Process For Recovery Of Metals Research Articles

4524049 Process for concurrent steam generation and metal recovery : Song-P Sit, Calgary, Canada assigned to Zimpro Inc

4524049 Process for concurrent steam generation and metal recovery : Song-P Sit, Calgary, Canada assigned to Zimpro Inc

An Ecologic and Economic Process for Transition Metal Recovery

This paper presents an experimentally derived method and equipment capable of removing heavy metals from solutions to below EPA maximum discharge limits as of July 1, 1984. This equipment consists of an electrowinning cell with its cathode replaced by a carbon fiber assembly having an actual surface area about 13,000 times greater than the apparent one. This cathode assembly is a three-dimensional flow-through, substantially reducing the concentration polarization layer and thus enhancing the mass transfer rates. This process is capable of depleting metal bearing solutions to a low enough concentration that is EPA compatible. Also, it is applicable to all platable metals.

Application of ion exchangers to recovery of metals from semiconductor wastes

Abstract This paper describes the equilibrium behaviour of a wastewater resembling that produced during semiconductor and printed circuit board manufacture when contacted with a chelating ion exchange resin (Chelex-100; Bio-Rad Laboratories). Distribution coefficients (solid phase metal concentrations/soluble metal concentration) were calculated, and it was determined that the order of affinity was Cu>Pb>Ni>Cr(III). Comparison of the distribution coefficient values obtained in these multicomponent studies with those obtained in prior single component investigations revealed gross discrepancies. Correction of the current and single component data for soluble phase complexation using an equilibrium computer model reduced the deviations. Computed selectivity coefficients based on calculated free ionic metal concentrations showed substantial variation with solid phase composition, indicating that significant solid phase non-idealities existed in this system. Regeneration experiments on spent resin indicated that simple acid regeneration could recover more than 90 percent of the exchanged copper. Based on this study it would appear that treatment of mixed metal wastes generated in printed circuit board and electroplating operation by ion exchange is a technically feasible process for removal and recovery of metals, especially copper.

The plasmadust process for recovery of metals from waste oxides

Considerable quantities of waste oxides are generated in the iron and steel industry. Present methods are not well suited for recycling these, and there are increasing environmental problems associated with their dumping or stockpiling. With the PLASMADUST process, many of these wastes can be treated economically to produce a liquid iron as well as metallic zinc and lead. Without previous sintering the fine material is pneumatically injected with coal powder into the lower part of a coke filled shaft furnace provided with plasma arc heaters where the material is injected. The oxides are instantaneously reduced, and liquid and gaseous metals are formed. The latter are extracted in a normal condenser. As the heat losses are small, the utilization of electrical energy is efficient, and the operating costs are well competitive with conventional methods. Because of the simple equipment required, the specific investment is low. Successful tests have been carried out in a small plant with a plasma arc heater of maximum 1.5 MW electric power and a feed rate of waste oxides of about 300 kg/h. Tests with normal baghouse dust from electric arc furnace steelmaking resulted in metal yields of more than 97 % for both iron, zinc and lead. Similar tests with dust from stainless steel-making resulted in a liquid iron alloyed with chromium, nickel and molybdenum, again with high metal yields. A central PLASMADUST plant in each steelmaking area could recycle most of the waste oxides from that area, thus solving an environmental problem and at the same time recovering valuable metals from waste material.

Economic metal recovery from fly ash

Although most coal combustion ash produced in the United States is discarded as a waste (⩾52 million metric tons per year), results are presented to show that fly ash can be an economical source of Al 2O 3, Fe 2O 3, and possibly several other metals, many of which are presently being imported. Although several metal recovery processes were studied, only the two of greatest economic potential and widest applicability were given detailed economic evaluation; the direct acid leach of ash with HCl (a minimum treatment process) and a pressure digestion acid leach (a maximum recovery process). Results show that both methods can remove from fly ash all metals that would otherwise be available for release to the environment after disposal and that a major portion of the leached metals can be separated in saleable form. Economic analyses indicate that the direct acid leach process is most attractive. A capital investment of $38.2 million will be required to handle 9.07 × 10 5 metric tons (dry basis) of ash per year, producing a net yearly cash flow of $15.2 million. Additional economic benefits will result from the recovery of these metals through elimination of the higher ash disposal costs that may be required for fly ash containing trace metals. National benefits will also result from reduced importation of metals and ores.

Separation of silver-copper mixtures by ion-exchange parametric pumping: I. Total reflux separations

Summary Silver-copper mixtures occur at various stages of metal recovery processes particularly in the refining of silver. Parametric pumping is proposed as a method of separating copper from silver. The process consists in making a periodic change in the temperature of a fixed bed of ion-exchange resin with a synchronized periodic relative flow of the liquid mixture. Experimental results at total reflux (batch) are presented that show that a good separation can be made by this method using Duolite C265 resin. The results are interpreted by a graphical approach using standard ion-exchange breakthrough curves obtained experimentally. Changes in total concentration are observed and interpreted as being the effect of temperature on Dorman electrolyte uptake.

The Recovery of Metals from Rinse Waters in ‘Chemelec’ Electrolytic Cells

SummaryThe performance of Chemelec cells embracing the use of non-conducting fluidised beds and mesh electrodes is compared with other types of electrolytic cells for the recovery of metals from rinse waters. The electrodeposition of copper and zinc and also scale-up factors are studied. A process for metal recovery from pickling and plating rinse waters is described. A comparison of alternative recovery systems, electrolytic or otherwise, is presented, and approximate costs are given.

Universities grapple with mineral processing

RETURN TO ISSUEPREVNewsNEXTUniversities grapple with mineral processingResearch goals are metal recovery processes that alleviate growing mineral shortages and pollution from ore processingCite this: Chem. Eng. News 1972, 50, 6, 25–28Publication Date (Print):February 7, 1972Publication History Published online7 November 2010Published inissue 7 February 1972https://doi.org/10.1021/cen-v050n006.p025Copyright © 1972 American Chemical SocietyArticle Views3Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (902 KB) SUBJECTS:Metals,Minerals Get e-Alerts

Left Heart Bypass: A Modified Technique

Abundantly available discarded cathode ray tubes are a serious threat to the environment and loss to resource conservation and therefore requiring immediate recycling efforts. In this study, extensive characterization of all parts of the discarded cathode ray tube was carried out using X-ray diffraction, thermo-gravimetric, X-ray photoelectron spectroscopy, Scanning electron microscope, and Energy Dispersive Spectroscopy. The detailed mass balance and the overall potential (market value calculations) of discarded cathode tubes as an urban source, and the techno-economic calculations were carried to provide guidelines for the development of recycling technology. Recycling techniques of cathode-ray tubes were reviewed, and a concise flow sheet for overall recycling was prepared for evaluation and assessment of recycling potential. The thermal response and dissociation kinetics of the phosphor were investigated, and the activation energy in the temperature range (600–930 °C) for thermal processing of phosphor was determined as 105.4 kJ/ mol. Effective recycling of cathode ray tube phosphor can yield 4.5 g of Y, Eu and, La metal values per 500 kg of discarded units with a market value of 835 INR and an overall market value of 115,870 INR ($1567.34). The different fractions of cathode-ray tube glass were recycled using a combination of the pyrometallurgical and hydrometallurgical processes for metal recovery. Recycling of different fractions of hazardous discarded cathode ray tubes is necessary and is beneficial for a circular economy for recovery of phosphor, copper, glass and coating material, plastics, and steel.