Precipitation Of Cu Research Articles

Stenotrophomonas pavanii MY01 induces phosphate precipitation of Cu(II) and Zn(II) by degrading glyphosate: performance, pathway and possible genes involved

Microbial bioremediation is an advanced technique for removing herbicides and heavy metals from agricultural soil. In this study, the strain Stenotrophomonas pavanii MY01 was used for its ability to degrade glyphosate, a phosphorus-containing organic compound, producing PO43− as a byproduct. PO43− is known to form stable precipitates with heavy metals, indicating that strain MY01 could potentially remove heavy metals by degrading glyphosate. Therefore, the present experiment induced phosphate precipitation from Cu(II) (Hereinafter referred to as Cu2+) and Zn(II) (Hereinafter referred to as Zn2+) by degrading glyphosate with strain MY01. Meanwhile, the whole genome of strain MY01 was mined for its glyphosate degradation mechanism and its heavy metal removal mechanism. The results of the study showed that the strain degraded glyphosate best at 34°C, pH = 7.7, and an inoculum of 0.7%, reaching 72.98% within 3d. The highest removal of Cu2+ and Zn2+ in the test was 75.95 and 68.54%, respectively. A comparison of strain MY01’s genome with glyphosate degradation genes showed that protein sequences GE000474 and GE002603 had strong similarity to glyphosate oxidoreductase and C-P lyase. This suggests that these sequences may be key to the strain’s ability to degrade glyphosate. The GE001435 sequence appears to be related to the phosphate pathway, which could enable phosphate excretion into the environment, where it forms stable coordination complexes with heavy metals.

Precipitation kinetics of Cu in FeCu and FeCuX (X=B, N, and BN) alloys using kinetic Monte Carlo simulations

We employed kinetic Monte Carlo simulations to investigate the precipitation of Cu in FeCu and FeCuX (X=B, N, and BN) alloys. The parameters of kinetic Monte Carlo simulations were obtained through first-principles calculations. In this study, we utilized a vacancy-mediated model that considers the migration barriers dependent on local impurity atomic environments. The dynamical stability of both FeCu and FeCuX (X=B, N, and BN) alloys was examined by the virtual crystal approximation method. Through the assessment of advancement factor, cluster number density, and mean cluster radius, the simulation results indicated that both B and N promote precipitation of Cu. While B doping has a minor effect, N doping significantly promotes Cu precipitation.

Efficient recovery of copper resources from copper smelting waste acid based on Cu(Ⅱ)/As(Ⅲ) competitive sulfuration mechanism

Currently, domestic and foreign copper smelting waste acid mainly employ sulfuration method to realize the separation of Cu(Ⅱ) and As(Ⅲ), facing the problem of unreasonable sulfidizing agent dosage and sulfidation time. If excessive sulfidizing agent dosage or overly long sulfidation time, it will lead to human health threat and large hazardous waste volume. If insufficient sulfidizing agent dosage or overly short sulfidation time, it will cause the waste of copper resources and substandard treatment solution.In this paper, the competitive sulfuration mechanism of Cu(Ⅱ)/As(Ⅲ) solution (C(As(Ⅲ)) = 10 g/L) with different Cu(Ⅱ) concentrations is revealed, i.e., when C(Cu(Ⅱ))≥7 g/L, the sulfidation sequence of Cu(Ⅱ) and As(Ⅲ) follows the solubility product constant (Ksp); when C(Cu(Ⅱ))≤6 g/L, the precipitation process of Cu(Ⅱ)/As(Ⅲ) is dominated by the liquid-phase mass-transfer mechanism (ion diffusion). The sulfide precipitation of Cu(Ⅱ)/As(Ⅲ) is a co-deposition process. With the increase of sulfidizing agent dosage (S/Cu ratio) and sulfidation time (t), the Cu(Ⅱ) concentration gradually decreases to reach complete removal, while the further increase of S/Cu ratio and t leads to the decrease of copper content in the sulfide precipitates. Finally, the methods are demonstrated that detected accurately Cu(Ⅱ) and As(Ⅲ) concentrations in a rapid and non-destructive manner. This work not only provides a novel perspective on the efficient separation of Cu(Ⅱ)/As(Ⅲ) in copper smelting waste acid, but also opens a unique approach for direct and rapid detection of Cu(Ⅱ)/As(Ⅲ) concentration during the sulfuration process. Hence, this research is a guide for the regulating means (S/Cu and t) in the actual multi-step sulfuration process of copper smelting waste acid treatment and electrorefining solution purification.

Characteristics of Ore-Forming Fluids and Genesis of the First Mining Area and Eastern Ore Section of the Pulang Porphyry Copper Deposit, Southeastern China: A Comparative Study

The Pulang copper deposit, formed in the Late Triassic, is the largest porphyry Cu-Mo-Au deposit in the eastern Tethys, and its genetic type and mineralization potential have received widespread attention. Identifying the characteristics of ore-forming fluids and the sources of ore-forming materials in the deep and peripheral ore bodies of Pulang is particularly important for constructing a complete porphyry copper mineralization system. Based on detailed core logging and geological observations, this article provides extensive petrographic, fluid inclusion micro-thermometry, laser Raman spectroscopy, and H-O-S isotope data on the veins of the main mineralization stage (B veins) in the first mining area and eastern ore section of the Pulang porphyry copper deposit. The genetic correlation between the eastern ore section and the first mining area is clarified, and their mineralization potential is inferred. The results indicate that the deep vein bodies in the first mining area exhibit multi-stage characteristics, and the fluid in B veins exhibits both high-temperature and salinity characteristics. The magma-derived early ore-forming fluids underwent processes such as boiling and experienced immiscibility during meteoric water mixing, which could be the primary mechanism of the precipitation of Cu, Mo, Au, and other metals. The outer eastern ore section is located in a medium-to-low-temperature hydrothermal mineralization zone far from the mineralization center. This outer eastern ore section is a distant part of the magmatic–hydrothermal system of the first mining area.

Evaluation of Type III Adhesive Mortar (ACIII) and Gypsum as Precipitating Agents of Copper and Lead

Heavy metals exhibit characteristics such as nonbiodegradable nature, toxic character, bioaccumulation capability, and ability to transit over long distances. The widespread application of these metal ions in various industrial sectors has led to an increase in their release into the environment. Chemical precipitation has been one of the technologies used to remove heavy metals from wastewater, involving a process in which chemical agents are added to wastewater with dissolved toxic metal ions, which react with the metals, forming insoluble precipitates. Therefore, the present study aimed to assess the potential of gypsum and adhesive mortar type III (ACIII) as precipitating agents for lead (Pb) and copper (Cu) ions, as well as to evaluate the toxicity of precipitation products on Drosophila melanogaster. Experiments using ACIII mortar waste as a precipitating agent for Cu ions were obtained using a glass filter composed of 04 chambers and 04 antechambers, while the potential of gypsum as a Pb ion precipitant was evaluated by adding gypsum powder to a beaker containing a Pb ions solution. The toxicity of the precipitation products was evaluated by observing the mortality and negative geotaxis parameters on D. melanogaster. In the tests using ACIII mortar as a precipitating agent for Cu, retention percentages progressively varied, obtaining 98.82% at a concentration of 30 mg/L. Meanwhile, gypsum obtained retention percentages that varied from 32.83 to 98.61% for Pb. It was found that the precipitates of Cu and Pb resulted in alterations in the survival and locomotion rates of D. melanogaster only at the highest evaluated concentrations. In conclusion, the results obtained indicated that geomaterials such as ACIII mortar and gypsum have potential for the removal of Cu and Pb from aqueous solutions. Moreover, the precipitation stages by these materials also impact in decreasing the toxicity of metal ions to the evaluated model organism.

Investigation of deformation comprised microstructure and precipitation of Cu–Sn–Ti alloy during hot deformation

The hot deformation behavior of Cu–Sn–Ti–(Cr) alloys was studied using Gleeble-1500D thermo-mechanical simulator ranging from 550 to 950 °C, and the strain rate was 0.001–10 s−1. The microstructure evolution of the alloy was analyzed using characterization methods such as electron backscatter diffraction (EBSD), scanning electron microscope (SEM) and transmission electron microscope (TEM). Cu–Sn–Ti–(Cr) alloys were calculated by establishing the constitutive equation of the alloy. The activation energies of Cu–Sn–Ti and Cu–Sn–Ti–Cr alloys are 275.884 and 283.550 kJ/mol, respectively. The results indicate that the addition of Cr element has an inhibitory effect on the nucleation and improve refinement of dynamic recrystallization (DRX) in Cu–Sn–Ti alloy. The texture of Cu–Sn–Ti alloy is Cu texture at 750 °C and the texture contained in Cu–Sn–Ti alloy is Goss texture, Cubic texture and Cu texture when the temperature is raised to 950 °C. The texture of Cu–Sn–Ti–Cr alloy at 750 °C is Goss texture. The Goss texture transforms into Cubic texture and Cu texture when the temperature is raised to 950 °C. The precipitates present in Cu–Sn–Ti alloy include CuSn3Ti5 phase and Cu4Ti phase. The addition of Cr element adds a new phase of Cr to the alloy and also makes the distribution of precipitates more uniform and increases in quantity.

Effect of misorientation of grain boundaries on the discontinuous precipitates of Cu–Ni–Si alloy

In this study, the effects of differences in grain size, grain boundary type and misorientation on the initiation of discontinuous precipitates are investigated for the Cu–5Ni–1.25Si alloy. Samples with different grain sizes are obtained by thermomechanical treatment, and the smaller the grain size, the higher the percentage of discontinuous precipitate at the same aging time, while there is no significant difference in the growth rate of the reaction front of discontinuous precipitates. EBSD is used to study the effect of grain boundary misorientation on discontinuous precipitates, the characteristics of discontinuous precipitates initiation on different grain boundaries are investigated by multivariate statistical analysis. It is found that discontinuous precipitates only initiate from random grain boundaries instead of coincident site lattice boundaries, where random grain boundaries with misorientation angles of 30–50° are more prone to discontinuous precipitates. And the initiation of DPs at different misorientation axes is different. There is a clear borderline for the axes such as <102>, <103>, and <203>. The grain boundaries below this borderline do not initiate DP, while all grain boundaries below this angle initiate DPs. The cases for axes such as <112>, <114>, and <214> are more complicated. On these misorientation axes, grain boundaries with lower or higher misorientation angles do not initiate DPs, while grain boundaries at intermediate range misorientation angles do initiate DPs.

Alloying element distributions of precipitates in Cu–Cr alloys aided by machine learning

The presence of the fcc Cr-rich precipitates is a significant factor for the excellent performance of Cu–Cr alloys. In this work, we proposed an efficient approach based on machine learning to study on the alloying element distributions of the fcc Cr-rich precipitates in Cu–Cr alloys. The random forest algorithm with lower mean absolute error was selected for the classification of alloying elements. The alloying elements Mg, Si, Sc, Ti, Co, Ni, Y, Nb, Ag, In and Sn were classified into two groups. Sc and Ni were located mainly on the periphery of the fcc Cr-rich precipitates, while others were distributed randomly in the fcc Cr-rich precipitates, which was basically consistent with the ab initio results. The distribution of V was also determined experimentally and predicted via machine learning, and excellent agreement was found among experiment, machine learning and ab initio calculation. This work can provide an effective way to investigate the distribution tendency of alloying elements for various kinds of precipitates.

Interphase precipitation of Cu in dual-phase steel

Two experimental 0.2C steels with 1 wt% and without Cu were studied. A dual ferritic-martensitic microstructure was prepared by controlled rolling and subsequent quenching. The heterogenous microstructure was obtained due to the severe cooling of the surface layer during the rolling process. The surface layer of the sheet had a significantly finer ferritic grain than the sheet’s core. Mechanical properties of the core were not correlated to the Cu content, whereas the surface layer revealed Cu-related strengthening due to Cu precipitation. Rows of particles typical for interphase precipitation were observed in some of the ferrite grains of the Cu-containing sample. Mode of the ferrite growth from austenite has apparently a crucial role in Cu ability to rapidly precipitate in ferrite grain during or shortly after its formation.

Porphyry copper mineralization triggered by sulfate reduction and alkali metasomatism: Constraints from an experimental investigation

The potassium silicate (K-silicate) alteration zone is the main ore contributor in porphyry copper deposits worldwide. Knowledge of element behaviors in the alteration and mineralization processes is essential for an improved understanding of porphyry copper mineralization, but they are still not well understood. In this study, we reacted synthetic Cl-rich fluids, containing K, Na, Cu, Mo, Zn, etc., with andesite in a complex experimental system to simulate the shallow porphyry copper mineralization process. We aimed to bridge the gap between simple experimental studies and complex natural systems and to evaluate the contribution of sulfate reduction to porphyry ore formation and its relationship with early alkali metasomatism. The results show that increasing temperature (from 300 to 500 °C) enhances the K-silicate alteration by promoting ion-exchange reactions, and the K-feldspar is mainly formed by the transformation of plagioclase via a dissolution-reprecipitation processes. The low-salinity vapor phase has a stronger capacity for K-silicate alteration than the liquid phase at similar temperatures. In addition, increasing temperature from 300 to 500 °C favors sulfate reduction to further enhance metal sulfide precipitation. The limited availability of reduced sulfur in the fluid causes preferential precipitation of Cu-(Mo) sulfides, while most of the Zn is soluble in the fluid, and Cu precipitation as sulfides in the vapor is much more efficient than in the coexisting liquid. The overlap between the K-silicate alteration zone and the mineralization triggered by sulfate reduction in porphyry copper deposits is controlled by several concomitant factors, e.g., relatively high temperature (e.g., at 400−500 °C), vapor formation, and decompression. Moreover, K-silicate alteration would further promote mineralization by changing fluid compositions, e.g., removing K from the fluid.

Anoxic iron electrocoagulation automatically modulates dissolved oxygen and pH for fast reductive decomplexation and precipitation of Cu(II)-EDTA: The critical role of dissolved Fe(II).

Fe-based replacement and precipitation are promising methods for removal of copper ethylenediaminetetraacetic acid (Cu(II)-EDTA) but are limited by the necessity of controlling pH and dissolved oxygen. The details of the decomplexation mechanism also remain unclear. The present work investigated an anoxic iron electrocoagulation process capable of automatically modulating anoxic conditions and solution pH during exposure to air and thus promoting the rapid and thorough decomplexation of Cu(II)-EDTA. Dissolved Fe (II), rather than Fe(II)-bearing minerals, was found to be primarily responsible for the reduction of Cu(II)-EDTA to Cu(I)-EDTA and for the subsequent replacement reaction to generate free Cu(I) ions within the initial pH range of 2-7. The Cu(I) was primarily precipitated as Cu2O on the surface of green rust and magnetite as the pH was increased. The aeration of these Fe-containing precipitates released free Cu(I) ions instead of chelated Cu into solution, allowing for recycling of the Cu. This release of Cu(I) was likely induced by the pH decrease during aeration. This study provides important insights regarding the reductive decomplexation of chelated Cu(II) and the recovery of Cu via anoxic iron electrocoagulation, which is a promising green approach to recycling Cu from wastewater.

Effect of Cu content on microstructure and properties of CoCrFeNiCux high-entropy alloy coatings prepared by induction cladding

CoCrFeNiCux (x = 0, 0.5, 1.0, 1.5) high entropy alloy coating (HEAc) on Q235 steel was successfully prepared by induction cladding technology. Before induction cladding, the final structure of the alloy powders after 30 h ball milling were single-phase face-centered cubic (FCC) structure. After induction cladding, the metastable Cu-containing alloy powders were transformed into a stable dual-phase, that was, Cu-depleted FCC1 and Cu-rich FCC2. It was worth noting that HEAc exhibited a hardness gradient from top to bottom due to the unique principle of induction cladding. With the increase of Cu content, the grain size of HEAc was refined, but the overall hardness and wear resistance of HEAc decreased due to the precipitation of Cu. Grain refinement also provided more channels for oxygen invasion, and the oxidation resistance decreased. The convergence of Cu element at grain boundaries led to local galvanic corrosion, which greatly reduced the corrosion resistance. Therefore, the precipitation of Cu and grain refinement had great influence on the wear resistance, high temperature oxidation resistance and corrosion resistance of HEAc.

Effect of annealing temperature on dual-structure coexisting precipitates in Cu–2.18Fe–0.03P alloy and softening mechanism at high temperature

Effect of annealing temperature on dual-structure coexisting precipitates in Cu–2.18Fe–0.03P alloy and softening mechanism at high temperature

Facile synthesis of copper carbonate/cobalt carbonate/manganese carbonate and copper oxide/cobalt manganese oxide/manganese oxide as novel nanocomposites for efficient photocatalytic degradation of crystal violet dye

ABSTRACT In this work, copper carbonate/cobalt carbonate/manganese carbonate and copper oxide/cobalt manganese oxide/manganese oxide new nanocomposites were fabricated via precipitation of Cu(II)/Co(II)/Mn(II) solution using sodium carbonate and ignition of precipitate at 600°C for 3 h, respectively. Several instruments, including UV–Vis spectrophotometer, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), nitrogen gas sorption analyser, and field emission scanning electron microscope (FE-SEM), were used to characterise the fabricated nanocomposites. Energy dispersive X-ray investigation confirmed that the composite produced owing to precipitation by sodium carbonate comprises carbon, oxygen, manganese, cobalt, and copper where the weight percentages are equal to 27.15, 52.49, 5.59, 5.75, and 9.02%, respectively. In addition, the composite produced owing to ignition at 600°C for 3 h comprises oxygen, manganese, cobalt, and copper where the weight percentages are equal to 8.62, 31.50, 38.58, and 21.30%, respectively. Transmission electron microscope examination confirmed that the composites produced owing to precipitation by sodium carbonate and ignition at 600°C for 3 h comprise polyhedral and spherical shapes with an average diameter of 36.85 and 22.34 nm, respectively. The BET surface area, average pore size, and total pore volume of the composite produced owing to precipitation by sodium carbonate are 29.8662 m2/g, 2.1634 nm, and 0.0323 cc/g, respectively. In addition, the BET surface area, average pore size, and total pore volume of the composite produced owing to ignition at 600°C for 3 h are 33.3714 m2/g, 5.2308 nm, and 0.0873 cc/g, respectively. 0.06 g of the fabricated nanocomposites degrade 100% of 60 mL of 15 mg/L of crystal violet dye solution within 20 min in the presence of hydrogen peroxide under UV irradiation.

A comprehensive research on internal short circuits caused by copper particle contaminants on cathode in lithium-ion batteries

Manufacturing defects are one of the main causes of internal short circuits (ISCs) and then lead to thermal runaway accidents of batteries, which seriously threatens the safety of electric vehicles. Cu particle contaminants are one of the most common and dangerous manufacturing defects. Cu particles that may cause ISC by dissolving on the cathode and precipitating on the anode are smaller in size and less likely to be detected during manufacturing, compared with those that cause ISC by directly piercing the separator. However, there is little research on the mechanism and evaluation of ISC caused by cathode Cu particle contaminants. In this paper, Cu particles were intentionally placed on the cathode of lithium-ion batteries (LIBs). The mechanism and type of ISC induced by the Cu dissolution-precipitation process in LIBs were successfully characterized for the first time, and the evolution process was concluded. The ISC introduced by Cu particles was successfully simulated by a pseudo three-dimensional model. And the size boundary of Cu particles causing ISC was also studied. It was found that the implanted Cu particles will necessarily cause ISC in the batteries. The key to the ISC caused by cathode Cu particles is the precipitation of Cu along the pores of the separator from the anode side to the cathode side. The type of ISC caused by this defect is a cathode-anode short circuit, which only induces a soft ISC. The maximum temperature of the battery with this defect can only increase by approximately 2 °C through the calculation of the model under the set conditions of this study, which would not cause thermal runaway of the battery. In addition, even when the size is as small as 20 μm, the cathode Cu particle contaminants will still cause an ISC with short-circuit resistance of tens of kΩ magnitude.

Systematic study of critical parameters on magnesium saturated thiosulfate gold leaching process; part A: Effect of ammonia and lime for pH adjustments and concentration of magnesium and copper(II)

Thiosulfate gold leaching is an alternative gold leaching method, especially for leaching of preg-robbing gold ores. Here we report a thiosulfate process that has been developed for gold leaching, with emphasis on lowering thiosulfate consumption in the process. Ammonium thiosulfate has been used as the primary lixiviant along with magnesium hydroxide to saturate the solution with magnesium in the presence of copper(II) as an oxidizing agent. The resulting magnesium thiosulfate solution (Mg-TS) can potentially leach gold from the ore at considerably high efficiency. The potential for substantial decrease in the thiosulfate consumption, while achieving high gold recovery, gives the Mg-TS process a cutting-edge advantage over other processes. The study demonstrates the effect of pH, magnesium, and initial Cu(II) concentration on gold leaching kinetics in the Mg-TS process. As a comparison, pH of the tests was controlled with Ca(OH)2 and NH4OH; it was concluded that high pH, if controlled by NH4OH, is beneficial for gold leaching due to increase in ligand (NH3) availability and favorable pH range. Increasing pH using Ca(OH)2 was only effective up to a pH threshold of 9.8, after which the efficiency of the process decreases due to the precipitation of Cu(II) catalyst/oxidant. Increasing copper(II) concentration to 8 mM leached 87.8% of gold which was very close to the gold recovery with cyanidation (87.3%). The Mg-TS process identified is an operationally green and sustainable, efficient and low-cost thiosulfate process, which is feasible for in-situ/heap leaching of low-grade gold ores and is believed to present a competitive advantage over cyanidation process.

Selected Properties of a Zr-Containing AlSi5Cu2Mg Alloy Intended for Cylinder Head Castings.

The aim of this paper was to analyze the impact of the addition of different amounts of zirconium (0.05; 0.10; 0.15 and 0.20 wt. % Zr in the form of the AlZr20 master alloy) on selected properties of AlSi5Cu2Mg aluminum alloy. This is a new alloy for cylinder head castings and has only been used for a relatively short time. The specificity of this alloy is its chemical composition—specifically the low permitted Ti content, which makes it impossible to refine the grain structure of this alloy using standard Al-Ti-B grain refiners. The aim of our ongoing research is to find a suitable alloying element that would positively mainly affect the mechanical and also physical properties of this alloy, which are crucial for complex automotive castings such as cylinder heads. The results of our research showed that increasing zirconium content had no effect on the increase in ultimate tensile strength, yield strength and hardness of as-cast samples. After T7 heat treatment, a more significant increase in UTS, YS and thermal conductivity occurred due to the precipitation of Cu- and Mg-rich strengthening precipitates. Zirconium-rich intermetallic phases were observed in the shape of separate thick needles or as a cluster of two crossed thinner needles. SEM observations showed that these phases crystallized near to the intermetallic phases based on Cu and Fe. Increasing the Zr content was accompanied by an increase in liquidus temperature, the density index and the area fraction of porosity values.

Effect of chromium content on precipitation in Cu–Cr–Zr alloys

Effect of chromium content on precipitation in Cu–Cr–Zr alloys

Excellent strength and electrical conductivity achieved by optimizing the dual-phase structure in Cu–Fe wires

Cu–Fe alloy wire with high strength, moderate electrical conductivity and low cost, has a promising application prospect in the electrical industry. In this study, high performance Cu80Fe20 wires were prepared by annealing and drawing at room temperature (RT). Based on the X-ray diffraction and electron microscopy characterization, the influence of microstructural parameters on the mechanical properties and electrical conductivity of the wires were analyzed. The pre-annealing at 500 °C, resulted in the nanoparticles precipitation of Cu in Fe-phase and Fe in Cu-phase, respectively. The drawing deformation greatly improved the strength of wires, while did not result in a significant reduction in the electrical conductivity. Cu nanoprecipitation promoted the refinement of the Fe-phase during deformation, which result in a nano lamellar structure of the Fe-phase with an average boundary spacing as low as 50 nm. Dynamic recovery and recrystallization of the Cu-phase were observed to occur during the drawing at RT with the <112> texture and annealing twinning. The plasticity and electrical conductivity of the Cu-phase were greatly preserved due to the drawing-induced dynamic recovery and recrystallization. Moreover, the strength of the wire was greatly enhanced by the formation of a nano-lamellar structure in the Fe-phase. Hence, the alloy wire at a strain of 3.94 had a high tensile strength of 863 MPa (125% higher than the original strain-free wire), a total elongation of 5%, and the electrical conductivity reached 47 %IACS (only 8 %IACS lower than the original strain-free wire), which shows higher cost properties than other copper alloys.

Metallic Copper (Cu[0]) Obtained from Cu2+-Rich Acidic Mine Waters by Two Different Reduction Methods: Crystallographic and Geochemical Aspects

The recovery of valuable metals from different types of wastes has become of prime strategic interest given the scarcity of primary critical raw materials at international scale. Implementation of new methods or refinement of classical techniques with modern technological advances is, therefore, an active research field. Mine wastes are of special interest because their high metal concentrations make them environmentally harmful and economically profitable at the same time. In this study, we evaluated two different methods of Cu recovery from extremely acidic mine waters seeping from wastes and abandoned mines in SW Spain. Through a series of different batch experiments, we compared the method efficiency and crystallographic properties of elemental copper (Cu[0]) obtained by reduction of Cu2+ ions by (1) chemical reduction using ascorbic acid at different environmental conditions of pH (1.50–3.95), temperature (25–80 °C) and ascorbic acid concentration (10 mM to 0.1 M), and (2) classical cementation method with scrap iron at pH 1.50 and 25 °C. Our study demonstrates that the precipitation of Cu[0] can take place at pH 3.95 and low AA concentrations (0.1 M), resulting in large (µm-scale), perfectly developed crystals of copper with pseudoprismatic to acicular habit after 24 h of aging, likely through formation of a transient compound consisting in Cu2+-ascorbate and/or cuprite (Cu2O) nanocolloids. Reduction experiments at higher AA concentrations (0.1 M) showed faster precipitation kinetics and resulted in high-purity (&gt;98%) copper suspensions formed by subrounded nanoparticles. The AA method, however, yielded very low recovery rates (15–25%) because of the low pH values considered. The cementation method, which produced tree-like aggregates formed by sub-micron crystals arranged in different directions, proved to be much more efficient (&gt;98% recovery) and cost-effective.