水合肼对铜电解液净化的作用

在铜电解液中加入水合肼产生沉淀,使铜电解液中砷、锑、铋杂质得到有效去除。当电解液Cu2+质量浓度为22g/L,硫酸质量浓度为203g/L,反应温度为42℃,反应时间为60mi,n砷、锑、铋质量浓度分别为8.80 g/L、0.36 g/L、0.20 g/L时,按照铜电解液与水合肼体积比为20:1在铜电解液加入水合肼,铜脱除率为97.04%,砷、锑、铋去除率分别为5.28%、37.92%、94.40%。在卤化物作用下,有助电解液中砷的去除。杂质的脱除有一定影响。在铜电解液中加入水合肼产生沉淀有Cu4SO4（OH）6·H2O、Cu2（OH）3NO3、Cu3（AsO4）（OH）3等。     

铜电解过程中As(Ⅲ)净化作用及其氧化动力学

研究铜电解过程中As(Ⅲ)初始浓度对电解液净化的影响及其氧化动力学。结果表明:当电流密度为235A/m2、电解时间为168 h、电解液中As(Ⅲ)初始浓度为0时,总As浓度(TAs)从10.00 g/L增加至10.62 g/L,Sb的浓度从0.40 g/L增加至0.45 g/L,Bi的浓度从0.22 g/L增加至0.24 g/L;当As(Ⅲ)初始浓度为5.00 g/L时,As(Ⅲ)从5.00 g/L下降至1.80 g/L,TAs从10.00 g/L下降至9.70 g/L,Sb的浓度从0.40 g/L下降至0.26 g/L,Bi的浓度从0.22 g/L下降至0.18 g/L;当电流密度为235 A/m2,电解时间为144 h时,As(Ⅲ)的浓度从7.62 g/L下降至3.71g/L,TAs浓度约为11.16 g/L,Sb的浓度从0.22 g/L微增至0.26 g/L,Bi的浓度为0.086 g/L。在铜电解过程中,As(Ⅲ)能够抑制电解液中TAs、Sb和Bi的浓度的增加,具有净化铜电解液的作用;As(Ⅲ)不断被氧化,其氧化反应符合一级反应动力学规律,活化能为46.11 kJ/mol。     

离子膜电解法分离氯化浸出液中宏量铜镍

硫化镍矿中常伴有铜,在浸出时镍和铜往往同步进入浸出液,但由于铜镍化学性质相近而难以分离。针对这一难题,采用阴离子膜电解,通过控制槽电压,分离溶液中的铜镍,考察极距、电解液温度、槽电压、铜镍浓度等因素对铜镍分离效果的影响。结果表明:当溶液中Cu~(2+)25 g/L、Ni~(2+)37.5 g/L时,在极距4 cm、电解液温度40℃、槽电压0.53 V、电解10 h的条件下,阴极液中残余总铜浓度可降到0.24 g/L,ΡNi/Cu比为155.7,铜镍分离效果良好。     

粉煤灰制氧化铝工艺电解除铁方法探索研究

为满足粉煤灰制氧化铝过程中除铁的工艺要求，研究了离子交换膜电解法去除浸出母液中杂质铁的工艺条件，使用离子交换膜分隔阳极室和阴极室，以FeCl₂溶液为阴极电解液，NaCl溶液为阳极电解液，钛板和石墨分别做阴极和阳极。考察了Fe²⁺初始浓度、电解液pH、电流密度、电解温度等条件对电解除铁效果的影响规律。试验结果表明：Fe²⁺初始浓度对电解除铁效果没有影响；电解液的最佳pH为2.50;电流密度过高会使电解除铁的效率变低，当Fe²⁺初始浓度为3 g/L时，最佳的电流密度为2 A/dm²;温度对低Fe²⁺浓度(<0.4 g/L)电解效率的影响不显著，但Fe²⁺浓度大于0.4 g/L,提高温度可以提升电解除铁速率。     

电解液中Ce对ZAlSi12Cu2Mgl微弧氧化层的影响

在稳定的Na2SiO3电解液体系中对ZAlSi12Cu2Mgl进行微弧氧化,研究了电解液中稀土Ce的质量浓度对电解液电导率、微弧氧化过程中正/负向电流及微弧氧化层特性的影响.研究结果表明,随着Ce的质量浓度从0到0.125 g/L逐渐增加,电解液的电导率从15.15 MS/m逐渐上升到16.54 MS/m,微弧氧化过程中的电流发生明显改变;随着Ce的质量浓度的提高,微弧氧化层厚度和显微硬度先增大随后逐渐减小,在Ce质量浓度为0.025 g/L时达到最大,其氧化层厚度约为258μm;显微硬度(HV)约为620.     

交直流叠加电解铜电极间距对阴极铜的影响

<正>0前言本文较系统研究了在小型电解精炼槽中,用交直流叠加电源电解精炼铜过程中的关键参数,以及影响交直流叠加电解精炼铜层质量的温度、电解液铜酸配比等因素。在确定了合适的镀铜工艺条件:交流电频率f=500 Hz,E=2 0 m V,电流密度280 A/m 2,电镀温度40℃[1],Cu SO 4·5H2O溶液浓度是150~160 g/L,H2 S O 4溶液浓度是140~180 g/L后[2],又进一步对电极     

银氧化锡合金废料电解综合回收工艺研究

采用直流电解法和化学法回收银氧化锡(AgSnO2)合金废料中的银和锡。优化得到的电解银工艺参数为:槽电压1.5~3.0 V,电解周期为24 h,电解液中Ag⁺浓度为150~260 g/L,HNO3浓度为15~20 g/L,同极距120~140 mm,极板排布为六阴极五阳极间隔交替排列。一个周期银氧化锡废料电解银直收率接近95%,主体纯银粉在阴极析出。富含氧化锡的阳极泥和残极用硝酸浸出少量残余银,不溶渣还原熔炼回收锡,硝酸浸出的含银溶液中加入氢氧化钠调节pH值到10,沉淀得氧化银,500℃焙烧得到单质银。废料中的银和锡均得到有效回收。全流程银的回收率不低于99%。     

太阳能电池浆料用亚微米球形银粉的制备工艺研究

以抗坏血酸为还原剂,AgNO3为银盐,聚乙二醇4000(PEG-4000)为分散剂,采用液相还原法制备亚微米球形银粉。采用L9(33)正交试验设计,考察抗坏血酸浓度、分散剂加入方式以及溶液pH值对银粉粒度的影响。分析得出制备亚微米球形银粉的优化条件为:pH=5,AgNO3浓度为0.5 mol/L,AgNO3和抗坏血酸溶液中分别加入一半分散剂,抗坏血酸的浓度为0.9 mol/L,PEG-4000/AgNO3(质量比)为1.2,反应温度为室温。通过激光粒度仪、XRD及SEM表征,表明在较优实验条件下制备的亚微米级银粉纯净,粒度分布均匀,呈球状。并将优化条件下所得银粉调制成太阳能电池用浆料,通过丝网印刷在硅片上并烧结,烧结膜银栅线的表面方阻为0.721 m/□,可满足太阳能电池的电性能要求。     

Cu2+及等离子电解氧化处理对Zr-4合金腐蚀性能的影响

采用电化学方法研究锆合金Zr-4在添加不同Cu2+浓度的0.5 mol/L NaCl溶液或0.5 mol/L Na2SO4中的腐蚀行为,探讨不同浓度Cu2+对Zr-4合金腐蚀性能的影响,同时,在10 g/L Na2SiO3.9H2O+10 g/L Na4P2O7.10H2O混合溶液中对Zr-4合金进行等离子电解氧化处理,并用极化曲线技术研究膜层的防护能力。结果表明:Cu2+能使Zr-4合金自腐蚀电位正移,降低极化曲线上钝化区的宽度,使得合金的抗孔蚀能力降低,腐蚀电流密度增加;在硫酸钠溶液中,Cu2+的添加没有使合金产生明显的孔蚀,这表明Zr-4合金的抗孔蚀能力下降是Cu2+和Cl共同作用的结果;等离子电解氧化处理能够大幅度提高Zr-4合金的抗孔蚀能力。     

高温高压触媒法金刚石合成块电解过程影响因素探讨

用石墨和金属触媒通过高温高压合成金刚石,合成块中的金刚石晶体被金属触媒等紧紧包裹,普通物理方法难以提纯。利用电解方法将合成块中的金属在阳极上氧化电解为金属离子而进入溶液中,之后再通过溶液迁移到阴极上还原析出,回收金属,是目前比较高效环保的方法。通过电解实验,分析电解过程中电解液的主要成分和电解工艺条件对电解效率的影响。结果表明:添加剂中活化剂的最佳质量浓度为15~30 g/L,复合稳定剂最佳质量浓度为25~30 g/L时,加入的添加剂能显著改善电解液性能;在电解液pH值为2~4,阴极、阳极间距为50~250 mm,电控柜电流为4000~4200 A的电解工艺条件下,电解效率显著提高。      

Separation and recovery of Cu and As from copper electrolyte through electrowinning and SO2 reduction

Cu and As were separated and recovered from copper electrolyte by multiple stage electrowinning, reduction with SO₂ and evaporative crystallization. Experimental results showed that when the current density was 200 A/m², the electrolyte temperature was 55 °C, the electrolyte circulation rate was about 10 mL/min and the final Cu concentration was higher than 25.88 g/L, the pure copper cathode was recovered. By adjusting the current density to 100 A/m² and the electrolyte temperature to 65 °C, the removal rate of As was 18.25% when the Cu concentration decreased from 24.69 g/L to 0.42 g/L. After As(V) in Cu-depleted electrolyte was fully reduced to As(III) by SO₂, the resultant solution was subjected to evaporative crystallization, then As₂O₃ was produced, and the recovery rate of As was 59.76%. The cathodic polarization curves demonstrated that both Cu²⁺ concentration and As(V) affect the limiting current of Cu²⁺ deposition.     

铜基银枝晶的制备和氧还原电催化性能

通过迦尔瓦尼置换反应在不同的Ag+溶液中制备出了铜基银枝晶,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和电化学工作站分别对样品的结构、微观形貌以及电化学性能进行了表征。结果表明,随着溶液中Ag+浓度和反应时间的增加,银的形貌从团簇状向树枝状转变,氧还原电催化性能也增强;在相同浓度Ag+溶液中,SO42-比NO3-更能促进枝晶的生长,但当阴离子是NO3-时比阴离子是SO42-时所制备的银枝晶的氧还原电催化性能更好;在10 mmol/L AgNO3溶液中,反应时间为1800 s时制备的银枝晶电极使H2O2的还原峰电流最大,在0.1 mol/L Na2SO4+5mmol/L H2O2溶液中,恒电位为-0.32 V时,其稳态电流密度可达2.83 mA/cm2。初步提出了银枝晶的生长机制和H2O2的氧还原催化机制。     

酒石酸对电解法制备树枝状超细银粉的影响研究

采用电解法制备树枝状银粉,研究了酒石酸对银粒子电化学沉积过程的形貌演变和生长机制的影响。通过SEM、TEM和XRD分析了酒石酸对沉积过程银粉的形貌和结构的影响。此外,利用阴极极化(LSV)、循环伏安(CV)和计时电流(CA)探究了酒石酸对电解法制备树枝状银粉的电化学行为影响规律。结果表明：当溶液中添加0 g/L酒石酸时,银离子在850A/m2电流密度下形成类球状结构,而当溶液中添加0.05g/L酒石酸时,银离子在相同电流密度下形成棒状结构,随着酒石酸添加量的增加,阴极极化程度增加,过电位增大。而当酒石酸增加到0.5 g/L时,成功制备出粒径3～4μm,松装密度1.1 g/cm³,振实密度0.6 g/cm³、结晶性好的树枝状银粉。计时电流结果表明溶液体系均遵循瞬时成核过程,但添加酒石酸影响了银的成核和生长动力学,并抑制了阴极极化。     

Recovery of valuable elements from spent YBa2Cu3O7-x/Ag composite superconductor bulks

Silver as a highly conductive metal is usually doped in YBa₂Cu₃O_7–x superconductor bulks to improve critical current density of YBa₂Cu₃O_7–x superconductor. The valuable metal elements silver, yttrium, barium and copper in waste YBa₂Cu₃O_7–x/Ag composite superconductor bulks were recovered, respectively. Silver was recovered with process at first, the waste was dissolved by nitric acid and silver chloride was precipitated by adding chloride acid, then silver pig was obtained by melting silver chloride together with sodium carbonate at 1 000 °C. The effective factors on recovery ratio and purity of silver were studied. The chemical analysis proves that the purity of silver ingot is 95.86%. The recovery ratio of silver is calculated to be 92.56%. The loss of silver may be due to the loss of silver chloride during filtering and the volatilization of silver when silver chloride and sodium carbonate are smelted at high temperature. For other three metal elements, Y³⁺, Ba²⁺ and Cu²⁺, in the surplus waste liquid after recovering silver, they were separated with the sequence of barium, copper and then yttrium step by step. First, sulfate acid was used to precipitate barium sulfate. Then, sodium sulfide was added to the surplus solution so that copper could be separated as copper sulfide. During this separation procedure, it was important to control the pH value to be 1–2. After that, oxalic acid was added into the surplus solution to obtain yttrium oxalate. Finally, yttrium oxide was formed by burning yttrium oxalate. The XRD results indicate that the final products are all single-phase compounds as BaSO₄, CuS and Y₂O₃, respectively.     

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.     

Co‐effect of bis(cyclohexanone) oxalyldihydrazone and copper(II) ion on the corrosion of cold rolled steel in 0.5 M hydrochloric acid solution

Effects of bis(cyclohexanone) oxalyldihydrazone (BCO) and copper(II) ion (Cu²⁺) on the corrosion of cold rolled steel (CRS) in 0.5 M hydrochloric acid (HCl) solution were investigated using Tafel polarization curve and electrochemical impedance spectroscopy (EIS) at 20 °C. Results elucidate that the inhibition efficiency increases with increase in BCO concentration, and the addition of 10^?5 M Cu²⁺ significantly enhances the inhibition efficiency of BCO. Polarization curve results elucidate that the single BCO acts as a mixed‐type inhibitor while the combination of Cu²⁺ and BCO acts as cathodic inhibitor. Ultraviolet and visible spectrophotometer (UV–Vis) results show that BCO molecules do not interact with Cu²⁺ and Fe²⁺ in 0.5 M HCl solution. Atomic force microscope (AFM) result indicates that a protective layer forms on CRS surface after immersion in 0.5 M HCl containing BCO in the absence and presence of Cu²⁺. The adsorption of BCO is found to follow the Langmuir adsorption isotherm in the presence and absence of Cu²⁺. The mechanism of typically chemical adsorption is proposed via the value of free energy of adsorption (ΔG) in the presence of BCO and Cu²⁺.     

嗜酸氧化亚铁硫杆菌（ATCC 23270）浸出黄铜矿过程中的EPS、Cu2+和Fe3+的相互作用机制（英文）

采用超声-离心方法提取嗜酸氧化亚铁硫杆菌(ATCC 23270)胞外多聚物(EPS)、EPS中的Cu2+、Fe3+离子,研究生物浸出黄铜矿过程中Cu2+、Fe3+和EPS的相互作用机制。结果表明:与Fe3+离子相比,Cu2+离子可刺激细菌产生更多的EPS;当Cu2+离子浓度从0.01mol/L增加到0.04mol/L时,EPS中Fe3+/Cu2+质量比从4:1降低到2:1;从1%黄铜矿的无铁9K介质中提取的EPS中铜铁含量是从含0.04mol/LCu2+离子的9K介质中提取的量的2倍。在生物浸出黄铜矿过程中,黄铜矿表面结合黄铁钾钒的EPS层减弱了Cu2+、Fe3+离子的迁移,逐渐成为离子扩散壁垒。     

The mechanism of dezincification and the effect of arsenic. II

Abstract

Dezincification occurs by dissolution of both zinc and copper, followed by redeposition of copper from the oxygen-free cuprous chloride/zinc chloride anolyte. Deposition of copper from such a solution by reduction of Cu⁺ requires a potentIal below ?0·41 V but Cu²⁺, formed by disproportionation of cuprous chloride, can be reduced to copper at potentials up to ?0·16 V. As the potential of film-free beta-brass iS ?0·56 V, reduction of copper at the advancing front of dezincification in beta-brass can occur by direct cathodic re~uction of cuprous ions. Alpha-brass, with a potential of ?0·38V, can only reduce cupricions; dezincification of alpha-brass therefore depends upon formation of Cu²⁺ by disproportionation of cuprous chlonde at the advancing front.

Under the conditions existing at the advancing front, disproportionation of cuprous chloride can be suppressed by a small amount of arsenic, acting through reactions in which it cycles between the As³⁺ and AS_(solid)states. Arsenic consequently inhibits dezincification of alpha-brass but the dezincification of beta-brass, which does not require the formation of cupric ions, is unaffected.     

Deep removal of copper from cobalt sulfate electrolyte by ion-exchange

SP-C was applied for the removal of Cu²⁺ from simulated cobalt sulfate electrolyte containing Co²⁺ 50 g/L and Cu²⁺ 0.5–2.0 g/L. Experimental conditions included pH of 2–4, temperature of 20–60 °C and contact time of 10–40 min. The investigation demonstrated that SP-C had recommendable efficiency in adsorbing Cu²⁺ from the electrolyte with 25- to 100-fold of Co²⁺. The optimal adsorption conditions of SP-C were pH of 4, contact time of 30 min and ambient temperature. The study also showed that the loaded resin could be effectively eluted with 2.0 mol/L H₂SO₄ solution at a contact time of 40 min; the peak concentration of Cu²⁺ in the eluate was about 35 g/L. The sorption characteristics of Cu²⁺ by SP-C could be described by Langmuir isotherm and the pseudo second-order kinetic equation. Infrared spectra showed that nitrogen atoms in the functional group coordinated with Cu²⁺ to form coordination bands.     

Insight into the Mechanism of Nanoparticle-Aggregated Crystallization for Mesocrystals

研究和探讨了银介观晶体的形成过程和机理,银介观晶体通过AgNO3溶液和Sn替换反应合成原始的纳米微粒。在200mmol/L浓度下,纳米颗粒沿着<211>方向聚集形成树突,银纳米颗粒是3×{422}位面;相应的,当浓度达到1mol/L时,形成的纳米颗粒在沿着<211>方向聚集的同时,在<110>方向形成第2个聚集单位,并最终形成多空的盘状结构的介观晶体,其厚度约为50nm;当浓度为2mol/L时,纳米颗粒继续沿着<110>方向聚集,形成三角形的板状结构,随着聚集的越来越多,最终形成厚度超过100nm的单晶介观晶体。