Metals Of Cu Research Articles

Heavy metals decreased by water elution method on bottom ash from municipal solid waste incineration plant

By incineration treatment became the most important g municipal solid waste disposal method. The bottom ash, which accounting for 20% to 30% of the original municipal solid waste has been a large content source of municipal solid waste in China. The heavy metal will be released to the environment by the eluent produced from the bottom ash. It has a negative influence on bottom ash treatment and reuse. This study analyzed the changing of heavy metals of Cu, Ni and Zn during the elution process by the column simulation experiment. The study revealed the regulation of heavy metals migration under the condition of slow speed elution. These results can help environmental release risk assessment of heavy metal in bottom ash from municipal solid waste incineration plant.

Anodization of Tantalum Films for the Enhancement of Monolayer Seeding and Electroless Copper Plating

Ta is a common barrier component for Cu metallization because of their immiscibility resulting in lack of mutual chemical reactivity and solubility. Conventionally, Cu is pre-sputtered on Ta as a seed layer, followed by Cu electroplating. Electroless metallization of Cu on Ta through self-assembled monolayer (SAM) seeding is rarely studied. Herein, electrochemical anodization of Ta films in an ethanol-based solution is performed to achieve a functionalized surface for sequential silanization of (3-aminopropyl)trimethoxysilane (APTMS), seeding, and electroless Cu plating. The SAM grown on hydrously (1% H2O) anodized Ta films is fully oriented, acting as an effective seed anchoring agent and adhesion promoter to yield high densities of Ni seeds (>5 × 1015 m−2) and tight binding of a Cu film (25.6 MPa). However, the SAM grown on anhydrously anodized Ta films has a substantially deteriorated ordering, giving poor seeding (<8 × 1014 m−2) and Cu-film adhesion (8.8 MPa). Similar deteriorations are observable from the pristine Ta film. The enhancements of SAM silanization and Ni seeding are caused by the improvement of chemical structure of anodization-induced surface tantalum oxide. The role of water in the anodization solution in enhancing anodization efficiency and SAM orientation is fully discussed.

Toxicity of heavy metals in the water quality of Ganga River in Kanpur, Uttar Pradesh, India

A study to find the toxicity of heavy metals in the water quality of Ggana river in Kanpur, Uttar Pradesh, India area was carried out over a period of Jan. 2018 to Dec. 2018. Water samples from Kanpur (Shuklaganj New Ganges Bridge, Ordnagar, Baba Ghat, Bhairav ​​Ghat and Khayora Kati) were analyzed for heavy metals like Cu, Cr, Fe, Mn, Zn, Cd and Pb. The pH of these water samples was found in alkaline range (7.21-8.18). The concentration of PB varies between 0.44±0.32 ppm and 0.33±0.31 ppm. Cd concentration was seen to range from 0.022±0.11ppm to 0.008±0.06 ppm. The content of Cr is from 0.054±0.56 to ppm 0.38±0.33ppm. Highest concentrations of heavy metals of Cu (0.173±0.283ppm) and PB (0.44±0.32ppm) were found in Ordnance town sample, Cr (0.054±0.56) in Khyora katari water sample, Cd (0.022±0.11ppm) in Baba ghat water sample, Fe (0.366±0.98ppm) in Khyora katari water sample.

Understanding the interdependence of strain of electrotroph, cathode potential and initial Cu(II) concentration for simultaneous Cu(II) removal and acetate production in microbial electrosynthesis systems.

Metallurgical microbial electrosynthesis systems (MES) are holding great promise for simultaneous heavy metal removal and acetate production from heavy metal-contaminated and organics-barren waters. How critical parameters of strain of electrotroph, cathode potential and initial heavy metal concentration affect MES performance, however, is not yet fully understood. Heavy metal of Cu(II) and four Cu(II)-tolerant electrotrophs (Stenotrophomonas maltophilia JY1, Citrobacter sp. JY3, Pseudomonas aeruginosa JY5 and Stenotrophomonas sp. JY6) were employed to evaluate MES performance at various cathode potentials (-900 or-600 mV vs. standard hydrogen electrode) and initial Cu(II) concentrations (60-120 mg L-1). Each electrotrophs exhibited incremental Cu(II) removals with increased Cu(II) at-900 mV, higher than at-600 mV or in the abiotic controls. Acetate production by JY1 and JY6 decreased with the increase in initial Cu(II), compared to an initial increase and a decrease thereafter for JY3 and JY5. For each electrotrophs, the biofilms than the planktonic cells released more amounts of extracellular polymeric substances (EPS) with a compositional diversity and stronger Cu(II) complexation at-900 mV. These were higher than at-600 mV, or in the controls either under open circuit conditions or in the absence of Cu(II). This work demonstrates the interdependence of strain of electrotroph, cathode potential and initial Cu(II) on simultaneous Cu(II) removal and acetate production through the release of different amounts of EPS with diverse composites, contributing to enhancing the controlled MES for efficient recovery of value-added products from Cu(II)-contaminated and organics-barren waters.

SPESIASI DAN BIOAVAILABILITAS LOGAM BERAT Cu DAN Zn DALAM TANAH PERTANIAN ORGANIK DAN ANORGANIK

Agriculture in Indonesia generaly applies agrochemical to improve the quality and quantity of the products, but the impact is, both lands and their products could be contaminated by pollutans especially heavy metals. This study aimed to determine the total metals, speciation, and bioavailability of Cu and Zn in organic and inorganic agricultural soils in Blahbatuh District, Gianyar Regency. The sequential extraction method was performed to release the bonds of heavy metals in each soil component and the determination of the metal concentration was carried out using AAS. The total metals of Cu and Zn in both organic and inorganic soils indicated that both type of soils were still classified as uncontaminated soils because the metal contents were below the maximum limit allowed. The total contents of Cu and Zn in the organic soil were of 45.3922 mg/kg and 47.7645 mg/kg, respectively, while Cu and Zn in the inorganic soil were 48.9121 mg/kg ??and 49.9474 mg/kg, respectively. Fractination in the organic and inorganic soil EFLE (easly, freely,leachable, and exchangeable), reducible, oxidisable, dan resistant including F4&gt; F3&gt; F2&gt; F1 for Cu and F4&gt; F3&gt; F1&gt; F2 for Zn. The bioavailability of Cu and Zn in the organic soils were 10.52-23.79% and 3.79-7.21% bioavailable, 10.03-25.50% and 14.99-32.68% potentially bioavailable, 38.64-63.19% and 41.20- 60.28% non bioavailable, while in the inorganic soil and were 18.31-32.63% and 4.54-7.85% bioavailable, 9.86-13.85% and 15.26-32.55% potentially bioavailable, and 40.20-59.14% and 42.84-58.26% non bioavailable. Consuquenthy, both types of the agricultural soils would be safe for planting various types of rice. &#x0D; Keywords: bioavailability, Cu and Zn, speciation, agricultural soil

Plasma-arc brazing of steel 08kp (rimmed) by using brazing filler metals OF Cu–Mn–Ni–Si system

Plasma-arc brazing of steel 08kp (rimmed) by using brazing filler metals OF Cu–Mn–Ni–Si system

A New Highly Efficient Algerian Clay for the Removal of Heavy Metals of Cu(II) and Pb(II) from Aqueous Solutions: Characterization, Fractal, Kinetics, and Isotherm Analysis

A physicochemical characterization, the irregularity of the surface quantified by the fractal dimension (DS), and the adsorption of copper (Cu(II)) and lead (Pb(II)) of a kaolin clay from aqueous solutions were studied. In addition, the effects of temperature, contact time, pH of solution, and clay mass on copper Cu(II) and Pb(II) adsorption were investigated. In this work, X-ray fluorescence, X-ray diffraction, and Fourier transform infrared spectroscopy were applied to study the composition and structure of the clay studied. The Brunauer–Emmett–Teller theory and the t-plot method were used to calculate the specific surface and porosity, respectively. The fractal analysis showed that the material has an irregular surface, with a very complex pore structure. This material has a very high adsorption capacity, which exceeds 97.5% and 99.95% for Cu(II) an Pb(II), respectively, for all concentrations under normal conditions of pH and temperature (pH7, T = 25 °C). The maximum adsorption capacity calculated by the Langmuir model was 52.63 mg g−1 for copper (Cu). For lead (Pb) ions, the maximum capacity was 57.30 mg g−1. The adsorption process was rapid, as equilibrium was achieved within 10 min for copper at 25 and 50 mg L−1 and within 30 min at 100 mg L−1. For lead (Pb) ions, equilibrium was achieved within the first minute at all concentrations. The kaolin clay has a better affinity for Pb(II) than Cu(II). The Temkin model showed better correlation with the experimental data for this material. The kinetic study demonstrated that Pb(II) and Cu(II) adsorption on kaolin was in a good accordance with the pseudo-second-order kinetic model.

A Study of Heavy and Essential Metals in the Amniotic Fluid for Pregnants Associated with High Blood Pressure

The research includes studying of some heavy metals and metal elements in amniotic fluid for pregnant associated with high blood pressure, which includes these metals: Lead (Pb), Cadmium(Cd), Chromium(Cr), Aluminum(Al), and essential metals for Magnesium(Mg), Calcium(Ca), Zinc(Zn), Iron(Fe), Copper(Cu) and Manganese(Mn). The study was done in Mosul city on (75) samples that had hypertension, and (78) with healthy pregnancies as control group, the age of pregnant women with hypertension and control group ranged from (16-45) year, then specimens divided into three age groups: The first group (16-25) year, the second group (26-35) year and the third group (36-45) year. The results showed that there was a significant increase in heavy metals in pregnant women associated with high blood pressure in the levels of Pb, Cd, Cr and Al compared with the group of normal pregnant women, as well as a significant increase in the levels of essential metals of Cu and Fe and a significant decrease in levels: Mg, Ca, Zn and Mn. Moreover, it was noted that there is a significant increase in the levels of heavy metals for Pb, Cd and Cr in pregnant women smokers with the pressure associated with pregnant women compared to non-smokers group and a significant decrease in essential metals for both Zn and Mn levels. .

Study of Distribution Metal From Shellfish at Coastal Beach in District of Central Tapanuli, Indonesia

The research of heavy metals spread in shellfish in the coastal area a zone of the high seas and zones of settlements waters in Central Tapanuli has done with the aim of knowing the content of heavy metals of Cu, Cr, Pb with parameters of the river water, sea water, shellfish and clamshell, basic sediments. Testing of river water, sea water, and shell meat was conducted using Atomic Absorption Spectrometer (AAS) by adsorption principle of light by atoms. Testing basic sediment and clamshell has done with XRD and TEM. The test results of river water showed are Cu ˂0,025 mg/l, Cr ˂0.006 mg/l - ˂0.025 mg/l, Pb ˂0.005 to 0.03 mg/l, in the conditions of under the river water quality standard. The test results on the sea water obtained are metal content of Cu. ˂0.006 mg/l, Cr ˂0,025 mg/l, Pb 0.13 to 0.24 mg/l. The test results show the shell meat are Pb. ˂0.005 to 2.34 mg/kg, Cu 0.85 to 14.4 mg/kg. The test results of clamshell with XRD showed peaks of CaCO3 aragonite. With TEM showed that crystalline, by electron diffraction pattern formed by irregular dot, which means the elements contained in the various clamshells. Differences levels of heavy metals at every point stations predicted has their natural factors such as the direction of ocean currents, rainfall and sediment material and anthropogenic factors such as demographics residential waste pollution, industrial and port activity.

Magneto-Optical Kerr Effect Driven by Spin Accumulation on Cu, Au, and Pt

The magneto-optical Kerr effect (MOKE) has recently been achieved on non-ferromagnetic metals by injecting spin currents. To use the magneto-optical Kerr effect as a quantitative tool, it is crucial to study the relationship between the Kerr rotation angle and the spin accumulation on non-ferromagnets. In this work, I measure a transient magneto-optical Kerr rotation on non-ferromagnetic metals of Cu, Au, and Pt driven by an ultrafast spin current from an adjacent ferromagnetic metal. Through comparing the measured Kerr rotation and the calculated spin accumulation, I determine the conversion ratio between the Kerr rotation and the spin accumulation to be: −4 × 10−9 (real part), −2.5 × 10−8 (real part), and −3 × 10−9 (imaginary part) rad m A−1 for Cu, Au, and Pt, respectively, at a wavelength of 784 nm.

Assessment of the degree of external corrosion of buried water pipelines and source identification of heavy metals due to surrounding soil conditions in humid environment

Water distribution pipelines installed underground has possible risks of pipe failure due to corrosion as it ages while urban soils have been noted to have highly elevated concentration of heavy metals due to various human activities. The study aimed to assess the degree of external corrosion of distribution pipe networks and identify probable sources of heavy metals in the surrounding aggressive soil environments. Soil samples were collected with the aid of soil auger at a depth of about 1.0 m while the analyzed soil properties and metals content were done using the standard procedures in the laboratory. The soil quality properties of interest are: soil pH, moisture content, soil temperature, soil resistivity, porosity, oxidation–reduction potential (ORP), chloride ions, sulphate ions, total carbon (TC), total nitrogen (TN), and microbial counts with heavy metals of Cu, Fe, Zn and Mn. Principal component analysis (PCA) was used to identify major soil quality indicators affecting soil corrosivity while multivariate analysis of variance (MANOVA) and cluster analysis (CA) were used to evaluate the spatial variability among the sampling locations, interrelationship between variables and source of heavy metals in soils, respectively. A total consideration of all the analyzed variables on the degree of external corrosion on buried pipelines indicates severely corrosive to mildly corrosive state. PCA identified chemical, moisture content, microbial influenced corrosion (MIC), and heavy metal as four principal factors accounting for 89.4% of total variation in soil quality properties. The results of multivariate statistical analyses identified two sources of metals as from soil parent materials and anthropogenic activities while MANOVA showed that the physio–chemical properties varied significantly different at $$\alpha =0.05$$ among the sampling locations.

The study of methanol aromatization on transition metal modified ZSM-5 catalyst

Abstract In this article, transition metals of Cu, La and Zn were used as adjuvant to prepare modified HZSM-5 by impregnation method. The catalysts were characterized by XRD, BET, NH3-TPD and Py-IR to reveal the microstructure and acid property. The catalysis performances of methanol aromatization of catalysts were investigated in a fixed-bed reactor. The results show that the strength and distribution of acid center of these catalysts are significantly influenced by the species of transition metal. There are more mediate strong Lewis acid center in Zn modified HZSM-5 catalyst and therefore exhibits higher selectivity to aromatic, benzene, toluene and xylenes in the MTA reaction..

MICRO-STRUCTURAL CHARACTERIZATION OF CEMENT STABILIZED TROPICAL lATERITE CLAY SOIL CONTAMINATED BY HEAVY METALS

The presence of contaminated soils due to industrials and mining activities is a major concern in today’s heavily industrialized world. The contaminants lead to poor engineering properties for these soils. In this study 10% cement is used to stabilize laterite clay soil contaminated by heavy metals of Cu and Zn. However, the effect of these contaminants on the geotechnical properties of clayey soils can be altered through chemical stabilization using traditional stabilizers like cement, which result in achieving suitable material for construction purposes. The micro-structural characterization of the cement-treated Laterite clay is presented in this research. The changes in the mineralogy and morphology structure due to the effect of stabilizer of cement and heavy metals were discussed based on X-ray Diffractometry (XRD), and Field Emission Scanning Electron Microscopy (FESEM). According to the micro-structural characterization of the stabilized soils, cement was effective stabilizer in terms of improving the strength of contaminated treated soils. However, the heavy metals have retarded effect on the cement treated samples. This was due to precipitation of the metals onto the surface of calcium and aluminium silicates as insoluble hydroxides or sulphates. Thus, these compounds form an impermeable coating that acts as a barrier to inhibit cement hydration by impending transport of water into cement grain. Finally, it can be concluded that the mechanical and the physico-chemical behaviours of the compacted specimens, as determined during testing, formed the basis for evaluating both the degree of immobilization of the heavy metal in the soil matrix, and the potential for rehabilitation of contaminated sites.

Application of Mineral‐Based Amendments for Enhancing Phytostabilization in Lolium perenne L. Cultivation

An experimental investigation is conducted to explore the suitability of Lolium perenne L., diatomite, chalcedonite, dolomite, and limestone for the phytostabilization of Ni and Cu in contaminated soil. A controlled greenhouse study is conducted. The soil is enriched with rising dose of Cu and Ni, that is, (0, 150, 250, and 350 mg kg−1) and (0, 150, 300, and 450 mg kg−1), respectively. The phytostabilization potential of perennial ryegrass is evaluated using a bioaccumulation coefficient and translocation factor. Pseudo‐total and available metal content (0.01 M CaCl2) in soils and bioaccumulated content in plants are defined in laboratory experiments using spectrophotometry experimental technique. L. perenne is adequate in phytostabilization aided programs, simultaneously, diatomite, chalcedonite, dolomite, and limestone used as modifiers are effective in reducing the accessibility and mobility of metals in Cu‐ and Ni‐polluted soils. The finding of the present study suggests that the studied element in the roots and above‐ground parts of L. perenne differs significantly upon applying mineral‐based modifications to the soil, synchronously the effect of increasing Cu and Ni levels. Application of dolomite and limestone to the soil cause the highest percentage of the above‐ground biomass. Diatomite along with limestone cause a significant boost of Cu and Ni absorption in the roots. Limestone causes an increase in the contents of K, Na, and Ca, as well as a reduction in P in the above‐ground parts of L. perenne. Limestone and chalcedonite leads to the highest decrease in available Cu and Ni.

Environmental friendly electroless copper metallization on FDM build ABS parts

In this paper, environment-friendly electroless metallization of copper (Cu) on acrylonitrile–butadiene–styrene (ABS) parts fabricated through fused deposition modelling route of rapid prototyping process has been proposed. The metallization process eliminates etching as well as the use of high cost palladium (Pd) for activation. For surface preparation, aluminium (Al)-enamel paste has been used. Five different acidic baths are used for electroless Cu deposition. Each bath contains 15 wt% copper sulfate (CuSO4) solution and 5 wt% of any one solution among hydrofluoric acid (HF), sulfuric acid (H2SO4), phosphoric acid (H3PO4), nitric acid (HNO3) and acetic acid (CH3COOH). Metallization of Cu on ABS part has been made at different deposition time (2, 24, 48 and 72 h) in ambient condition. After successful deposition of Cu, the surfaces are characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. Adhesion assessment of samples in different baths has been made. It is observed that all baths are capable of formation of Cu crystals on ABS surface. However, superior deposition on surface in terms of electrical conductivity and uniformity in deposition surface is obtained in HF, H2SO4 and H3PO4 baths.

Hydrothermally Synthesized Copper Gallium Delafossite Nanoflakes for (Photo)Electrocatalytic Water Splitting

The surge of alternative clean energy with minimal environmental impact in a cost-effective way requires the exploration of new materials and/or structures as efficient electrodes for industry-level photoelectrochemical (PEC) water splitting into usable H2 fuel. Considerable efforts have been made on anodic/cathodic photoelectrolysis of water with metal oxides, which have been featured by their abundance, environmental friendliness, and chemical stability. As a type of fascinating functional materials, delafossites with an ABO2-type general composition, where ‘A’ is monovalent (1+ metals of Cu, Ag, etc.) and ‘B’ is trivalent (3+ metals of Al, Ga, In, Fe etc.) have been highly oriented for applications as optoelectronics. Recently some aspects have been uncovered in the delafossite material field, e.g. they can be used as electrocatalysts and photocatalysts which are invaluable to rational design and optimization for various catalytic applications. Therefore, it is emergent to improve their optical and electrochemical activity for their electrochemical and photoelectrochemical (PEC) catalytic applications. One widely used strategy is to increase the surface area of functional materials. Here delafossite CuGaO2 nanoflakes have been synthesized by a hydrothermal method in the presence of sodium dodecyl sulfate (SDS) as surfactant at 190oC for 60 h and compared with CuGaO2 microplates synthesized under the same conditions without SDS. The synthesized samples were thoroughly characterized by powder X-ray diffraction, SEM, EDX, XPS, FT-IR, UV-Vis and BET surface area measurements. Moreover, their electrocatalytic and photoelectrocatalytic performance for OER in 0.5 M KOH electrolyte versus Ag/AgCl along with their stability were studied for cost-effective and active electrode material. It was demonstrated that the delafossite CuGaO2 nanoflakes synthesized in the presence of SDS showed better (photo)electrocatalytic performance and stability for OER than those synthesized without surfactant SDS. Thus, this hydrothermal method in combination of surfactant was an efficient approach towards the synthesis of delafossite CuGaO2 with reduced size as cost-effective and high performance (photo)electrocatalysts.

Maximal methane potential of different animal manures collected in northwest region of China

Maximum methane potential (B0) is an important parameter used in assessing suitability of a substrate for biogas production. This study examined maximum methane potential of different manures generated from three major Chinese livestock, namely chicken, hog and cattle, and evaluated the important factors that affect the maximum methane potential of a substrate. The livestock manures collected from the local farms were incubated under a thermophilic anaerobic condition (55°C). The results showed that the maximum methane potential (B0) of cattle, hog and chicken manures were 292.0 mL/g VS, 272.0 mL/g VS and 266.4 mL/g VS, respectively. The B0 value decreases with increasing contents of crude protein and crude fat, while increases with increasing the contents of carbohydrates and crude fiber in manures. The content of NH4+-N in chicken manure was significantly higher during the digestion period, reached as high as 1962.5 mg/L by the end of incubation period. Heavy metals of Cu and Zn in the manure also affect the B0. Empirical relationships that describe the B0 decrease in response to increase of Zn and Cu contents in manure were developed and used as a simple tool to assess the effects of these metals on the B0. It was concluded that the protein, Cu and Zn contents of manure are most important chemical compositions that negatively affect maximum methane potential. Based on the three experimental manures, the maximum methane potential was limited by either ammonium content or Cu and Zn content in the manure. For a commercial biogas production facility using these manures as main feedstock, one should consider to add co-substrate or co-substrates to reduce concentration of these chemicals to maximize biogas production. Keywords: anaerobic digestion, manure compositions, biomethane potential, volatile solid degradation DOI: 10.3965/j.ijabe.20171001.2469 Citation: Chen F, Yu G, Li W, Liu F W, Zhang W P, Bu Y S, et al. Maximal methane potential of different animal manures collected in northwest region of China. Int J Agric & Biol Eng, 2017; 10(1): 202－208.

Trimetallic Au‐Cu‐K/AC for acetylene hydrochlorination

AbstractThe metal chloride of KCl was chosen to modify Au‐Cu/AC to decrease the noble metal of gold and enhance the catalytic performance. Then a mercury‐free catalyst of Au‐Cu‐K/AC was prepared by the impregnation method. The catalytic performances of mercury‐free catalyst for acetylene hydrochlorination were conducted for 1600 h in a fixed bed reactor by a single‐tube pilot unit. The fresh and used catalysts were also characterized in comparison. The results showed that the acetylene conversion on mercury‐free catalyst decreased slowly from 98 % to 89 %, and the vinyl chloride monomer (VCM) selectivity was kept at 99.7 % under reaction conditions of temperature 165 °C, gas hourly space velocity (GHSV) 40 h−1, and feed volume ratio of HCl to C2H2 of 1.05 during 1600 h on stream. The results showed that the additives of K with Cu can make the active species of gold dispersed well and retard the aggregation of particles. The reason for the slow decline of acetylene conversion for Au‐Cu‐K/AC catalyst was the whisker carbon deposition, shown in a faint yellow colour over the catalyst surface, which consisted of short‐chain hydrocarbon molecules. Further study for accelerated deactivation of sole metal in the catalyst gives the clues that the non‐noble metal of Cu in Au‐Cu‐K/AC catalyst plays a key role to form the deposition.

ПОВЕРХНОСТЬ РАСТВОРИМОСТИ УГЛЕРОДА, КИСЛОРОДА И ХРОМА В ЖИДКОЙ МЕДИ

Thermodynamic modeling of phase equilibria in the liquid metal of Cu–C–O and Cu–Cr–C–O systems was done for the temperature range 1100–1300 °С. Thermodynamic analysis of interaction processes in the investigated systems was performed using the method of constructing of the components’ solubility surface in the metal melt. Such diagram allows connecting the compositions of the metal melt with the type of products of interaction, including solid particles of oxides, components of oxide melt and gaseous reaction products. Temperature dependences of the equilibrium constants of the reactions, which are taking place in the copper melt of the investigated systems, was clarified during thermodynamic modeling. The first order interaction parameters (Wagner) of elements in the liquid copper were evaluated during simulation. The thermodynamic modeling results are presented in the form of graphs on which the compositions of the metallic melt (depending on the temperature) are reflected. On these graphs metal melt compositions are in equilibrium with one or another interaction product. Based on the results of the simulation, it was determined that the formation of copper oxide particles in the presence of carbon and chromium dissolved in liquid copper is thermodynamically unlikely. Using graphite as a deoxidizing element, it is necessary to take into account the low solubility of carbon in liquid copper.

Weathering behavior and metal mobility of tailings under an extremely arid climate at Jinchuan Cu-Ni sulfide deposit, Western China

A detailed mineralogical and geochemical study of a sulfide tailings impoundment was carried out in Jinchuan Cu-Ni sulfide deposit in western China. Since 1963, the tailings impoundment has been exposed to weathering in an extremely arid climate with dry-warm seasons. Samples from different depths of two boreholes, each located in the center and border of the impoundment, were analyzed to evaluate the oxidative weathering behaviors of the tailings. The obvious shift of Cu and Ni from the sulfide fraction to more mobile forms, increasing trend of SO42− in the shallow of the tailings and decreasing trend of Fe content in sulfide fraction, show direct signs of sulfides oxidation, especially in the upper part of the tailings impoundment. Besides the upward migration of Ca2+ and SO42− under the strong evaporation in hyper-arid climate, the heavy metals of Cu and Ni are retained by the in-situ adsorption and/or co-precipitation with secondary Fe3+ precipitates. These secondary minerals are poorly crystalline and unstable. So, for sulfide tailings with a simultaneous large production of carbonates and under extremely arid climate, acid pollutants can be avoided but heavy metal pollution from the windblown dust of secondary minerals is the key pollution source that should be taken seriously.