioleaching processes. The present work focused on the investigation of different bioleaching conditions using the thermoacidophilic archaeon Acidianus copahuensis DSM 29038 to elucidate which steps are pivotal during the chalcopyrite bioleaching. Fluorescent in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) were used to visualize the microorganism–mineral interaction. Results showed that up to 85% of copper recovery from chalcopyrite could be achieved using A. copahuensis. Improvements in these yields are intimately related to an early contact between cells and the mineral surface. On the other hand, surface coverage by inactivated cells as well as precipitates significantly reduced copper recoveries.

scholarly journals Experimental Investigation of Wave Velocity-Permeability Model for Granite Subjected to Different Temperature Processing

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Guanghui Jiang ◽  
Jianping Zuo ◽  
Teng Ma ◽  
Xu Wei
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Wave Velocity ◽  
Pore Fluid ◽  
Rock Matrix ◽  
Permeability Model ◽  
Wave Velocities ◽  
Before And After ◽  
Different Temperatures ◽  
Increasing Temperature

Understanding the change of permeability of rocks before and after heating is of great significance for exploitation of hydrocarbon resources and disposal of nuclear waste. The rock permeability under high temperature cannot be measured with most of the existing methods. In this paper, quality, wave velocity, and permeability of granite specimen from Maluanshan tunnel are measured after high temperature processing. Quality and wave velocity of granite decrease and permeability of granite increases with increasing temperature. Using porosity as the medium, a new wave velocity-permeability model is established with modified wave velocity-porosity formula and Kozeny-Carman formula. Under some given wave velocities and corresponding permeabilities through experiment, the permeabilities at different temperatures and wave velocities can be obtained. By comparing the experimental and the theoretical results, the proposed formulas are verified. In addition, a sensitivity analysis is performed to examine the effect of particle size, wave velocities in rock matrix, and pore fluid on permeability: permeability increases with increasing particle size, wave velocities in rock matrix, and pore fluid; the higher the rock wave velocity, the lower the effect of wave velocities in rock matrix and pore fluid on permeability.

scholarly journals Cefquinome Controlled Size Submicron Particles Precipitation by SEDS Process Using Annular Gap Nozzle

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Kefeng Xiao ◽  
Weiqiang Wang ◽  
Dedong Hu ◽  
Yanpeng Qu ◽  
Zhihui Hao ◽  
...  
Keyword(s):  
Particle Size ◽  
Xrd Analysis ◽  
Solution Concentration ◽  
Operating Conditions ◽  
Submicron Particles ◽  
Optimal Operating ◽  
Surface Appearance ◽  
Precipitation Temperature ◽  
Annular Gap ◽  
Feeding Speed

An annular gap nozzle was applied in solution enhanced dispersion by supercritical fluids (SEDS) process to prepare cefquinome controlled size submicron particles so as to enhance their efficacy. Analysis results of orthogonal experiments indicated that the concentration of solution was the primary factor to affect particle sizes in SEDS process, and feeding speed of solution, precipitation pressure, and precipitation temperature ranked second to fourth. Meanwhile, the optimal operating conditions were that solution concentration was 100 mg/mL, feeding speed was 9 mL/min, precipitation pressure was 10 MPa, and precipitation temperature was 316 K. The confirmatory experiment showed that D50 of processed cefquinome particles in optimal operating conditions was 0.73 μm. Moreover, univariate effect analysis showed that the cefquinome particle size increased with the increase of concentration of the solution or precipitation pressure but decreased with the increase of solution feeding speed. When precipitation temperature increased, the cefquinome particle size showed highest point. Moreover, characterization of processed cefquinome particles was analyzed by SEM, FT-IR, and XRD. Analysis results indicated that the surface appearance of processed cefquinome particles was flakes. The chemical structure of processed cefquinome particles was not changed, and the crystallinity of processed cefquinome particles was a little lower than that of raw cefquinome particles.

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