Characterisation of copper slag in view of metal recovery (original) (raw)
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Research on the Recovery of Copper from Metallurgical Slag
Mining Revue, 2021
Metallurgical slag is one of the most common industrial wastes. Many of these wastes are not stable over time, by reacting with water and air, continuously generating emissions of heavy metals. Metallurgical slag processing is necessary for at least two reasons: reducing pollutant emissions and broadening the raw material base. The recovery of these slags is very difficult because they are the result of metallurgical processes that aimed to fix metals considered impurities in chemical matrices as stable as possible. This paper presents the initial research on the behavior of metallurgical slags against different leaching technologies.
Characterization of copper slag for beneficiation of iron and copper
Heliyon, 2021
Before disposal of any metallurgical waste to the environment, it is the responsibility of mining institutes to adhere to the permissible metal content limits. Base metals, especially iron and copper, have adverse effects of reducing the soil pH and excessive concentrations of these in the disposed waste may result in soil pollution and toxicity, with adverse effects on plant growth and animal health. Copper slag is a metallurgical waste that is disposed by way of stockpiling at designated dump sites within a mining site. The observed depletion of highgrade iron ores in Botswana and the environmental hazards associated with disposal of untreated metallurgical waste, presents an opportunity for research on secondary sources of iron and copper. Our characterization results show that this BCL copper slag is a good secondary source of base metals, especially iron and copper. These results reveal that the elemental proportion of iron was around 35.4%. Literature states that an iron grade that is considered viable for economic beneficiation should be at least 25% and this slag has an iron content above this limit, hence poses a serious environmental threat upon disposal. This article presents an investigation into the mineralogy of the copper slag at a plant situated in Selebi Phikwe, a town in the northern part of Botswana. Quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) quantified that no cobaltsulphide was detected and strongly indicated that the cobalt within the sample occurs in solid solution in either the fayalite phase or glass phase. Spot analysis from electron probe microanalyzer (EPMS) images indicated an unusually high content of copper compared to any other metal. We elucidate that, this was due to the inefficient processing techniques employed during operational years of the mine. The relative compositions of Co, Fe, Ni and Cu were 0.14%, 35.4%, 0.28% and 0.29% respectively. This analysis justifies our interest in considering this copper slag as a secondary source of iron for beneficiation purposes.
Characterization of copper smelter slag and recovery of residual metals from these residues
Revista Facultad de Ingeniería, 2017
The pyrometallurgical copper extraction process generates 2.2 t of residues for each ton of produced metal. Initially, this paper shows the physical and chemical characterization of a copper processing residue, followed by the procedure to obtain the gold and silver that are contained in the copper residue. The characterization of a white metal oxidized calcine indicates a high content of copper as cupric ferrite, and important values of gold and silver. Gold and silver concentrations were 38.5 g t-1 and 1085 g t-1, respectively. The gold was found scattered in cupric ferrite grains, while the silver was dissolved in a matrix of Cu-S in amounts between 1 % and 50 %. Cyanidation tests showed that 95 % gold recovery could be obtained with a concentration of 0.06 g l-1 KCN, a pH of 10.5, room temperature, and a residence time of 80 h. When the temperature was increased to 75 °C, and the other cyanidation parameters were maintained intact, the same recovery was obtained but with a short...
Copper slags are usually considered a waste and characterized only by the final copper content. Large and increasing quantities are being produced and disposed of by stockpiling near the metallurgical plants. This paper stresses the importance of physico-chemical characterization when considering uses for slags and the possibility of recovering the valuable metals still remaining in this phase. The purpose of this work is to support and encourage a change in the classical perception of slag from a 'waste' to a 'resource'; promote the development of new technologies for treatment to recover residual values and encourage a search for new uses; with the ultimate objective of eliminating slag stockpiles thereby diminishing the environmental impact of smelting operations. Some of the results of experimental laboratory work done by the authors and examples of commercial applications will be shown. A promising future for valorization and utilization of slags is expected and will provide an example when considering the use of all the other large quantities of wastes generated by the mining industry.
Microscopy Analysis of Copper Slag and Its Processing by Flotation
A smelting plant in Bor extract copper from copper ores and copper concentrates by a pyro metallurgical process. During years of operation, a considerable amount of copper slag has been generated as a by-product and has been dumped. Copper contents in these slags are as high as 0.6 up to 0.8%. As such, this slag could be considered as a secondary source for copper re-utilization. In this context, microscopy analysis of slag samples was carried out in order to determinate its mineralogical composition and to find a possibility for re-extraction of remaining copper from the slag. According to results of the investigation and phase occurrences in slag, it is possible to apply flotation for recovery of copper from these slags.
Recovery of Copper and Cobalt from Copper Slags as Selective
Journal of environmental science & engineering, 2017
This study focuses on the recovery of copper and cobalt from copper slags obtained from Kure district of Kastamonu city, which is in the north of Turkey, and removal of Se, Te, Sb and As from mixture of copper slag and copper concentrate has been conducted. Homogeneous mixtures of slag/pyrite/copper concentrate rate were subjected to roasting at high temperatures in a closed medium and then it was processed roasting at air atmosphere at 600 °C. In the leaching experiments, the effects of roasting time, rate of slag/pyrite/copper concentrate and the effect of the added iron powder to leaching on the metals dissolution were investigated. Under optimum conditions, 99.6% of copper and 98.4% of cobalt were extracted in roasting at high temperatures in a closed medium 3:6:6 of slag/pyrite/copper concentrate rate then roasting at 600 °C at 5 hours. Besides, it was determined that all of Se, Te, Sb and As can be removed from the mixture of slag/pyrite/copper concentrate rate.
Copper Metallurgical Slags – Current Knowledge And Fate: A Review
Critical Reviews in Environmental Science and Technology, 2015
Cu-slags are a by-product of pyrometallurgical processing and contain elevated concentrations of metallic elements that may be released during weathering. Hence, they may pose environmental risk and thus need to be properly disposed off. On the other hand, the high residual content of metals makes slags interesting as secondary resources for metal recovery. This review presents current knowledge about the chemical and phase composition of Cu-metallurgical slags and discusses environmental issues related to their disposal. Furthermore, it provides an overview of experimental approaches assessing environmental risk as well as recent achievements regarding the leaching and recovery of valuable metals from Cu-slags.
Characterisation and recovery of non-ferrous metals met in a copper-slag processed by flotation
2021
Detailed process oriented characterisation on representative samples from plant survey of the slag flotation plant belonging to Aurubis, Bulgaria has been realised in order to evaluate the mineralogical occurrences of Cu, Ni, Mo and Co bearing phases. The slag subjected to flotation consisted in majority of fayalite, magnetite-iron oxides and a glass-like phase. Ni and Mo have been found to be closely associated to magnetite and fayalite. The tailing from the slag flotation has been subjected to sulphation roasting followed by water leaching as a hydrometallurgical means to recover the remaining Cu, Mo, Ni and Co. Based on the various sulphation roasting conditions (acid dosage, duration, temperature) copper, nickel and cobalt were brought to solution to a different extent. Molybdenum was the most difficult to be rendered soluble due to its close association with iron, suspected to form an insoluble compound with it. Sulphation roasting performed at 350oC has secured the best extrac...
Environmental and Socioeconomic Impact of Copper Slag—A Review
Crystals, 2021
Copper slag is generated when copper and nickel ores are recovered from their parent ores using a pyrometallurgical process, and these ores usually contain other elements which include iron, cobalt, silica, and alumina. Slag is a major problem in the metallurgical industries as it is dumped into heaps which have accumulated into millions of tons over the years. Moreover, they pose a danger to the environment as they occupy vacant land (space problems). Over the past few years, studies have been conducted to investigate the copper slag-producing outlets to learn their behavior, as well as properties of slag, to have the knowledge of how to better reuse and recycle copper slag. This review article provides the environmental and socioeconomic impacts of slag, as well as a characterization of copper slag, with the aim of reusing and recycling the slag to benefit the environment and economy. Recycling methods are considered an attractive technological pathway for reducing waste and green...