The chemistry of copper patination

The chemistry of copper patination was investigated by two series of experiments. The chemistry of an aqueous copper-sulphate solution was studied at concentrations and pH values near those predicted in an electrolyte on copper exposed to the atmosphere. The electrochemical reactions in an electrolyte in contact with cuprite were investigated in a reaction vessel which used cuprite powder in artificial rainwater to study the electrochemistry of the atmospheric corrosion and patination of copper. Typical sulphate concentrations in rainwater are sufficient to precipitate posnjakite (Cu₄SO₄ (OH)₆2H₂O)), a possible precursor to brochantite, within an hour of wetting a cuprite surface. Brochantite (Cu₄SO₄ (OH)₆), the most commonly found copper salt in natural patinas is responsible for their green appearance. Precipitation of brochantite from the electrolyte resulted from an increase in pH due to the cathodic reduction of oxygen and an increase in cupric ion concentrations by cuprite oxidation.     

Sorption of heavy metal ions by fullerene and polystyrene/fullerene film compositions

The kinetics and equilibrium of the process of sorption of heavy metals from aqueous electrolyte solutions by polystyrene, fullerene, and polystyrene/fullerene composites have been studied. The kinetics of sorption of copper, nickel, zinc, and cadmium ions by the studied sorbents is described by the pseudo-firstand pseudo-second-order kinetic models. The rate constants of the process of sorption are determined. It is established that the equilibrium isotherm of sorption of copper ions by fullerene is related to the Langmuirtype isotherms. The sorption capacity of a monomolecular layer with reference to the Cu(II) ions is determined as equal to 14.6 mmol/g. Based on the calculated Henry constants, it is shown that the sorption efficiency increases in the series polystyrene < composition < fullerene.     

Preparation of fine nickel powders via reduction of nickel hydrazine complex precursors

Fine nickel(Ni) powders with controllable particle sizes were synthesized via the reduction of nickel hydrazine complex precursors of pure [Ni(N2H4)2]Cl2 and a mixture of [Ni(N2H4)2]Cl2 and [Ni(N2H4)3]Cl2 in aqueous solution. The mechanism of the formation of metallic Ni powders experiences the reduction of nickel hydroxide by hydrazine released from the ligand exchange reaction between nickel hydrazine complex and NaOH. In comparison with the method of preparing Ni powders from nickel salts, the method of making Ni powders via the reduction of nickel hydrazine complex precursors shows the advantages of using half dosage of hydrazine for complete reduction of nickel ions in solution, and the obtained Ni particles show less agglomeration and better dispersibility. Moreover, the average particle size of nickel powders can be controlled from 180 to 260 nm by adjusting the reaction molar ratio and concentration.     

硅胶-聚合胺树脂从模拟低品位铜矿浸出液中富集纯化铜

研究SP-C硅胶-聚合胺树脂在模拟低品位铜矿硫酸浸出液中富集纯化铜的工艺,在Cu2 1~2 g/L、Fe3 2~8 g/L范围内,考察该树脂吸附分离铜铁的性能。结果表明:该树脂对铜具有良好的选择性能,对铁的选择性能较差;湿树脂铜的穿漏交换容量及饱和交换容量分别为0.27和0.34 mol/L,解析高峰液Cu2 约30 g/L,铜铁分离系数达到397;最佳工艺条件为:料液pH 1.86,接触时间30 min。     

Synthesis of novel silica-supported chelating resin containing tert-butyl 2-picolyamino-N-acetate and its properties for selective adsorption of copper from simulated nickel electrolyte

A novel silica-supported tert-butyl 2-picolyamino-N-acetate chelating resin (Si-AMPY-1) was successfully synthesized and characterized by elemental analysis, FT-IR, SEM and ¹³C CP/MAS NMR. The adsorption behaviors of the Si-AMPY-1 resin for Cu(II) and Ni(II) were studied with batch and column methods. The batch experiments indicated that the Si-AMPY-1 resin adsorbed Ni(II) mainly via physisorption, while adsorbed Cu(II) via chemisorption. The column dynamic breakthrough curves revealed that the Si-AMPY-1 resin can efficiently separate Cu(II) from the simulated nickel electrolyte before the breakthrough point. Moreover, the concentration of Cu(II) in the column effluent was decreased to be less than 3 mg/L within the first 43 BV (bed volumes), and the mass ratio of Cu/Ni was 21:1 in the saturated resin, which completely satisfied the industrial requirements of the nickel electrorefining process. Therefore, it was concluded that the Si-AMPY-1 resin can be a promising candidate for the deep removal of Cu(II) from the nickel electrolyte.     

Polarization behaviour of copper whisker crystal in acidic cupric sulphate solution

The polarization behaviour of copper whisker crystal was investigated in acidic cupric sulphate solution by a potential sweep method limited to 120 mV of overpotential. When the overpotential limit was above 130 mV, sweep experiments gave scattered results due to random nucleation. The apparent exchange current density on a whisker was around 10^?5 A/cm², three orders of magnitude less than that on a polycrystalline copper.The exchange current density is increased by the twisting of a whisker: it is proportional to the twist angle. The defect dependency of the exchange current is discussed in relation to a surface-diffusion model.Polarization curves at low overpotentials show asymmetry of the cathodic and anodic branch. The surface defects introduced by twisting appear to be four times as effective for anodic dissolution as for cathodic deposition.     

Adsorption of copper ions on porous ceramsite prepared by diatomite and tungsten residue

In order to realize resource utilization of industrial tungsten residue and treatment of heavy metal wastewater in mining and metallurgical area of south China, a novel ceramsite was prepared with the main raw materials of diatomite and tungsten residue. The adsorption behavior of copper ions in solution on the ceramsite was investigated. Results indicated that the surface of the newly-developed ceramsite was rough and porous. There were lots of pores across the ceramsite from inner to outside. MnFe₂O₄ was one of the main components of the ceramsite. The Cu²⁺ adsorption capacity by the ceramsite reached 9.421 mg/g with copper removal efficiency of 94.21% at 303 K, initial Cu²⁺ concentration of 100 mg/L and dosage of 0.5 g after 300 min adsorption. With increase of ceramsite dosage, the total adsorption amount of Cu²⁺ increased, but the adsorption capacity decreased. The adsorption capacity increased with the increase of solution pH. The isothermal adsorption of Cu²⁺ by the ceramsite fitted the Freundlich model better. The adsorption mainly occurred on a heterogeneous surface, and was a favorable process. The adsorption process closely followed the pseudo-second kinetic equation. In initial stage of wastewater treatment, the adsorption process should be controlled mainly by diffusion, and the removal of Cu²⁺ can be improved by enhancing agitation.     

Study of decomposing carbonyl slag

1 Introduction Carbonyl slag is a kind of solid from the material with nickel by carbonylation. It usually contains Cu, Ni, Co, Fe, S, As, Sb, Au, Ag and platinum metals, and holds great recovery value. At present, with the development of the technology o…     

Microstructure and mechanical properties of Mg-Cu-Y-Zn bulk metallic glass matrix composites prepared in low vacuum

Mg-Cu-Y-Zn bulk metallic glasses(BMG) and in situ bulk metallic glass matrix composites were prepared by copper mold casting under the low vacuum with the argon atmosphere,and the raw materials used in preparing the Mg-Cu-Y-Zn alloys were commercially pure materials.The microstructures of the bulk samples were analyzed by X-ray diffractometer(XRD) and the thermal stability of samples was investigated by using a differential scanning calorimeter(DSC).The thermal stability of sample prepared with commercia...     

铜电解液中铜的快速自动分析

研究了铜电解液中高含量铜的光度分析。直接利用水合铜离子的蓝色，双波长扣除试样浑浊干扰；标样以硫酸为介质消除硫酸根干扰；于标样中加入定量的镍，并选择适当的波长克服镍的干扰。实现了贵溪冶炼厂铜电解液中铜（３０～６０ｇ／Ｌ）的自动快速分析，２４０次进样／ｈ，结果令人满意     

Influence of copper on amorphous nickel based brazing alloy

Abstract

Brazing of stainless steel using nickel based alloys has sometimes been avoided, in spite of its various advantages, because it is a somewhat unreliable process in terms of the mechanical characteristics and corrosion resistance of the brazed joints. Addition of copper to amorphous Ni–Cr–B–Si brazing alloys has been shown to be a promising method of improving the performance of joints. Because copper can form a solid solution with nickel at any concentration, addition of copper has a great effect on the microstructures of the nickel based filler metal and braze seam, by improving the volume ratio of nickel based solid solution to the embrittled intermetallic compounds. As a result, a significant increase in the critical brazing clearance (CBC) was obtained in the present work. Furthermore, copper might increase the electrode potential of nickel based solid solution, so that addition of copper could improve the corrosion resistance of the brazed joints. The results show that an appropriate copper addition to the present Ni–Cr–B–Si group amorphous brazing foil provides an effective method of overcoming the weaknesses of joints brazed using conventional nickel based filler metals, such as low value of CBC and low corrosion resistance.     

Role of additives in electroless copper plating using hypophosphite as reducing agent

In electroless copper plating baths using hypophosphite as the reducing agent, nickel ions was used to catalyze hypophosphite oxidation. However, the color of the copper deposits was dark or brown and the electrical resistivity was much higher than that obtained from formaldehyde baths. Polyethylene glycol (PEG) and K₄Fe(CN)₆ were used to improve the microstructure and properties of copper deposits obtained from electroless copper plating bath using hypophosphite as the reducing agent. The effects of PEG concentration on the deposition rate, the microstructure, morphology and electrical resistivity of the copper deposits, and the electrochemical reactions of hypophosphite (oxidation) and cupric ion (reduction) were investigated. The traces of hydrogen escaping from the deposits surface disappeared and the color of the copper deposits changed from dark-brown to dark red when the PEG concentration was 1.67 × 10^− 5 M or more. The deposition rate increased and the electrical resistivity of the copper deposits decreased slightly with the addition of PEG to the plating solution. The electrical resistivity of copper deposits decreased to 2.85 μΩ cm with 1.67 × 10^− 5 M PEG and 4.70 × 10^− 6 M K₄Fe(CN)₆ in the bath. Larger grain size and higher (220) plane orientation were obtained with the increase of PEG concentration in the bath. The electrochemical current–voltage results showed that PEG accelerated the catalytic oxidation of hypophosphite at active nickel sites and had little effect on the reduction reaction of cupric ions on the deposit surface by adsorption on the electrode.     

焦磷酸铜浓度对TC4合金微弧氧化层摩擦性能的影响

在电解液中加入不同浓度的焦磷酸铜对TC4进行微弧氧化处理,对微弧氧化层进行了粗糙度和显微硬度测试,通过扫描电镜(SEM)、X射线衍射仪(XRD)及摩擦磨损测试分析了焦磷酸铜浓度对微弧氧化层微观结构及磨损性能的影响.结果表明:加入2 g/L焦磷酸铜后,微弧氧化层表面孔隙增大,数量增多,但随焦磷酸铜浓度的继续增加,微弧氧化...     

二段脱铜液还原结晶法脱砷新工艺

对铜电解液脱砷方法进行研究,提出以二段脱铜液为原料,采用SO2还原结晶法脱砷新工艺。在二段脱铜液中通入SO2,将其中的As(Ⅴ)还原成As(Ⅲ),还原后的溶液通过蒸发结晶析出As2O3,达到二段脱铜液脱砷的目的。结果表明:当As(Ⅴ)浓度为12.41 g/L、H2SO4浓度为253.00 g/L、反应温度为60℃时,向二段脱铜液中通入SO290 min后静置90 min,二段脱铜液中As(Ⅴ)的还原率达到94.54%。还原后的溶液进行蒸发结晶,当蒸发前与结晶后的体积比(V0:V1)为3.5时,砷的脱除率达到91.33%,结晶产物为As2O3。与传统脱砷工艺相比,新工艺具有操作简单、成本低廉及砷的脱除效果明显等优势。     

Electrodeposition of Rubber

Transmission electron microscopy has been used to investigate the structure of nickel electrodeposits plated from solutions containing copper and zinc as contaminants. Ductility of deposits was determined and subsequently deformed deposits were examined by transmission electron microscopy. An addition of copper or zinc (within concentration range 0–0.134 g/1 metal ion) to the dull Watts nickel solution did not result in significant changes in microstructure or ductility at 40 A/ft², 135°F and pH 4. Additions of copper or zinc to a semi-bright nickel solution (Watts +0·1 g/1 coumarin) resulted in a small grain size and a moderate reduction in ductility. The dislocation density in deformed deposits was increased and strain fields formed at twin boundaries.     

硫酸镍铵复盐结晶法分离回收铜电解液中的镍（英文）

研究采用硫酸镍铵复盐结晶从铜电解液中分离回收镍的方法。研究发现,在相同温度的溶液中,硫酸铜的溶解度小于硫酸镍的溶解度,而硫酸铜铵的溶解度大于硫酸镍铵的溶解度。因此,加入(NH₄)₂SO₄可使铜电解液中的镍选择性结晶析出。按(NH₄)₂SO₄/NiSO₄摩尔比≤0.8加入(NH₄)₂SO₄,在-15℃冷冻结晶10 h,可使其中的镍以Ni(NH₄)₂(SO₄)₂·6H₂O的形式结晶析出。将所得结晶物热解,再将热解产物加水溶解,最后将溶解液浓缩结晶得到合格的NiSO₄·6H₂O产品。复盐结晶法是一种清洁环保、经济高效的从铜电解液中分离回收镍的方法。     

Effect of inhibitors on corrosion behavior of copper—nickel in concentrated lithium bromide solution at high temperature

1　ＩＮＴＲＯＤＵＣＴＩＯＮＷｉｔｈｔｈｅｉｎｃｒｅａｓｉｎｇｏｆｃｏｎｓｃｉｏｕｓｎｅｓｓｏｆｅｎｖｉｒｏｎ ｍｅｎｔａｌｐｒｏｔｅｃｔｉｏｎ ,ｍｏｒｅａｎｄｍｏｒｅｐｒｏｄｕｃｔｓａｒｅｒｅ ｑｕｉｒｅｄｎｏｔｔｏｐｏｌｌｕｔｅｅｎｖｉｒｏｎｍｅｎｔ .Ｌ     

S300树脂对汽车失效催化剂浸出液中Pd(Ⅱ)的吸附行为

基于实验室合成的S300树脂对汽车失效催化剂浸出液中Pd2+吸附过程进行研究,考察温度、溶液体系中HCl浓度、吸附时间等因素对Pd2+在S300树脂上吸附行为的影响,并对Pd2+在S300树脂中的动力学特性、交换等温线、复杂体系中的选择性以及解吸过程进行研究,根据表征结果分析在盐酸体系下S300树脂的吸附机理.结果表明...     

Studies on copper-semiconducting layer-electrolyte systems—II. Galvanostatic anodic polarization of Cu/Cu2S/S2− applying stationary and rectangular pulse techniques

Copper sulphide layers formed by anodically polarizing copper in a Na₂S bath were investigated electrochemically using galvanostatic techniques. The variation in potential of unpolarized copper/copper sulphide electrodes with pS suggested a film of cuprous sulphide containing some cupric sulphide. The overpotential measurements indicated sulphide films of low porosity, deficient in Cu⁺ ions. The transfer coefficients and exchange currents computed from the results were interpreted as a system involving an impervious layer of cuprous sulphide overlayered with a film of cupric sulphide. The influence of Cu²⁺, S^2? and OH^? on the anodic processes are also discussed.     

工艺参数对Ni-纳米La2O3复合电沉积的影响

在氨基磺酸镍镀液中加入La2O3纳米颗粒,制备了Ni 纳米La2O3复合镀层.利用正交试验法研究了微粒悬浮量、电流密度、搅拌速度、温度等工艺参数对复合电沉积的影响,并用扫描电子显微镜对复合镀层的表面形貌进行了分析.结果表明,La2O3颗粒悬浮量对复合镀层La2O3共沉积量的影响最大;复合镀层中La2O3颗粒共沉积量越大、电流密度越小,其表面越平整、组织越致密.