Copper Oxide Minerals Research Articles

Study of a Copper Oxide Leaching in Alkaline Monosodium Glutamate Solution

Oxide copper minerals are commonly extracted via acidic leaching, using acids such as H2SO4, HCl, or HNO3. These strong acids are the most widely used because of their high dissolution kinetics. However, their main concern is the high acid consumption because copper oxide deposits contain large amounts of acid-consuming gangue. This paper proposes using an alternative aqueous alkaline monosodium glutamate (MSG) system to leach copper oxide minerals. Tenorite (CuO) was used as the copper oxide mineral under study. The influence of process variables (such as temperature and glutamate concentration) and kinetics of this system on copper leaching from tenorite were studied. The results showed that temperature has a significant effect on copper dissolution rates. Increased temperature from 15 °C to 60 °C enhanced the copper extraction from 9.1% to 97.7% after 2 h. Leaching kinetics were analyzed using the shrinking core model (SCM) under various conditions, indicating that the leaching rate presented a mixed control. This method, however, fails to describe leaching for broad particle sizes due to its requirement for single-sized solid grains. This study demonstrated that a large particle size distribution in tenorite supported a successful extension of the SCM for leaching it from mixed glutamate solutions. The activation energy for the 15–60 °C temperature range was calculated to be 102.6 kJ/mol for the chemical control.

Effect of Incorporation of Sulfation in Columnar Modeling of Oxidized Copper Minerals on Predictions of Leaching Kinetics

Effect of Incorporation of Sulfation in Columnar Modeling of Oxidized Copper Minerals on Predictions of Leaching Kinetics

Flotation activation mechanism of trithiocyanuric acid to malachite

Malachite is a typical refractory copper oxide mineral. In this paper, trithiocyanuric acid (TMT) was used as a novel activator for the activated flotation of malachite for the first time. The effect of TMT on the flotation behavior of malachite was studied and the activation mechanism was discussed. The flotation test results showed that TMT exhibited superior activation performance over sodium sulfide, achieving a high flotation recovery rate of 97.50 % at TMT 90 mg/L and pH 7. The contact angle confirmed malachite improved from 53.3° to 90.1° after TMT treatment, indicating enhanced hydrophobicity of the mineral surface. FTIR and EDS analyses provided clear evidence of chemical adsorption of TMT tautomers onto the malachite surface. SEM images further illustrated the presence of dense particles formed after TMT treatment. XPS revealed that TMT exhibited a strong adsorption effect on malachite, leading to an increase in copper sites and the formation of highly reactive Cu+. The activation mechanism was elucidated as the reaction between Cu sites on malachite and S and N atoms in TMT, forming Cu-S and Cu–N fractions crucial for activation. The high efficiency and low dosage of TMT make it a promising activator for malachite, offering a novel avenue for the effective recovery of malachite-type copper oxide ore resources.

Investigation of an indigenous chalcopyrite ore leaching in ammonia solution: characterization, leaching and kinetics

ABSTRACT Chalcopyrite ore is one of the most abundant and pertinent oxidized copper minerals. In this research, the dissolution kinetics of chalcopyrite in an ammonia solution was examined. During leaching, the influences of leachant concentration, temperature, and particle diameter on the extent of copper ore dissolution were investigated. However, it was affirmed that the dissolution efficiency of chalcopyrite ore increased with decreasing particle fraction and increasing reaction temperature and ammonia concentration. About 68.6% copper ore dissolution was achieved with 2.0 mol/L NH3, 75 ºC reaction temperature, and 45 μm particle diameter within 120 minutes. The dissolution reaction mechanism was found to be described by diffusion-control with a calculated activation energy of 32.26 kJ/mol. In the XRD spectra of the residual product obtained at established conditions, CuFeS2 peaks were absent, indicating the leachability of the sample. Hence, the leach residue could serve as an important by-product for some local industries.

Extraction of copper (II) ions from oxidized ore in the presence of an ethylenediaminetetraacetic acid solution in a basic environment

An experiment was conducted to obtain copper (II) ions in a basic environment using ethylenediaminetetraacetic acid (EDTA) and oxidized copper minerals from Cerro Azoguini in Puno, Peru. Specific objectives included investigating the solubility of Cu2+ ions in a mineral with high silica, limestone, and iron content, as well as studying the influence of pH, EDTA concentration, and extraction time. 1.5 grams of ground mineral at -100 mesh (150 µm), with 80% pass and 6% solids, were leached with a 0.5 M NaHCO3 solution at different pH levels and EDTA concentrations. The results indicated the extraction of 3.5 g/L of Cu2+ ions at pH 10 with 0.12 M EDTA, without agitation, at room temperature (19°C), over a period of 83 hours. It was observed that the NaHCO3 solution extracted copper from the mineral, and EDTA quickly chelated it, forming ionic complexes such as CuHEDTA ∧ (1−), CuHEDTA ∧ (2−), and CuHEDTA ∧ (3−). Other metals present in the gangue were not chelated by EDTA, demonstrating its high selectivity based on solubility constants and precipitation formation at different pH levels. Additionally, high copper extraction rates were obtained at a pH of 13.15, possibly due to decreased protons and increased ions from both the reagent and leached mineral. In conclusion, the physicochemical analyses revealed the feasibility of obtaining Cu2+ ions by solubilizing oxidized minerals, followed by rapid chelation with EDTA to form diverse metal complexes depending on the pH of the medium.

Ammonium-Amine Co-Activation: Promoting the Sulfurization of Azurite and Its Effect on Xanthate Adsorption.

Enhanced sulfurization has always been the focus of research on the flotation of copper oxide minerals. In this study, combined ammonium-amine salts were innovatively applied to improve the sulfurization of azurite. Flotation tests were carried out to evaluate the promoting effect of ammonium-amine co-activation on the sulfurization-xanthate flotation of azurite, and the microstructure evolution of sulfurized products was investigated to reveal the mechanism underlying this promoting effect. Compared with single ammonium (amine) salt activation, ammonium-amine co-activation improved the floatability of azurite to a greater extent, i.e., the flotation recovery increased by over 4 percentage points. ToF-SIMS, ICP-OES, FESEM-EDS, AFM, XRD, and UV-vis analyses indicated that ammonium-amine co-activation combined the advantages of inorganic ammonium for buffering pH and organic amine for copper ion complexation, thus promoting the growth of sulfurized crystal products (covellite) and enhancing the adhesion stability of sulfurized products on azurite. Therefore, increasing amounts of copper sulfide components were generated under the ammonium-amine-Na2S system, promoting the adsorption of additional xanthate on azurite. This study provides theoretical support for the application of combined ammonium-amine salts for the sulfurization flotation of copper oxide.

Surface modification of malachite using DMTD and its effect on xanthate adsorption

Malachite is a representative copper oxide mineral, and its direct flotation using the xanthate method is challenging in industrial settings. Therefore, the selection of activators becomes pivotal for malachite enrichment. One such activator is 2,5-Dimercapto-1,3,4-thiadiazole (DMTD), a chelating agent capable of enhancing mineral surface activity through interaction. This property makes DMTD applicable in industrial production, although its mechanism of action remains unclear. This study delves into the activation mechanism responsible for surface modification of malachite using DMTD. DMTD, owing to its superior activation properties compared to Na2S, proves to be more effective in enhancing copper recovery in practical production scenarios. Consequently, the flotation of malachite treated with DMTD significantly improved under identical flotation conditions. Zeta potential experiments corroborated these findings, revealing that the surface modification of malachite using DMTD promotes greater adsorption of butyl xanthate (BX). The Fourier transform infrared spectroscopy (FTIR) results clearly demonstrated the chemical absorption of DMTD onto the malachite surface. Subsequently, the X-ray photoelectron spectroscopy (XPS) analysis unveiled the formation of a hydrophobic and stable copper-sulfide species on the malachite surface. Furthermore, time of flight secondary ion mass spectrometry (ToF-SIMS) analysis indicated that DMTD exhibits strong adsorption onto malachite, leading to the generation of CuS- and CuCN- species. Atomic force microscopy (AFM) analysis showed that DMTD predominantly adsorbed onto the malachite surface in a punctate pattern, displaying a uniform distribution across the entire surface. This finding was further validated by the contact-angle test, which confirmed that DMTD-treated malachite exhibited a more hydrophobic interaction with BX compared to untreated malachite. Consequently, the surface modification of malachite using DMTD was found to have a positive impact on BX adsorption, rendering it more hydrophobic.

Microscale exploration of the sulfidization flotation theory in malachite

With the gradual depletion of copper sulfide resources, efficient flotation technologies for the recovery of copper oxide minerals, such as malachite, have received significant attention. Although sulfidization plays a critical role in malachite flotation, the fundamental theory of sulfidization flotation remains uncertain in the context of practical industrial applications. In this study, evolution of the sulfide product morphology on the malachite surface was observed after treatment with various concentrations of sodium sulfide. In addition, the valence states and phase compositions of the sulfide products were investigated using different X-ray techniques. Furthermore, the evolution of the malachite surface morphology after the formation of a sulfide film was investigated, as were the interaction forces between the malachite and bubbles under the action of butyl xanthate. As a result, it was possible to directly observe the growth process of the sulfide film on the malachite surface, and the presence of Cu(I) was confirmed in the sulfide products. Moreover, the compositions of the sulfide products were investigated using X-ray techniques. The obtained results demonstrated that the sulfide film facilitated the formation of butyl xanthate product layers on the malachite surface, whilst also enhancing the interfacial interaction forces between the malachite and the bubbles.

A novel activation approach for promoting chrysocolla flotation: Performance and mechanism

Chrysocolla is an important copper oxide mineral. However, owing to the unique structure of chrysocolla, effective recovery of chrysocolla using conventional sulfidization xanthate flotation methods proves challenging. In this work, the effects of Pb2+ on the surface properties, sulfidization, activation, hydrophobicity, and floatability of chrysocolla were systematically investigated in a sulfidization xanthate system. Compared to the direct sulfidization flotation results, the flotation recovery of chrysocolla significantly increased from 7.84% to 69.46% after Pb2+ stepwise activation. The results of X-ray photoelectron spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analyses indicated that Pb species and sulfidization products on chrysocolla surfaces obviously increased in the Pb2+ stepwise activation system, the content of highly reactive PbS components on the surface of chrysocolla was higher, and the stability of sulfidization products on the chrysocolla surface was stronger than that in a single Pb2+ activation system. The results of contact angle, Fourier-transform Infrared (FTIR), and adsorption amount characterizations showed that more xanthate components were adsorbed on the surface of chrysocolla after Pb2+ stepwise activation, and the hydrophobicity of chrysocolla surface was significantly enhanced. Therefore, Pb2+ stepwise activation not only enhanced the sulfidization of chrysocolla surface but also improved the reactivity and hydrophobicity of mineral surfaces, thus realizing the effective recovery of silicic copper oxide minerals, which are extremely difficult to float.

New insight into enhancing sulfurization of azurite with ethylenediamine and its response to xanthate adsorption

Organic amine salt is an efficient sulfurization accelerator for copper oxide minerals. In fact, its underlying function mechanism is scarce. In this study, the evolution of sulfurized products of azurite under ethylenediamine (EDA) regulation and its response to the xanthate adsorption and surface hydrophobicity were investigated. ToF-SIMS, ICP-OES, XPS and total nitrogen analyses showed that pretreatment with EDA promoted the additional formation of copper sulfide products on azurite, and the sulfurization efficiency increased by 17%. The solution chemistry and transition state search analyses revealed that EDA changed the sulfurization reaction pathway by the formation of copper ethylenediamine ion (Cu(en)n2+, n = 1, 2) resulting in the increase of the reaction energy barrier from 55.12 kcal/mol to 197.83 kcal/mol. Therefore, the deposition rate of copper sulfide on azurite was slowed down, thus creating stable solution environment for the dense adhesion of products, which was observed by FESEM. The increasing copper sulfide products created favorable conditions for the stable adsorption of SBX on azurite, ultimately improving the surface hydrophobicity of azurite. These results may provide a deeper understanding for EDA promoting the sulfurization of copper oxide minerals.

Formation of core–shell structure on azurite with DMTD surface modification and its response to flotation

2,5-Dimercapto-1,3,4-thiadiazole (DMTD) is an excellent activator of carbonate minerals containing Cu. However, few studies have been conducted on this activation mechanism. In this study, the effects of DMTD modification on the floatability and flotation interface characteristics of azurite and xanthate adsorption were systematically investigated. Micro-flotation tests demonstrated that pretreatment with an appropriate concentration of DMTD in the range of 20–40 mg/L increased the flotation recovery of azurite by 50% when potassium butyl xanthate (KBX) was used as the collector. FESEM-EDS, XPS, UV–Vis, ICP-OES, ToF-SIMS and contact angle analyses demonstrated that DMTD surface modification proceeded through a chemical reaction, resulting in the formation a three-dimensional core–shell structure consisting of a core (azurite) and a shell (Cu(I)-DMTD). Compared to the surface of natural azurite, that of azurite modified with DMTD had an increasing number of Cu active sites, which promoted the effective adsorption of KBX on azurite, thus significantly improving azurite hydrophobicity. The decreased floatability of azurite is closely related to the formation of colloidal Cu(I)-DMTD components in solutions with excess DMTD. This study improves our understanding of DMTD modification and presents a direction for enhancing the xanthate flotation of copper oxide minerals using DMTD as an activator.

Contribution of ammonia in xanthates adsorption onto copper oxide mineral surface in high-alkaline solution

Ammonia is a useful modifier for enhancing surface sulfurization in copper oxide ore flotation using xanthate as a collector. However, its potential role in the reaction of sulfhydryl collector with sulfurized copper oxide mineral in a complex pulp has been neglected. This work investigates the contribution of ammonia to xanthate adsorption on the sulfurized malachite surface, independent of its effect on sulfurization. Zeta potential measurements indicate that NH3·H2O increases the surface potential of malachite and enhances the proximity of xanthate to the malachite surface in a strong-alkaline solution. Adsorption tests and time-of-flight secondary ion mass spectrometry analysis demonstrate that NH3·H2O can increase the xanthate adsorption density. Spectroscopic analysis reveals copper(I) xanthate and dixanthogen as the primary xanthate products, with their quantities increasing upon NH3·H2O treatment. Thermodynamic analysis of the reaction of malachite, HS−, and xanthate to form copper(I) xanthate and dixanthogen shows that NH3·H2O treatment enhances the stability of the reaction compared to its absence. Thus, NH3·H2O treatment increased the recovery of sulfurized malachite by over 10%. This study offers a comprehensive understanding of ammonia modification for enhancing sulfurization–xanthate flotation of copper oxide minerals and provides a scientific basis for developing high-efficiency collectors.

Thermodynamic Calculations of Direct Reduction Smelting Technology of Copper Oxide Ores Based on Smelting Slag from the Yubeidi Site, Yunnan Province

The current research on metallurgical remains from scientific excavations in northeast Yunnan from the Bronze Age period is insufficient. In order to study the smelting technology of the Bronze Age in north-eastern Yunnan, samples of slag and mineral excavated from the Yubei Di site in Dongchuan were examined. Based on the outcome of the characterization analysis, a simulation was executed utilizing the software Factsage 7.1 in order to generate a phase diagram that accurately portrays the melting procedure. This simulation aimed to produce the most credible representation of the phase transition by employing computational methods. Characterisation methods included Metallographic Microscopy, Scanning Electron Microscopy Energy Dispersive Spectromicropy (SEM-EDS), X-ray diffraction (XRD), and Radiocarbon Date (14C dating). The results showed that there was much copper ore left in the slag of the site. Most of these copper ores were in the form of copper ferrite or cuprous oxide. The copper ore was copper oxide ore, and metal copper particles appeared in a small amount of the slag. Most of the slags unearthed from the site of the Yubeidi site were products of sulfur-containing oxide reduction and smelting into copper. Based on the outcomes of the simulations, it was established that the slag excavated from the Yubeidi site was mainly from the reduction and smelting process of sulphur-containing copper oxide minerals into copper, without consciously adding fluxes, not having mastered the slag-making techniques for different types of copper ores, and with primitive techniques. The carbon 14 dating results show that the age of the slag was during the Spring and Autumn Period and the Warring States Period.

A novel method for improving sulfidization xanthate flotation of malachite: Copper–ammonium synergistic activation

Malachite, as an important copper oxide mineral, is mainly separated and recovered from ores using sulfidization xanthate flotation method. In this paper, copper ions and ammonium salts were used as activators to modify the malachite surface, which improved its reactivity and improved the sulfidization and hydrophobicity of the mineral surface. Micro-flotation test results show that the flotation recovery of malachite can be greatly improved by this synergistic activation system, compared with that upon treatment in a direct sulfidization system. Zeta potential, XPS and ToF-SIMS analysis showed that the content of highly active cuprous sulfide species and copper sites on the malachite surface increased after the copper–ammonium synergistic activation treatment. FTIR characterization and contact angle measurement indicated that more xanthate components were stably adsorbed on the malachite mineral surface after the synergistic activation of the copper–ammonium, thereby increasing the hydrophobicity of the surface. Therefore, the synergistic activation not only resulted in the enhanced sulfidization of malachite surfaces, but also enhanced the reactivity and hydrophobicity of malachite surfaces, thus promoting the hydrophobic flotation of malachite. This represents a new concept and process for the efficient flotation recovery of oxidized copper minerals.

STUDYING THE PROCESS OF SULFIDING AN OXIDIZED COPPER ORE BY THE METHOD OF MECHANOCHEMICAL ACTIVATION

In recent years, a new direction has appeared in metallurgical processes according to which the processing of concentrates is carried out by a combination of mechanical and metal-thermal methods of recovery. This contributes to the intensification of further redox processes and the production of fundamentally new modified products. In the case of enrichment of oxidized copper minerals, a more acceptable type of surface activation are mechanical activation processes with a combination of added reagents. It is established that sulfiding of oxidized copper minerals with elemental sulfur, silicon and sodium sulfides proceeds actively. As a result of the research, the optimal modes of sulfiding oxidized copper ores are determined. As a result of comprehensive research, a technology has been developed for processing oxidized copper minerals in a mill by sulfiding and subsequent flotation.

Flotation of copper oxide minerals: A review

Flotation of copper oxide minerals: A review

Validation of predictive flotation models in blended ores for concentrator process design

The use of geometallurgical modelling is becoming common in the design of a concentrator plant and during its operational phase. Predictive modelling aims to define optimized process parameters for the concentrator plant to accommodate the variability of the ore feed characteristics. The main objective of this study is to simulate the metallurgical response for distinct ore unit types and their blends using kinetic models derived from experimental flotation tests. Kinetic flotation tests, including both rougher and cleaner, were applied on four ore types containing different ratios of chalcopyrite, chalcocite and copper oxide minerals from Rich Metal Group’s Madneuli copper–gold mine, Georgia. The metallurgical performance of complex copper ores Madnueli XI and V differs from each other significatively due to the different mineralogical distribution of copper sulphides and oxides. The blend of ore units in various ratios affects the efficiency of the process by decrementing the recovery and mass pull due to copper oxide-sulphate in the ore Madnueli V. HSC Chemistry® software was used to simulate the metallurgical response of blended ores based on mineral compositions of the ores, Klimpel kinetic rectangular distribution model and flowsheet model. Simulated and experimental results of copper grade, copper recovery and concentrate mass pull correlated well with R2 values of over 0.95. These results demonstrate that the metallurgical response of ore blends can be simulated based on the flotation kinetics of distinct ore types. The use of predictive simulation can create savings during the test work phase and increase the flexibility and certainty in the process design stage.

Bioleaching Process for Copper Extraction from Waste in Alkaline and Acid Medium

Flotation wastes are becoming a valuable secondary raw material and source of many metals and semimetals worldwide with the possibilities of industrial recycling. The flotation tailings contain oxide and sulfide minerals that have not been sufficiently stabilized and form acidic mine waters, which in turn contaminate groundwater, rivers, and reservoi6sediments. An effective way to recycle these mine wastes is to recover the metals through leaching. While the focus is on acid bioleaching by iron- and sulfur-oxidizing bacteria, alkaline leaching, and the removal of iron-containing surface coatings on sulfide minerals contribute significantly to the overall environmental efficiency of leaching. For this study, static and percolate bioleaching of copper from flotation waste at the Bor copper mine in Serbia was investigated in alkaline and then acidic environments. The aim of the study was to verify the effect of alkaline pH and nutrient stimulation on the bioleaching process and element extraction. A sample was taken from a mine waste site, which was characterized by XRF analyses. The concentration of leached copper was increased when copper oxide minerals dissolved during alkaline bioleaching. The highest copper yield during alkaline bioleaching was achieved after 9 days and reached 67%. The addition of nutrients in acidic medium enhanced the degradation of sulfide minerals and increased Cu recovery to 74%, while Fe and Ag recoveries were not significantly affected. Combined bioleaching with alkaline media and iron- and sulfur-oxidizing bacteria in acidic media should be a good reference for ecological Cu recovery from copper oxide and sulfide wastes.

Effect of ferric ion on cuprite surface properties and sulfidization flotation

The pulp from the sulfidization flotation of copper oxide ores contains several metal ions, among which ferric ion (Fe3+) depresses the flotation of copper oxide minerals. Thus, it is necessary to investigate the effect of Fe3+ on the sulfidization and xanthate adsorption of copper oxide minerals to provide theoretical support for mitigating the negative effects of Fe3+. In this work, the effect of Fe3+ on cuprite flotation was determined via micro-flotation tests. The mechanism of the depression of cuprite sulfidization by Fe3+ was revealed through zeta potential measurements, scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDS) analysis, and X-ray photoelectron spectroscopy analysis. The impact of Fe3+ on xanthate adsorption onto cuprite surfaces was investigated via surface-adsorption measurements and infrared spectroscopy. The micro-flotation test results indicated that the cuprite floatability was significantly weakened by Fe3+. The results of zeta potential, SEM-EDS, and X-ray photoelectron spectroscopy showed that Fe3+ could generate hydrophilic species and reduce the number of active sites on cuprite surfaces, thus hindering the formation of copper sulfide species on cuprite surfaces. The results of surface-adsorption measurements and infrared spectroscopy showed that xanthate hardly interacted with the Fe3+-treated cuprite surfaces. Given the above, Fe3+ could weaken the cuprite surface hydrophobicity by reducing the number of active sites on cuprite surfaces, thereby depressing the cuprite flotation.

Sulfidization regulation of cuprite by pre-oxidation using sodium hypochlorite as an oxidant

The direct sulfidization of cuprite is inefficient because cuprite is a copper-oxide mineral with a strong surface hydrophilicity. In this study, oxidant was used to modify cuprite surfaces to regulate the sulfidization of cuprite. Microflotation tests showed that the flotation recovery of pre-oxidized cuprite was nearly 25% higher than that of direct sulfidization flotation, which indicates that the cuprite surface activity was enhanced after pre-oxidation by Cu(I) species (weak affinity with sulfur ions) transformation to Cu(II) species (strong affinity with sulfur ions). Zeta potential, scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry results showed that pre-oxidation improved cuprite sulfidization and promoted the formation of copper-sulfide species on the cuprite surfaces. The mineral surface stability and thus, xanthate species adsorption on the cuprite surfaces were improved. The surface-adsorption measurements and infrared spectroscopy showed that a large amount of xanthate species was adsorbed onto the sulfidized cuprite surfaces after pre-oxidation, which enhanced the cuprite hydrophobicity and improved the cuprite flotation.