Bernd Friedrich

Properties of Zr(V0.25Ni0.75)(2) metal hydride as active electrode material

We have investigated the Zr(VxNi1−x)2 alloy series in the range of 0 ⩽ x ⩽ 0.4 and observed very pronounced absorption and desorption properties in Zr(V0.25Ni0.75)2. We have shown previously that Zr(V0.25Ni0.75)2 has a high reversible capacity of 364 mA h g−1 (C/30 rate) and a good electrochemical cycle stability (8%/100 cycles capacity loss, C/3 rate). However, large-scale production of this alloy seems to be difficult, and annealing deteriorates the high capacity and the good kinetics as well. In this study we have analyzed the microstructure of the alloy and the thermodynamics of hydride formation of the alloy electrodes. Two different phases were observed, Zr7Ni10 and Zr(V0.33Ni0.67)2.3; however, both of them are, as single phase alloys, not quite as good as their combination in Zr(V0.25Ni0.75)2.

Cytotoxicity of Gold Nanoparticles Prepared by Ultrasonic Spray Pyrolysis

The aim of this work was to study the cytotoxicity of different fractions of gold nanoparticles prepared by ultrasonic spray pyrolysis from gold scrap. The target cells were rat thymocytes, as a type of nonproliferating cells, and L929 mouse fibroblasts, as a type of continuous proliferating cells. Fractions 1 and 2, composed of pure gold nanoparticles, as determined by scanning electron microscopy with a combination of energy dispersive X-ray analysis, were nontoxic for thymocytes, but reduced moderately the proliferative activity of L929 cells. The inhibitory effect of fraction 2, containing particles smaller in size than fraction 1, was stronger. Fraction 3, composed of Au and up to 3% Cu was noncytotoxic for thymocytes, but was cytotoxic for L929 cells. Fraction 4, composed of Au and Ag nanoparticles, and fraction 5, composed of Au together with Cu, Ni, Zn, Fe, and In were cytotoxic for both thymocytes and L929 cells. These results suggest that USP enables the synthesis of pure gold nanoparticles with controlled size, even from gold scrap. However, microstructural analyses and biocompatibility testing are necessary for their proper selection from more cytotoxic gold nanoparticles, contaminated with other elements of gold alloys.

Use of ionic liquid in leaching process of brass wastes for copper and zinc recovery

Brass ash from the industrial brass manufacturer in Turkey was leached using the solutions of ionic liquid (IL) 1-butyl-3-methyl-imidazolium hydrogen sulfate ([bmim]HSO4) at ambient pressure in the presence of hydrogen peroxide (H2O2) and potassium peroxymonosulfate (oxone) as the oxidants. Parameters affecting leaching efficiency, such as dissolution time, IL concentration, and oxidizing agent addition, were investigated. The results show that [bmim]HSO4 is an efficient IL for the brass ash leaching, providing the dissolution efficiencies of 99% for Zn and 24.82% for Cu at a concentration of 50vol% [bmim]HSO4 in the aqueous solution without any oxidant. However, more than 99% of zinc and 82% of copper are leached by the addition of 50vol% H2O2 to the [bmim]HSO4 solution. Nevertheless, the oxone does not show the promising oxidant behavior in leaching using [bmim]HSO4.

SELECTION OF CRUCIBLE OXIDES IN MOLTEN TITANIUM AND TITANIUM ALUMINUM ALLOYS BY THERMO-CHEMISTRY CALCULATIONS

Titanium and its alloys interstitially dissolve a large amount of impurities such as oxygen and nitrogen, which degrade the mechanical and physical properties of alloys. On the other hand crucible oxides based on CaO, ZrO2 Y2O3, etc., and their spinels (combination of two or more oxides) can be used for melting titanium and its alloys. However, the thermodynamic behavior of calcium, zirconium, yttrium on the one side, and oxygen on the other side, in molten Ti and Ti-Al alloys have not been made clear and because of that, it is very interesting for research. Owing of literature data, as well as these crucibles are cheaper than standard crucibles for melting titanium and titanium alloys, in this paper will be presented the results of selection of thermo-chemistry analysis with the aim to determine the crucible oxide stability in contact with molten titanium and titanium-aluminum alloys.

THERMODYNAMIC CALCULATIONS IN ALLOYS Ti-Al, Ti-Fe, Al-Fe AND Ti-Al-Fe

Thermodynamic calculations of three binary Ti-based alloys: Ti-Al, Ti-Fe, and Al-Fe, as well as ternary alloy Ti-Al-Fe, is shown in this paper. Thermodynamic calculations involved thermodynamic determination of activities, coefficient of activities, partial and integral values for enthalpies and Gibbs energies of mixing and excess energies at different temperatures: 1873K, 2000K and 2073K, as well as calculated phase diagrams for the investigated binary and ternary systems. The FactSage is used for all thermodynamic calculations.

Hydrometallurgical Processing of Eudialyte Bearing Concentrates to Recover Rare Earth Elements Via Low-Temperature Dry Digestion to Prevent the Silica Gel Formation

Eudialyte belongs to the group of cyclosilicate minerals and has a significant content of valuable heavy rare earth elements. In comparison to conventional ores like bastnaesite or monazite, the content of radioactive elements like thorium and uranium is quite low; thus, it is an ideal source for the sustainable extraction of rare earth elements (REE). In this way, a further processing or a disposal, direct or after using phase, of radioactive elements could be minimized. The cyclosilicate structure facilitates the easy decomposition of eudialyte by mineral acids. On one hand, this is a positive effect to lixiviate the REEs but leads to an excess liberation of silicon in the water-based system which involves the risk of silica gel formation. Within this research project, a hydrometallurgical pre-treatment is developed to decompose the eudialyte for the extraction of REEs and to stabilize the silicon in the residue during the following leaching step.

Large-scale production and quality assurance of hydrogen storage (battery) alloys

The new generation of high-capacity metal hydride rechargeable batteries is a cadmium-free energy alternative to current types of accumulators. While the first steps were made for consumer wireless applications, the newest developments aim toward traction systems (zero-emission cars). This article introduces the materials selection, quality control, and production principles of alloy systems suitable for storing hydrogen either electrochemically or by gas absorption. Examples of Zr-Ni, Ti-Mn2, and rare earth-Ni5 are demonstrated from the metallurgical standpoint. These alloys (currently produced in large scale— tons/day) are now used in industry after approximately 20 years of development.

The EURARE Project: Development of a Sustainable Exploitation Scheme for Europe’s Rare Earth Ore Deposits

Numerous European industries are heavily dependent on imported rare earth element (REE) raw materials. This has created a need for the European Union (EU) to ensure a sustainable supply of REE minerals, as well as develop from the ground up the currently non-existent European REE extraction and processing industry. In order to support this, the European Commission, through the Seventh Framework Programme (FP7) scheme, funded the EURARE project which runs from 1st January 2013 to 31st December 2017. Through the EURARE project, selected European REE deposits have been researched and in certain cases identified resources were successfully processed for REE production. Several REE deposits across Europe have been the focus of detailed geological field and laboratory work. Mineral concentrates obtained from the Norra Karr deposit in Sweden, the Kringlerne deposit in Greenland and the Kvanefjeld deposit in Greenland, Rodberg ore from Norway and bauxite residue from Greece were tested from laboratory to pilot scale by means of conventional and innovative metallurgical processing. The novel technologies developed provide efficiency and selectivity in various steps of the metallurgical processing, from ore beneficiation to metal production. A road map for sustainable REE production in Europe is now being developed, which includes an evaluation of the environmental benefits and risks of the EURARE technologies.

Recycling of Rare Metals

Abstract Most of the rare metals, described in this chapter, are used as key metals in numerous technical applications and were classified as “critical raw materials for the EU” by the European Commission in 2010: precious metals, rare earth metals, electronic metals, refractory metals and others like lithium and antimony. For these rare metals, main end-use-markets and a selection of developed and especially commercial practiced recycling routes are described. It is shown that conventional recycling processes for rare metals are often based on the process routes of mass metals (e.g. Cu, Pb, Zn, Al) and that geogenic (primary winning) and anthropogenic (secondary recycling) process chains widely overlap. Against the background of a resource-efficient process design, recycling routes for secondary raw materials like catalysts, permanent magnet scrap, battery scrap, phosphors scrap, and steelwork slags are discussed.

Precipitation Trends of Scandium in Synthetic Red Mud Solutions with Different Precipitation Agents

This research presents an alternative method for scandium (Sc) recovery from impure bauxite residue solutions containing Fe(III), Al, Ca, Nd, and Y through the use of hydroxide and phosphate precipitation. Among hydroxide donors, ammonia solution removed the most Fe(III) from solution, while co-precipitation of other elements in the synthetic pregnant leach solution remained negligible. When using dibasic phosphate as the precipitant, in the pH range of 1.5–2.5, both Sc and Fe were removed rapidly, while co-precipitation of other ions remained low. Experimental results were used to propose the preliminary design of a three-stage precipitation process capable of producing a scandium product from highly impure process solutions.