scholarly journals Mesophilic leaching of copper sulphide sludge

2009 ◽  
Vol 74 (2) ◽  
pp. 213-221 ◽  
Author(s):  
Vladimir Cvetkovski ◽  
Vesna Conic ◽  
Milovan Vukovic ◽  
Milena Cvetkovska
Keyword(s):  
Residue Analysis ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Sulphide Mineral ◽  
Copper Sulphide ◽  
X Ray Diffraction ◽  
Ferrous Ions ◽  
Extraction Curve ◽  
Straight Line ◽  
Bioreactor System

Copper was precipitated using a sodium sulphide solution as the precipitation agent from an acid solution containing 17 g/l copper and 350 g/l sulphuric acid. The particle size of nearly 1 ?m in the sulphide sludge sample was detected by optical microscopy. Based on chemical and X-ray diffraction analyses, covellite was detected as the major sulphide mineral. The batch bioleach amenability test was performed at 32?C on the Tk31 mine mesophilic mixed culture using a residence time of 28 days. The dissolution of copper sulphide by direct catalytic leaching of the sulphides with bacteria attached to the particles was found to be worthy, although a small quantity of ferrous ions had to be added to raise the activity of the bacteria and the redox potential of the culture medium. Throughout the 22-day period of the bioleach test, copper recovery based on residue analysis indicated a copper extraction of 95 %, with copper concentration in the bioleach solution of 15 g/l. The slope of the straight line tangential to the exponential part of the extraction curve gave a copper solubilisation rate of 1.1 g/l per day. This suggests that a copper extraction of 95 % for the period of bioleach test of 13.6 days may be attained in a three-stage bioreactor system.

scholarly journals Pretreatment to Leaching for a Primary Copper Sulphide Ore in Chloride Media

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1260
Author(s):  
Víctor Quezada ◽  
Antoni Roca ◽  
Oscar Benavente ◽  
Montserrat Cruells ◽  
Evelyn Melo ◽  
...  
Keyword(s):  
Copper Extraction ◽  
Copper Sulphide ◽  
Curing Time ◽  
X Ray Diffraction ◽  
Initial Sample ◽  
Mining Company ◽  
Sulphide Ore ◽  
Sulphide Ores ◽  
Reflected Light ◽  
Mineral Sample

The dissolution of copper sulphide ores continues to be a challenge for the copper industry. Several media and leaching alternatives have been proposed to improve the dissolution of these minerals, especially for the leaching of chalcopyrite. Among the alternatives, pretreatment prior to leaching was proposed as an option that increases the dissolution of copper from sulphide ores. In this study, a mineral sample from a copper mining company was used. The copper grade of the sample was 0.79%, and its main contributor was chalcopyrite (84%). The effect of curing time (as pretreatment) in a chloride media on copper sulphide ore was evaluated at various temperatures: 25, 50, 70 and 90 °C. The pretreated sample and leaching residues were characterized by X-ray diffraction, scanning electron microscopy, and reflected light microscopy. Pretreatment products such as CuSO4, NaFe3(SO4)2(OH)6, and S0 were identified although with difficulty, due to the low presence of chalcopyrite in the initial sample (1.99%). Under the conditions of 15 kg/t of H2SO4, 25 kg/t of NaCl, and 15 days of curing time, a copper extraction of 93.1% was obtained at 90 °C with 50 g/L of Cl− and 0.2 M of H2SO4.

Roxbyite, a New Copper Sulphide Mineral from the Olympic Dam Deposit, Roxby Downs, South Australia

1988 ◽  
Vol 52 (366) ◽  
pp. 323-330 ◽  
Author(s):  
W. G. Mumme ◽  
G. J. Sparrow ◽  
G. S. Walker
Keyword(s):  
South Australia ◽  
New Mineral ◽  
Sulphide Mineral ◽  
Drill Core ◽  
Copper Sulphide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Single Crystal Study ◽  
El Teniente ◽  
Olympic Dam

AbstractRoxbyite (Cu1.74–1.82S), a new mineral, was isolated from drill core from the Olympic Dam deposit, from copper flotation concentrates from the Olympic Dam pilot plant, and from reaction residues obtained by treating certain concentrates with sulphuric acid. Powder X-ray diffraction data and the composition of the mineral are similar to results reported previously for the unnamed mineral of composition Cu1.83S (with a trace of iron) from the El Teniente deposit in Chile, and to copper sulphides of composition CuxS, 1.75 ⩽ x ⩽ 1.86, prepared electrochemically by several workers. A Weissenberg single-crystal study shows roxbyite to be monoclinic with a = 53.79, b = 30.90, c = 13.36Å, β = 90.0° and space group alternatives C2/m, Cm or C2. Some iron in the structure may stabilize the mineral.

scholarly journals Effects of Fe+2 and Fe+3 in Pretreatment and Leaching on a Mixed Copper Ore in Chloride Media

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 866
Author(s):  
María E. Taboada ◽  
Pía C. Hernández ◽  
Aldo P. Padilla ◽  
Nathalie E. Jamett ◽  
Teófilo A. Graber
Keyword(s):  
Chloride Concentration ◽  
Solution Concentration ◽  
Copper Extraction ◽  
Curing Time ◽  
Ferrous Ions ◽  
Copper Ore ◽  
Second Stage ◽  
Acid Consumption ◽  
Nacl Concentration ◽  
Leaching Solution

A study of the pretreatment stage and subsequent leaching of a mixed copper ore with different chloride solutions containing iron was carried out. The first stage considered pretreatment tests to decide the best conditions. Two levels of each factor were analyzed, 20 and 50 kg/t of NaCl, 17 and 25 kg/t of H2SO4, 0 and 25 kg/t of Fe2(SO4)3·9.2H2O, 0 and 25 kg/t of Fe2SO4·7H2O, and a curing time of 15 and 30 days. The results showed a significant effect of NaCl and curing time on the extraction, and less effect was found with the variation of acid and iron salts. The second stage included column leaching using a solution with 0.5 g/L of Cu+2, 80 g/L of Cl−, 10 g/L of H2SO4, and variable concentrations of ferric and ferrous ions (0 and 2 g/L). The best copper extraction of 80.2% was found considering a pretreatment of 30 days, 25 kg/t of H2SO4, 50 kg/t of NaCl, and a leaching solution concentration described previously with 2 g/L of Fe+2. The results showed the leaching of all copper oxide species and 20% of the copper sulfide species. In addition, there was a reduction in the acid consumption as the resting time increases. Furthermore, to evaluate a possible decrease in time and acid in pretreatment and chloride in leaching, tests including 10 and 25 kg/t of H2SO4 and 1, 15, and 30 days of curing and a diminution of the NaCl concentration to 20 g/L (content from seawater) were executed. The results showed a significant effect on curing time below 15 days. Furthermore, the slight influence of the decrease of acid on copper extraction gives cost reduction opportunities. The diminution of chloride concentration (80 to 20 g/L) in leaching solution decreases the extraction from 79% to 66.5%. Finally, the Mellado leaching kinetic model was successfully implemented.

Synthesis of Photodefinable RuO2 Precursors For Electrode Contacts

1997 ◽  
Vol 493 ◽  
Author(s):  
K. J. Law ◽  
Y. H. Spooner
Keyword(s):  
Chemical Process ◽  
Ruthenium Complexes ◽  
Ferroelectric Thin Film ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ruthenium Compounds ◽  
Straight Line ◽  
Wet Chemical ◽  
Pattern Forming ◽  
Pattern Resolution

ABSTRACTA wet-chemical process for depositing and patterning RuO2 contacts for use in ferroelectric thin film capacitive devices is described. Three new ruthenium compounds containing photocrosslinkable organic groups have been synthesized which polymerize upon UV exposure. Preliminary pattern forming ability of the new precursors has been tested with the use of a simple straight line contact mask. The exposed portions of the precursor films are resistant to ethanol, acetone, and light abrasion. The formation of crystalline RuO2 upon organic pyrolysis was confirmed by x-ray diffraction. Synthesized ruthenium complexes were compared to commercially available ruthenium acetylacetonate. The synthesized organo-ruthenium complexes showed improvement in pattern resolution and clarity.

Interdiffusion in Co/Ta Multilayer Thin Films

2005 ◽  
Vol 237-240 ◽  
pp. 554-559 ◽  
Author(s):  
Hui Myeong Lee ◽  
Byeong Seon Lee ◽  
Chan Gyu Lee ◽  
Yasunori Hayashi ◽  
Bon Heun Koo
Keyword(s):  
Structural Relaxation ◽  
Multilayer Thin Films ◽  
X Ray Diffraction ◽  
Stress Release ◽  
X Ray ◽  
Angle Measurements ◽  
Peak Intensity ◽  
Straight Line ◽  
Initial Stage ◽  
Interdiffusion Coefficients

We will discuss the stress release phenomena, structural relaxation and interdiffusion processes during annealing. The [Co(4nm)/Ta(4nm)]38 multilayers were prepared by dc magnetron sputtering on Si substrate. The multilayers were annealed at various temperatures (523 - 673K) in vacuum (under 10-5 torr) furnace. The effective interdiffusion coefficients were determined from the slope of the best straight line fit of the first peak intensity versus annealing time [d ln(I(t)/I(0)) /dt] by X-ray diffraction (XRD) low angle measurements. The drastic decrease of the relative intensity in the initial stage shown due to the structural relaxation was excluded in the calculation of effective interdiffusion coefficients. The temperature dependence of interdiffusion in the range of 523 - 673K is described by D = 3.2×10-19 exp(-0.51±0.11 eV/kT) m2s-1.

Correction of X-ray Diffraction Profiles Measured by PSPC System

1989 ◽  
Vol 33 ◽  
pp. 397-402 ◽  
Author(s):  
Shin'ichi Ohya ◽  
Yasuo Yoshioka
Keyword(s):  
Profile Analysis ◽  
X Rays ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
X Ray ◽  
Geometrical Problem ◽  
Straight Line ◽  
Background Line ◽  
Diffraction Angle ◽  
Position Sensitive

When an x-ray diffraction profile Is measured for stress analysis or profile analysis by the use of a linear (straight line) position sensitive proportional counter (PSPC) , a convex-type background line is obtained because of the geometrical problem and the absorption of x-rays. Such phenomenon is remarkable when a wide angular range is set on a linear PSPC and it is, in particular, necessary to correct with a straight background for accurate measurement of diffraction angle or half-value breadth of the broadened diffraction profile.

scholarly journals Mechanism and Kinetics of Malachite Dissolution in an NH4OH System

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 833
Author(s):  
Alvaro Aracena ◽  
Javiera Pino ◽  
Oscar Jerez
Keyword(s):  
Ammonium Hydroxide ◽  
Copper Recovery ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
Acid Dissolution ◽  
Acid Consumption ◽  
Mechanism And Kinetics ◽  
Solid Liquid ◽  
Kinetics Of ◽  
Highly Porous

Copper oxide minerals composed of carbonates consume high quantities of leaching reagent. The present research proposes an alternative procedure for malachite leaching (Cu2CO3(OH)2) through the use of only compound, ammonium hydroxide (NH4OH). Preliminary studies were also carried out for the dissolution of malachite in an acid system. The variables evaluated were solution pH, stirring rate, temperature, NH4OH concentration, particle size, solid/liquid ratio and different ammonium reagents. The experiments were carried out in a stirred batch system with controlled temperatures and stirring rates. For the acid dissolution system, sulfuric acid consumption reached excessive values (986 kg H2SO4/ton of malachite), invalidating the dissolution in these common systems. On the other hand, for the ammoniacal system, there was no acid consumption and the results show that copper recovery was very high, reaching values of 84.1% for a concentration of 0.2 mol/dm3 of NH4OH and an experiment time of 7200 s. The theoretical/thermodynamic calculations indicate that the solution pH was a significant factor in maintaining the copper soluble as Cu(NH3)42+. This was validated by the experimental results and solid analysis by X-ray diffraction (XRD), from which the reaction mechanisms were obtained. A heterogeneous kinetic model was obtained from the diffusion model in a porous layer for particles that begin the reaction as nonporous but which become porous during the reaction as the original solid splits and cracks to form a highly porous structure. The reaction order for the NH4OH concentration was 3.2 and was inversely proportional to the square of the initial radius of the particle. The activation energy was calculated at 36.1 kJ/mol in the temperature range of 278 to 313 K.

Bioleaching of Low-Grade Chalcopyrite Ore by the Thermophilic Archaean Acidianus brierleyi

2017 ◽  
Vol 262 ◽  
pp. 237-241 ◽  
Author(s):  
Norizoh Saitoh ◽  
Toshiyuki Nomura ◽  
Yasuhiro Konishi
Keyword(s):  
Environmentally Friendly ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Low Grade ◽  
Column Reactor ◽  
Stirred Reactor ◽  
Acidianus Brierleyi ◽  
Environmentally Friendly Process ◽  
Chalcopyrite Ore

The thermophilic archaean, Acidianus brierleyi, was examined for its feasibility to bioleach copper from a low-grade chalcopyrite ore (1.15 % copper, 20.4 % iron and 2.63 wt% sulfur) at 65°C and pH 1.8-2.5. The chalcopyrite leaching was markedly accelerated in the presence of A. brierleyi, and an extremely high 80% leaching of copper in the low-grade ore (25-38 μm particles) was achieved in 14 days in a batch stirred reactor. By comparison, the leaching of iron was very slow and only a slight 5 % iron was leached in 14 days in the presence or absence of A. brierleyi. In other words, A. brierleyi selectively leached chalcopyrite while magnetite leaching by A. brierleyi was negligible. Moreover, bioleaching of the low-grade ore (53-75 μm particles) yielded 55% copper recovery after 20 days of operation in a column reactor. The good results for the copper bioleaching in the column reactor are very similar to those in the stirred reactor. These results lead to the conclusion that the thermophile bioleaching with A. brierleyi is attractive as an economical and environmentally friendly process for good copper extraction from low-grade chalcopyrite ore.

Evidence for loss of protons and octahedral iron from oxidized biotites and vermiculites

1971 ◽  
Vol 38 (294) ◽  
pp. 121-137 ◽  
Author(s):  
V. C. Farmer ◽  
J. D. Russell ◽  
W. J. McHardy ◽  
A. C. D. Newman ◽  
J. L. Ahlrichs ◽  
...  
Keyword(s):  
High Refractive Index ◽  
X Ray Diffraction ◽  
Ferric Ions ◽  
Ferrous Ions ◽  
Octahedral Layer ◽  
Irreversible Loss ◽  
X Ray ◽  
External Phase ◽  
Infra Red ◽  
Oxide Ions

SummaryInfra-red examination of a weathered biotite and of biotites that have been converted to vermiculites and subsequently oxidized, indicates that oxidation of octahedral ferrous ions to ferric ions is associated with a reversible conversion of hydroxyl ions to oxide ions. Subsequently, in high-iron biotites, there is an irreversible loss of ferric ions from the octahedral layer, resulting in an increased number of dioctahedral sites. Electron microscopy and X-ray diffraction indicate that ejected ferric ions form either amorphous interlayer oxides or, when bromine is used as an oxidant, a crystalline external phase of β-FeOOH. The high refractive index of some oxidized vermiculites is shown to be due largely to submicroscopic iron oxides.

scholarly journals Investigation of the optimal technology for copper leaching from old flotation tailings of the copper mine bor (Serbia)

10.30544/514 ◽  
2020 ◽  
Vol 26 (2) ◽  
pp. 209-222 ◽  
Author(s):  
Vesna Conić ◽  
Srđan Stanković ◽  
Branislav Marković ◽  
Dragana Božić ◽  
Jovica Stojanović ◽  
...  
Keyword(s):  
Iron Concentration ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Efficient Technology ◽  
Flotation Tailings ◽  
Copper Mine ◽  
Moderately Thermophilic ◽  
Acidophilic Bacteria ◽  
Leaching Experiment ◽  
Optimal Technology

This work aimed to investigate optimal leaching technology for copper extraction from old flotation tailings of the Copper Mine Bor. The leaching degree of copper after leaching with sulphuric acid at 80 °C was 50%, the maximal leaching degree was achieved after 30 minutes. Then, old flotation tailings were leached with adapted moderately thermophilic acidophilic bacteria in a bioreactor at 40 °C. Maximal leaching degree of 84% was achieved after nine days of the experiment. The third leaching experiment was conducted with biogenic lixiviant obtained by bacterial oxidation of the ferrous iron (concentration of Fe3+ 1300 mgL-1, pH 2.14). Biogenic lixiviant with ferric sulphate was then used in the leaching experiment at 80 °C. Maximal leaching degree was 78%, and it was achieved after five minutes. Results of the leaching experiments show that the most efficient technology for copper recovery from the old flotation tailings of the Copper Mine Bor was leaching with biogenic lixiviant.

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