湿法炼锌置换柱式净化装置传质过程(英文)

浸出液中铜、镉的净化是湿法炼锌中的重要步骤。提出一种置换柱式净化装置,并对其净化规律及传质系数进行实验研究。结果表明,净化效率随着锌粉粒径的减小及浸出液流速的减小而增大,若结构参数和操作参数使用恰当,净化率可达99%,但所使用的锌粉粒径必须大于0.45 mm。当流速范围为0.05~0.7 cm/s时,置换柱内传质系数kc为3.94×10-7~2.76×10-6 m/s,且kc随着锌粉粒径的减小及浸出液流速的增大而增大,满足传质准数方程:Sh=0.1069Re0.5Sc0.33(0.3相似文献   

Overlapped peaks resolution for linear sweep polarography using Gaussian-like distribution

A resolution method based on Gaussian-like distribution for overlapped linear sweep polarographic peaks was proposed to simultaneously detect the polymetallic components, such as Zn(II) and Co(II), coexisting in the leaching solution of zinc hydrometallurgy. A Gaussian-like distribution was constructed as the sub-model of overlapped peaks by analyzing the characteristics of linear sweep polarographic curve. Then, the abscissas of each peak and trough were pinpointed through multi-resolution wavelet decomposition, the curve and its derivative curves were fitted by using nonlinear weighted least squares (NWLS). Finally, overlapped peaks were resolved into independent sub-peaks based on fitted reconstruction parameters. The experimental results show that the relative error of half-wave potential pinpointed by multi-resolution wavelet decomposition is less than 1% and the accuracy of I_p fitted by NWLS is higher than 96%. The proposed resolution method is effective for overlapped linear sweep polarographic peaks of Zn(II) and Co(II).     

湿法锑白的晶型转变

研究了湿法锑白的白度和光敏性。通过真空干燥试验研究，对样品进次了Ｘ射线衍射定量分析，首次发现真空干燥可以使湿法锑白发生晶型转变，由斜方晶体转变为立方晶体。在适宜条件下，其转变率可达９９．６％。转变为立方晶的锑白白度高且见光稳定，光敏性消失。     

A comprehensive review on recycling methods for cemented tungsten carbide scraps highlighting the electrochemical techniques

The scraped and end-of-life tungsten carbide materials demand innovative recycling methods to recover valuable refractory and strategic metals like tungsten, cobalt, nickel etc. The efficient treatment of this material significantly benefits to economics as compared to its ore. Several methods based on pyrometallurgy or hydrometallurgy or their suitable combination have been explored. These methods encompass several unit operations tested at the laboratory as well as on the pilot scale. Some of the methods also matured into technology on a commercial scale. However, the demonstration at the pilot plant scale is towards the validation of the developed process. Each of the methods tested so far has its own pros and cons. For instance, the combination of pyro-hydrometallurgical process has some advantages over hydrometallurgical processes such as higher efficiency, lower costs, and a few industrial requirements, but it is energy-intensive and requires high capex. Besides, considerable attempts have been put into the development of the electrodissolution processes, recently. Several studies available through reports, research articles, and patents recommend a selective electro-dissolution process, which is flexible enough to recycle different varieties of WC scraps. Various electrolytes based on acidic (H₂SO₄, HCl, H₃PO_4, HNO₃) and alkaline (NaOH and NH₃) media worked well to dissolve the refractory metal. Several additives are often added as supporting agents to obviate the most common constraint in electrodissolution, i.e., passivation of the anode. This review particularly highlights the electrochemical methods for the recycling of WC materials along with other recycling methods in brief.     

Recovery of valuable metals from zinc leaching residue by sulfate roasting and water leaching

Zinc leaching residue (ZLR), produced from traditional zinc hydrometallurgy process, is not only a hazardous waste but also a potential valuable solid. The combination of sulfate roasting and water leaching was employed to recover the valuable metals from ZLR. The ZLR was initially roasted with ferric sulfate at 640 °C for 1 h with ferric sulfate/zinc ferrite mole ratio of 1.2. In this process, the valuable metals were efficiently transformed into water soluble sulfate, while iron remains as ferric oxide. Thereafter, water leaching was conducted to extract the valuable metals sulfate for recovery. The recovery rates of zinc, manganese, copper, cadmium and iron were 92.4%, 93.3%, 99.3%, 91.4% and 1.1%, respectively. A leaching toxicity test for ZLR was performed after water leaching. The results indicated that the final residue was effectively detoxified and all of the heavy metal leaching concentrations were under the allowable limit.     

The use of fibrous ion exchangers in gold hydrometallurgy

This article examines a family of ion-exchange fibers, FIBAN, containing primary and secondary amine groups. These ion exchangers have a fiber diameter of 20–40 Μm, high osmotic and mechanic stability, a high rate of adsorption and regeneration, and excellent dynamic characteristics as filtering media. Inparticular, this article discusses the use of FIBAN fibrous ion exchangers in the recovery of gold cyanide andbase-metal cyanides (copper and mercury) from mineral-leaching solutions. The influence of polymer structure and water content on their extraction ability is described, along with key parameters of gold hydrometallurgy such as extraction efficiency, selectivity, pH dependence, gold cyanide loading, kinetics, and stripping.     

Metal- and Polymer-Matrix Composites: Functional Lightweight Materials for High-Performance Structures

The special topic “Metal- and Polymer-Matrix Composites” is intended to capture the state of the art in the research and practice of functional composites. The current set of articles related to metal-matrix composites includes reviews on functionalities such as self-healing, self-lubricating, and self-cleaning capabilities; research results on a variety of aluminum-matrix composites; and investigations on advanced composites manufacturing methods. In addition, the processing and properties of carbon nanotube-reinforced polymer-matrix composites and adhesive bonding of laminated composites are discussed. The literature on functional metal-matrix composites is relatively scarce compared to functional polymer-matrix composites. The demand for lightweight composites in the transportation sector is fueling the rapid development in this field, which is captured in the current set of articles. The possibility of simultaneously tailoring several desired properties is attractive but very challenging, and it requires significant advancements in the science and technology of composite materials. The progress captured in the current set of articles shows promise for developing materials that seem capable of moving this field from laboratory-scale prototypes to actual industrial applications.     

Analysis of the integration between operations management manufacturing tools with discrete event simulation

The purpose of this paper is to analyse the integration of discrete event simulation (DES) in operations management manufacturing tools. Due to the movement of the fourth industrial revolution (Industrie 4.0), the integration of manufacturing is a topic constantly discussed in many areas. Moreover, it presents great research and innovation opportunities. To achieve the objective of this study, a search was conducted using the main keywords found in papers related to manufacturing systems and operations management manufacturing tools. Also, academic databases were literature research to identify the keywords relevant to the study added to DES. We considered only articles from the last 8 years. At the end between the search, the integration between tools such as manufacturing execution system, enterprise resource planning, radio frequency identification, core manufacturing simulation data, e-Kanban with DES were analysed. Furthermore, it was observed that the tools cannot always be used separately, but in some cases, these tools should be used jointly to solve problems related to production systems. Another aspect observed was how the data collected in production systems are fed to the DES models. Through, it was possible to analyse an existing gap regarding how the data is used between DES and manufacturing systems, thereby enabling research development in this area.     

‘Nickel Allergy’ arising from decorative nickel plated and alloyed articles: prevention at source

This work builds on papers published in Transactions during 2015 and 2018 reporting research into low-cost commercial methods for the prevention of nickel release from decorative nickel plated articles, rendering them suitable for placement on the European market in accordance with the requirements of REACH. ‘Nickel Allergy’ sometimes occurs when nickel-containing articles are in direct and prolonged contact with the skin, leading to corrosion of elemental nickel by sweat, liberating sufficient nickel ions to be absorbed through the skin and initiate an allergenic effect. The EU ‘Nickel Restrictions’ impose limits on the amount of nickel released from articles intended for use in this application, but permits a non-nickel surface coating that can ensure the rate of nickel release does not exceed 0.5?µg?cm^?2 week^?1 after 2 years of normal use. The official tests for coated items are simulated wear and corrosion under EN 12472 followed by determination of nickel release under EN 1811. Earlier work concluded that suitable barrier coatings over bright electrodeposited nickel are regular chromium deposited from a hexavalent electrolyte, microporous trivalent chromium from a chloride electrolyte and UV cured PU electrophoretic coatings. Further tests reported here focused on nickel release from examples of wearable articles such as costume jewellery and watch cases. A typical flash coating of gold over bright nickel is thin and porous and being more noble, causes the rate of nickel release to be accelerated; but this can be prevented by an intermediate barrier coating of electrodeposited palladium. To round out the relevance of this study on wearable articles, nickel release tests were also conducted on nickel-containing Grades 304 (UNS S30400) and 316 (UNS S31600) austenitic stainless steels, plus a typical gold alloy containing nickel. All passed the nickel release tests satisfactorily.     

五价锑离子与氯离子配位稳定常数测定及Sb-S-Cl-H2O体系热力学(英文)

测定五价锑离子与氯离子的配位常数,并进行Sb-S-Cl-H₂O体系的热力学研究。采用分光光度法进行配位稳定常数的测定,在一定波长(380nm)下测定含五价锑离子溶液在不同氯离子条件下的光度值,通过理论计算得到五价锑离子与氯离子的配位稳定常数。配位稳定常数以10为底的对数函数值分别为1.795、3.150、4.191、4.955、5.427和5.511,填补了锑湿法冶金中的部分数据空白。结合配位稳定常数,通过热力学计算研究五价锑离子的赋存形式和分布规律,并将锑离子与氯离子配位行为的影响带入Sb-S-Cl-H₂O体系进行热力学研究,得到复合电位-pH图。     

Technology development for rare earth cleaner hydrometallurgy in China

China is the global leader in rare earth(RE)production using hydrometallurgical processes. Advantageous extraction techniques of rare earths from Baotou mixed rare earth minerals, bastnaesite, and ion-adsorption clays of rare earth deposits have been developed in China.The separation and purification technologies have also achieved rapid development. The industrial application processes for rare earth hydrometallurgy were summarized in the present paper. With the large demands and rapid development of rare earths, the issues of resources and environment are more prominent. This review gives an overview of the main processes that were developed in the past toward greener hydrometallurgy of rare earths in China. Based on the development of the rare earth industry,comprehensive utilization and cleaner production should still be focused on in the future, to support the sustainable development.     

Transient response analysis of steel in concrete

A new approach is presented for the analysis of galvanostatically induced transients allowing for the rapid evaluation of the corrosion activity of steel in concrete. This method of analysis is based on the iterative fitting of a non-exponential model based on a modified KWW (Kohlrausch-Williams-Watt) formalism. This analysis yields values for the parameters related to corrosion such as the concrete resistance, polarisation resistance, interfacial capacitance and β, the non-ideality exponent.     

双氧水行业含钯废催化剂回收工艺的研究

对双氧水行业含钯废催化剂的回收工艺作了研究。采用湿法工艺分两步实现了钯的高效富集,富集物精炼得到99.95%的钯粉,全流程钯的回收率为98.66%。此外,对取样、除有机物、渣的处理等关键过程做了讨论,提出了优化的工艺流程。     

金刚石工具胎体预合金粉末制取与应用

预合金粉末是采用多种金属熔炼成低熔点合金后再喷制成的粉末,其制取可以用雾化法和湿法冶金等工艺生产.文中介绍了气体雾化法预合金粉末的工艺过程;描述了湿法冶金制取预合金粉末的工艺流程.分析了预合金粉末胎体金刚石工具的优点,说明了国外预合金粉末技术现状和发展趋势,剖析了国内预合金粉末及工具的研究情况,探讨了金刚石地质钻头胎体用预合金粉末的制取和实际应用情况,研究了切割花岗岩的预合金粉末胎体金刚石锯片.     

提高锌浸出渣中银浮选回收率的研究

某湿法炼锌厂低酸度锌浸出渣中53.8%的银存在于难完全回收的闪锌矿上,其回收是提高浮选回收率的关键。经对比浮选和正交试验获得了浮选粗选最佳药剂制度,捕收剂为丁铵黑药(900g/t)和Z-200(50 g/t),载体活性炭(2000 g/t),起泡剂2#油(100 g/t)。一粗一精一扫开路试验表明,在非强充气和非强搅拌条件下,浮选精矿银品位为8210 g/t,较现有工艺(3000 g/t)大幅提高;银回收率为64.7%,与现有工艺(60%~64%)相当。     

Study on Extracting Low Concentration Cadmium from Zinc Hydrometallurgy System by Liquid Membrane Crystallizing Technique

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Kinetics of atmospheric corrosion of mild steel, zinc, galvanized iron and aluminium at 10 exposure stations in India

As a part of updating Corrosion Map of India project, atmospheric corrosion behaviour of commercially available engineering materials such as mild steel, galvanized iron, zinc and aluminium metals was studied in marine, industrial, urban, and rural environments by weight loss method at 10 exposure stations in India over a period of 5 years. The results of these studies demonstrated that galvanized iron, zinc and aluminium metals were several times more durable than mild steel. Compared to galvanized iron and zinc, aluminium provided superior protection in industrial and marine environment except at Mormugao Port Trust (MPT). It also offered much better resistance to corrosion in rural environments. At certain places, galvanized iron proved to be more durable than aluminium. The results obeyed well with the empirical kinetics equation of the form C = Ktⁿ, where K and C are the corrosion losses in μm after 1 and ‘t’ years of the exposure, respectively, and ‘n’ is a constant. Based on ‘n’ values, the corrosion mechanisms of these metals are predicted. The corrosion products formed on the metal samples in Chennai marine atmosphere were identified by X-ray diffraction analysis.     

锌浸出渣中银的回收方法综述

湿法炼锌是当今世界炼锌主要方法,生产中所得锌浸渣中含有较多的锌及其他有价金属(如银、铅、铜、镉、铟、锗等),作为尾矿堆存不仅会占用大量的土地资源,而且还会造成资源的严重浪费,加之锌浸出渣的长期堆存环境危害性高,因此对锌浸出渣中的有价金属进行综合回收具有十分重要的意义。本文结合国内外锌浸出渣的研究状况,重点针对锌浸出渣中银的回收现状进行论述,全面阐述锌浸出渣中银的工艺矿物学性质、提取工艺流程及发展趋势,对该类资源的综合回收利用具有十分重要的借鉴作用。     

Treatment of cadmium dust with two-stage leaching process

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化工废催化剂中钯的回收

采用火法富集-湿法工艺相结合的工艺,从Pd/Al_2O_3废催化剂中回收钯,介绍了工艺流程及控制参数。