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By Dong-Wei Li, Tao Zhang, Diao Jiang, Zhou Wang

The feasibility of simultaneous vanadium extraction and phosphorus removal from vanadium-containing hot metal was demonstrated with laboratory experimental investigation.The effect of CaO addition on the distribution behavior of vanadium, phosphorus between basic vanadium slag and semi-steel as well as the influence of basicity on the leaching behavior of vanadium, phosphorus was particularly studied. Results show that vanadium oxidation ratio slightly decreases with the increase of basicity, but phosphorus oxidation ratio rapidly increases with the increase of basicity. The leaching of roasted vanadium slag with various CaO contents indicated that the optimal slag basicity for extracting vanadium was 1.5. The maximum leaching efficiency of vanadium could reach 84.02% and the sequence of vanadium leaching efficiency by using different leaching reagents was: 160 g/L Na2CO3 > 100 g/L NaHCO3 > 400 g/L (NH4)2CO3 > 5% H2SO4.

Mar 1, 2017

By Xudong Liu, Ganghua Fu, Yufeng Guo, Wei Chen, Yujia Tan, Tao Jiang

Willemite is usually found in high-silicon oxide zinc ore and zinc metallurgical secondary resources but without effective extraction method yet. In this study, zinc was extracted from willemite by sodium salt roasting and ammonia-leaching process based on the idea of zinc phase reconstruction. The effects of Na2CO3 dosage, roasting temperature and roasting time on phase transformation and zinc leaching rate were studied, respectively. The results show that Zn2SiO4 was transformed into ZnO or Na2ZnSiO4 during roasting process. After roasting at 800 °C for 2.5 h at ratio of n(Na2CO3)/n(Zn2SiO4) = 2.5:1, willemite was thoroughly transformed into ZnO. The zinc leaching rate of the roasted sample was 97.62% in NH4Cl–NH3–H2O leaching system, which increased by 91.57% compared with zinc leaching rate of 6.05% when willemite was directly leached in NH4Cl–NH3–H2O system.

Mar 1, 2017

By Timothy W. Ellis, John A. Howes

The production of lead-acid batteries is defined by a closed-loop product life-cycle. Active material and grid alloys converge on an adaptable specification that improves both performance and recyclability. This mapping of product requirements for lead-acid batteries has taken over 80 years to develop. But, as the use of batteries made with other chemistries continues to grow, the need for a comparable life-cycle management process becomes increasingly apparent given societal needs to manage raw materials, e.g. the European Union Battery Directive recycling targets. What has taken more than 80 years for lead-acid to evolve in a closed-loop paradigm must now be accomplished in less time for batteries using other chemistries and technologies. End-of-life costs are embedded in the product cost of lead-acid batteries. However, end-of-life costs are not reflected in the product cost of batteries made with other chemistries. Those costs are borne by other constituencies with often inefficient and environmentally damaging results. Lead-acid is a materials technology management model for other products.

Mar 1, 2017

By V. Reiter, K. Reinharter, C. Wenzl, D. Gregurek, A. Spanring

The refractory linings in lead furnaces are exposed to several stresses rather complex in their interaction. In the present study the magnesia-chromite brick out of a lead recycling furnace suffered from a high chemical attack by the process slag. The high CaO, BaO and sulfur bearing silicate slag, as well as a high NaO2 supply from soda resulted both in a deep-reaching infiltration of the brick microstructure and a severe corrosion of the brick components. Both the sintered magnesia and chromite were attacked chemically. The FactSage calculations showed the formation of high amounts of liquid phase in the infiltrated microstructure. Further phenomena affecting the refractory performance such as iron oxide attack, redox effects, and boron attack are also discussed in the paper. The obtained information and insights serve as a basis for improving refractory materials (i.e., choice of refractories for individual process and new developments) and consequently furnace operations.

Mar 1, 2017

By Shijie Wang

Lifetime achievements of Professor Reddy ’s teaching, research and scholarship in the field of chemical and materials science and engineering are briefly described. He has devoted his entire career in the introduction and application of process engineering principles to the quantitative description of materials processing reactions, and industrial operations. He has formulated quantitative methodologies based on first principles of thermodynamics, phase equilibria and kinetics to: design of slags and fluxes for production and purification of metals and alloys; development of Reddy-Blander model for a priori prediction of impurities capacities of melts; development of novel ionic liquid electrolytes for materials processing; development of new theories for alloys and molten salts; design materials for fuel cells and capacitors; use of thermodynamic approaches to predict physical properties of materials; industrial energy waste separation and remediation; and thermal energy storage. He is a scholar and mentor, and has made numerous scientific and service contributions to the society and metallurgical and materials engineering education.

Mar 1, 2017

By Elizabeth Carvalho L. Cardoso, Ademar B. Lugão, Sandra R. Scagliusi

This research investigated how gamma-radiation affected PP/HMSPP structural foams filled with biodegradable synthetic polyester PLA in terms of thermal properties, biodegradability and infrared spectrum. Polymers are used in various applications providing enormous quantities of wastes in environment and contributing with 20–30% of total volume of solid residues. Besides, shortage of plastics resins obtained from fossil base is addressing research and development toward alternative materials; environmental concerning in litter reduction is being directed to renewable polymers for manufacturing of polymeric foams. Biodegradable polymers, a new generation of polymers produced from various natural resources, environmentally safe and friendly, can contribute for pollution reduction. PLA (poly(lactic) acid)) was chosen to be blended with PP/HMSPP. Blends thereof were subjected to gamma radiation at 50, 100, 150, 200 and 500 kGydoses.Soilburialtestpointedtowardapartialbiodegradationofirradiated PLA-PP/HMSPP foams; other characterizations involved TG/DTG technique and FTIR assessments.

Mar 1, 2017

By Christoph Czettl, Christian Storf, Gregor Kücher, Stefan Luidold

The purpose of this investigation is to provide a basis for the semidirect recycling of hard metals. The present investigation focuses on revealing the fundamental chemical kinetic aspects during cemented carbide leaching in hydrochloric acid media. The kinetic relations of cobalt binder leaching from WC-Co cemented carbide are studied using a central composite face-centered design of experiments with temperature, acid concentration, and hydrogen peroxide as variables.

Mar 1, 2017

By M. A. Usman, E. I. Akpan, S. O. Adeosun

Preliminary studies on the extraction and characterisation of biodegradable lignin from palm oil fruitbunch (POFB) for carbon fibre production has been conducted. Centra lComposite Design was used to determine the optimum operating conditions for maximum yield and properties of the extracted lignin. Soda concentration (1–3 wt/vol%), temperature (50–90 °C) and reaction time (20–30 min) were analysed using Rcore software. Experimental results show that using reaction temperature of 90 °C, time of 30 min and 3 wt/vol% soda concentration yields 3.3 g of lignin from 30 g of the POFB. The path of steepest ascent from ridge analysis shows that with temperature of 130 °C, time of 40 min. and soda concentration of 3. wt/vol%, 8.7 g of lignin can be extracted from 30 g of POFB. Analysis of FTIR and SEM show that the lignin has the same structure in all cases with minimal impurities.

Mar 1, 2017

By Muammer Kaya

This paper reviews the existing and state of art knowledge for electronic waste (e-waste) recycling. Electrical/electronic equipments (EEEs) which are unwanted, broken or discarded by their original users are known as e-waste. The main purpose of this study is to provide a review of e-waste problem, give e-waste management strategies and introduce various physical e-waste recycling processes with special attention towards extraction of both metallic values and nonmetallic substances. The hazards arise from the presence of heavy metals (e.g. Hg, Cd, Pb etc.), brominated flame retardants (BFRs) and other potentially harmful substances in e-waste. Due to the presence of these substances, e-waste is generally considered as hazardous waste and may pose significant human and environmental health risks if improperly managed. This review paper describes the potential hazards and economic opportunities of e-waste. First of all, an overview of e-waste/printed circuit board (PCB) components and substances are given. Current status and future perspectives of e-waste and waste PCB recycling techniques are described. E-waste characterization, dismantling, liberation, classification and separation processes, are also covered. Manual selective dismantling after desoldering and metal-nonmetal liberation at −150 μm with two step crushing are seen to be the best techniques. After size reduction, mainly physical separation processes employing gravity, electrostatic, magnetic separators etc., which are commonly used in mineral processing, have been critically reviewed here for separation of metals and nonmetals. The recovery of pure metals from e-waste after physical separation can be performed by pyrometallurgical, hydrometallurgical or biohydro metallurgical routes, which are not covered here. Suitable PCB recycling flowsheets for industrial applications are also given. E-waste recycling will be a very important sector in the near future from economic and environmental perspectives for both developing and developed countries. Recycling technology aims to take today’s waste and turn it into conflict-free, sustainable polymetallic secondary resources (i.e. Urban Mining) for tomorrow. Recycling technology must ensure that e-waste is processed in an environmentally friendly manner, with high metal/nonmetal recovery efficiency a lowered carbon footprint. Taking into consideration our depleting natural resources, this Urban Mining approach offers quite a few benefits; it provides a substantial secondary resource, while also ensuring that the environment is kept free from harmful toxins in e-waste. This results in increased energy efficiency and lowers demand for mining of new raw materials.

Mar 1, 2017

By D. C. Austin, P. J. Hazell, A. A. H. Ameri, J. P. Escobedo-Diaz, D. East, M. A. Bevan, A. D. Brown

Additive Manufacturing (AM) has become increasingly popular due to the ability to produce components with complex geometries and properties. The efficiency of this manufacturing method is investigated in this paper by examining the mechanical performance of AM austenitic stainless steel 316L under different strain rates. Dynamic compression experiments were conducted by using a Split Hopkinson Pressure Bar (SHPB). Microstructural observations were performed by utilizing optical microscopy. The behavior of this material is compared against stainless steel 316L manufactured by conventional methods. The results show that theAM316L used in this study display a considerable difference in the mechanical properties compared with conventional stainless steel alloys.

Mar 1, 2017

By Zhiqiang Zhou, Shengnan Zhou, Zizong Zhu, Yuchuan Ding

The effect of silicon on removal of phosphorus from high phosphorus Si–Mn alloy was investigated at 1673 K by CaO-based slag. It was found that the dephosphorization efficiency increases significantly as increasing the silicon content, which is due to the reaction between silicon and CaO at slag/alloy interface. The relation between silicon content with oxygen activity and phosphorus activity coefficient of Si–Mn melt was determined respectively as follows: lg aO = -1:55xSi - 1:67; ln rP = 9:26e xSi 0:0433 + 11:0839 The carbon content in Si–Mn melt decreases continuously with the increasing silicon content, meanwhile, the decreasing rate of carbon content becomes rapid when the mole fraction of silicon is about 0.32. Si addition is beneficial for both dephosphorization process and low carbon Si–Mn alloy production.

Mar 1, 2017

By Fábio O. Braga, Sergio Monteiro, Artur C. Pereira, Foluke S. de Assis

The jute fiber is one of the most investigated natural lignocellulosic fibers due to its easy processing and extensive occurrence. However, the studies with some varieties of jute fiber such as the Corchorus capsularis are rare, so this wor kinvestigated the toughness behavior of polyester matrix composites reinforced with up to 30% in volume of a fabric made of jute fiber by means of Charpy impact tests. It was found that the addition of jute fabric results in a marked increase in the absorbed energy by the composites. Macroscopic observation of the post-impact specimens and SEM fracture analysis showed that transversal rupture through the jute fabric interface with the polyester matrix is the main mechanism for the remarkable toughness of these composites.

Mar 1, 2017

By Brajendra Mishra, Mark L. Strauss, Gerard P. Martins

Europium is a critical material required for LED, florescent lamp, cell phone screen, and flat panel display production. This process recycling europium from waste lamp phosphors is an innovative method to supply europium. The selective reduction and precipitation method using sulfate precipitation is investigated to recover high-purity europium from yttrium-europium mixed solutions.

Mar 1, 2017

By Mikiya Tanaka, Hirokazu Narita, Takeshi Ogata

There is an increasing attention to recover dilute rare earth elements (REEs) from acidic solutions in order to meet their demands and stabilize their supply chain. Adsorption is suitable for recovering target metal ions when their concentrations are low. Many adsorbents for REEs have been studied; nevertheless, there are no adsorbents in practical use. We have developed adsorbents consisting of silica gel particles modified with diglycolamic acid groups. The adsorbent has the ability to selectively adsorb RE ions from solutions containing high concentrations of base metal ions in a low pH region, and the adsorption capacities of the adsorbent for the heavy REEs were higher than those for the light ones. Moreover, this adsorbent meets the requirements for a practical adsorbent, such as high durability, easy desorption, and high adsorption rate. We therefore conclude that the adsorbent can contribute the production of heavy REEs from underutilized resources.

Mar 1, 2017

By Jian Li, Pei Liu

In recent years FIB has become a powerful instrument to perform ion beam sectioning and site-specific TEM specimen preparation. However, there are still gaps in understanding FIB-induced artifacts. Gallium ion beam damage and specimen heating during FIB milling can produce unwanted artifacts during FIB work.Calculations ofmaximumspecimentemperature increaseshavemostlybeen based on the assumption that ion beam implantation into substrate of infinite size. This deviates from finite specimen volume in FIB TEM specimen preparation that impedes specimen heat dissipation. In this paper, the authors will demonstrate a few commonly observed FIB artifacts, and discuss the concerns of specimen temperature rise during FIB milling process.

Mar 1, 2017

By G. E. S. Lima, J. V. B. Lemes, F. G. D. Machado, S. Monteiro, L. G. Pedroti, L. A. F. Fioresi, W. E. H. Fernandes, R. C. S. S. Alvarenga

With advances in industrial processes, new products have emerged and become essential in everyday life. These activities generate different types of wastes, which can be harmful tothe environmentif not properly disposed. Having this problem in sight and considering the importance of concrete in the construction industry, this study analyzes the behavio of Reactive Powder Concrete (RPC) with addition of granite processing waste. Scanning Electron Microscopic (SEM) tests, compressive strength and Young’s modulus tests after 1, 3, 7 and 28 days of production and shear and flexural strength after 28 days of production were performed during the analysis. The results indicated that incorporation of this residue into RPC does not affect its performance. RPC was still able to present high compressive and flexural strength.

Mar 1, 2017

By A. P. I. Popoola, D. O. Okanigbe, A. A. Adeleke

In view of the steady depletion of primary sources of copper and the increased global demand for refined copper, it becomes necessary to explore some secondary sources for possible extraction of copper. The waste copper smelter dust (CSD) is a rich secondary resource for copper as shown by the chemical composition of the South African Palabora coppers smelter plant CSD that assayed 18.02, 13.36, and 3.4 wt% copper, iron and sulphur, respectively. Studies on CSD have focused majorly on either dust characterization or treatment, while hydrometallurgical extraction without pretreatment and with pretreatment using techniques such as oxidative roasting are also considered quite attractive. The challenge of iron dissolution during the leaching stage in these processes necessitates adequate purification of the leach liquor before the extraction of the metal as nano-particles. Hence, this review examined the theories relating to the characterization and treatment of CSD for copper recovery as nanoparticles; with factors having a bearing on the treatment process such as kinetics considered with the aim of providing scientific basis for the research.

Mar 1, 2017

By Fuqiang Zheng, Yufeng Guo, Guanzhou Qiu, Tao Jiang, Xiaoming Qu

MxTi3-xO5 is the main titanium-bearing mineral in the titanium-bearing electric furnace slag (TEFS), which is produced by direct reduction-electric furnace smelting process with vanadium titanomagnetite concentrate in Panzhihua-Xichang region of China. In order to effectively utilize the titanium resource in TEFS, the thermomechanical analysis and conditions for the growing up of MxTi3-xO5 grain were investigated, which emphasized on the effects of CaF2 and cooling rate on the crystallization of MxTi3-xO5 in the melting process. The mineral phase and morphology of titanium-bearing slag were determined by XRD and electron microscope technique, respectively. The results indicated that the average grain size of MxTi3-xO5 grown up from 30 to 92 lm and the area fraction of MxTi3-xO5 reached about 66% from 61% under the conditions of 5 wt% CaF2 and cooling rate at 1 °C/min.

Mar 1, 2017

By Niander A. Cerqueira, Pâmela Berçot, Afonso G. Azevedo, Victor B. Souza, Victor T. Bartolazzi, Bruno Padilha

In recent years, concern about environmental issues has become a parameter to consider in the projects in engineering. In order to reduce the impact that the tire improper disposal may result for the environment, we sought a solution to this problem. This article proposes the use of rubber scrap tires as fine aggregate in concrete production. The material produced was analyzed by a bending test, resulting in product quality, in particular for application in situations requiring a more ductile material.

Mar 1, 2017

By D. Tait, M. A. Halim, V. I. Lakshmanan, R. Sridhar

Rare earth elements (REEs), nickel and cobalt find their use in developing strategic materials and their demand is consistently increasing in the world while the extractable ores of these metals are gradually depleting. Process Research ORTECH Inc. (PRO) has developed innovative mixed chloride leaching processes for the recovery of REEs from alumino-silicate ores, and nickel and cobalt from laterite ores. The addition of magnesium chloride in hydrochloric acid enhances the activity of the hydrogen ion by orders of magnitude, which permit rapid leaching rates at moderate temperature and atmospheric pressure, along with high metal recovery. Innovative solvent extraction process steps are used for the separation of these metals from pregnant leach solutions. PRO’s processes also produce value added by-product of high purity iron oxide and recycle chloride lixiviant to the leaching stage. This paper describes the leaching and separation reaction mechanisms and potential process flowsheets.

Mar 1, 2017