Selective Recovery Of Copper Research Articles

Selective copper recovery from complex mixtures of end-of-life electronic products with ammonia-based solution

Electronic waste treatment within EU has focused on valuable metal recycling and has been defined by the EU directives. The difficulties for recycling are induced by the high complexity of such waste. In this research, a hydrometallurgical process was developed to recycle copper from industrially processed information and communication technology (ICT) waste. By using air as the oxidant and ammonia–ammonium carbonate leaching solution, copper could be extracted with high recovery – more than 90%, and high extraction selectivity – around 98%. In order to understand the copper extraction process and the reaction mechanisms, the effects of a range of parameters during copper leaching were comprehensively investigated, including ammonia concentration, leaching temperature, ammonium carbonate concentration, the liquid-to-solid ratio, air flow rate and mechanical stirring rate. The controlling step for the leaching kinetics was identified and the effects of different parameters were investigated. This research is potentially beneficial for further optimisation of the copper leaching process and the whole process design for copper recycling after incorporating with solvent purification and electrowinning of the copper-rich solution.

Ammoniacal leaching and recovery of copper from alloyed low-grade e-waste

The paper concerns a hydrometallurgical method for selective recovery of copper from low-grade electric and electronic wastes. The following consecutive stages were proposed: smelting of the scraps to produce Cu–Zn–Ag alloy, leaching of the alloy in ammoniacal solution, and selective copper electrowinning. Cu–Zn–Ag alloy was a polymetallic and five-phase system. It was leached in chloride, carbonate, sulfate and thiosulfate solutions. This resulted in the separation of the metals, wherein metallic tin and silver as well as lead salts remained in the slimes, while copper and zinc were transferred to the electrolyte. Copper was selectively recovered from the ammoniacal solutions by the electrolysis, leaving zinc ions in the electrolyte. The best conditions of the alloy treatment were obtained in the ammonia–carbonate system, where the final product was copper of high purity (99.9 %) at the current efficiency of 60 %. Thiosulfate solution was not applicable for the leaching of the copper alloy due to secondary reactions of the formation of copper(I) thiosulfate complexes and precipitation of copper(I) sulfide, both inhibiting dissolution of the metallic material.

Enhancement mechanisms behind exclusive removal and selective recovery of copper from salt solutions with an aminothiazole-functionalized adsorbent

The aminothiazole-functionalized adsorbent (CEAD) could exclusively remove and to selectively recover copper. The adsorption and separation properties of Cu(II) onto CEAD from aqueous media, with or without salts such as NaNO3, Ca(NO3)2 and Ni(NO3)2, were systematically compared by carrying out single, binary and multiple component static and dynamic experiments. In binary systems, the adsorption capacities of Cu(II) were obviously increased by 39.47%, 47.37% and 57.89% with Ni(NO3)2, NaNO3 and Ca(NO3)2, respectively. Besides, simulation study was performed to selectively recover Cu(II) from multi-component aqueous media, with the separation factor of only 54.91 in aqueous media without salts. The separation factor became infinite in the presence of NaNO3 and the enhancement ratio for Cu(II) was raised by 126.31%. Dynamic adsorption could separate Cu(II) and Ni(II) completely and the amount of effluent for pure Ni(II) increased to 127 BV with the help of NaNO3. In the predominant chelating mode simulated by density functional theory calculation, a metal ion coordinated with three nitrogen atoms and formed a chelating complex with two five-membered rings, and Cu(II) showed stronger coordinating ability than Ni(II) did. Meanwhile, anions exerted significant beneficial effects by electrostatic screening, and thus strengthened the exclusive removal and selective recovery of Cu(II).

Sulfuration treatment of electroplating wastewater for selective recovery of copper, zinc and nickel resource

In the electroplating process, various metal salts are used and the residues on the surface of electroplated materials are rinsed out as wastewater, followed by hydration in a wastewater disposal step. Although a variety of metals are concentrated in the sludge, the mixed heterogeneous state of these metals in sludge makes it difficult to recycle and reuse them. From the viewpoint of environmental protection as well as resource saving, effective methods for recycling and reuse of these mixed metal sludge are required to be developed urgently. In the present work, selective recovery of the metals from mixed-metal wastewater by sulfuration treatment is proposed. Sulfuration treatment is characterized by low solubility of metal sulfides; metal sulfides are, in general, lower in solubility than that of metal hydroxides. For the experiments, three metals of copper, zinc and nickel which are commonly used in the electroplating process were chosen. Separation of these metals from the mixed solution in various pH ranges was conducted by employing three sulfurating agents: sodium sulfide (Na2S), sodium disulfide (Na2S2) and sodium tetrasulfide (Na2S4). Aqueous solutions of CuSO4, ZnSO4 and NiSO4 and those of real plating wastewater, of which the initial concentrations were adjusted to 100-300 mg dm-3 were employed. By sulfuration treatment of the simulated solution using each sulfurating agent without adjusting pH, CuS was first precipitated, but ZnS and NiS were also precipitated at the same time. In addition, pH value increased with the amount of sulfurating agents in the solution. The results demonstrated that the formation behavior of metal precipitates depended on pH value of the solution. For the sulfuration with three kinds of sulfurating agents, copper was first separated from the solution as CuS in pH=1.4-1.5, then ZnS was precipitated in pH=2.4-2.5, followed by the precipitation of nickel sulfide, NiS in the residual solution at pH=5.5-6.0. It was also found that Na2S is most effective for selective precipitation of metal sulfides, among the three sulfurating agents of Na2S, Na2S2 and Na2S4. The selectivity of CuS in the filtrated cake obtained by the sulfuration treatment in pH=1.4-1.5 was about 94 % and was sufficiently high, in terms of allowable metal content level for recycling. The sequent selectivity of ZnS and NiS in the cake after the sulfuration treatment in pH=2.4-2.5 were 75-77 % and about 20 %, respectively. The selectivity of NiS and ZnS in the cake after the sulfuration treatment in pH=5.5-6.0 was 64-66 % and 33-35 %, respectively.

Integrating sulfidization with neutralization treatment for selective recovery of copper and zinc over iron from acid mine drainage

The most commonly used commercial process for acid mine drainage (AMD) treatment today is lime neutralization. However, it is accompanied by the treatment of produced metal hydroxide precipitate. Because of the decrease in the capacity of landfill disposal site and the increase in the price of base metals such as copper (Cu) in recent years, it is expected that not only to treat but also to recover these base metals from AMD. For the subsequent smelting process, the major issue is how to separate the Cu and zinc (Zn) over iron (Fe) from AMD as selectively as possible.In this work, we attempted to achieve this objective by modifying the present lime neutralization treatment process with sodium hydrosulfide (NaHS) sulfidization. An AMD sample generated from an abandoned copper mine located in east Japan was utilized in this study. At first, lime neutralization was applied to the AMD to find the precipitation behaviors of Cu, Zn, and Fe. Next, NaHS sulfidization as well as the integration with lime neutralization were conducted to separately precipitate Cu, Zn, and Fe from the AMD. Finally, two modified treatment approaches for selectively recovering Cu and Zn over Fe from the AMD were proposed. The results of consecutive experiments for the two proposed approaches showed that Cu, Zn, and Fe in the AMD were removed and separated into individual precipitates, and that the concentrations of each heavy metal in the final effluent were also able to meet the Japanese effluent standards.

Selective Recovery of Copper, Cobalt, and Nickel from Aqueous Chloride Media using Solvent Impregnated Resins

Selective recovery of copper, cobalt, and nickel from acidic chloride media was investigated with solvent impregnated resins (SIRs) containing acidic organophosphorus extractants. The adsorption of each metal with the SIR proceeds via a cation exchange mechanism. An SIR containing 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC-88A) has high selectivity for Cu2+, and the order of selectivity is Cu2+ > Co2+ > Ni2+. Effective adsorption-elution can be achieved by chromatographic operation for the selective recovery of Cu2+ from a ternary metal solution. High selectivity for Co2+ was observed using a SIR comprising bis-2,4,4-trimethylpentylphosphinic acid (Cyanex 272) and can be effectively separated from a Co and Ni binary metal solution by column adsorption. A simple and effective process flow sheet is proposed for selective recovery of Cu2+, Co2+, and Ni2+ from aqueous chloride media using the two SIRs.

Hydrometallurgical Process for Copper Recovery from Waste Printed Circuit Boards (PCBs)

Present paper focuses on the selective recovery of copper from the enriched ground printed circuit boards (PCBs) using leaching and solvent extraction. The metal-enriched ground sample obtained from the beneficiation of the sized PCBs in a laboratory scale column type air separator contained mainly 49.3% Cu, 3.83% Fe, 1.51% Ni, 5.45% Sn, 4.71% Pb, and 1.85% Zn. The leaching of the enriched sample with 3.5 mol/L nitric acid dissolved 99% copper along with other metals at 323 K temperature and 120 g/L pulp density in 1 h time. The composition of the leach liquor with wash solution was found to be 42.11 g/L Cu, 2.12 g/L Fe, 4.02 g/L Pb, 1.58 g/L Zn, and 0.4 g/L Ni. The McCabe–Thiele plot indicated the requirements of three counter-current stages for maximum extraction of copper from the leach liquor at pH 1.5 using 30, 40, and 50% (v/v) LIX 984 N at the phase ratios (A/O) of 1:3, 1:2, and 1:1.5, respectively. The counter-current simulation studies show the selective extraction of 99.7% copper from the leach liquor feed of 1.5 pH in three stages with 50% LIX 984 N at A/O phase ratio of 1:1.5. The stripping of copper from the loaded organic with sulfuric acid produced copper sulfate solution from which copper metal/powder could be recovered by electrolysis/ hydrogen reduction.

Selective recovery of copper, nickel and zinc from ashes produced from Saccharomyces cerevisiae contaminated biomass used in the treatment of real electroplating effluents

The aim of this work was to seek an environmentally friendly process for recycling metals from biomass-sludges generated in the treatment of industrial wastewaters. This work proposes a hybrid process for selective recovery of copper, nickel and zinc from contaminated biomass of Saccharomyces cerevisiae, used in the bioremediation of electroplating effluents. The developed separation scheme comprised five consecutive steps: (1) incineration of the contaminated biomass; (2) microwave acid (HCl) digestion of the ashes; (3) recovery of copper from the acid solution by electrolysis at controlled potential; (4) recycle of nickel, as nickel hydroxide, by alcalinization of the previous solution at pH 14; (5) recovery of zinc, as zinc hydroxide, by adjusting the pH of the previous solution at 10. This integrated approach allowed recovering each metal with high yielder (>99% for all metals) and purity (99.9%, 92% and 99.4% for copper, nickel and zinc, respectively). The purity of the metals recovered allows selling them in the market or being recycled in the electroplating process without waste generation.

Hydrometallurgical recovery of copper and cobalt from reduction-roasted copper converter slag

The paper is concerned with a simple hydrometallurgical method for selective recovery of copper and cobalt from industrial copper converter slag. The following consecutive stages are proposed: roasting of the slag in reduction conditions to produce Cu–Co–Fe–Pb alloy, electrolytic dissolution of the alloy in an ammonia–ammonium chloride solution, ammoniacal leaching of the slime, selective copper and cobalt electrowinning. Cu27–Co6–Fe64–Pb1.5 alloy was a five-phase system and did not dissolve uniformly during electrolysis. This resulted in the separation of the metals, wherein iron remained in the slime, while copper and cobalt were components of slime, electrolyte and cathodic deposit. A mechanism of the alloy dissolution was developed. A series of secondary processes took place in the system: precipitation of iron compounds, copper cementation with cobalt and iron; adsorption of copper and cobalt ions on the iron precipitates. Final products were metals of high purity (99.9% Cu, 92% Co).

Manganese metallurgy review. Part I: Leaching of ores/secondary materials and recovery of electrolytic/chemical manganese dioxide

The world rapidly growing demand for manganese has made it increasingly important to develop processes for economical recovery of manganese from low grade manganese ores and other secondary sources. Part I of this review outlines metallurgical processes for manganese production from various resources, particularly focusing on recent developments in direct hydrometallurgical leaching and recovery processes to identify potential sources of manganese and products which can be economically produced.High grade manganese ores (>40%) are typically processed into suitable metallic alloy forms by pyrometallurgical processes. Low grade manganese ores (<40%) are conventionally processed by pyrometallurgical reductive roasting or melting followed by hydrometallurgical processing for production of chemical manganese dioxide (CMD), electrolytic manganese (EM) or electrolytic manganese dioxide (EMD).Various direct reductive leaching processes have been studied and developed for processing low manganese ores and ocean manganese nodules, including leaching with ferrous iron, sulfur dioxide, cuprous copper, hydrogen peroxide, nitrous acid, organic reductants, and bio- and electro-reductions. Among these processes, the leaching with cheap sulfur dioxide or ferrous ion is most promising and has been operated in a pilot scale. The crucial issue is the purification of leach liquors and the selective recovery of copper, nickel and cobalt is often difficult from solutions containing soluble iron and manganese. For treatment of manganese bearing materials including waste batteries, spent electrodes, sludges, slags and spent catalysts, a leaching or reductive leaching step is generally needed followed by various purification steps, which makes the processes less economically viable.It is concluded that the recovery of manganese from nickel laterite process effluents which contain 1–5 g/L Mn offers a growing low cost resource of manganese. Part II of this review considers the application of various solvent extraction reagents and precipitation methods for treating such manganese liquors.

めっき廃水中の銅，亜鉛，ニッケルの硫化反応挙動と生成硫化物のろ過特性

Selective recovery of copper, zinc and nickel from electroplating wastewater was studied by investigating the sulfuration behaviors of these metal components and the filtration characteristics of the metal sulfides produced. As model metal solutions, CuSO4, ZnSO4 and NiSO4 aqueous solutions of 100mg/dm3 initial concentrations were employed. Three kinds of sulfurating agents : sodium sulfide (Na2S), sodium disulfide (Na2S2) and sodium tetrasulfide (Na2S4) of 6.8×10−2mol/dm3 were used. For selective sulfuration of CuSO4, ZnSO4 and NiSO4, the sulfurating agent was added to the metal solutions, adjusting the pH of these solutions at pH=1.4-1.5, 2.4-2.5 and 5.5-6.0, respectively.As a result, it was found that Na2S was most effective for selective sulfuration of copper, zinc and nickel. The sulfuration behaviors of copper, zinc and nickel in electroplating wastewater were almost the same as those in model solutions.Furthermore, the filtration characteristics such as the average specific filtration resistance and the compressibility coefficients of the metal sulfide produced with different sulfurating agents were measured. It was recognized that the average specific filtration resistance of the metal sulfides produced with different sulfurating agents was different. It was also found that the compressibility coefficient of the metal sulfides was lower than that of metal hydroxide. The compressibility coefficient of the metal sulfides decreased in the order of Na2S, Na2S2 and Na2S4.

めっき廃液中の銅，亜鉛およびニッケルの硫化反応による選択的分離回収

Selective recovery of copper, zinc and nickel from electroplating wastewater was studied by precipitating the metal sulfides formed by sulfuration treatment. CuSO4, ZnSO4 and NiSO4 involved in model solutions and those of plating wastewater were adjusted to 100-120mg dm−3 of the initial metal concentration. Two kinds of sulfurating agents, sodium sulfide (Na2S) and sodium hydrosulfide (NaHS) of 6.8×10−2 mol dm−3, were employed.As a result, it was found that Na2S was more effective for the separation of the metal sulfides precipitated. The formation of metal sulfides was dependent on the pH value of the solution. In the sulfuration process using Na2S, copper was first separated from the solution as copper sulfide in pH1.4-1.5, followed by the formation of zinc sulfide in pH2.4-2.5. Subsequently, nickel sulfide was precipitated after the formation of copper and zinc sulfides in the residual solution in pH5.5-6.0.The same results of the formation behavior of copper sulfide, zinc sulfide and nickel sulfide in a simulated plating solution were obtained for those in an electroplating solution.

Synthesis and sorption properties of filled fibrous sorbents with immobilized hetarylformazan groups

New sorbents were prepared by immobilization of structurally different sulfur-containing hetarylformazans on nonwoven polyacrylonitrile fiber filled with AV-17 anion exchanger. Sorption of some heavy metals on these materials was studied as influenced by various factors. Sorbents for selective recovery of copper(II) in the presence of nickel(II), zinc(II), and cadmium(II) cations were found.

モータ屑からの銅・鉄の分離回収に関する研究 （第１報） Ｃｕ（ＩＩ）アンミン水溶液による銅の溶解

A hydrometallurgical process, in which aqueous Cu (II) ammine solution is used as leachant, is proposed for the selective recovery of copper and iron from motor scrap. In this paper, the chemistry of the selective dissolution of copper with aqueous Cu (II) ammine solution is described, and some fundamental experiments have been carried out. Copper is dissolved easily with aqueous Cu (II) ammine solution, leaving iron as unattacked. Copper can be dissolved from the enamel coated copper wire which is treated by heating or shot blasting. These findings suggest that copper can be dissolved selectively from motor scrap with aqueous Cu (II) ammine solution after the removal of the enamel coat. The dissolution rate of copper increases with the increase in NH3 concentration up to 7 kmol m-3. The concentration of (NH4)2SO4 affects the dissolution rate. The optimum (NH4)2SO4 concentration exists corresponding to NH3 concentration. The dissolution rate of copper is negligibly small in the Cu (II) ammine solution without (NH4)2SO4. The dissolution of copper can be accelerated by the exposure of the leachant to the air, by which the Cu (I) produced by the dissolution reaction is oxidized to Cu (II).

アンモニア浸出法を用いるモータ屑からの銅の回収 モータ屑からの銅・鉄の分離回収に関する研究 （第２報）

To develop a hydrometallurgical process for the selective recovery of copper and iron from motor scrap. the leaching of copper with Cu (II). ammine solution using a spray-type or an up-stream penetration type reaction tank has been examined, and a closed circuit process has been proposed for the copper recovery. Copper can be leached by either spray leaching or up-stream penetration leaching with large leaching rate, where the resultant Cu (I) is oxidized to Cu (II) with air during the circulation of leachant. The leaching rate is greater in the up-stream penetration leaching than that in the other, since the whole copper sample is submerged in the leachant in the up-stream penetration leaching. Copper is leached efficiently from motor scrap as well as copper wire. Copper can be recovered from motor scrap in the closed circuit process which consists of the Cu (II) ammine leaching, solvent extraction with Lix 84, and electrowinning of copper from the stripping solution.

Selective recovery of copper from copper-nickel sulfide concentrates by applying segregation technology

Copper can be selectively segregated from roasted copper-nickel sulfide concentrates. Conditions are reported for desulfurizing-roasting followed by segregation treatment to selectively reduce and segregate copper without nickel contamination. A process is described which is applicable for treating low grade sulfide concentrates such as are produced in Botswana (4.6 pct Cu, 3.1 pct Ni) and higher grade concentrates that can potentially be produced from sulfide deposits in Minnesota (13 pct Cu, 2.5 pct Ni). Steps include roasting to remove at least 97 pct of the sulfur, segregation treatment of calcine and flotation to recover a copper product, a middlings fraction which is recycled to the desulfurizing roast and a tailings fraction which can be subsequently treated for nickel recovery.

Selective copper recovery with two types of liquid membranes

AbstractCopper can be selectively separated and concentrated by diffusion across liquid membranes. These membranes are effective either as thin films supported by porous polymer sheets or as liquid microcapsules or liquid surfactant membranes.