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.

scholarly journals Investigation of the use of ammonium acetate as an alternative lixiviant in the leaching of malachite ore

2013 ◽  
Vol 19 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Asım Künkül ◽  
Abdulvahap Gülezgin ◽  
Nizamettin Demirkiran
Keyword(s):  
Ammonium Acetate ◽  
Solution Concentration ◽  
Copper Extraction ◽  
Leaching Rate ◽  
Selective Leaching ◽  
Liquid Ratio ◽  
Copper Ore ◽  
Experimental Parameters ◽  
Leaching Reaction ◽  
Kinetics Of

The solutions containing ammonia allow for selective leaching of the copper from a copper ore. In this study, the leaching and kinetics of malachite ore were examined using ammonium acetate solutions as an alternative lixiviant. The effects of some experimental parameters on the leaching of malachite ore were investigated. A kinetic model to represent the effects of these parameters on the leaching rate was developed. It was determined that the leaching rate increased with increasing solution concentration, temperature and stirring speed, and decreasing particle size and solid-to-liquid ratio. It was found that the leaching reaction followed the mixed kinetic control model. The activation energy of this leaching process was determined to be 59.6 kJmol-1. Consequently, it was determined that ammonium acetate solutions could be used as an effective leaching agent for the copper extraction form malachite ore.

scholarly journals Leaching of Pure Chalcocite in a Chloride Media Using Sea Water and Waste Water

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 780 ◽  
Author(s):  
Norman Toro ◽  
Williams Briceño ◽  
Kevin Pérez ◽  
Manuel Cánovas ◽  
Emilio Trigueros ◽  
...  
Keyword(s):  
Sea Water ◽  
Chloride Concentration ◽  
Xrd Analysis ◽  
Quadratic Model ◽  
Copper Extraction ◽  
Copper Ore ◽  
Copper Dissolution ◽  
Rapid Dissolution ◽  
Chloride Environment ◽  
Kinetics Of

Chalcocite is the most important and abundant secondary copper ore in the world with a rapid dissolution of copper in an acid-chloride environment. In this investigation, the methodology of surface optimization will be applied to evaluate the effect of three independent variables (time, concentration of sulfuric acid and chloride concentration) in the leaching of pure chalcocite to extract the copper with the objective of obtaining a quadratic model that allows us to predict the extraction of copper. The kinetics of copper dissolution in regard to the function of temperature is also analyzed. An ANOVA indicates that the linear variables with the greatest influence are time and the chloride concentration. Also, the concentration of chloride-time exerts a significant synergic effect in the quadratic model. The ANOVA indicates that the quadratic model is representative and the R2 value of 0.92 is valid. The highest copper extraction (67.75%) was obtained at 48 h leaching under conditions of 2 mol/L H2SO4 and 100 g/L chloride. The XRD analysis shows the formation of a stable and non-polluting residue; such as elemental sulfur (S0). This residue was obtained in a leaching time of 4 h at room temperature under conditions of 0.5 mol/L H2SO4 and 50 g/L Cl−.

scholarly journals Cupric and Chloride Ions: Leaching of Chalcopyrite Concentrate with Low Chloride Concentration Media

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 639 ◽  
Author(s):  
Cynthia M. Torres ◽  
Yousef Ghorbani ◽  
Pía C. Hernández ◽  
Francisca J. Justel ◽  
Matías I. Aravena ◽  
...  
Keyword(s):  
Chloride Concentration ◽  
Xrd Analysis ◽  
Formation Constants ◽  
Chloride Ions ◽  
Chloro Complex ◽  
Copper Extraction ◽  
Chloro Complexes ◽  
Complex Species ◽  
Leaching Solution ◽  
Chalcopyrite Concentrate

In this paper, the effect of the cupric and chloride ions concentrations on copper dissolution from chalcopyrite concentrate was studied in acidified media. Variables included three different concentrations of Cu2+ (0.5, 1.5, and 2.5 g L−1), four different concentrations of Cl− (0, 5, 7, and 10 g L−1), two different pH values of 1 and 2, and a constant temperature of 60 °C. Results indicated that addition of Cl− to the system improves copper extractions, especially at higher concentrations of Cu2+. Initial copper concentrations in the leaching solution did not significantly affect the copper extraction when Cl− was not present. Better copper extractions were obtained at pH 1 as compared with pH 2. As the Cu2+ and Cl− concentrations were increased, higher values of redox potential were obtained. According to the formation constants of the chloro-complexes, the predominant species in the Cu2+/Cl− system in the studied interval were CuCl+ and Cu2+. Using a model of copper speciation in the experimental range predicted for a single copper concentration with increasing Cl− concentration, the Cu2+ concentration decreased significantly while the concentration of the chloro-complex species CuCl+ increased. In the leached residue, evidence of sulfur formation was found using SEM and corroborated by XRD analysis. When chloride is present in the medium, the amounts of copper and iron in the residue decrease, confirming a positive effect of chloride on the extraction of copper from concentrate for the studied conditions.

Size-Dependent Interdiffusion in Nanomaterials

2005 ◽  
Vol 101-102 ◽  
pp. 123-130 ◽  
Author(s):  
Lyudmila N. Paritskaya ◽  
Yuri S. Kaganovsky ◽  
V.V. Bogdanov
Keyword(s):  
Grain Growth ◽  
Volume Fraction ◽  
Bulk Diffusion ◽  
Solution Concentration ◽  
Lattice Parameter ◽  
Structural Element ◽  
Size Dependent ◽  
Second Stage ◽  
Temperature Homogenization ◽  
Two Stages

The phenomenon of low-temperature homogenization (LTH) during interdiffusion is studied under condition a t Dv £ 2 / 1 ) ( (Dv is the bulk diffusion coefficient, a is the lattice parameter) using nano-objects of binary Cu-Ni and Cr-Ni systems compacted from nano-powders and produced by mechanical alloying. Two stages of LTH were detected: at the first stage (t £ 103 s) the volume fraction of solution rapidly grows; at the second stage (t > 103 s) the volume fraction of solutions grows slowly with practically constant average solution concentration. The first stage of LTH correlates with active grain growth caused by small size (l) of structural element and nonequilibrium structure of nano-objects. Obtained results are analyzed theoretically in terms of interdiffusion along migrating GBs due to grain growth at the first stage and DIGM mechanism at the second stage. It is shown that the GB concentration distribution during interdiffusion along migrating GBs and the kinetics of LTH depend on a parameter l/l where 2 / 1 ) / ( b b V sD d l= is the characteristic diffusion length. The mechanisms and criteria of LTH are proposed.

scholarly journals Characterization of Virus Adsorption by Using DEAE-Sepharose and Octyl-Sepharose

2002 ◽  
Vol 68 (8) ◽  
pp. 3965-3968 ◽  
Author(s):  
Patricia A. Shields ◽  
Samuel R. Farrah
Keyword(s):  
Sodium Chloride ◽  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Chloride Concentration ◽  
Sodium Chloride Concentration ◽  
Virus Adsorption ◽  
Nacl Concentration

ABSTRACT Viruses were characterized by their adsorption to DEAE-Sepharose or by their elution from octyl-Sepharose by using buffered solutions of sodium chloride with different ionic strengths. Viruses whose adsorption to DEAE-Sepharose was reduced most rapidly by an increase in the sodium chloride concentration were considered to have the weakest electrostatic interactions with the solids; these viruses included MS2, E1, and φX174. Viruses whose adsorption to DEAE-Sepharose was reduced least rapidly were considered to have the strongest electrostatic interactions with the column; these viruses included P1, T4, T2, and E5. All of the viruses studied adsorbed to octyl-Sepharose in the presence of 4 M NaCl. Viruses that were eluted most rapidly following a decrease in the concentration of NaCl were considered to have the weakest hydrophobic interactions with the column; these viruses included φX174, CB4, and E1. Viruses that were eluted least rapidly from the columns after the NaCl concentration was decreased were considered to have the strongest hydrophobic interactions with the column; these viruses included f2, MS2, and E5.

scholarly journals Ammoniacal System Mechanisms for Leaching Copper from Converter Slag

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 712
Author(s):  
Alvaro Aracena ◽  
Andrés Valencia ◽  
Oscar Jerez
Keyword(s):  
Particle Size ◽  
Converter Slag ◽  
Research Work ◽  
Ammonium Hydroxide ◽  
Copper Extraction ◽  
Solution Ph ◽  
Intraparticle Diffusion Model ◽  
Electron Microscopy Analysis ◽  
Leaching Solution ◽  
Conversion Stage

In pyrometallurgical processes refining copper, the main source of loss in the conversion stage is from slag. This paper reports on research work treating converter slag containing high percentages of copper (36 wt%) using ammonium hydroxide at room temperature. Variables analyzed are solution pH, agitation, temperature, NH4OH concentration and particle size. Results showed that the hydronium ion resulting from ammonium hydroxide dissociation was the main oxidant of copper compounds in slag, such as CuO, Cu2O and Cu, with the exception of CuFeO2. The particles contain a large amount of microcracks (porosity) in their refractory structure (analyzed by compositional image capture (BSE)). Thus, the diffusion of the leaching solution through the microcracks making contact with the copper oxides would be allowed. Leaching mechanisms were corroborated by X-ray diffraction and scanning electron microscopy analysis. Increasing temperature and NH4OH concentration while decreasing particle size obtained higher copper recoveries, reaching values of 84.8%. Under the same conditions, the main impurity (iron) was minimal (<2%). Solution pH also affected slag leaching. Agitation of the solution positively affected the rate of copper extraction. Leaching kinetics of the leaching solution through the porosity formed in the slag was analyzed under the intraparticle diffusion model. The reaction order was 1.2 with respect to the concentration of ammonium hydroxide and the model was inversely proportional to the square of the particle radius. The activation energy obtained was 42.3 kJ/mol for temperature range 283 to 333 K.

scholarly journals Experimental Study of the Microstructural Evolution of Glauberite and Its Weakening Mechanism under the Effect of Thermal-Hydrological-Chemical Coupling

Processes ◽  
2018 ◽  
Vol 6 (8) ◽  
pp. 99 ◽  
Author(s):  
Shuzhao Chen ◽  
Donghua Zhang ◽  
Tao Shang ◽  
Tao Meng
Keyword(s):  
Sodium Chloride ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Crack Nucleation ◽  
Chloride Concentration ◽  
Solution Concentration ◽  
Expansion Velocity ◽  
Research Subjects ◽  
Characteristic Index ◽  
Chemical Coupling

The microstructures of rock gradually evolve with changes in the external environment. This study focused on the microstructure evolution of glauberite and its weakening mechanism under different leaching conditions. The porosity were used as a characteristic index to study the effect of brine temperature and concentration on crack initiation and propagation in glauberite. The research subjects were specimens of ϕ3 × 10 mm cylindrical glauberite core, obtained from a bedded salt deposit buried more than 1000 m underground in the Yunying salt formation, China. The results showed that when the specimens were immersed in solution at low temperature, due to hydration impurities, cracks appeared spontaneously at the centre of the disc and the solution then penetrated the specimens via these cracks and dissolved the minerals around the crack lines. However, with an increase of temperature, the dissolution rate increased greatly, and crack nucleation and dissolved regions appeared simultaneously. When the specimens were immersed in a sodium chloride solution at the same concentration, the porosity s presented gradual upward trends with a rise in temperature, whereas, when the specimens were immersed in the sodium chloride solution at the same temperature, the porosity tended to decrease with the increase of sodium chloride concentration. In the process of leaching, the hydration of illite, montmorillonite, and the residual skeleton of glauberite led to the expansion of the specimen volume, thereby producing the cracks. The diameter expansion rate and the expansion velocity of the specimen increased with temperature increase, whereas, due to the common-ion effect, the porosity of the specimen decreases with the increase of sodium chloride solution concentration.

scholarly journals Effect of Chloride Ions on the Electrochemical Oxidation of Chalcopyrite at 340 °C and 21 MPa

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1071
Author(s):  
Luying Wang ◽  
Heping Li ◽  
Qingyou Liu ◽  
Liping Xu ◽  
Lei Zha ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Protective Property ◽  
Electrochemical Impedance ◽  
Chloride Ions ◽  
Ionic Diffusion ◽  
Copper Extraction ◽  
Dissolution Mechanism ◽  
Oxidation Layer ◽  
X Ray ◽  
Nacl Concentration

Understanding the oxidative mechanisms of chalcopyrite in various hydrothermal fluids is of great significance to improve copper extraction and to model the geochemical cycling of copper, iron, and sulfur. This paper investigated the effect of NaCl on the electrochemical oxidation of chalcopyrite at 340 °C and 21 MPa using polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. The experimental results showed that NaCl can promote chalcopyrite leaching. As NaCl concentration increases, the protective property of the oxidation layer degraded. In the absence of NaCl, the oxidation layer that consisted of CuSn, (n ≥ 1), probably with some Fe2O3 and Fe(OH)3 and also in the presence of NaCl, Fe2O3, is the principal oxidation product. More rapid ionic diffusion and further chemical reaction contributed to the improvement of chalcopyrite dissolution with increasing NaCl concentration. A dissolution mechanism is proposed in this paper to explain the chalcopyrite leaching processes which is dependent on NaCl concentration.

scholarly journals Influence of grain size on chalcopyrite ore leaching in acidic medium

2007 ◽  
Vol 72 (8-9) ◽  
pp. 911-919 ◽  
Author(s):  
M.M. Antonijevic ◽  
G.D. Bogdanovic ◽  
S.M. Serbula ◽  
S.M. Milic
Keyword(s):  
Grain Size ◽  
Dissolved Oxygen ◽  
Sulphuric Acid ◽  
Acidic Medium ◽  
Raw Material ◽  
Leaching Rate ◽  
Acid Consumption ◽  
Leaching Solution ◽  
Chalcopyrite Ore

This work presents an investigation of column leaching of a chalcopyrite ore using sulphuric acid where dissolved oxygen and iron(III) ions play the role of oxidants. The investigations were carried out in PVC columns, diameter 110 mm and height 1000 mm, by percolation of the leaching solution through the ore layer. The influence of ore grain size on the degree of leaching and acid consumption was examined. The formation of gypsum on limestone results in the comminution of the initial raw material during leaching. The grain size of chalcopyrite was found to have no important influence on the leaching rate of copper. A higher consumption of sulphuric acid was found for the fractions (-3+1) mm, (?5+0) mm and (?5+3) mm than for the fractions (?10+5) mm, (?20+10) mm and (?20+0) mm. .

Evaluation of changing the structure of aqueous solutions in the near-wall layers with using dielectrometry and resonance method

2015 ◽  
Vol 9 (2) ◽  
pp. 0-0
Author(s):  
Саркисов ◽  
Yu. Sarkisov ◽  
Сидоренко ◽  
G. Sidorenko ◽  
Лаптев ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Fluid Layer ◽  
Chloride Concentration ◽  
Resonance Method ◽  
Solution Concentration ◽  
Wall Layer ◽  
Oscillatory Circuit ◽  
Structure Of Aqueous Solutions ◽  
Sodium And Potassium

In this work the authors evaluated changes of the structure of aqueous solutions of chlorides of sodium and potassium in various concentrations in the parietal layer by means of the dielectrometry and resonance method. In experiments at 20 ° C, the concentration of sodium and potassium chloride concentration of 0.01 M to 1 M in thenear-wall layer &#34;glass - water solutions&#34; height of less than 1000 microns observed multiple reduction of capacitance of solutions, and Q of an oscillatory circuit and a multiple increase coefficient KS which allows to evaluate the structure of the solutions. It is shown that the structure of the solutions in the wall layer depends on the solution concentration, the nature of the solute and the material of surface. Methods of dielectrometry and resonance are informative in the interpretation of the processes in the fluid layer at the interface, &#34;solid – aqueous solution&#34;.

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