Hydrogen reduction of spent copper electrolyte

The recovery of copper powder and the removal of arsenic from spent copper electrolyte by means of hydrogen reduction aimed at purifying the spent copper electrolyte were studied. About 90% of the copper in the electrolyte could be recovered in the form of pure copper powder after 20 min reduction at 180° at a hydrogen pressure of 20 kg cm^?2 (2.0 MPa). An induction period, due to slow hydrogen reduction of As⁵⁺ to As³⁺, could be eliminated as a result of the addition of copper powder as a reductant. Arsenic, antimony and bismuth in the liquor have been found to catalyze the hydrogen reduction of copper. When the copper concentration in the treated solution reached a certain low level, copper arsenide, Cu₃As₁ was formed on the surface of copper through hydrogen reduction of As³⁺ ions. This reaction was very slow and a long reaction time was required for complete removal of arsenic. Therefore, in order to purify spent copper electrolyte, some arsenic removal technique (e.g., solvent extraction) should be combined with hydrogen reduction.     

Hydrogen detrapping from grain boundaries and dislocations in high purity iron

Hydrogen detrapping in high purity iron was studied by measuring evolution rates of quenched-in hydrogen from 80 to 800 K using a quadrupole mass spectrometer in an ultra high vacuum system. The peak of the evolution rate was observed at 395 K in single crystal specimens and 415 K in polycrystalline specimens with a heating rate of 1 K min⁻¹. Effects of grain size and deformation on the evolution rate was also studied. It was shown that the results are consistent with the evolution rates calculated with the binding energy B = 0.51 ± 0.02 eV and the trap density term γC_{T = (4 ∼ 15) × 10⁻⁵} in polycrystalline iron, and B = 0.47 ± 0.02 eVand γC_T = (2 ∼ 13) × 10⁻⁵ in single crystal iron. The dominant traps are considered to be grain boundaries in polycrystalline specimens and dislocations in single crystal specimens.     

高纯金属钒粉烧结性能研究

利用电子探针观察高纯金属钒粉粒度和形貌, 使用油压机将高纯金属钒粉压制成坯条, 并采用万能试验机测定钒坯条压溃变形力曲线, 分析钒坯条最优压制压力; 分别通过热压烧结和冷等静压+真空烧结的方法对高纯钒粉进行烧结, 研究烧结工艺对高纯钒粉烧结特性和力学性能的影响。结果表明: 采用冷等静压+真空烧结的方法, 在压制成形过程中, 钒粉压坯密度和相对密度随压力的增加而逐步提高, 压力提高到280 MPa时, 压坯密度和相对密度分别为3.99 g·cm-3和66.94%;经真空烧结后, 坯料密度和相对密度分别为5.28 g·cm-3和88.59%。压制压力由80 MPa提高到200 MPa时, 压溃强度从0.4 MPa增加到6.0 MPa, 增大趋势较为明显; 压制压力提高到280 MPa时, 压溃强度增加到7.4 MPa, 增大趋势变缓。经热压烧结坯料的相对密度比冷等静压+真空烧结坯料的相对密度高, 280MPa压力下热压烧结坯料密度和相对密度分别达到5.51g·cm-3和92.91%。     

黄金冶炼厂中萃取法提铜研究

本文针对黄金冶炼厂中萃取法提铜,通过实验研究,探讨萃取剂和稀释剂的选择,并提出萃取法提铜的主要思路,最后分析了杂质对萃取提铜需要。分析结果表明,在黄金冶炼厂,通过萃取法在废水、废渣中可以提出大量的铜,既有助于提升黄金冶炼厂的经济效益,也可以降低对周围生态环境造成的污染,值得高度重视。     

Kinetics of continuous hydrogen reduction of copper from a sulfate solution

The objective of this experimental investigation was to obtain information on the reaction kinetics for the hydrogen reduction of copper from copper sulfate solutions in a continuous, countercurrent tubular reactor. Aqueous copper sulfate solution was introduced at the top of the reactor while hydrogen was sparged into the bottom. Separations of the bottom (liquid-solid) and overflow (gas-liquid) products were accomplished in individual high pressure separators. The rate of reaction increases with temperature up to about 180 to 220 °C depending on the residence time and thereafter levels off or decreases slightly. Feed solutions having a pH greater than 1.8 yielded a product which was contaminated with cuprus oxide. Over the range of this study, the operating pressure, and consequently the solubility of hydrogen in the aqueous reactant demonstrated negligible effect on the depletions. Likewise, very little change in depletions was observed beyond residence times of 10 minutes. Acid addition to the feed retarded the rate of reaction, whereas addition of sulfate ion increased the rate; these two observations agree with the results of previous investigators.     

废杂Cu冶炼烟尘碱法工艺制备高活性Zn粉

采用清洁工艺回收再生Cu烟尘中的金属资源,并副产高附加值的产品。工艺流程包含微波碱浸、净化除杂和电解等工序。在浸出环节,通过微波(30 s×4循环)辅助,利用浓度为200 g/L的Na OH可浸取出约83%(质量分数)的Zn,而大部分Cu留在浸出渣中;微波辐射促进了Zn溶出,提高了溶液中Zn2+的相对浓度,并且降低了Na OH的使用量。在净化阶段,采用Na2S粉作为净化剂,使得杂质金属残留浓度低于100 mg/L。电解净化后的碱液,可获得Zn粉;最佳电解条件为:反应温度35℃,电流密度1 000~1 500 A/m2,Zn2+浓度30~40 g/L,Na OH浓度180~220 g/L。采用扫描电镜、X射线衍射仪和马尔文激光粒度仪来表征产品Zn粉。此清洁工艺投资成本低,设计简单,在工业危险废物Zn回收领域具有良好前景。     

Direct electrolytic refining of end-of-life industrial copper waste scraps for production of high purity copper powder

The end-of-life electric cables from both domestic and industrial sources offer an attractive resource of copper metal. In addition, copper wastes generated during fabrication of copper components remains another valuable source of recyclable copper. This work reports a simple, cost-effective and eco-friendly direct electrolytic refining using waste electrical copper wire scrap and copper plate rejects for producing the value added high purity copper powder. Suitable anode support system was applied in which compressed wire scrap or copper plate rejects were held to make anode for electrolytic cell. Electrolysis parameters like current density, acid concentration and copper ion concentration were varied to arrive at optimum condition. Results showed the energy consumption of 1.44 kW h/kg at 89% current efficiency for producing the copper powder, that consisted of >80% of–325 mesh size particles, from waste copper wire anodes. However, slightly lower energy consumption of 1.32 kW h/kg at 91% current efficiency was observed during production of copper powder from copper fabrication rejects. The copper powder thus produced was characterised by chemical analysis, XRD and optical microscope to examine the purity and morphology etc. and found suitable for powder metallurgical applications. Present investigations have established the potential utilisation of copper waste wire scrap and copper plate rejects for the production of value added high purity copper powder.     

Recovery of metal values from copper smelter flue dust

A hydrometallurgical process has been developed for the recovery of valuable metals from the flue dust of a copper smelter. The dust containing various metals, such as lead, zinc, copper, bismuth, indium, cadmium, iron, arsenic etc., was treated using this hydrometallurgical process to recover all these metals and also to solve environmental pollution problems. Leachings were carried out under atmospheric and elevated pressure utilizing sulfuric acid. Sulfuric acid pressure leaching in the absence of oxygen provided the best separation of copper and arsenic. About 80% of arsenic went into solution during leaching, and more than 90% of copper remained in the residue as cupric sulfide. Zinc, cadmium and indium from the solution and bismuth, copper and lead from the residue were recovered by various well-known processes. Arsenic and iron were removed from the solution by oxidation and precipitation as ferric arsenate. Both laboratory and bench-scale experiments were carried out with satisfactory results.     

Application of annular centrifugal contactors in the extraction flowsheet for producing high purity yttrium

Compared with mixer-settlers applied widely in the hydrometallurgical industry of rare earths (RE), centrifugal contactors have several advantages such as low hold-up volume, excellent phase separation, high mass transfer efficiency, compact and short pieces of equipment, etc., and have been successfully used in some industrial fields. Yttrium (Y) is an important element and in great demand in many industries. For a variety of uses in many specialized areas, the high purity Y is often required. However, the separation and purification of Y by solvent extraction from RE mixture is widely known to be difficult due to their similar chemical properties. This paper studied both the separation factors of RE ions in the 32% HA (naphthenic acid) − 20% iso-octylalcohol–48% kerosene–RECl system and the distribution ratios of RE ions in the 32% HEHEHP (2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester) − 68% kerosene–RECl system. Based on these studies, an extraction flowsheet for producing high purity Y with HA and HEHEHP as extractants has been developed. Both the bench scale test and the pilot-plant test of the flowsheet have been performed with ϕ20 mm and ϕ120 mm centrifugal contactors respectively. It is shown that Y₂O₃ with 99.99% purity was obtained, and the total recovery of Y was about 95%.     

大冶冶炼厂高电流密度铜电解工业试验

介绍了大冶冶炼厂在现有生产条件下进行的高电流密度铜电解工业试验。结果表明,高电流密度电解所得阴极铜外观质量较好,电流密度280A/m~2时高纯阴极铜合格率为98.15%～98.37%,290A/m~2时高纯阴极铜合格率为95.51%～98.29%。     

高纯阴极铜中铅超标的解决措施

分析了高纯阴极铜铅超标的原因,介绍了解决措施和取得的效果。     

ICP-AES法测定高纯阴极铜中杂质元素

研究了EDTA存在下 ,氯化钠 -二乙基二硫代氨基甲酸钠 -丙醇体系萃取分离铜 ,用ICP AES法同时测定高纯阴极铜样品中Pb ,Fe ,Bi,Sb ,As ,Sn ,Ni,Zn ,P ,S ,Ag ,Se ,Te ,Si,Mn ,Cr的新方法。方法的检出限为 0.0 0 3～ 0.0 2 8μg/mL ,回收率为 94.5 %～ 10 7.2 % ,RSD小于 4.7%。该法准确、快速、简便 ,应用于阴极铜中杂质元素的测定 ,结果满意     

固体废物铜熔炼渣的快速鉴定

鉴定进口矿渣是否为海关监管的固体废物主要根据行业标准《进口矿渣的鉴定通则》(SN/T 3107-2012)。根据本通则进行外观检查、主要物相等特征分析, 仅满足对常见矿渣样品的初步筛查。对复杂的“非常规”的矿渣样品, 研究表明, 通过增加X射线衍射法与X射线荧光光谱法在样品分析中的应用, 再深入分析铜矿冶炼过程中的反应机理, 对照常见FeO-Fe₂O₃-SiO₂铜熔炼渣体系相图, 同时参考《固体废物属性鉴别案例》, 可实现对复杂矿渣样品是否为固体废物的准确和快速鉴定。     

高纯阴极铜中铅超标的解决措施

分析了高纯阴极铜铅超标的原因,介绍了解决措施和取得的效果。     

Scanning electron microscope fractography of continuously cast high purity copper after high temperature creep

Fracture surfaces produced by high temperature creep were studied using the scanning electron microscope. The material investigated was continuously cast high purity copper containing a nodal impurity segregation structure at which grain boundary voids are formed during creep. The observed void shape suggests that vacancies are supplied mainly via grain boundaries, and also by enhanced diffusion via segregation nodes; the vacancies seem to originate mainly at internal sources. The known distribution of potential nucleation sites was used to study the efficiency of the segregation structure in nucleating voids under various test conditions. Within the range of conditions employed, three different fracture modes were observed in separate regions of the stress-temperature plane. The regions are sequentially denotedA, B, and C as the temperature is increased at a given stress; they shift to lower temperatures as the stress is increased. In regionA fracture is initiated by extensive cavitation along grain edges (line of junction of three grains); cavitation at the segregation structure seems to be of secondary importance. In regionB formation and growth to coalescence of voids at segregation nodes governs fracture; the change of growth mechanisms with test conditions is discussed. In region C fracture is controlled by plastic instability. A. RUKWIED,Physicist , formerly with Mechanical Properties Section, Metallurgy Division, Institute for Materials Research, National Bureau of Standards, U. S. Department of Commerce, Washington, D. C.     

The recovery of non-ferrous metals from secondary copper smelter discard slags

Abstract

The use of carbothermic reduction as a method of recovering copper and other non-ferrous metals from smelter discard slags has been examined. Although several pilotscale tests (referred elsewhere) showed that the recovery of copper into a base metal can exceed 70%, even for a slag originally containing only 1.5% copper, it was considered that further studies under controlled laboratory conditions were necessary to obtain a better understanding of the reduction mechanisms involved. Results from these laboratory studies show that not only is the extraction of copper related to the copper and iron contents of the original slag, but the initial slag composition also influences the composition of the base-metal. With the data obtained it is now possible to estimate the grade-recovery relationship from slags of different compositions. The physical and chemical nature of the slags after treatment is also discussed and it is concluded that refractory attack, and the subsequent assimilation of the refractory into the slag matrix may play a significant role in the mechanism by which metals are retained in slags.

Résumé

La méthode de réduction carbothermique pour la récupération du cuivre et d'autres métaux non ferreux des laitiers mis au rebut d'une fonderie a été examinée. Plusieurs essais à l'échelle pilote ont démontré que la récuperation du cuivre au moyen d'un vil métal peut excéder 70%, même pour un laitier contenant seulement 1.5% eu au départ. On considère alors que les etudes approfondies dans les conditions contrôlées en laboratoire étaient nécessaires pour obtenir une meilleure connaissance des mécanismes de la réduction. Les résultats expérimentaux montrent que l'extraction du cuivre dépend de la teneur originale en cuivre et en fer dans Ie laitier. De plus, la composition initiale du laitier a une influence sur la composition du vil métal. Avec les données expérimentales on peut estimer le rapport teneur-récupération des laitiers aux differentes compositions. Les comportements physique et chimique sont aussi abordés et on constate que l'usure du réfractaire aussi bien que la dissolution subséquente du réfractaire vers la matrice du laitier peuvent jouer un rôle significatif dans le mécanisme de retenu des métaux par les laitiers.     

Bioleaching of copper from smelter dust in a series of airlift bioreactors

Bioleaching of copper from the flue dust of the Sarcheshmeh copper smelter has been investigated. A series of continuous tests were carried out in two-stages of airlift bioreactors inoculated with the acidophilic, iron and sulfur oxidizing bacteria, initially derived from acid mine drainage. The effects of different parameters such as pulp density, retention time and temperature on the mesophile bioleach performance of the copper sulfide rich dust were evaluated after pre-leaching with dilute acid. Pulp densities of 2% and 4% gave the same oxidation–reduction potential in both reactors. However, increasing the average pulp density to 7% generated an unstable oxidation–reduction potential in the first bioreactor at 34 °C. Overall copper extractions calculated for 2%, 4% and 7% pulp densities were 90%, 89% and 86% with mean retention times of 2.7, 4 and 5 days, respectively. The process is net acid consuming and has the potential for further development and feasibility studies.     

电解钛氢化脱氢制备超细高纯钛粉工艺

以电解钛为原料,采用氢化、球磨破碎和脱氢的工艺,制备超细高纯钛粉。采用激光衍射粒度分析、SEM及氢和氧元素分析等手段,研究各工艺过程所得的TiH2粉和Ti粉的粒度及其分布、粉末形貌和氧含量的变化趋势。结果表明:电解钛经420℃氢化后,初次球磨得到中位径(D50)为9.81μm的超细TiH2粉,再经600℃保温脱氢,最后经球磨分散得到D50为11.04μm,氧含量为0.48%(质量分数)的不规则形状超细高纯钛粉。在各个工艺过程中,氧含量(质量分数)增加量由低到高依次是TiH2粉脱氢、TiH2球磨制粉、脱氢钛粉球磨和电解钛氢化。