Historically, the generation of zinc-rich dusts from steel recycling was a source of loss from the life-cycle landfill ; however, technologies today provide incentive for steel recyclers to minimize waste. This fact may seem amazing in this day of high-powered computer simulation and design tools. Actually, it was not even possible to make any sort of remotely believable economic analysis under the conditions. . Further enhancing the economics of recycling through advances in technology and practices is the predominant theme of many of the technical papers prepared for this conference.
In the best of cases, working out the kinks is not a trivial exercise. Something as simple as virtually outlawing nickel-cadmium batteries has created vast problems in many processing plants of what to do with cadmium, especially those handling recycled materials in which cadmium was an important or at least benign constituent. Annual global production of zinc is more than 13 million tons. This chapter describes the main processes for zinc recycling from different scraps and residues. The problem was by no means simple to begin with, but due to concerns with confidentiality the plant resorted to reinventing and redeveloping the basic processing steps.
The only way good zinc could be produced was to use lower temperatures than elsewhere. Both are now shut down and can no longer provide that useful outlet not only for scrap metal but also for other copper containing residues. . Peer review process is available for the papers submitted. This time around, the metal is contaminated with radioactivity.
One part of the waste plastic stream can be recycled mechanically without any significant quality loss; another part can be de- polymerized for monomer recovery Grause et al. Process Metallurgy 7 Academic Press, Elsevier 1992 Solvent Extraction 1990, Part B 978-0-444-88677-4, 0-444-88677-X J. Vander Linden, R, De Ketelaere, and M Verhaege. The need and participation of competent process metallurgists has been ignored in most cases, causing failure when the equipment cannot achieve the production rate, product quality, economic viability and environmental goals set for it. In another example, familiar to the author but not covered at this meeting, was an advanced process for extracting aluminum via a chlorination and electrolytic recovery process.
Regulations that now designate materials as hazardous wastes which could formerly be shipped rather easily for reprocessing elsewhere are added restrictions. And, more importantly, it involves somebody else's money; lots of it. The shutdown of the Southwire and Carteret secondary copper plants referenced earlier and the demise over the last 20-30 years of a number of lead smelters have dried up many formerly viable outlets. They simply mixed their feed ores so that they had the requisite proportions of iron present to uniformly remove germanium. In sum, closing the material balance around the plant with useful product streams can with many technology options no longer be possible, or perhaps possible only with greatly added costs. But even at best sufficient process and mechanical engineers must be made a part of the startup crew. Doctoral student Alejandro Llamas, Freiberg University, Germany Development of a comprehensive product-centric sustainability indicator framework.
Hürman Eriç, University of the Witwatersrand, South Africa Quo Vadis Metal Processing? Equipment selections are made in a vacuum of understanding of the process needs, materials of construction ignore temperatures and other operating conditions, vendors are selected based on cost even where they have a history of failures, communication within the design team is poor to non-existent, conflicting priorities between technology vendor, plant owner, design company and capital provider confuse choices, and even overly strong personalities drive choices to preferences that objectively are often worse than inappropriate. Stephens Cominco Research Trail, B, C. The malady was later shown to be due first to basic salts and the need to keep the solution slightly acid, and secondly that even minute quantities of some impurities such as arsenic could bring about spongy zinc. In the last decade, global metallurgical industries have experienced fast and prosperous growth. Most frequently lacking are the Edited by D. Since the past 50 years, the use of plastics has dramatically increased in our daily lives.
But that industry has largely been replaced by one based on petroleum and natural gas. Perhaps a more useful use of life cycle inventories is to look for activities where improvements would reduce pollution or the consumption of resources by the greatest amount. Other industrial examples covered in this symposium include dealing with arsenic sludges fi-om a copper cellhouse and determining and maintaining product quality in cathodes made fiom secondary copper. Hence, the task now is finding the way to combine the weighting factors representative for these two points of view into only one composite weighting factor w i,comp representative for composite viewpoint. . Accumulation of accretions or residues, gradual buildup of impMties, quantification of by products or dewtion of recycle requirements all fall into this categpry. .
While not inexpensive, all this focused activity has allowed uniform progress toward commercialization, as well as development of several unique aspects, such as the separate zinc and lead products, the ability to get high thermal efficiency, and minimization of iron dust in the fumed products. Combination of Weighting Factors Using Entropy Weighting Method In multicriteria problems, it is reasonable to assign a weight to each criterion in order to represent the relative importance of criterion against each others. With integrated mill dusts and mill scales, tests at up to 70% of the iron unit charge could be attained with the briquettes. A4 Schade Van Westrum, 0. A few rooms in cheaper categories are available too. . .
In this study the technical and economical feasibility of this process is investigated based on experimental data and the implementation of proven technology where possible. The sheer weight and momentum of the desire to upgrade the standard of living will drive substantial expansions in the metals extraction industries. The above described development of the Tainton process, as well as resolution of the germanium problem a material that analytical techniques could not even detect are models for new millennium technology developers. Proceedings of the International Symposium on Computer Software in Chemical and Extractive Metallurgy. . Mari Lindgren, Outotec Technologies enabling circular economy and opportunities that lie within Prof. Not metals, but much that is instructive nonetheless.
So who will be building metals extraction facilities in the next 50 or 100 years? Process Metallurgy 10 Elsevier, Academic Press 2000 Extractive Metallurgy of Activated Minerals 0444502068, 9780444502063, 9780080531533 J. However, solubilization rate of the waste printed board was insufficient for practical industrializing. The chemical process involves the reduction of zinc compounds to elemental zinc boiling point 907 °C which volatalises, which oxidises in the vapour phase to zinc oxide. And often development has reduced testing to a bare minimum, not allowing for generation of adequate data in the above areas. Over several years a number of research projects had been financed by various government institutions and private parties to develop the process.