锌浸出渣中重金属的环境活性和生态风险评价

采用矿物学分析、BCR三步连续浸提、动态淋洗实验以及Hakanson潜在生态风险评价4种方法对锌浸出渣重金属的环境活性以及生态风险进行评价.结果表明,锌浸出渣中重金属的环境活性大小依次为Cd＞Zn＞Cu＞As＞Pb.废渣中主要重金属的潜在生态风险评价表明,该种废渣对环境具有很高的生态风险,单个重金属的生态危害顺序为Cd＞Zn＞Cu＞As＞Pb.Cd有很严重的生态风险,是对生态环境造成毒性的主要原因.     

Pb/Zn冶炼废渣中有价金属生物浸出条件优化

为提高生物浸出Pb／Zn冶炼废渣中有价金属的浸出率,利用正交设计,通过摇瓶实验,研究微生物浸出某Pb／Zn冶炼废渣过程中温度、pH值、废渣浓度及浸出时间等对废渣中Cu,Zn,In,Ga,Pb和Ag等有价金属浸出的影响。结果表明,在pH值为1．5、废渣浓度为5％、温度为65℃的优化浸出条件下生物浸出4d,Pb／Zn冶炼废渣中有价金属Cu,Zn,In和Ga的浸出率分别达到95．5％,93．5％,85．0％和80．2％,而Pb和Ag则主要以硫酸铅、黄钾铁矾类物质或硫化银形式富集在余渣中。     

生物浸出体系中中等嗜热菌对锌冶炼窑渣中金属的提取及其电化学特性的影响(英文)

研究中等嗜热菌对锌冶炼窑渣中金属提取的影响以及生物浸出过程中锌冶炼窑渣碳糊电极的电化学特性。结果表明,在矿浆浓度2%、pH1.0、温度65°C、转速为120r/min的浸出条件下,去除生物浸出体系中吸附菌后,废渣中Fe、Cu和Zn的浸出率分别为86.7%、90.3%和66.7%,而在没有去除吸附菌体系中3种金属的浸出率分别为91.9%、96.0%和84.5%。对生物浸出渣和酸浸渣表面细菌分泌物进行FT-IR测试分析可知,生物浸出渣颗粒表面出现了新的官能团振动峰,如1007cm1和1193cm1处的峰,间接说明残渣颗粒表面吸附细菌的存在。生物浸出体系和空白体系的循环伏安曲线和塔菲尔曲线特性进一步表明生物浸出体系中细菌促进了锌冶炼窑渣中有价金属的溶出。     

硫酸肼还原浸出锌中浸渣中镉(英文)

湿法炼锌中性浸出渣(中浸渣)是含有Cd和Zn等重金属元素的一种危险中间物料,对环境造成严重危害。本研究所用锌中浸渣含有约35.99%Zn、15.93%Fe和0.26%Cd,而Cd主要以铁酸盐的形式存在。研究硫酸肼浓度、硫酸初始浓度、温度、时间以及液固比对酸性还原浸出锌中浸渣Cd、Zn和Fe浸出率的影响。结果表明,中浸渣在硫酸肼浓度为33.3 g/L、硫酸初始浓度为80 g/L、浸出温度为95°C、液固比为10 m L/g、搅拌速度为400 r/min条件下还原浸出120 min,Cd、Zn和Fe的浸出率分别达90.81%、95.83%和94.19%。X射线衍射及扫描电镜-能谱分析显示还原浸出渣的主要物相为硫酸铅(Pb SO4)以及硫酸锌肼复盐((N2H5)2Zn(SO4)2)。     

由氧化锌烟灰氨法制取高纯锌

开发了用NH3-NH4Cl水溶液浸出炼铅炉渣烟化炉氧化锌烟灰制取高纯锌的新工艺.Zn的浸出率＞96%,浸出液加H2O2后净化除Sb和As,然后采用加锌粉两段逆流除Cu,Cd,Pb,电积过程中电能消耗2 500～2 700 kW@h/t.电锌含Zn＞99.999%,杂质元素Cu,Cd,Co,Ni,Fe,As,Sb均小于0.0001%,Pb＜0.000 3%.     

常压-氧压联合浸出锌置换渣中的镓和锗

针对锌置换渣中有价金属元素种类多、物相组成复杂的特点,本研究提出采用一段常压-二段氧压浸出的方法高效浸出锌置换渣中的有价金属。采用XRD和SEM-EDS对浸出渣物相以及形貌进行了分析。结果表明：在硫酸浓度1.5 mol/L、温度80℃、液固比7.5 mL/g、浸出时间3 h的条件下,常压浸出过程中Cu、Zn、Cd、Fe、Ni、Ga和Ge的浸出率分别为97.48%、99.43%、99.82%、97.21%、98.97%、97.74%、82.46%。对常压浸出渣进行二段氧压浸出,在氧气分压0.6 MPa以及硫酸浓度为0.25 mol/L条件下,Cu和Ge的浸出率可进一步分别提高至99.87%和91.66%。通过两段浸出,原来在置换渣中存在的Cu、Zn、Fe等物相消失,浸出渣主要由Pb和Si组成;铅的主要物相为PbSO₄,Si以粒径较小的聚合硅胶颗粒和块状SiO₂颗粒形式存在;聚合硅胶颗粒和块状SiO₂颗粒中Ge含量较高,对Ge的浸出造成不利影响。     

南昌市污水处理厂污泥中重金属的污染危害（英文）

对南昌市红谷滩、朝阳、青山湖和象湖4个主要污水处理厂污泥中重金属的污染危害进行探讨。依据污泥样品中重金属的总含量、化学形态和可浸出量,对污泥中Cu、Pb、Zn、Cd、Cr和Ni 6种重金属的污染特性和环境风险进行评估。研究结果表明,除了重金属Pb,青山湖污水厂污泥中重金属的总量高于其他3个污水厂污泥(红谷滩、朝阳和象湖)。大部分污水厂污泥中重金属Cd和Ni总含量超过了相应的标准。重金属Cu、Cr和Pb主要以潜在影响和稳定态的形式存在,而重金属Zn和Ni则具有较高的活性,重金属Cd的化学形态分布较为均衡。重金属的可浸出量几乎都超过相应的标准值,尤其是重金属Zn和Ni。污泥中重金属的潜在生态风险指数高达4263.34~7480.26,也即,重金属的生态风险处于"非常高"的水平。另外,污泥中重金属Cd的污染占主要地位。     

回转窑内渣成分优化实现锌铅元素的高效回收（英文）

在回转窑内从高硅锌浸出渣中实现高效回收锌铅金属。XRD、SEM、EDS及ICP表征结果表明,浸出渣含12.4%SiO₂、16.1%Zn和7.4%Pb(质量分数)。热力学分析表明,在回转窑内1150～1250℃的冶炼环境下,锌浸出渣中极易产生锌和铅的金属蒸气。通过分析13种冶金渣成分的黏度及熔点,发现3种渣成分(47%SiO₂-23%CaO-30%FeO、40%SiO₂-28%CaO-32%FeO、40%SiO₂-30%CaO-30%FeO,质量分数)具有合适的物理特性,即熔点和黏度分别为1150～1280℃和0.2～0.5 Pa·s。工业实验表明,采用优化的渣成分,锌和铅的回收率分别高达97.3%和94.5%,冶炼后渣内锌和铅的含量分别低至0.51%和0.45%(质量分数)。水淬渣的国标浸出实验表明,浸出液中含1.82 mg/L Zn、～0.01 mg/L Cu、0.0004 mg/L As、～0.01 mg/L Cd、0.08 mg/L Pb和～0.02 mg/L Hg,证实锌浸出渣同步实现无害化...     

湿法炼锌酸浸出渣浮选回收银试验

传统锌精矿伴生银回收,均是从挥发窑渣中进行,由于矿物性质变化,导致银无法有效回收。进行了从锌酸浸出渣中浮选回收银的研究,解决了锌精矿中伴生银回收的问题。某湿法炼锌浸出渣含Ag 350 g/t,Au0.01 g/t,Pb 3.87%,Zn 17.45%,Cu 1.38%,银主要以自然银存在,占60.13%。采用高效捕收剂HT-1#、起泡剂HT-2#进行浮选,经过一粗四精三扫工艺,获得银精矿产率4.39%,含银6616 g/t,银回收率82.98%,取得良好的经济技术指标。     

对含铅及高铁固体废物还原造锍熔炼炉渣和铁锍的环境评价（英文）

还原造锍熔炼技术是可综合回收利用高铁、含铅固体废物的一种新技术。其主要副产物是炉渣和铁锍。采用浸出毒性实验、BCR三步连续浸提以及Hakanson潜在生态风险评价等方法系统地对还原造锍主要副产物和进炉炉料中重金属(Cd、Zn、Pb和As)的环境风险进行评价。结果表明,经过还原造锍熔炼后,水淬渣和铁锍中重金属潜在的环境生态风险明显比进炉炉料的低。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.