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By Richard D. Hagni

Process mineralogy has not been given adequate attention in years past, because geologists have not been sufficiently interested in applying mineralogical techniques to industrial processes, and most process engineers are not adequately trained to use them. Although some individuals and institutions have made efforts to improve the situation, it is only in the last few years that the significance of applying the methods of mineralogy to a wide variety of industrial processes has been fully appreciated. Presently, the formation and organization of several groups devoted to applied mineralogy have created a more amenable climate for the development of process mineralogy. As a result, the presentation, discussion, and publication of the results and case histories of process mineralogy have become fairly common. Short courses affording hands-on experience with applied techniques are now available to the many geologists and process engineers engaged in industrial mineralogical processes. The future role of the process mineralogist is viewed as an expanded one, which will increase in value.

Jan 1, 1982

By A. L. Miller, A. J. Chambers, P. R. Griffiths, D. A. Parks

"Diesel engines are one of the primary contributors to the presence of nano and ultrafine aerosols in ambient air and occupational environments. Exposure to diesel emissions has been shown to contribute to various adverse health outcomes of the pulmonary system and cardiovascular system. Currently diesel emissions in the workplace are monitored by way of collecting the aerosol onto filters, which are then sent to a lab for thermal-optical analysis using the NIOSH 5040 method, which measures elemental and organic carbon explicitly. This process can take days or even weeks, and workers can potentially be exposed to excessive levels of diesel particulate matter (DPM) before the problem is identified. To remedy this, researchers from the National Institute for Occupational Safety and Health (NIOSH) are seeking to develop a field-portable method for measuring elemental and organic carbon in DPM aerosols. In the current study, we investigated the use of Fourier transform mid-infrared (FT-IR) spectrometry, which lends itself more readily to implementation in a real-time system than do the thermal-optical analysis methods. We have demonstrated a method for measuring organic and elemental carbon in DPM for a broad range of organic carbon (OC) to elemental carbon (EC) ratios (from 50.3 to 0.8). The ability to handle a wide range of OC to EC ratios is critical given the evolving diesel technology. INTRODUCTION Respiratory illnesses are common in mining industry workers [1] and exposures to toxic aerosols such as DPM can result in serious respiratory illness [2]. Health studies show a correlation between workplace exposure to diesel exhaust and an increased risk of lung cancer [3-8]. The International Agency for Research on Cancer (IARC) has characterized diesel exhaust as a human carcinogen [9], and similar classifications have been made by the World Health Organization and the California Air Resource Board. A recent study [10] suggests that the risk of lung cancer is approximately three times greater for heavily exposed workers. When compared to other aerosols in the mine environment, the settling time of DPM is significantly longer than that of dust due to their small particle size (typically < 1 µm) [11]. Additionally, submicron particles (such as DPM) are deposited in the lungs much more efficiently than their larger counterparts such as dust [12]. Previous studies focusing on particle morphology [13] show that the largest mass contributor to lung disease in mining is elemental carbon, which provides a solid core onto which hydrocarbons are adsorbed. In accord with those findings the Mine Safety and Health Administration (MSHA) decided on submicron total carbon as a surrogate for monitoring diesel particulate matter in the mining environment."

Jan 1, 2018

By P. S. Rao

In 1951, Tata Steel became the pioneer in Asia by setting up its first ever washery in West Bokaro Colliery. The first beneficiation plant used to produce clean coal of 19% ash with chance cone. Feed size of chance washers were -75 mm to +6 mm. The fine coal (-6 mm) were used directly. With change in technology,in 1986,chance cones were replaced by DM cyclones and coal was washed in two circuits. In the coarse circuit -13 mm to +0.5 mm coal was washed in two stages while the fine coal of -0.5 mm was treated in froth floatation cell. With further improvement in the process the higher ash raw coal was feed to produce clean coal of 13% ash. In 1998, DSM cyclones were replaced by scrolled Evolute design cyclone which has Ep of 0.020 to 0.025 ranges resulting in increase efficiency of separation. With the increase in demand of clean coal, lower seam proportion has increased in raw coal production. The washability studies of individual seams indicated large difference in the seam characteristics in terms of washability and specific gravity cut points of the individual seams. So washing all seams together had resulted in frequent change in the character of coal and warrants frequent changes in the operating parameters of the plant in which the separating efficiency comes down and ultimately resulted in yield loss initially. With increase in knowledge and experience in coal washing the solution to this problem was achieved by adopting, seam-wise washing which is enabling process engineers by keeping set point for longer periods there by to enhance the separation efficiency. Keywords: coal processing, froth floatation, steam washing

Sep 1, 2012

By Yuemin Zhao

Pre-combustion cleaning of coal plays a key role in the process of efficient and clean utilization of coal resources. Recently, wet beneficiation of coal is predominant around the world. Nevertheless, wet beneficiation processes are limited by the increasingly serious problem of worldwide shortage of water, especially in China. Thus, it is imperative to develop efficient dry coal beneficiation techniques. Currently, several technologies such as air dense medium fluidized bed, compound dry cleaning and air jigging have successfully achieved high-efficiency separation of 50~6 mm coal. However, in recent years, a large amount of fine coal is generated as the mechanized mining technology has been progressively deployed in coal sector. Thus, it is necessary to develop efficient dry beneficiation techniques for fine coal. In recent years, many countries including China, India, Canada, Germen, and Australia have carried out many research works on fine coal dry beneficiation techniques. China University of Mining and Technology has carried out systematic researches on the introduction the vibrated energy to traditional air dense medium fluidized bed for fine coal beneficiation. This paper studied air dense medium vibrated fluidized beds (ADMVFB) for fine coal dry beneficiation. The experimental results show that the coal of <6 mm size can be beneficiated in an ADMVFB efficiently with the E value of 0.065~0.085, the separating density can be adjusted in the range of 1.45~2.2 g/cm3, and the lower limit of beneficiation can reach to 0.5 mm. Keywords: fine coal, air dense medium vibrated fluidized bed, coal separation, dry separation

Sep 1, 2012

By William J. Orlandi

The intent and scope of this paper is to present to you, as concisely as possible, the problems and requirements -- and what we consider advantages -- of all-belt haulage in a modern underground coal mine. Mine No, 10, at Pawnee, Illinois, was opened in 1951; consequently, all the planning and consideration given to haulage selection was based on information then available and on Peabody Coal Company? s experience to that date,

Jan 1, 1961

By N. A. Abdel-Khalek

An experimental study was carried out to compare the results of laboratory column flotation versus conventional flotation for the cleaning of fine coals of different rank and their oxidized samples as well as discrete size fractions. Surface oxidation caused a significant reduction in the flotation yields achieved with both methods. However, the column flotation produced concentrates? of lower ash content. The recovery -size curve achieved with column was similar in shape to that obtained with conventional cell, with superior results in the region of fine fractions. The influence of some column operating parameters was also discussed.

Jan 1, 1990

By Yusuke Kimura, Ken-ichi Yamaguchi

"Secondary materials have long been processed at the S-furnace of the Mitsubishi continuous copper smelting and converting process at Naoshima Smelter and Refinery. Intensive recycling in the recent years has formed concerns that impurities in the secondary materials may cause drastic changes in the chemical properties of the CL-slag, which is separated from matte in the smelting stage. Among various impurities included in secondary materials, the authors have studied the influences of sodium oxides in the CL-slag because the behavior of sodium oxide has scarcely been studied with respect to the copper smelting slag. The examinations have been applied experimentally on the distribution between slag and matte of arsenic whose acidic characteristics suggest strong affinity to sodium-oxide of basic characteristics in silicate melts. The results have been discussed by thermodynamic evaluations and the results of pyro-tests at the commercial furnace.IntroductionAt Naoshima Smelter and Refinery, the existing line of the Mitsubishi continuous copper smelting and converting process has been operated since 1991. The Mitsubishi Process consists of three furnaces namely the S-, CL- and C-furnace as shown in Figure 1. In the S-furnace, copper concentrate and powdery secondary materials (scraps, sludges, etc) are charged through the top lances with oxygen enriched air. The other secondary materials of lumpy shapes are charged through the chute installed on the furnace roof. Charged materials are smelted by the reaction heat in accordance with the oxidization of copper concentrate. The mixed melt of matte and slag overflows through the launder into the CL-furnace, where the melt is separated into slag and matte by the difference of their specific gravity. Matte is siphoned out and sent to the C-furnace and converted to blister copper continuously. The CL-slag overflows continuously through the slag outlet to be water-granulated. Granulated slag is sold as a raw material used for the cement production and so on. Various secondary materials have been processed at the S-furnace of Naoshima Smelter and Refinery. Intensive recycling in the recent years has formed concerns that the chemical properties of the CL-slag may change drastically due to impurities originating from secondary materials. Among various impurities included in secondary materials, the authors have studied the influence of sodium oxide in the CL-slag because the impact of sodium oxide has scarcely been studied with respect to the copper smelting slag. The examinations have been applied experimentally on the distribution between slag and matte of arsenic whose acidic characteristics suggest strong affinity to sodium-oxide of basic characteristics in silicate melts."

Jan 1, 2012

By F. J. Hrach, K. P. Flynn, P. J. Miranda

"ST Equipment & Technology, LLC (STET) has developed a processing system based on tribo-electrostatic belt separation that provides the mineral processing industry a means to beneficiate fine materials with an entirely dry technology. In contrast to other electrostatic separation processes that are typically limited to particles greater than 75 µm in size, the triboelectric belt separator is ideally suited for separation of very fine (<1 µm) to moderately coarse (300 µm) particles with very high throughput. The high efficiency multi-stage separation through internal charging/recharging and recycle results in far superior separations that can be achieved with a conventional single-stage free-fall tribo-electrostatic separator. The triboelectric belt separator technology has been used to separate a wide range of materials including mixtures of glassy aluminosilicates/carbon, calcite/quartz, talc/magnesite, and barite/quartz. Separation results are presented for selected industrial mineral sources. An economic comparison of using the tribo-electrostatic belt separation versus conventional flotation for barite / quartz separation illustrates the advantages of dry processing for minerals.INTRODUCTIONThe lack of access to fresh water is becoming a major factor affecting the feasibility of mining projects around the world. According to Hubert Fleming, former global director for Hatch Water, “Of all the mining projects in the world that have either been stopped or slowed down over the past year, it has been, in almost 100% of the cases, a result of water, either directly or indirectly” (Blin et al., 2013). Dry mineral processing methods offer a solution to this looming problem."

Jan 1, 2016

By R. Hendricks

"IT IS a pleasure for me to appear before yon today and to have this opportunity of reviewing with you recent developments in the world lead and zinc industry. To provide essential background material, I propose reviewing the period from 1950 to the present, a period which has undoubtedly been the most hectic in the long history of the industry.In capsule form, the pattern for this period is one of repeating cycles of boom and recession, of failure through research to develop adequately new markets and new uses for lead and zinc, of surplus production and growing inventories, of price instability, and lastly, of an abdication in some sections of the industry of responsibility for control of its own destiny by turning to governments for support in time of stress. This is not a pretty picture but, as the 1950 decade ends, there are signs of a new maturity and of a growing determination on the part of the industry to put its own house in order.The difficulty suffered by the world's lead and zinc industry in the current decade originated with the support extended to it in 1950 by the U.S. Government at the time of the Korean conflict. Recalling the shortage of base metals in World War II and fearing that the Korean conflict might develop into World War III, the U.S. Government in 1950 adopted a policy to encourage the production of lead and zinc, both domestically and abroad by means of development loans and long-term floor priced purclu.se contracts."

Jan 1, 1960

By T D. H McGrath, W P. Staunton

Benchmarking, comparing an operation or process with the industry standard, is known to be a useful method for identifying plant optimisation opportunities, and in many cases providing the pathway to realise the benefits. The difficulty is generating the database of plant data necessary for a benchmarking exercise. Larger companies can benchmark internally; this option is not available to smaller companies, and the full value can only be realised with a comprehensive “industry wide” approach.The Gold Technology Group at Curtin University through the AMIRA P420 series of projects has undertaken several comprehensive metallurgical industry surveys in the gold industry over the last two decades. Analysis of these surveys has demonstrated areas where many operations can benefit from re-assessment of their operating practices.This paper will review the work undertaken by the Group in this area, in particular the 1999 surveys of gold companies in the Australasian region, and the 2012 international survey of the industry. The challenges of, and opportunities arising from these surveys will be discussed. Some of the highlights from analysis of these databases will be presented as well as noting changes in processing practices observed by the Group over the last 20 years.CITATION:McGrath, T D H and Staunton, W P, 2018. Keeping up with the Joneses – the value of industry surveys and benchmarking, in Proceedings 14th AusIMM Mill Operators&#39; Conference 2018, pp 509–516 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By K. Torigoe, S. Owad, C. Tokoro, Y Tsunazawa

The mechanism of an abrasion process to recover metal values by removing components from printed circuit boards (PCBs) is modeled using a discrete element method (DEM) simulation. To simulate the abrasion process, a model PCB geometry was constructed consisting of bonded particulates. The simulation allowed connections between particles to be broken if the bonding force calculated from DEM exceeded a threshold level. Simulation results were compared with experimental comminution data using an agitation mill with test PCBs on which nine capacitors were surface solder-mounted. Simulation results obtained from the DEM with the anchoring model corresponded to experimental observations.

Jan 1, 2011

By Dr. R. W. Mead

There are two basic problems when one attempts to separate a solution of metal ions utilizing a chelation-solvent extraction cascade (commonly called liquid ion exchange). First, it is impossible to produce any great degree of separation unless the separation factor (also called selectivity, which is the ratio of the distribution coefficients) is very large. Second, the richest possible extracted product, using an infinite number of equilibrium stages, is at best only in equilibrium with the feed solution. These factors combined with equipment design considerations have led to a situation where only the most selective chelating agents are applicable to economic industrial operations. The authors know that distillation techniques are used routinely to separate compounds with nearly identical relative volatilities and that there should be a way of operating solvent extraction cascades in an analogous manner to obtain separations of metal ions. The advantage of this approach would be that solutions of metal ions of any desired purity could be obtained even if the separation factor was close to unity. This paper presents this idea and suggests some possible applications.

Jan 1, 1977

By Charles I. Richman

Aquispirillum magnetotacticum (AM) is gram-negative hetrotrophic bacteria that belongs to a class ,of magnetotactic bacteria that have an ecological niche in marine marches and fresh water swamp sediments. Thiobacillus Ferrooxidans (TF) is a Gram-negative, acidophillic chemoliths that may have similar chemical conditions within the cytoplasmic membrane as Aquaspirillum M. to support growth of Magnetosomes. Magnetosomes are cellular bodies that accumulate under slightly aerobic conditions. Magnetotactic motion occurs in an external magnetic field and depends on the medium viscosity. The Atomic Force Microscope equipped with a magnetic tip shows the presence of Magnetosomes in these bacteria strains. The size, shape of magnetosomes in AM and TF strains are characterized.

Jan 1, 1998

By Vladislava A. Ignatkina, Victor D. Samyguin

"Within the limits of two-phase approach, considering mass transfer with pulp and air streams was shown that each bubble appears to be an elementary carrier, transporting particles from the collection zone into the froth. The kinetics of flotation was described by the exponential equation in which first order flotation speed constant has to be replaced with two-phased coefficient of a mass transfer. Criteria of selectivity of two ore fractions separation, based on determination of optimum time at which maximum difference between extractions and components content in separated fractions were offered. An interrelation between optimum time of pulp residence in a flowing chamber of a flotation machine, time of bubbles mineralization and an optimum airflow has been ascertained. Cumulative criterion of mass transfer efficiency of flotation process has been ascertained to be a form of the spectrum and its position on axis of three-phase coefficient of a mass transfer.INTRODUCTIONRegularities of a mass transfer of three bearing streams: pulp stream, air stream and froth stream underlie theory of mineral complexes flotation (Samygin, Filippov, & Shekhirev, 2003)However, only description of mass transfer in pulp stream by means of kinetic equations that were simple and convenient for practical use, has gained a full distribution (Tykhonov, 2009;Rubinstein&Filippov, 1980; Saleh, 2010).Within the limits of a single-phase approach, the role of gas stream in increase of speed and selectivity of flotation, was associated with an improvement of hydrodynamic mode. An influence of particles and bubbles sizes (Rubinstein&Filippov, 1980; Rubinstein&Samygin, 1998, Samygin et al., 2003; Dai, Fornasiero,& Ralston, 2000), of pulpflow and airflow (Finch& Dobby, 1990) and turbulent energy intensity (Shubert, 1979; Massinaei, 2007) on the flotation process has been studied. It was stated that flotation selectivity is increasing by means of gradual airflow increase from first to final cameras of the impeller flotation machine (Aslan&Boz,2010; Finch, 2011) and by means of using a multizone flotation machine (Samyguin, Filippov, Matinin, Lekhatinov, &Tertyshnikov, 2013)."

Jan 1, 2016

By N. L. Wimmler

"INRODUCTIONSedimentary deposits of titaniferrous magnetite occur at various localities in the eastern foothills of the Teton Ranse in Deer Lodge County, Mont. The Choteau deposit was examined by a Bureau of Mines engineer in August 1942. An exploration project was recommended.Core drilling exploration was begun in June 1945; it was concluded in August 1945, Seventy-six holes were drilled. This report presents the data obtained by the Bureau of Mines exploration.ACKNOWLEDGMENTIn its program of exploration of mineral, deposits, the Bureau of Mines has as its primary objective, the more effective utilization of our mineral resources to the end that they make the greatest possible contri¬bution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, Chief, conducts preliminary examination, performs the actual exploratory work, and prepares the final, report. The. Metallurgical Branch, R. G. Knickerbocker, Chief, analyzes samples and performs beneficiation tests. Both of these branches are under the supervision of Dr. R. S. Dean, Assistant-Director. The field work was supervised by Earshel W. Newman, engineer in charge of the Helena Field Office. D. B. Hoiekvam was the project engineer; he provided most of the data used in the preparation of this report."

Dec 1, 1946

By Fuqiang Zheng, Shuai Wang, Feng Chen, Yufeng Guo, Guanzhou Qiu, Tao Jiang

"The direct reduced iron powder and Ti-V-rich material was prepared from vanadium titanomagnetite concentrate by solid-state reduction-magnetic separation. The result indicated that under the studied conditions, adding KS can effectively improve the metallization rate of pellets. 2% KS was well mixed with vanadium titanomagnetite concentrate to make the pellets. The green pellet was preheated at 900 ? for 6 min. The preheated pellet was reduced at 1050 ? for 100 min, then crushed and ground to more than 80% was below 0.045 mm. The direct reduced iron powder and Ti-V-rich material were separated from the slurry by wet magnetic separation at 800Gs. The TFe content of magnetic material was 90.63%, and the Fe recovery rate reached 96.53%. The TiO2 and V2O5 contents of Ti-V-rich material were 28.40 % and 1.64 %, respectively. The TiO2 and V2O5 recovery rates were 69.05% and 96.82%, respectively. 1. Introduction The ilmenite and rutile are the main titanium resources which can be used in the present technical level and economic conditions[1,2]. However, with the rapid development of China’s economy, the market demand of titanium products is increasing sharply. The current supply of ilmenite and rutile cannot meet the needs of chemical industry[3]. China is rich in vanadium titanomagnetite concentrate which contains abundant titanium and vanadium resources. The TiO2 and V2O5 content of vanadium titanomagnetite concentrate are usually about 7% and 0.3%, respectively[4]. Because the TiO2 and V2O5 grades are low, it generally requires pre-concentrated to Ti-V-rich material before extracting the titanium and vanadium. Therefore, it is vital to find effective processes for pre-concentrating the titanium and vanadium in vanadium titanomagnetite concentrate. There are many methods[5-13] developed or under development to pre-concentrate Ti-V-rich material from vanadium titanomagnetite concentrate, including the blast furnace process, pre-reduction electric furnace process, to utilized vanadium titanomagnetite concentrate are direct reduction-electric furnace smelting, sodium salt roasting-direct reduction-electric furnace smelting and direct reduction-magnetic separation and so on. The blast furnace process and other methods cannot effectively utilize the titanium and vanadium resource due to the technical or environmental problems[9]. In this study, the vanadium titanomagnetite concentrate was obtained from Panxi region of China, the reserves of which account for 11.6% of vanadium and 35.17% of titanium all over the world[3]. The preparation of direct reduced iron powder and Ti-V-rich material based on reduction-magnetic separation is proposed. The process utilizes a new catalyst for titanium ore reduction in rotary kiln followed by magnetic separation. Using this novel technology, the titanium-vanadium and iron are successfully separated. Compared to the traditional reduction of Ti-bearing ore, the reduction temperature reduced to 1050 ?, leading to higher efficiency, lower energy consumption and investment, and broader applications."

Jan 1, 2018

By M. Saghaeian, R. Hejazi, H. Abedini

Vertical ring and Pulsating Wet High Intensity Magnetic Separator (VP-WHIMS) is widely used for week magnetic mineral beneficiation or ferrous impurity removal from non-metallic minerals. Because of the complexity of this machine, mathematical modelling of its process is complicated and time consuming. In this paper, artificial neural network (ANN) and response surface methodology (RSM) were applied to evaluate the VP-WHIMS performance and optimize its main operating parameters in beneficiating of the Chadormalu hematite sample. The operational parameters of this magnetic separator are considered as: magnetic field intensity (2500-8500 gauss), pulsating frequency (20-100 %max), ring rotation speed (0.6-4.6 r/min) and slurry concentration (15-35 w/w %). Concentrate grade and recoveries (weight and Fe) are monitored as responses. Centre composite design (CCD) was used for experimental study. Four process variables were set using small CCD. Eight star points (a=±1), eight axial points (a=±2) and five replicates at the centre point (a=0) were chosen as experimental points. In ANN system, the best network topology was obtained as (4-5-3). The weights connection and biases were obtained using batch back propagation (BBP) method for 21 experimental data points. The results indicate that ANN

Jan 1, 2014

By B. Courtaud, L. Donati, V. Weigel

As a growing mining company, ERAMET is looking for new positions in the strategic metals market. In this context, the Gabonese Maboumine pyrochlore deposit is currently being studied for the recovery of niobium, tantalum, rare earths and uranium. This ore shows mineralogical and chemical characteristics that make it challenging to process by existing practices, from both technical and economic points of view. ERAMET has developed since 2008 an innovative hydrometallurgical process, which has been successfully operated at a pilot plant scale (more than 35 weeks in continuous). The upstream part of the process aims to dissolve valuable elements in sulphuric acid. The first step is dedicated to dissolve the ore matrix, leaving the pyrochlore unleached. The second step consists in chemically breaking down pyrochlores in order to form soluble species of the valuable elements. After dissolution, the valuable elements are separated into different flows: niobium and tantalum are recovered and transformed as commercial ferroniobium on one side, and rare earths and uranium remain in the solution to be recovered in the downstream part of the process. The main goal of this paper is to discuss the upstream part of the process, which has given successful results.

Jan 1, 2014

By Luciano Gadonski

O Laminador Reversível a Frio 4-Hi de uma cadeira da CSN-PR não foi projetado para reduzir 100% da Bobina Quente Decapada (BQD), ficando sempre o trecho de miolo e capa fora da espessura de especificação. O descarte deste material é realizado na entrada da Linha de Galvanização Contínua (LGC) da CSN-PR, sendo o processo de descarte feito de forma manual baseado em critérios visuais, acarretando em diferentes resultados por turno de operação, assim como o descarte desnecessário de material bom como sucata na maioria dos casos. Este trabalho aborda o estudo e desenvolvimento de um projeto conduzido através da metodologia do Lean Seis Sigma, automatizando a decisão do descarte e atingindo à máxima utilização do material dentro da especificação de espessura, diminuindo assim o trecho fora de bitola descartado como sucata na entrada da LGC, o que afetava diretamente o indicador de Rendimento Metálico da linha.

Aug 17, 2017

By Juergen Antrekowitsch, Stefan Steinlechner

"Within the last decades, mainly the base metals, like zinc, copper and lead were recycled from different industrial residues without taking into account that accompanied minor side-elements are often also present. A high supply risk for critical raw materials derives mainly due to the high share of the worldwide production in a limited number of countries. Examples include indium and germanium in China, PGM in South Africa and Russia or cobalt and tungsten in the Democratic Republic of Congo. By taking the market of critical metals into account, the recycling of potential residues does not only contribute to an economic treatment but also to the European strategy to decrease the supply risk of certain metals. Depending on the metal discussed, political unrest, decreasing primary resources leading to supply risks in different countries or also simply economic interests moved these mentioned side elements and with this the residues where they are present in, into the focus of the recycling industry.Because of this, the typical routes of lead, zinc and copper production are evaluated concerning generated residues and their typical contents of contained minor elements. Finally, the paper tries to answer the questions how a possible treatment of these wastes could contribute to the overall supply of for example silver but also other minor elements."

Jan 1, 2016