A novel sulfidization system for enhancing hemimorphite flotation through Cu/Pb binary metal ions

The low reactivity of hemimorphite surfaces hinders the effective action of sulfidizing agents and xanthate,resulting in unsatisfactory flotation performance.To enhance the surface reactivity of hemi-morphite with sulfidizing agents and xanthate,Cu/Pb binary metal ions were introduced into the sul-fidization flotation system to enhance the sulfidization process and thereby promote hemimorphite flotation.The flotation results demonstrated a remarkable improvement in the hemimorphite flotation recovery when Cu/Pb binary metal ions were added prior to sulfidization.The flotation recovery of hemi-morphite increased from less than 5%to over 80%.After strengthening the sulfidization of hemimorphite with Cu/Pb binary metal ions,the mineral surface formed multicomponent sulfide products composed of zinc,copper,and lead sulfide.The reactivity of the copper-lead sulfide components exceeds that of the zinc sulfide component;thus,the enhancement by Cu/Pb binary metal ions not only increases the content of sulfide products on the hemimorphite surface but also augments their reactivity.Contact angle and adsorption experiments indicated that after enhanced sulfidization with Cu/Pb binary metal ions,the hemimorphite surface adsorbed a greater amount of xanthate,significantly increasing the mineral sur-face hydrophobicity.Consequently,the enhanced sulfidization by Cu/Pb binary metal ions effectively improved the flotation behavior of hemimorphite,presenting an innovative sulfidization system for the flotation recovery of zinc silicate minerals in zinc oxide ores.

Nondestructive Determination of Cu Residue in Orange Peel by Laser Induced Breakdown Spectroscopy

Laser induced breakdown spectroscopy （LIBS） is an emerging tool with rapid, nondestructive, green characteristics in qualitative or quantitative analyses of composition in materials. But LIBS has its shortcomings in detect limit and sensitivity. In this work, heavy metal Cu in Gannan Navel Orange, which is one of famous fruits from Jiangxi of China, was analyzed. In view of LIBS＇s limit, it is difficult to determinate heavy metals in natural fruits. In this work, nine orange samples were pretreated in 50-500 μg/mL Cu solution, respectively. Another one orange sample was chosen as a control group without any pollution treatment. Previous researchers ob- served that the content of heavy metals is much higher in peel than in pulp. So, the content in pulp can be reflected by detecting peel. The real concentrations of Cu in peels were acquired by atomic absorption spectrophotometer （AAS）. A calibration model of Cu I 324.7 and Cu I 327.4 was constructed between LIBS intensity and AAS concentration by six samples. The correlation coefficient of the two models is also 0.95. All of the samples were used to verify the accuracy of the model. The results show that the relative error （RE） between predicted and real concentration is less than 6.5%, and Cu I 324.7 line has smaller RE than Cu I 327.4. The analysis demonstrated that different characteristic lines decided different accuracy. The results prove the feasibility of detecting heavy metals in fruits by LIBS. But the results are limited in treated samples. The next work will focus on direct analysis of heavy metals in natural fruits without any pretreatment. This work is helpful to explore the distribution of heavy metals between pulp and peel.

Improving bonding strength of W/Cu dual metal interface through laser microstructuring method

Selective laser melting(SLM)is a promising technology for fabricating complex components with W/Cu dual metal.To enhance the interfacial bonding of W/Cu dual metal,we propose a novel approach using laser texturing to fabricate micro/nanostructures on the W surface.The micro/nanostructures promoted the spreading of Cu in the liquid,inhibited defects,and considerably increased the contact area between W and Cu by mechanical interlocking.To the best of our knowledge,a W/Cu dual metal was successfully prepared by SLM without a transition layer the first time.The bonding strength of the two materials reached 123 MPa,close to that of a W/Cu dual metal joint prepared by diffusion bonding.

Simulations of Metal Cu in Heating Process

Based on the Finnis-Sinsclair (FS) many-body potential model, the melting process of a system, which consists of 500 Cu atoms, controlled by period boundary condition has been simulated. The means of pair correlation func-tion, mean square displacement and Honeycutt-Anderson bonded pair have been used to characterize the melting behavior of Cu at different heating rates. The simulation indicates that melting point of metal Cu is 1444 K during a continuous heating process, and the calculated diffusion constant at the melting point is 4.31×10-9 m2/s. These re-sults are better than those from the EAM method, showing that the FS potential model works well in some disor-dered systems.

One-step synthesis of Cu(Ⅱ) metal–organic gel as recyclable material for rapid, efficient and size selective cationic dyes adsorption

Efficient removal of non-biodegradable and hazardous dyes from wastewater remains a hot research topic.Herein,a rationally designed a Cu(Ⅱ)-based metal–organic gel(Cu-MOG)with a nanoporous 3 D network structure prepared via a simple one-step mixing method was successfully employed for the removal of cationic dyes.The Cu-MOG exhibited high efficiency,with an adsorption capacity of up to 650.32 mg/g,and rapid adsorption efficiency,with the ability to adsorb 80%of Neutral Red within 1 min.The high adsorption efficiency was attributed to its large specific surface area,which enabled it to massively bind cationic dyes through electrostatic interaction,and a nanoporous structure that promoted intra-pore diffusion.Remarkably,the Cu-MOG displayed size-selective adsorption,based on adsorption studies concerning dyes of different sizes as calculated by density functional theory.Additionally,the adsorption performance of the Cu-MOG still maintained removal efficiency of 100%after three regeneration cycles.These results suggested that the Cu-MOG could be expected to be a promising and competitive candidate to conveniently process wastewater.

Microstructural formation and mechanical performance of friction stir double-riveting welded Al-Cu joints

A novel friction stir double-riveting welding(FSDRW) technology was proposed in order to realize the high-quality joining of upper aluminum(Al) and lower copper(Cu) plates,and this technology employed a Cu column as a rivet and a specially designed welding tool with a large concave-angle shoulder. The formations, interfacial characteristics, mechanical properties and fracture features of Al/Cu FSDRW joints under different rotational velocities and dwell times were investigated. The results showed that the well-formed FSDRW joint was successfully obtained.The cylindrical Cu column was transformed into a double riveting heads structure with a Cu anchor at the top and an Al anchor at the bottom, thereby providing an excellent mechanical interlocking.The defect-free Cu/Cu interface was formed at the lap interface due to the sufficient metallurgical bonding between the Cu column and the Cu plate, thereby effectively inhibiting the propagation of crack from the intermetallic compound layer at the lap interface between the Al and Cu plates. The tensile shear load of joint was increased first and then decreased when the rotational velocity and dwell time of welding tool increased, and the maximum value was 5.52 k N. The FSDRW joint presented a mixed mode of ductile and brittle fractures.

Achieving High‑Quality Aluminum to Copper Dissimilar Metals Joint via Friction Stir Double‑Riveting Welding

In order to achieve a high-quality joining of aluminum(Al)and copper(Cu)dissimilar metals,a new friction stir doubleriveting welding(FSDRW)with a Cu rod as the rivet was proposed,and the rotating tool with a large concave angle shoulder was specially designed.The results showed that under the thermal–mechanical effect of rotating tool,the Cu rod was deformed to be a double riveting heads structure with a Cu anchor at the upper surface of Al plate and an Al anchor above the lap interface of joint,and these two anchors greatly enhanced the mechanical interlocking of Al/Cu joint.The effective bonding interfaces were formed among the double riveting heads structure,the upper Al plate and the lower Cu plate,which contained the Cu/Cu interface and the Al/Cu interface.The Cu/Cu interface without the kissing bond and the Al/Cu interface with the rationally thin AlCu and Al_(2)Cu intermetallic compounds(IMCs)layers were beneficial to heightening the joint tensile shear strength.The maximum tensile shear load of the FSDRW joint achieved 5.52 kN,and the joint under different plunging depths of rotating tool presented a mixed mode of ductile fracture and brittle fracture.This novel FSDRW technique owns the advantages of strong mechanical interlocking and superb metallurgical bonding,and provides a new approach to acquiring a high-quality Al/Cu dissimilar metals joint.