Copper Leach Solution Research Articles

Sustainable strategies for recovering metallic copper from waste printed circuit boards: Clean leaching and micro-nano copper powder preparation

Recovery and utilization of valuable metals from waste printed circuit boards (WPCBs) have the dual significance of alleviating resource shortages and protecting the ecological environment. This study focuses on the feasibility analysis of copper in WPCBs for preparing micro-nano copper powders by clean leaching and chemical reduction processes. Firstly, the effect of temperature and other parameters on copper leaching rate in glycine-hydrogen peroxide (Gly-H2O2), ammonia-ammonium chloride (NH3·H2O-NH4Cl) leaching systems with sulfuric acid-hydrogen peroxide (H2SO4-H2O2) system as control group were emphasized. Subsequently, the leaching characteristics of copper concentrate particles were analyzed by leaching kinetics to elucidate the leaching mechanism and apparent activation energy of copper. Finally, the micro-nano copper powders were prepared using ascorbic acid and sodium borohydride reduction system with different copper leach solutions as precursors. The micro-nano copper morphology and phase compositions were analyzed by SEM and XRD. The results show that both the Gly-H2O2 and NH3·H2O-NH4Cl system can replace the H2SO4-H2O2 system to achieve efficient leaching of copper. Increasing temperature can significantly enhance the copper leaching rate. When the temperature was increased from 15 °C to 45 °C, the maximum copper leaching rate in the three systems increased from 58.13 %,71.26 %,78.26 % to 90.36 %,91.21 %,92.87 %, at − 0.074 mm for 40 min. The Avrami model accurately describes the leaching behavior of copper concentrate particles, and the copper leaching process is dominated by chemical reaction control. SEM and XRD results show that micro-nano copper particles of hundreds of nanometers are successfully prepared by both reduction systems.

Adsorption of Scandium and Yttrium from Aqueous Solutions by Purolite C100Na Resin: Equilibrium and Kinetic Modeling

ABSTRACT: Adsorption of Sc from single and bi-component Sc-Y solutions by Purolite C100Na was studied experimentally and kinetic and thermodynamic characteristics are described. The extended Freundlich isotherm was found to be successful in validating the experimental results. Moreover, curve fitting the time-dependent data into different kinetics mechanisms showed a satisfactory correlation with the pseudo-second-order model. Binary system results show a decrease in Sc adsorption capacity of the absorbent in the presence of secondary ions because of competition for adsorption sites. Furthermore, thermodynamic parameters indicate similarity of reaction mechanisms for both single and binary systems, with Sc absorption adversely affected by temperature. Data from experiments on synthetic electrolytes with Y/Sc ratio of 5 found in actual mining copper leach solution were used for extracting scandium by circulating mine-leach solution through a resin column. The results demonstrate a preferential collection of Sc ions despite the fivefold concentration of Y over Sc. The elusion studies showed that the yttrium desorption peak occurs before that of Sc which, corroborates the adsorption isotherm findings. This results in a 180 mgL-1 Sc rich solution or 60:1 concentration ratio over the original copper leach solution.

Scandium recovery from raffinate copper leach solution as potential new source with ion exchange method

Abstract Raffinate copper leach solution of the Iran Sarcheshmeh copper complex has up to 3 mg/L scandium (Sc), which is significantly better than many existing sources, making it a possible source for the recovery of Sc using the ion exchange method. Visual Minteq software was employed to ascertain the ionic species likely to be formed under operational conditions in the mine and for selecting the suitable ion exchange resin. The cationic resin thus chosen was employed statically with ions-bearing synthesized solutions and statically/dynamically for actual copper mining raffinate solution. Room temperature and pH of 1.5 showed the highest Sc adsorption. The dynamic tests established the full saturation of the resin at 450 BV of the raffinate solution flow. Using sodium carbonate for elution, desorption of Sc, Y and Ce from the resin during static elution tests at constant duration was higher than that of Fe, Al and Cu. The results from the dynamic tests followed similar trends for the priority and the extent of the elution process. Desorption results from specimens of dynamic tests show a 60:1 concentration ratio leading to a 186 mg/L Sc-rich solution.

Copper Extraction Using Aluminum in Acidic Leachate Media

Copper is found in several minerals with varied elemental composition. For instance, copper minerals occur as chalcopyrite (CuFeS 2 ), bornite (Cu 5 FeS 4 ), chalcocite (Cu 2 S), covellite (CuS), cuprite oxide (Cu 2 O), and malachite (Cu 2 CO 3 (OH) 2 ) among many other minerals. In Kenya, extraction of valuable minerals like copper is hampered by high capital and technological investment requirements. Mineral ores found in Tharaka sub – county in Tharaka Nithi County in Kenya in particular contains significant concentrations of copper which are worth extraction. These minerals cannot be exploited due to financial and technological constraints. However, efficient and cheaper methods of extraction of copper with affordable technology are currently required. Electrolysis of copper leach solution after reaction of ground ore with acid has been done. Since the available methods involve the use of large amount of power for large scale production, alternative method for extraction has been investigated. The method involves dipping aluminum in acidic leach solution at room temperatures. The copper recovered was found to contain 80 to 90% purity depending with ore composition. Keywords: key copper extraction, aluminum half-cell reaction, displacement of copper using aluminum. DOI: 10.7176/CMR/12-7-06 Publication date: September 30 th 2020

Comparison of various extractants for recovery of Copper from Sarcheshmeh Chalcopyrite concentrate Ammonia/Ammonium Carbonate Leaching

Solvent extraction of copper from the copper leach solution obtained from the ammoniacal carbonate leaching of the Sarcheshmeh copper concentrate was carried out, and the performance of CP-150, LIX984N, and Kelex100 as well as the effects of different parameters involved were investigated. According to the results obtained, the extraction kinetics of all the three extractants was fast. High concentrations (7.5%, V/V) of CP-150 and Kelex100 were required to completely extract copper, while only 1% of LIX984N was sufficient. Addition of hexane to the diluent decreased the capability of CP-150 to extract copper, while it showed less effects on LIX984N and Kelex100. A desirable stripping of copper from the loaded organic phase could be obtained using H2SO4 solution.

Recovery of yttrium and neodymium from copper pregnant leach solutions by solvent extraction

The solvent extraction of yttrium and neodymium from copper pregnant leach solutions (PLS) using Primene JM-T, a primary aliphatic amine, has been studied. Effect of contact time, pH, sulfate concentration, and extractant concentration were investigated using synthetic and actual PLS systems. Standard experimental conditions were 5 min contact time, pH ~ 2.5, 10 % v/v Primene JM-T concentration, and 1:1 O:A phase ratio. Distribution isotherms were constructed for the pure systems and for actual copper leach solutions. Synthetic solutions contained 100 ppm Y and ~75 ppm Nd. Copper PLS contained 14.9 ppm Y and 2.1 ppm Y. Results showed that complete extraction of both yttrium and neodymium occurred within 5 min and at pH values greater than 1. It was also found that sulfate concentration does not inhibit extraction at any concentration. Using synthetic solutions of yttrium and neodymium, it was found that the reaction stoichiometry requires 2 moles of Primene JM-T per mole of metal extracted. This suggests that a both bi-sulfate and tri-sulfate complexes are being extraction. For the copper bearing PLS, 3 moles of Primene JM-T were required per mole of metal extracted. This support the tri-sulfate complex as being the predominate species being extracted.

Recovery of rhenium from copper leach solutions using ion exchange with weak base resins

This paper investigated the efficient extraction of rhenium from the leach solution generated by roasting the copper concentrates in a copper smelting plant by direct ion exchange process using weak base resins. The adsorption behaviors of rhenium with other coexisting impurity ions belonged to kinetic control by particle diffusion process, and the reaction rate constant was calculated. Then, the influences of temperature, pH value, stirring rate and calcium oxide dosage on the equilibrium adsorption capacity of rhenium were studied by batch experiments. To verify the process of extracting rhenium in industrial application, three ion exchange columns packing with 105L resins were operated to recover rhenium by direct ion exchange method. In the adsorption process, the recovery rate of rhenium reached 97.13% after approximately 960BVs of leach solution flow. The loaded resins were eluated using 2.5% concentration of aqueous ammonia, producing a rhenium-rich solution containing 1995mg/L rhenium, in which the rhenium concentration enriched 309 times compared to the original leach solution.

Removal of iron from sythetic copper leach solution using a hydroxy-oxime chelating resin

Iron removal is a common procedure in hydrometallurgy of non-ferrous metallic ores. Chemical precipitation and solvent extraction are currently the main methods employed for separation of iron from copper leach solution. However, chemical precipitation methods have the problem of producing large amounts of iron precipitates, and/or requiring high temperature and high pressure conditions for precipitation. The precipitates are difficult to separate from the solution. Emulsification is a general problem for solvent extraction, which causes loss of extractants and contamination of the electrolyte. A common problem for solvent extraction and chelating ion exchange processes is the difficult iron stripping process. Therefore, finding an efficient and environmentally friendly method for iron removal is of great significance. In this paper, new processes of using ion exchange resins to remove iron from copper leach solution have been investigated.Salicylic acid, amino carboxylic acid, amino phosphonic acid and hydroxy-oxime resins were employed to adsorb iron from a synthetic copper leach solution containing 40g/L of Cu2+ and 36g/L of Fe3+. It was found that a hydroxy-oxime resin, named Z-Fe, has excellent adsorption selectivity on Fe3+. Desorption behavior of the resin was studied by two step elutions using dilute H2SO4 and oxalic acid solution, respectively. After optimizing the adsorption-elution processes, the extent of removal of iron from the simulated copper leach solution using resin Z-Fe was 89.83%, while copper recovery could reach 100% in closed circuit processing.

Recovery of rhenium from copper leach solution by ion exchange

There is current interest in recovering rhenium from solutions produced as a result of copper heap and stockpile leaching. Copper-bearing leach solutions typically contain rhenium at concentrations near 1mg/L. This work has demonstrated that rhenium can be efficiently extracted from these solutions using weakly basic anion exchange resins. Breakthrough of Re occurs after approximately 5000BVs of solution flow. Rhenium is eluted from the resin using 1M NaOH, producing a rhenium-rich solution containing about 1400mg/L Re. The overall concentration ratio is about 2400:1.

Acid leaching of copper in a saturated porous material: Parameter identification and experimental validation of a two-dimensional transport model

In this study, a two-dimensional mathematical solute transport model is proposed to simulate the leaching of copper ore tailings using sulfuric acid as the leaching agent, injection wells to introduce the leaching agent, and pumping wells to retrieve the pregnant copper leach solution. To calibrate the model, a tracer experiment and a leaching experiment were performed, both under conditions of a single-direction flow pattern established between two boundaries of constant height. These experiments enabled the model hydraulic, dispersion and reaction parameters to be determined. Validation of the model was performed by comparison of the numerical results given by the model with experimental results obtained from a second leaching experiment, performed under conditions of a radial flow pattern established through the use of four injection wells and one pumping well and making use of the parameters estimated previously during the calibration process. The comparison between predicted and measured leaching behavior was good (20–22% error). The study has significant implications for applications related to the use of the proposed numerical model for predicting the performance of in-situ soil washing alternatives.

Recovery of cobalt from spent copper leach solution using continuous ion exchange

Significant amounts of cobalt are present in readily accessible spent copper leach solutions. The Bureau of Mines investigated the feasibility of extracting cobalt from one of these solutions in a multiple-compartment ionexchange (MCIX) column. The effects of aqueous flow rate, resin flow rate, column height, and compartment height on cobalt extraction were determined. Cobalt extractions of 92% or higher were achieved at solution flow rates of up to 5.5 gpm/ft 2 (13.4 m 3/h m 2) of column cross-sectional area and an aqueous-to-resin flow ratio of 40:1. Overall cobalt extraction increased as the column height increased, but cobalt extraction per unit of height was more efficient in 2.4 and 3.7 m columns that in a 5.5 m column. Solvent extraction procedures were utilized to purify and concentrate the MCIX column eluates and produce a cobalt sulfate solution containing 70 to 80 g/L Co. Metallic cathodes, containing over 99% Co, were electrowon from this solution. Nickel, zinc, and copper byproducts were also recovered during processing of the ion-exchange eluates. Estimated total capital cost for a commercial-scale plant processing 10,000 gpm (2,270 m3/h) of a spent leach solution containing 26 mg/L Co was $23.1 million (U.S.). With credits for zinc, nickel, and copper byproducts, the estimated net operating cost was $5.10/lb ($11.24/kg) of cobalt.

Separation and Recovery of Cobalt from Copper Leach Solutions

Significant amounts of cobalt, a strategic and critical metal, are present in readily accessible copper recycling leach solutions. However, cost-effective technology is not available to separate and recover the cobalt from this low-grade domestic source. The Bureau of Mines has developed a procedure using a chelating ion-exchange resin from Dow Chemical Co. to successfully extract cobalt from a pH 3.0 copper recycling solution containing only 30 mg/1 cobalt. Cyclic tests with the commercial resin XFS-4195 in 4-ft-high by 1-in.-diameter columns gave an average cobalt extraction of 95% when 65 bed volumes of solution were processed at a flow rate of 4 gpm/ft.2 Elution of the cobalt using a 50 g/l H2SO4 solution yielded an eluate containing 0.5 gli Co. Selective elution of the loaded resin and solvent extraction procedures using di-2-ethylhexyl phosphoric acid (D2EHPA) and Cyanex 272 removed the impurities and produced a cobalt sulfate solution containing 25 g/l Co.

Determination of uraniim in aqueous solution by X‐ray fluorescence

AbstractAnlysis of uranium (VI) by X‐ray fluorescence methods, using selective solvent extraction with tri‐n‐ octulphosphin‐oxide (TOPO) has been studied. The analysis of uranium in copper leach solutions has proved successful and results indicate that this method can be used for uranium levels doen to 3ppm. The coefficient of variation (CV) at a value of 30 ppm was calculated to be CV = 2.6%.