铋精矿加压氧化氨浸高效分离铜、硫和铋

针对湖南柿竹园铋精矿火法冶炼过程中存在的成本高、低浓度SO₂和散烟排放污染环境、有价金属综合回收率低等问题, 以柿竹园铋精矿为原料, 提出了加压氧化氨浸分离铋与铜、硫的新工艺, 研究了氨水加入量、浸出温度、浸出时间、浸出压力及浸出液固比等因素对铜、硫、铋浸出率的影响。在氨水用量1.8 mL/g_铋精矿、液固比4∶1、釜压2.8 MPa、浸出温度160 ℃、浸出时间5 h、搅拌速度600 r/min的优化工艺条件下, 铜、硫浸出率分别达93.57%和92.87%, 铋不浸出并以氧化铋形态全部入渣, 实现了铜、硫与铋的高效分离。     

Casting methods for the production of rotationally symmetric copper bimetals

ABSTRACT

Multiple-material products are characterised by a complex property profile which is achieved by combining the particular advantages of at least two different materials. Bimetal casting is an energy- and material-efficient technology for the production of multi-metallic objects. This paper describes the development of a semi-continuous casting process for the formation of a rotationally symmetric bimetal with a cohesive bonding character at the interface of a copper–tin alloy (CuSn6) and pure copper (Cu99.5). Initial experiments are conducted by static casting to evaluate the thermal process window. Based on the results of the initial experiments, a vertical semi-continuous compound casting process is developed. A stable cohesive bond between the joining partners is accomplished by forming a solid solution at the interface.

This paper is part of a Thematic Issue on Copper and its Alloys.     

Experimental study and thermodynamic modeling of the Cu–Sn–Si–O system and sub-systems

Phase equilibria between slag, Cu–Sn alloy and solid oxide phases, SnO₂ (cassiterite) or SiO₂ (tridymite, cristobalite) are important for oxidizing fire refining of black copper produced during the recycling of copper scrap and waste electrical and electronic equipment. Integrated experimental and thermodynamic modeling study is presented for the Cu–Sn–Si–O chemical system and its sub-systems. Experimental technique involved high-temperature equilibration, followed by rapid quenching and direct measurement of Cu, Sn and Si concentrations in the liquid and solid phases using the electron probe X-ray microanalysis. Experimental results and literature data have been used to develop the thermodynamic database for the system. The database works within the environment of FactSage software, as well as ChemApp, ChemSheet and SimuSage. Combined with other assessments, it can be used to optimize and develop recycling processes using the black copper route.     

Speciation of copper in high chloride concentrations,in the context of corrosion of copper canisters

Canisters with a cast iron insert for mechanical strength and a 50-mm thick copper shell as corrosion protection are planned to be used for disposal of spent nuclear fuel in Sweden and Finland. Chloride can be considered “beneficial”, as it promotes active dissolution of copper rather than passivation (which might result in pitting), but a high concentration of chloride in solution would increase the driving force for corrosion through the formation of soluble copper chloro complexes. Thermodynamic calculations are performed in this study with the PHREEQC software and three of its accompanying databases, and a comparison with experimental data is performed to select the database to be used when evaluating repository performance. The activity coefficient models are given special attention. For the assessment of chloride-assisted corrosion of a KBS-3 canister, chloride concentrations pessimistically up to 5 mol/kg are used (in Finland and Sweden, the groundwater and bentonite porewater chloride concentrations are not expected to exceed 1 mol/kg). The resulting copper solubilities are then considered in different mass transport cases.     

铜矿床一般工业指标研究

针对2002年铜地质勘查规范中一般工业指标存在的问题,基于大量实际生产数据,对铜矿床实际采用的边界品位指标、最低工业品位、矿床平均品位、最小可采厚度、夹石剔除厚度、开采技术条件等进行研究,论证了铜矿床的一般工业指标,并首次明确了铜矿床工业指标的适用条件,解决了铜矿床一般工业指标体系应用不一致和指标区间取值主观性的问题。     

Gas‐phase removal of indoor volatile organic compounds and airborne microorganisms over mono‐ and bimetal‐modified (Pt,Cu, Ag) titanium(IV) oxide nanocomposites

The photocatalytic deactivation of volatile organic compounds and mold fungi using TiO₂ modified with mono‐ and bimetallic (Pt, Cu, Ag) particles is reported in this study. The mono‐ and bimetal‐modified (Pt, Cu, Ag) titanium(IV) oxide photocatalysts were prepared by chemical reduction method and characterized using XRD, XPS, DR/UV‐Vis, BET, and TEM analysis. The effect of incident light, type and content of mono‐ and bimetallic nanoparticles deposited on titanium(IV) oxide was studied. Photocatalytic activity of as‐prepared nanocomposites was examined in the gas phase using LEDs array. High photocatalytic activity of Ag/Pt‐TiO₂ and Cu/Pt‐TiO₂ in the reaction of toluene degradation resulted from improved efficiency of interfacial charge transfer process, which was consistent with the fluorescence quenching effect revealed by photoluminescence (PL) emission spectra. The photocatalytic deactivation of Penicillium chrysogenum, a pathogenic fungi present in the indoor environment, especially in a damp or water‐damaged building using mono‐ and bimetal‐modified (Pt, Cu, Ag) titanium(IV) oxide was evaluated for the first time. TiO₂ modified with mono‐ and bimetallic NPs of Ag/Pt, Cu, and Ag deposited on TiO₂ exhibited improved fungicidal activity under LEDs illumination than pure TiO₂.     

MOF-derived PPy/carbon-coated copper sulfide ceramic nanocomposite as high-performance electrode for supercapacitor

To obtain a battery-type ceramic electrode material for supercapacitors, we used a metal-organic framework (HKUST-1) as a template to prepare ceramic material Cu₉S₈@C. Firstly, we adopted the calcination–vulcanization method to synthesize Cu₉S₈@C. Then we deposited it onto a carbon fiber cloth and employed it. Moreover, polypyrrole PPy/Cu₉S₈@C-CC nanocomposite electrodes were prepared via electrochemical deposition. By means of high-temperature calcination and vulcanization, the copper atoms of HKUST-1 were successfully transformed into Cu₉S₈ nanoparticles, and the organic ligand was carbonized into amorphous carbon in Cu₉S₈@C. The results showed that the PPy/Cu₉S₈@C-CC electrode presented a specific capacitance of 270.72F/g at a scan speed of 10 mV/s in a 1 M KCL aqueous solution. This value was much higher than that of Cu₉S₈@C-CC and Cu₉S₈-CC electrodes, as confirmed by the results of electrochemical test. At a scan rate of 10 mV/s, the capacitance retention rate for PPy/Cu₉S₈@C-CC after 3000 cycles was 80.36%, indicating its superior cycle characteristics. Moreover, PPy/Cu₉S₈@C-CC exhibited good frequency response. These results indicate that PPy/Cu₉S₈@C is an ideal electrode material for energy storage and conversion applications.     

Solids Under Extreme Shear: Friction‐Mediated Subsurface Structural Transformations

Tribological contacts consume a significant amount of the world's primary energy due to friction and wear in different products from nanoelectromechanical systems to bearings, gears, and engines. The energy is largely dissipated in the material underneath the two surfaces sliding against each other. This subsurface material is thereby exposed to extreme amounts of shear deformation and often forms layered subsurface microstructures with reduced grain size. Herein, the elementary mechanisms for the formation of subsurface microstructures are elucidated by systematic model experiments and discrete dislocation dynamics simulations in dry frictional contacts. The simulations show how pre‐existing dislocations transform into prismatic dislocation structures under tribological loading. The stress field under a moving spherical contact and the crystallographic orientation are crucial for the formation of these prismatic structures. Experimentally, a localized dislocation structure at a depth of ≈100–150 nm is found already after the first loading pass. This dislocation structure is shown to be connected to the inhomogeneous stress field under the moving contact. The subsequent microstructural transformations and the mechanical properties of the surface layer are determined by this structure. These results hold promise at guiding material selection and alloy development for tribological loading, yielding materials tailored for specific tribological scenarios.     

电感耦合等离子体原子发射光谱法测定钛及钛合金中铬和铜

铬、铜含量影响钛及钛合金组织结构和性能,须对其准确测定。采用硫酸-硝酸溶样体系溶解样品,选择Cr 267.716nm、Cu 327.393nm为分析线并采用两点校正法扣除背景,使用钛基体匹配的方法绘制校准曲线,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钛及钛合金中铬和铜。方法中各元素校准曲线线性良好,相关系数均大于0.999;检出限为0.04~6.0μg/g。按照实验方法测定3个钛及钛合金样品中铬和铜,结果的相对标准偏差(RSD,n=10)小于5%。按照实验方法测定5个钛合金标准物质中铬和铜,测定结果与认定值相吻合,分析误差在实验室允许的误差范围内。     

Gas Responsive Nanoswitch: Copper Oxide Composite for Highly Selective H2S Detection

A nanocomposite material based on copper(II) oxide (CuO) and its utilization as a highly selective and stable gas‐responsive electrical switch for hydrogen sulphide (H₂S) detection is presented. The material can be applied as a sensitive layer for H₂S monitoring, e.g., in biogas gas plants. CuO nanoparticles are embedded in a rigid, nanoporous silica (SiO₂) matrix to form an electrical percolating network of low conducting CuO and, upon exposure to H₂S, highly conducting copper(II) sulphide (CuS) particles. By steric hindrance due to the silica pore walls, the structure of the network is maintained even though the reversible reaction of CuO to CuS is accompanied by significant volume expansion. The conducting state of the percolating network can be controlled by a variety of parameters, such as temperature, electrode layout, and network topology of the porous silica matrix. The latter means that this new type of sensing material has a structure‐encoded detection limit for H₂S, which offers new application opportunities. The fabrication process of the mesoporous CuO@SiO₂ composite as well as the sensor design and characteristics are described in detail. In addition, theoretical modeling of the percolation effect by Monte‐Carlo simulations yields deeper insight into the underlying percolation mechanism and the observed response characteristics.