Extractive Metallurgy of Beryllium

Abstract

A comprehensive review of the extractive metallurgy of beryllium is presented. Due to the strategic importance and element of secrecy surrounding the metal, any open literature on beryllium is rather limited. However, this review has been made to cover all important aspects of beryllium extraction technology namely, resources of the metal; processing of ores; reduction of fluoride and oxide to get metal and alloy; refining of the metal; post preparation processes to shape metal through powder metallurgical route and preparation of foils and ceramics. Special attention has been given to the topic of toxicology and pollution control. Recyclfng of beryllium will form the concluding section. Information on the removal of impurities during the preparation of intermediate products as well as during reduction to metal and its alloys are described with process principles. Thus this review, with the help of discussion on each unit process and at the same time emphasising on the problems faced in large scale handling of this toxic metal and its compounds, shall provide substantial information presently available on the extractive metallurgy of beryllium.     

金属铍生产过程还原渣回收净化工艺研究

金属铍生产过程中氟化铍还原工序直收率低,40%～45%的铍进入还原烟尘及还原渣中,造成铍生产过程的回收率低。研究了从金属铍生产过程中产出还原渣及还原烟尘中回收铍及净化除杂的新工艺,使回收净化后的铍达到生产核高纯级铍的要求,直接用于生产金属铍,为提高铍的品级率及回收率提供技术支撑。     

机械加工对粉末冶金铍材表面残余应力的影响

铍具有低密度、弹性模量高的特性，常用于航天结构件。粉末冶金铍材在机械加工时，表面会产生残余应力，对铍结构件的尺寸稳定性和使用寿命造成直接影响。因此，使用X-ray衍射仪测量铍材表面残余应力，测量了粗车、精车、时效工艺下残余应力沿表面的分布情况；进一步研究了不同机加工艺对铍材表面残余应力影响。结果表明，机械加工时，粉末冶金铍材残余应力均表现为压应力；残余应力与加工线速度负相关，与进刀量正相关，时效处理可有效降低铍材表面残余应力，还能有效提高残余应力的均匀性。     

Physical Metallurgy of Beryllium and Its Alloys

Some of the physical metallurgy aspects of beryllium and its alloys have been briefly described and discussed in this paper. To start with, many of the attractive properties of beryllium and some of its major applications have been mentioned. This is followed by a short discussion pertaining to the polymorphism of the metal and the stability of the relevant phases. The solid solution behaviour of beryllium and the formation of beryllium rich intermetallic phases have been dealt with subsequently. Some of the broad characteristics of the phase diagrams of binary beryllium systems have then been mentioned. A short account of beryllium based as well as beryllium containing alloys and composites has been provided after this. The next topic to be discussed is the deformation behaviour of the metal, with particular reference to slip systems, stacking faults, twinning modes and fracture modes. This is followed by a brief account of grain size effects and of recrystallization and grain growth in beryllium. Finally, the brittleness problem in beryllium has been discussed.     

我国铍冶金工艺发展概况

对我国铍冶金工艺几十年来的发展概况作了评述，并介绍了铍合金的发展情况。     

Beryllium Extraction—A Review

This paper reviews the current status of beryllium process metallurgy. Emphasis is laid on the extraction of beryllium metal from beryl ore. The resource position, demand and application of the metal and its alloys are also summarised.     

Extractive Metallurgy of Tantalum

This paper presents a brief review of extractive metallurgy of tantalum starting from processing of its ore to two pure intermediates K₂TaF₇ and Ta₂O₅ and their conversion to pure tantalum metal by various technically feasible processes. Though tantalum metal can be produced by several means only two processes – sodium reduction of K₂TaF₇ and fused salt electrolysis of K₂TaF₇ in the presence of oxide, have been successful on industrial scale. Besides providing salient features of these two processes, the paper presents brief accounts of studies carried out on the reduction of oxide by metallic reductants – calcium and aluminium as well as nonmetallic reductants – carbon and carbon–nitrogen. The crude metal obtained by various reduction techniques outlined are purified either by solid state pyrovacuum treatment or by melt refining in an electron beam furnace. Mechanism of refining processes taking place during these post reduction treatments are also included in the review.     

Extractive Metallurgy of Tantalum

Abstract

This paper presents a brief review of extractive metallurgy of tantalum starting from processing of its ore to two pure intermediates K₂TaF₇ and Ta₂O₅ and their conversion to pure tantalum metal by various technically feasible processes. Though tantalum metal can be produced by several means only two processes - sodium reduction of K₂TaF₇ and fused salt electrolysis of K₂TaF₇ in the presence of oxide, have been successful on industrial scale. Besides providing salient features of these two processes, the paper presents brief accounts of studies carried out on the reduction of oxide by metallic reductants - calcium and aluminium as well as nonmetallic reductants - carbon and carbon-nitrogen. The crude metal obtained by various reduction techniques outlined are purified either by solid state pyrovacuum treatment or by melt refining in an electron beam furnace. Mechanism of refining processes taking place during these post reduction treatments are also included in the review.     

Beryllium Extraction and Utilisation— Prospects and Constraints

Beryllium and beryllium compounds find wide variety of applications in diverse industries. Low density, high strength, and attractive nuclear properties like low neutron absorption cross section and high scattering cross section have created great interest in the metal for space, aeronautical, and nuclear applications. The extraction technology of beryllium is now fairly well established and significant progress has also been made in the powder metallurgy fabrication of the metal. Conventional fabrication methods like rolling, wire drawing, extrusion etc. have not been found quite suitable for beryllium because of its low ductility.

This paper presents an overview of the extraction processes and the fabrication methods presently employed for beryllium metal and alloys. The various applications are described and the prospects and constraints in the large scale utilization of beryllium in industry are analysed.     

从高氟硫酸铍溶液中萃取铍工艺研究

高氟铍矿石中的成分复杂,其中氟、磷、硅、铝、铁等杂质在传统法工艺中对氧化铍的回收率及质量影响很大;萃取法生产氧化铍过程中,P204对铍浸出液中的阳离子进行交换,浸出液中的阴离子氟、硅、磷等基本不被萃取;利用阳离子在P204中的萃取顺序,将铁还原成二价铁,并在还原气氛中减少铝铁与铍同萃机会。同时高氟铍矿石中的氟与铝的络合作用可抑制铝的萃取,萃入有机相中的铝铁经洗涤后基本可除去。洗后的有机相经反萃、水解沉淀、煅烧得到合格的工业氧化铍。     

Powder metallurgy of beryllium: The developments of the national scientific center “Khar’kov physicotechnical institute”

For the first time in the production of construction beryllium an integrated technology for the production of a new generation of high-purity isotropic materials has been developed and mastered. The technology combines processes of vacuum distillation of the metal, gas flow atomization of a melt, specialized processing of the powder prior to densification and hot isostatic pressing. A technology for the production of spherical powders of beryllium and beryllium-based alloys by atomization of a melt is also developed and employed for the first time. A technology is developed and optimal conditions of isostatic pressing of spherical powders are determined. Isotropic beryllium with high physico-mechanical characteristics is obtained. The properties of the materials thus obtained are studied. The strength of the new materials is 20%, and their plasticity two to three times greater, than commercial beryllium. It is shown that the high purity of the initial powder, the cellular structure, uniform distribution, and dispersity of the particles of beryllium oxide and segregations of secondary phases are the principal factors that govern the level of the properties of compact beryllium materials. __________ Translated from Poroshkaya Metallurgiya,Nos. 3–4(448), pp. 118–125, March—April, 2006.     

Extractive Metallurgy Today,Progress and Problems

In the past few years extractive metallurgy has been advancing gradually. There have beun probably few remarkable new ideas but there has been an important progress in the metallurgical literature. Numerous meetings devoted to various aspects of extractive metallurgy were held and,the proceedings of these meetings were published in the form of useful books readily available to the scientific community. Besides, annual reviews covering all areas of extractive metallurgy arc being published. One may outline the progress and the problems in the following points: (i) processing of low-grade ores, (ii) processing of complex ores, (iii) preparation of metals in a high purity, (iv) increased demand for metals, (v) conservation of mineral resources, (vi) abating pollution of the environment, (vii) minimum expenditure of energy, and (viii) process control, manpower, and automation.     

铍板材深冲压成形异形件探讨

冲压成形是金属板材加工异形件的最基本方式。金属材质不同,冲压成形异形件的难易程度不同,主要影响因素是冲压成形性能和冲压成形极限。文章结合铍板材的冲压成形性能和冲压成形极限,对铍板材冲压成形异形件的难易性作了探讨。     

粉末冶金内涵百年演变

近代粉末冶金诞生迄今已届百年,在此其间,粉末冶金技术取得令人瞩目的发展,其内涵随之拓展和延伸.粉末冶金技术不断提供各种关键性材料和制品,在人类经历的4次技术革命所形成的全部产业中均有应用,甚至促使某些工业分支产生重大变革,引发相关技术的更新换代.粉末冶金技术属于先进的材料制备和成形加工技术.现代粉末冶金技术凭借发展高性能金属材料和复合材料的卓越成果,将金属材料科学与工程提高到新的高度.笔者试图通过分析粉末冶金百年来的重大成就,认识其内涵的演变.     

EBSD分析粉冶铍材标定率的影响因素和解决办法

铍材具有特殊的物理性能,主要应用在核、航空航天领域。EBSD(电子背散射衍射)作为新型的分析技术,在铍材的生产过程中,应用越来越广泛。稀有金属材料国家重点实验室在EBSD分析铍材的实际应用中,发现对铍的标定率低成为限制铍材EBSD分析的一个难点。本文通过优化制样参数,有效降低铍样表面的残余应力;通过调整EBSD增益参数,减少背底和噪声信号的影响;通过调整解析器设置参数,提高对被干扰的信息的识别,将铍材EBSD标定率平均提高了27%。     

Electrolytic Extraction of Beryllium

Beryllium possesses certain unique mechanical and physical properties which make it a special engineering material and an important alloy addition. However, its low density, high reactivity and high melting point along with its occurrence in the form of a very stable beryl ore—containing only about five percent beryllium—make its extraction difficult. The electrowinning of beryllium from molten beryllium and sodium chloride salt-mix is a low temperature commercial process. Conversion of beryl ore into beryllia precedes the fused salt electrolysis and several purification techniques are followed to produce high purity beryllium metal. This paper reviews the existing major industrial processes for beryllium production. A modified beryllium chloride-beryllium fluoride fused salt electrolysis is suggested on similar principles but with added advantage of a semi-continuous high efficiency process. The electrode reactions for this salt system have been analysed on the basis of reaction rate theory and the influence of operating parameters, such as the temperature, electrode areas, current density, etc., on the cell potential has been identified. A possible basic cell design has also been proposed.     

Converting an idea into a worldwide business commercializing smelting technology

Pyrometallurgy is an ancient art which has defined significant stages of human development. Today, new opportunities for improvements in the economic, environmental, and workplace costs of metal production continue to provide challenges for the profession and industry. Top-submerged lancing technology for the high-temperature processing of a range of metals and wastes is an example that has been taken up by many companies around the world. The furnace system now marketed under the names of Ausmelt and Isasmelt was, in the early stage of its 33 years of development, known as Sirosmelt. The voyage from the original idea through theoretical, laboratory, pilot plant, and commercial developments to establishment of a worldwide business has been both stimulating and rewarding. The Extraction and Processing Lecturer Award honors an outstanding scientific leader in the field of nonferrous extractive metallurgy with an invitation to present a comprehensive lecture at the TMS Annual Meeting. John Floyd is Deputy Chair, Ausmelt Limited, Australia. He earned his B.Sc. and M.Sc. from the University of Melbourne, Ph.D. from London University, and DIC from Imperial College. Dr. Floyd has authored or co-authored more than 70 published technical articles and has invented or co-invented 15 patented process or equipment inventions in the extractive metallurgy and high-temperature processing plant areas.     

New Trends and Challenges in Leaching Process

Hydrometallurgical ways of extracting metals are becoming an important technology in extractive metallurgy. In this paper, industrially successful leaching processes are reviewed. The strengths and weaknesses of leaching processes are discussed and the needs for future research in the leaching process are presented.

Industrially successful processes considered in the current discussion include aluminum, uranium, cobalt, nickel, gold and silver extraction. It is noted that hydrometallurgical processes of secondary metal sources will become an important area in extractive metallurgy. High temperature and pressure autoclave leaching should be studied in more depth both from the points of fundamental aspects and practical applications.     

The Hydrometallurgical Extraction and Recovery of High-Purity Silver

With the continuous reduction in the availability of extractive metallurgical curricula in colleges and universities, the concern has in part been from where will the next generation of extractive metallurgists come? One objective of this article is to emphasize the fact that extractive metallurgy is, in fact, one of many areas of chemical engineering technology. Thus, although the extractive metallurgist may have disappeared in name, its activity is alive and well, subsumed in the field of chemical engineering. One goal of this lecture is to demonstrate the applicability of chemical engineering principles to what is typically considered ??the field of extractive metallurgy.?? Two processes will be described that have supplanted typical pyrometallurgical fire refining of precious metals, particularly silver. The origins of fire refining can be traced back to biblical times. There are numerous references to it in the old testament: Ezekiel 22:20, ??As men gather silver and bronze and iron and lead and tin into a furnace to blow the fire upon it in order melt it??; Jeremiah 6:29, ??The bellows blow fiercely; the lead is consumed by the fire; in vain the refining goes on??; and Malachi 3:2 (The Oxford Annotated Bible with the Apocrypha), ??For he is like a refiners fire.?? Many references to it will also be found in ??De Re Metallurgica?? and as well in Lazarus Ercker??s 1574 Manual ??Treatise on Ores and Refining.?? Today, fire refining has been improved greatly by innovative furnace design, new fluxing technologies, and the improved use of oxygen. However, fundamentally, the process chemistry has not changed much in the last millennium. Illustrations of hydrometallurgical processing of silver-bearing inputs will be provided by the treatment of sulfated silver-bearing materials and chlorinated slimes. The first of these technologies will be described briefly as practiced by the Phelps Dodge Refining Corporation for several years. The second, the treatment of silver chloride-bearing inputs, will be described in detail to demonstrate how typical chemical engineering unit process and unit operations have supplanted classic smelting and fire refining techniques. The Kennecott Copper Company, which has operated a hydrometallurgical circuit successfully for the recovery of high-purity silver from the slimes wet chlorination residue, has permitted me to provide some operation information and results using the technology. Both Phelps Dodge and Kennecott should be recognized for their forward-looking attitude in undertaking the conversion of conceptual chemistry into successful, full-scale plants. The process as employed at Phelps Dodge is discussed at length in reference (J.E. Hoffmann and B. Wesstrom: Hydrometallurgy, 1994, vol. 94, pp. 69?C105).