Waste Management and Treatment of Copper Slag BCL, Selebi Phikwe Botswana: Review (original) (raw)
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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.
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...
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.
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.
RECYCLING OF SLAG FROM COPPER PRODUCTION
Yusupkhodjaev A.A., Khojiev Sh.T., Ismailov J.B. Recycling of slag from copper production // Инновационные процессы в науке и образовании: сборник статей Международной научно-практической конференции. В 3 ч. Ч. 1. – Пенза: МЦНС “Наука и Просвещение”. – 2019. С. 51 – 53. , 2019
In the production process of copper large amounts of solid waste products (slag) mainly containing iron silicate-fayalite (2FeO•SiO2), aluminum oxide, calcium oxide as well as lead, zinc, copper and molybdenum, arsenic and selenium presenting in less than 1 percent concentration is generated. The waste products deposition into the environment causes serious environmental problems and depots maintenance operations require significant expenses [1, p. 5]. Materials and methods. It is well-known that the fayalite (2FeO•SiO2) is resistant to dilute acids and hydroxides. Concentrated acids and hydroxides dissolve copper slag, but unfortunately this process is accomplished with high reagents consumption. On the other hand, the alkali metals (Na, K) react with silicon dioxide (silica-SiO2) forming water-soluble silicates. Actually, under oxidation conditions the fayalite (2FeO•SiO2) is transformed into a mechanical mixture of oxides (Fe2O3, Fe3O4 and SiO2).
In pursuit of carbon neutrality, the demand for metals that are necessary for the development of clean energy technologies is rapidly increasing. Metallurgical waste, such as slag, presents a promising secondary source of these key metals. This research aims to develop an eco-friendly hydrometallurgical process to recover Cu, Ni, and Co from discarded copper/nickel slag. The high-pressure acid leaching (HPAL) was used to selectively leach Ni, Cu, and Co from the fayalite slag, yielding high leaching efficiencies of 99.9%, 89.4%, and 99.9%, respectively, with low Fe and Si tenors to the pregnant leach solution (PLS). The solvent extraction (SX) technique utilizing LIX 984N was used to selectively extract and enrich copper from the dilute PLS to about 23 g/L Cu with a very low Fe concentration of 0.05 g/L. Potassium amyl xanthate (PAX) solution was used to form Ni and Co xanthate complexes from the raffinate solution. Nickel was selectively recovered using ammonia solution, while coba...
Recovery of iron from copper slag
Archives of Metallurgy and Materials, 2018
Copper slag is a by-product obtained during smelting and refining of copper. Copper smelting slag typically contains about 1 wt.% copper and 40 wt.% iron depending upon the initial ore quality and the furnace type. Main components of copper slag are iron oxide and silica. These exist in copper slag mainly in the form of fayalite (2FeO ·SiO 2). This study was intended to recover pig iron from the copper smelting slag by reduction smelting method. At the reaction temperature of below 1400°С the whole copper smelting slag was not smelted, and some agglomerated, showing a mass in a sponge form. The recovery behavior of pig iron from copper smelting slag increases with increasing smelting temperature and duration. The recovery rate of pig iron varied greatly depending on the reaction temperature.
Sustainable Construction Material -Copper Slag: A Review
International Journal of Engineering Research (IJER) , 2019
With increase in the population day by day, consumption of the resources also increases. With this, the waste material production also increases. Manufacturing process of copper production produces enormous amount of the copper slag which contains required chemical properties, so it can be used as construction material. This paper contains information regarding survey of copper slag manufacturing process and different uses of copper slag. This paper reviews the use of industrial waste material 'copper slag' in the construction work as a replacement of cement, sand and aggregate to reduce the cost of construction and simultaneously to reduce environmental effect due to the landfilling of copper slag. As well as construction is the only industry where the waste materials can be utilized successfully.
Application of Physical and Chemical Methods for Processing Slags of Copper Production
International Journal of Advanced Research in Science, Engineering and Technology, 2019
The article deals with the problem of reducing copper losses from waste slags. A comprehensive solution to the problem with the use of physicochemical methods of influence on the melt is proposed. It is shown that the success of the depletion process depends on the sulfiding of oxidized copper compounds, the reduction of magnetite in the slag to wustite, and the creation of conditions for the coalescence of fine drops of matte. Creating these conditions makes it possible to reduce the residual concentration of copper to the level applied. This can be obtained poor matte, which is processed by pouring them into a melting furnace. Depleted slag is waste products and can be implemented in the construction industry. In fact, this makes it possible to abandon the creation of slag heaps.
Sustainability, 2020
Copper smelting slag is a solution of molten oxides created during the copper smelting and refining process, and about 1.5 million tons of copper slag are generated annually in Korea. The oxides in copper smelting slag include ferrous (FeO), ferric oxide (Fe 2 O 3), silica (SiO 2 from flux), alumina (AI 2 O 3), calcia (CaO) and magnesia (MgO). The main oxides in copper slag, which are iron oxide and silica, exist in the form of fayalite (2FeO·SiO 2). Since copper smelting slag contains high content of iron, and copper and zinc, common applications of copper smelting slag can be used in value-added products such as abrasive tools, roofing granules, road-base construction, railroad ballast, fine aggregate in concrete, etc. Some studies have attempted to recover metal values from copper slag. This research was intended to recover ferrous alloy contained Cu, a raw material of zinc, from copper slag, and produce reformed slag such as blast furnace slag for Portland cement. As a result, it was confirmed that with reduction smelting by carbon at temperatures above 1400 • C, it is possible to recover pig iron containing copper from copper smelting slag, and the addition of CaO in reduction smelting helped to reduce iron oxide in the fayalite and change the chemical and mineralogical composition of the slag. The copper oxide in the slag can be easily reduced and dissolved in the molten pig iron, and zinc oxide is also reduced to a volatile zinc, which is removed from the furnace as fumes, by carbon during the reduction process. When CaO addition is above 5%, acid slag is completely transformed into calcium silicate slag and is observed to be like blast furnace slag.