铅鼓风炉中铜、硫、砷和锑对银分布的影响(英文)

研究铅鼓风炉中杂质对银分布的影响。将含有不同Cu、S、As和Sb含量的铅烧结块在管式炉中于1573K下进行烧结,然后随炉冷却。烧结气氛为还原性的CO+CO2气体(p(CO)/p(CO2)=2.45)。采用SEM-EDS对所得样品进行表征。结果表明:烧结样品中含有5种不互溶的相,即炉渣(CaO,FeO,SiO2)、冰铜(S,Cu,Fe)、硬渣(As,Fe,Cu)、Cu-Sb相和铅块。银在Cu与Sb形成的熔体中的溶解度比在液态铅中的高。S与Cu形成冰铜,As与Cu形成硬渣。S和As能减少Cu-Sb合金的生成量,从而降低铅块中银的损失。     

稀土元素在金属材料中的一些物理化学作用

针对不同金属溶液体系，采用了不同的实验方法，研究得到了铁液中Ｃｅ，Ｙ，Ｌａ，Ｎｄ，Ｓｍ分别与Ｓ，Ｏ，Ｓ＋Ｏ，Ｃ，Ｎ，Ｓｂ，Ｓｎ Ｐｂ，Ｐ，Ｃｕ，Ｔｉ，Ｎｂ，Ｖ溶质元素，镍液中Ｃｅ，Ｙ分别与Ｓ，Ｏ，Ｓ＋Ｏ溶质元素，铜液中Ｃｅ，Ｙ分别与Ｓ，Ｏ，Ｓ＋Ｏ，Ｓｎ，Ｚｎ，Ｐｂ，Ａｌ，Ｓｉ，Ｔｉ，Ｆｅ溶质元素，铝液中Ｃｅ分别与Ｍｇ，Ｔｉ，Ｍｎ，Ｚｎ，Ｆｅ，Ｓｎ，Ｐｂ，Ｎｉ，Ｃｕ，Ｓｉ，Ｓ溶质元素构成的６７个三元     

Ida~(2-)-H_2O体系浸出低品位氧化锌矿(英文)

采用Ida2--H2O体系(亚氨二乙酸盐水溶液)处理高碱性脉石型低品位氧化锌矿,考察浸出时间、液固比、配体总浓度、温度及pH值对矿物中主金属Zn及杂质元素Ca、Mg、Cu、Ni、Fe、Pb、Cd的溶出影响。结果表明:在弱碱性Ida2--H2O体系中,Ca、Mg、Fe不会被大量溶出,有价金属Cu、Ni、Pb、Cd可部分随主金属Zn溶出而进入浸出液;在浸出时间4h、液固比5:1、配体总浓度0.9mol/L、温度70℃、pH8的优化条件下,锌浸出率为76.6%。     

Ida~（2-）-H_2O体系浸出低品位氧化锌矿

采用Ida2--H2O体系（亚氨二乙酸盐水溶液）处理高碱性脉石型低品位氧化锌矿,考察浸出时间、液固比、配体总浓度、温度及pH值对矿物中主金属Zn及杂质元素Ca、Mg、Cu、Ni、Fe、Pb、Cd的溶出影响。结果表明：在弱碱性Ida2--H2O体系中,Ca、Mg、Fe不会被大量溶出,有价金属Cu、Ni、Pb、Cd可部分随主金属Zn溶出而进入浸出液;在浸出时间4h、液固比5：1、配体总浓度0.9mol/L、温度70℃、pH8的优化条件下,锌浸出率为76.6%。     

Effects of Pb and Cu additives on microstructure and wear corrosion resistance behaviour of PM Al–Si alloys

Abstract

The wear and wear corrosion resistance behaviour of Al–20Si–XPb–YCu (X=0–10 wt-%, Y=0–3 wt-%) alloys fabricated by a powder metallurgy (PM) technique and subsequent heat treatments were evaluated by a block on ring tribotest. The microstructure of all aluminium alloys was observed by optical microscopy and scanning electron microscopy with X-ray energy dispersive spectroscopy. The effects of applied potentials and environments including dry air and 3.5 wt-%NaCl aqueous solution were studied. The results of microstructure analysis indicated that Pb exhibited a bimodal distribution in the Pb containing alloys, and Cu particles become to form the intermetallic phase CuAl₂. Furthermore, the hardness rises significantly for both Pb and Cu containing alloys only after solid solution quenching treatment. The wear and corrosion results showed that the addition of both lead and copper would improve the wear resistance but lead to a higher corrosion rate whereas heat treatment had a beneficial effect of reducing the corrosion rate of most alloys with the exception of Al–Si alloy. Furthermore, by comparison of all alloys after heat treatment, the wear corrosion resistance of Al–Si alloy was inferior to the other alloys; consequent additions of Pb and Cu further improved its wear corrosion resistance. Moreover, at an anodic potential, the wear corrosion rate and current density of both Al–Si and Al–Si–Cu alloys containing particle Pb decrease significantly owing to a corrosion product layer composed of Al, O and Pb elements.     

微电解絮凝耦合技术处理含重金属铅锌冶炼废水

采用"石灰中和曝气微电解絮凝沉淀法"技术处理含重金属铅锌冶炼废水,考察微电解进水pH值、水力停留时间、铁炭质量比、絮凝pH值和助凝剂用量等反应条件对废水中铅、锌、镉、铜和砷离子去除率的影响。采用扫描电镜(SEM)和能谱(EDS)等测试手段,研究微电解反应前后铁屑和活性炭的表面形貌及物质组成的变化,分析铁炭微电解原理及铁炭床失效原因。结果表明:在微电解铁炭质量比为1:1.5、进水初始pH值为2.5、水力停留时间为40 min、絮凝pH值为11、助凝剂PAM用量为4×10 6(质量分数)的条件下,微电解絮凝耦合技术对废水中各离子的去除效果最佳,Cd2+出水浓度达到了《污水综合排放标准》(GB8978—1996)中的一级标准,Pb2+、Cu2+、Zn2+和总砷的出水浓度满足《地表水环境质量标准》(GB 3838—2002)中Ⅲ类水标准。     

Iron extraction from lead slag by bath smelting

A new bath smelting process was proposed to recover iron for solid wastes reduction. 99.79% of iron metallization, 99.61% of iron recovery, pig iron with 93.58% Fe, 0.021% S, 0.11% P, 1.38% C, 0.22% Si, 0.01% Pb and 0.031% Zn were achieved after the wastes were smelted at 1575 °C for 20 min under C/Fe molar ratio of 1.6 and basicity of 1.2. The produced pig iron could be used in steel-making. This study provides a way for recycling iron from smelting slag and hydrometallurgical residue.     

镀锌钢-6016铝合金激光焊接组织性能与第一性原理计算

采用基于密度泛函理论的第一性原理方法,计算Fe8Al8及(Fe7X)Al8(X=Pb,Sn,Ti,Cu,Mn,Si,Zn)超胞模型的弹性模量与电子结构,在分析合金化元素改善FeAl金属间化合物力学性质的基础上,选取降低脆性效果较好的Cu和最好的Pb,对1.2 mm厚DC56D+ZF镀锌钢和1.15 mm厚6016铝合金平板试件进行加入中间夹层Cu和Pb的激光搭接焊试验。结果表明:FeAl金属间化合物为脆性相,其电子结构根源在于Fe的sd态与Al的sp态存在电子轨道杂化,为明显的共价键特征;FeAl合金化后,脆性降低,相应脆性由低到高的顺序为(Fe7Pb)Al8、(Fe7Sn)Al8、(Fe7Ti)Al8、(Fe7Cu)Al8、(Fe7Mn)Al8、(Fe7Si)Al8、(Fe7Zn)Al8、Fe8Al8,Pb合金化降低脆性效果最好,激光搭接焊加入中间夹层Pb,钢侧母材与焊缝界面区由母材侧较大晶粒和焊缝的细小晶粒交错形成,熔池金属与母材铝之间没有明显的分界线,焊接接头界面熔合良好;与未加夹层相比,加入中间夹层Cu和Pb后,焊接接头力学性能提高,其中Pb的作用优于Cu的,试样断口均具有韧性断裂特征。     

利用嗜酸混合菌从尼日利亚闪锌矿和方铅矿中生物浸出Zn（Ⅱ）和Pb（Ⅱ）

利用嗜酸混合菌在尼日利亚闪锌矿和方铅矿中生物浸出Zn（Ⅱ）和Pb（Ⅱ）,研究pH值和铁离子对闪锌矿和方铅矿浸出率的影响。结果表明：闪锌矿和方铅矿中Zn（Ⅱ）和Pb（Ⅱ）的氧化物在pH值分别为2.1和2.7时浸出效果最好。用模拟的琼脂糖培养基使细胞分泌出含铁离子的外聚合物,以此加强氧化。闪锌矿和方铅矿达到氧化平衡分别需要3和4d。闪锌矿和方铅矿在1d内的浸出率分别为38.3%和34.2%,5d内Zn（Ⅱ）和Pb（Ⅱ）分别还原92.0%和89.0%。使用XRD研究两种矿物的未浸出的剩余产物,闪锌矿的组成为S、ZnSO4和少量Ca3Al2O6,方铅矿的组成为S、PbSO4和少量的Pb（S,Ge）（O,OH）4和Pb8Co（Si2O7）3。     

氧分子在黄铁矿和方铅矿表面的吸附

采用密度泛函理论对氧分子在黄铁矿和方铅矿表面的吸附进行研究。计算结果表明:黄铁矿和方铅矿表面经历了较小的弛豫;氧分子在黄铁矿和方铅矿表面都呈解离吸附状态,且在黄铁矿表面的吸附能远低于在方铅矿表面的吸附能;在黄铁矿表面上,氧原子分别与铁原子和硫原子键合,电子由铁原子和硫原子转移到氧原子上,主要由硫的3p态、氧的2p态和铁的3d态参与反应,铁与氧之间形成d→p反馈键,而在方铅矿表面上,氧原子只与硫原子键合,主要由硫的3p态、氧的2p态和铅的6p态参与反应,未形成反馈键;氧吸附后黄铁矿表面产生键合的铁原子和氧原子都产生自旋现象,而方铅矿表面原子及吸附的氧原子仍然是低自旋态的。     

基于遗传算法的铜闪速熔炼过程控制优化

基于已建立的铜闪速熔炼神经网络模型,以能耗费用最低为目标,在工艺指标控制范围内,采用遗传算法对铜闪速熔炼过程的工艺参数进行了仿真优化计算。结果表明,当空气、分配风、工艺氧和中央氧的市场价格折合比值分别为0.05、0.1、0.4和0.45,精矿量为128 t,其成分(质量分数)为Cu 20.61%、S 27.59%、Fe 24.72%、SiO2 11.64%和MgO 1.39%时,铜闪速熔炼工艺参数的遗传优化值为空气15 011 m3、分配风1 302 m3、工艺氧17 359 m3、中央氧1 000 m3、熔剂13.6 t;与实践平均值相比,若采用优化工艺参数控制,熔炼能耗费用可降低4.6%。     

Electrochemical and mechanical behaviour of Sn‐2.5Ag‐0.5Cu and Sn‐48Bi‐2Zn solders

In this paper, two tin‐based alloys (Sn‐2.5Ag‐0.5Cu and Sn‐48Bi‐2Zn) are proposed as new lead‐free solders. Alloys have been developed by melting pure elements. Samples have been evaluated in terms of microstructure, corrosion resistance and mechanical features. Corrosion tests have been performed in 3% NaCl solution by polarization curves and electrochemical impedance spectroscopy (EIS). SEM observations and EDS analysis were carried out on samples before and after corrosion tests. Static monotonic tensile tests have been performed on three specimens for each alloy. SEM and EDS analysis revealed the presence of Sn‐Ag and Sn‐Cu intermetallic compounds within the Sn‐Ag‐Cu alloy. As a result of corrosion test, the Sn‐Ag‐Cu alloy showed a better corrosion resistance with respect to Sn‐Bi‐Zn. Both alloys evidenced good mechanical properties higher than the traditional Sn‐Pb system. Sn‐Ag‐Cu seems to be a suitable soldering material.     

NaOH分解含铟铁矾渣新工艺

提出NaOH分解含铟铁矾渣新工艺,考察NaOH用量、液固比、温度和时间对铁矾渣分解率的影响,并讨论铁矾渣中杂质金属,如Zn、In、Cu、Cd、Pb、As、Sb、Sn和Ag等在NaOH分解过程中的行为.结果表明:在m(NaOH)-m(铁矾渣)=0.381 4-1、温度60 ℃、液固比2-1、反应时间2 h的最优条件下,铁矾渣的分解率达到98.03%,而原料中的杂质金属,如Sn、Sb、Zn、In、Cu、Cd、Pb和Ag等绝大部分留在分解渣中,As则以AsO43-的形态大部分进入溶液,浸出率达到83.36%.DSC-TGA热分析和X射线衍射分析结果表明:在NaOH分解过程中,铁矾渣中的铁主要以Fe3O4形式沉淀入渣;分解渣中Fe、In和Zn的含量分别为38.81%、0.23%和12.89%;经稀盐酸选择性浸出铟和锌后,进一步磁选富集可作为炼铁原料.     

FeCl3浸取含Au复杂硫化矿的动力学研究

研究了FeCl_3溶液浸取复杂含金硫化精矿中有价金属Cu,Ag,Pb和Zh的过程,考察了主要过程参量对浸取速率的影响.实验数据用非线性回归方法处理,给出动力学模型,说明精矿中Cu的溶解过程由表面化学反应控制,其速率是Fe~(3+)的0.5级和Cl~(-)的零级反应.实验条件下Cu,Ag,Ph和Zn的最终浸取率分别达到96,95,90和91%,超过90%的Fe进入浸取液,总硫的70%以上转化为元素硫,而Au的浸取率则小于3%表明FeCl_3溶液浸取是含Au复杂硫化精矿预处理并回收有价金属的有潜力的方法     

离心铸造ZCuPb10Sn10轴套时铅偏析的防止措施

由于Pb与Cu互不固溶,而且铅的密度较大,铅青铜铸件容易产生铅的偏析。尤其在离心力场的作用下,偏析愈易发生。针对实际生产,介绍了离心铸造铅青铜(ZCuPb10Sn10)轴套时防止偏析的措施。     

Theoretical design and distribution control of precipitates and solute elements in Al−Zn−Mg−Cu alloys with heterostructure

In order to simultaneously improve strength and formability, an analytical model for the concentration distribution of precipitates and solute elements is established and used to theoretically design and control the heterogeneous microstructure of Al−Zn−Mg−Cu alloys. The results show that the dissolution of precipitates is mainly affected by particle size and heat treatment temperature, the heterogeneous distribution level of solute elements diffused in the alloy matrix mainly depends on the grain size, while the heat treatment temperature only has an obvious effect on the concentration distribution in the larger grains, and the experimental results of Al−Zn−Mg−Cu alloy are in good agreement with the theoretical model predictions of precipitates and solute element concentration distribution. Controlling the concentration distribution of precipitates and solute elements in Al−Zn−Mg−Cu alloys is the premise of accurately constructing heterogeneous microstructure in micro-domains, which can be used to significantly improve the formability of Al−Zn−Mg−Cu alloys with a heterostructure.     

The electrochemical behaviour of leaded brass in neutral CL and SO4 media

The electrochemical behaviour of lead brass with different leaded content in neutral chloride and sulphate solutions was investigated using the EIS technique. For comparison, the behaviour of the pure components of the alloy was investigated under the same conditions. The corrosion process was found to proceed via oxygen reduction following a diffusion controlled mechanism. The Cu electrode showed a higher polarization resistance due to film formation during oxygen reduction. Zn and Pb showed markedly lower impedance values due to continuous dissolution. The two investigated brass alloys (1.8% and 3.5% Pb, respectively) showed higher impedance values indicating the passivation of the surface in the Cl⁻ or SO₄⁻ media. Brass II was found to be more stable against corrosion indicating the beneficial effect of the lead content in the alloy.At cathodic potentials, the only process is the oxygen reduction. Anodic polarization leads to selective dissolution of Zn. At more positive potentials simultaneous dissolution of the alloy components with the deposition of Cu(I) salt takes place leading to the passivation of the alloy surface. At higher potentials, film breakdown occurs producing Cu(II) compounds whose diffusion control the corrosion process. At potentials higher than − 0.1 V, pitting corrosion was observed and a transmission line type in the impedance spectra was recorded.     

Prediction of the distribution of alkali and trace elements between the condensed and gaseous phases generated during clinical waste incineration

The mobilisation of alkali and trace elements present in clinical waste can lead to accelerated deterioration of the plant and to environmental damage. The damage can be caused by transfer of low levels of trace elements, which are difficult to monitor, and a model of the underlying processes which predicts the degree of mobilisation of each element from waste of specified characteristics is thus desirable. The Equilibrium module of the FACT suite of computer programs has been used to make predictions for alkali and trace element mobilisation from a typical waste composition with variation in the S/Cl ratio which influences the volatilisation/condensation processes. Although thermodynamic data for some of the potential melts are incomplete, predictions made using the various oxide melt models, matte, salt and solid solution models available in FACT are combined to allow meaningful comment on Pb, Cu, Zn, Ni and Cr distributions. Separate consideration is given to mobilisation in primary (pyrolysis) and secondary combustion (oxidation) chambers. Comparisons are made with published data from municipal waste incineration plants. An interesting feature of the predictions for condensation during cooling of the waste gases is that if solution of Pb, Zn and Cu chlorides is permitted in alkali chloride or Pb sulphate into sulphate melts then Pb and Cu are predicted to be largely removed from the gas stream into these melts.     

DFT research on activation of sphalerite

Activation of sphalerite ZnS, (Zn, Fe)S, (Zn, Cu)S were carried out using the density functional theory (DFT) method. The electronic structures and related properties of three kind of zinc sulfide compounds were investigated. In addition, the relation between electronic structure and flotation behavior was discussed. The results show that, ZnS has a broader band gap than (Zn,Cu)S and (Zn,Fe)S do, and it has low electrochemistry activity to react with flotation collectors to render the surface hydrophobic. When the Zn atom in ZnS is replaced by Cu atom,the band gap will be reduced, and the top valence band will be occupied by Cu 3d orbit, thus it is beneficial to the interaction between mineral surface and collector.     

ICP-AES法测定三苯基膦氯化铑中的微量杂质

将三苯基膦氯化铑用硝酸、高氯酸消解,以混合酸溶解样品,用ICP-AES法测定三苯基膦氯化铑中的微量Al、Cu、Fe、Mg、Pd、Ni、Pb、Pt、Zn杂质元素含量。选择合适波长消除光谱干扰,用背景点扣除的方式消除铑对Fe、Ni、Pb、Pt、Zn的基体干扰。各杂质元素的检测范围为0.001%~0.1%,加标回收率为93.25%~117.0%,精密度(RSD)为0.18%~15.41%。与直流电弧发射光谱分析方法相比,准确度和精密度均得到提高,高纯铑基体消耗减少,操作简化。