RECYCLING OF SLAG FROM COPPER PRODUCTION (original) (raw)
Related papers
Slag Cleaning Equilibria in Iron Silicate Slag–Copper Systems
Journal of Sustainable Metallurgy
In this study, the equilibrium distributions of selected trace elements between molten iron-saturated copper alloy and selected iron silicate slags were measured, and the effects of silica fluxing on them. In addition to the copper and iron main components of the system, trace elements like antimony, gallium, germanium, gold, indium, and silver were added in experiments that spanned the temperature range of 1473-1573 K (1200-1300 °C). Experimental charges were quenched and prepared in polished mounts. In situ analyses of the resulting phases were made directly on the mounts without the need of phase separation prior to analysis. Electron probe X-ray microanalysis was used for concentrations at or above approximately 100 ppmw, and laser ablation-inductively coupled plasma-mass spectrometry for the lower concentrations in the slags. The very low slag concentrations of germanium, antimony, and indium obtained indicate that these elements can be removed from the slag by reduction, whereas gallium concentrations in the slag were high. Consequently, gallium removal from iron residues, such as zinc smelting jarosite, is difficult without volatilization. Based on the present observations, the industrial reduction processes for the treatment of smelting and refining slags as well as for the processing of iron residues, and extracting the reducible metal oxides and their metal values can be optimized. The target in fluxing should be to maintain the slag compositions with a silica concentration higher than about 28 wt%.
Phase equilibria of fayalite-based slags for the slag cleaning process in copper production
Proceedings of the …, 2011
Limited data are available on the phase chemistry of the multi-component slag system at intermediate oxygen partial pressures used in the copper smelting, converting and slag cleaning processes. Recently experimental procedures have been developed and have been successfully applied to characterise a number of complex industrial slags. The experimental procedures involve high temperature equilibration and quenching followed by the electron probe X-ray microanalysis. This technique has been used to construct the phase equilibrium diagram for the "Cu 2 O"-FeO-Fe 2 O 3-SiO 2-CaO-MgO-Al 2 O 3 slag system at controlled oxygen partial pressure and metallic copper saturation conditions, in the range of compositions and temperatures directly relevant to the Slag Cleaning Electric Furnace. The liquidus temperatures in the tridymite and spinel primary phase fields at metallic copper saturation were measured for the fayalite-based slag with 2 wt% of CaO, 0.5 wt% of MgO and 4.0 wt% of Al 2 O 3. In this paper, the experimental technique is explained in detail. The new experimental equilibrium results are presented in the form of the liquidus temperature vs. Fe/SiO 2 phase diagram. The application of the results to the practical operation of the slag cleaning furnace is discussed. The experimental results are compared with the FactSage model predictions.
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.
Metals, 2020
Ferrous-calcium-silicate (commonly known as FCS) slags are used in the valuable metal recycling from urban ores through both primary and secondary copper smelting processes. In the present study, the structure of selected FCS-MgO (FCSM) and FCS-MgO-Cu 2 O-PdO (FCSM-Cu 2 O-PdO) slags, relevant to the processes, were investigated using Fourier-transform infrared (FTIR) spectrometry. Deconvolution of the FTIR spectra was carried out to calculate the relative abundance of different silicate structural units (Q n), the overall degree of polymerization (DOP) of the slags and the oxygen speciation in the FCS slags. It was observed that, for the slag investigated, the relative intensity of both the high-frequency band ≈ 1100 cm −1 (Q 3) and low-frequency band ≈ 850 cm −1 (Q 0) were affected by Fe/SiO 2 ratio, basicity, temperature (T) and oxygen partial pressure (pO 2). The DOP and the average number of bridging oxygen (BO) were found to decrease with increasing both Fe/SiO 2 ratio and basicity. Improved semi-empirical equations were developed to relate the DOP of the slags with chemistry, process parameters and partitioning ratio (i.e., the ratio of the amount of element in the slag phase to metal phase, also known as distribution ratio) of Pd and Ge. Possible reactions, expressed as reactions between metal cations and silicate species, as a way to evaluate thermodynamic properties, are presented herein.
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.
Re-Use of Silico-Manganese Slag
Sustainability
The world’s rapidly growing demand for raw manganese has made it increasingly important to develop methods for the economic recovery of manganese from secondary sources. The current study aims to present possible ways for the recycling and reuse of silico-manganese slag landfilled in Tulcea, City on the Danube River close to the Danube Delta Biosphere Reserve in order to save the natural resources raw of manganese. In the last three decades, the ferroalloy production plant has over 2.6 million tons of slag. Slag dumping constitutes a significant source of air, water and soil pollution, which adversely affects the environment and human health. Mn present in the slag dump is an environmental pollutant with potentially toxic effects. The results obtained with a leaching method to recover manganese from slag shows two efficient ways to valorize manganese from solid fraction (54%) with size particles between 80 and 315 µm and/or reuse the leaching medium (56% Mn) with a slag size of <...
Technological scheme for copper slag processing
International Journal of Mineral Processing, 2017
A technological scheme for copper slag processing is proposed. It comprises 5 stages, namely: (i) air oxidation of the copper slag at a temperature above 800 o C for 2 h; (ii) hydrothermal treatment of the oxidized slag with sodium hydroxide solution (140 g/l) at 190 o C for 3 h; (iii) separation of the solid from the liquid phase by hot filtration; (iv) gel formation through hydrolysis of the liquid silicate phase by changing pH; (v) obtaining of amorphous SiO 2 (silica gel) by drying at 80 o C. The processes used for slag manipulation were elucidated and optimized for silicon extraction. It was established that the increase in the oxygen partial pressure in the oxidizing gas does not change the mechanism nor significantly intensifies the oxidizing process. A decisive factor for the extraction of SiO 2 during hydrothermal treatment was the concentration of NaOH. Its increase from 60 to 140 g/l reduced the amount of residual SiO 2 more than half and significantly decreased the formation of analcime (NaAlSi 2 O 6 .H 2 O) in the solid phase. Hydrolysis of the liquid silicate phase by changing pH is an appropriate process for gel formation.
TECHNOLOGY FOR THE COMPLEX RECYCLING SLAGS OF COPPER PRODUCTION
S.T. Matkarimov, A.A. Yusupkhodjaev, Sh.T. Khojiev, B.T. Berdiyarov, Z.T. Matkarimov. Technology for the Complex Recycling Slags of Copper Production // Journal of Critical Reviews, Volume 7, Issue 5, April 2020. P. 214 – 220. , 2020
The article considers the inevitability of copper losses with slag and the possibility of reducing them by various methods and using local secondary technogenic formations. It has been established that the developed and widely used in industry technologies for decopperizing of slag only partially solve the problem and lead to significant irretrievable losses of metal with dump slag. The main factors affecting the magnitude of the casualties are established, and suggestions for reducing their negative impact are recommended. The use of perfect mixing devices is recommended, as in this case, it is possible to achieve a maximum reduction in the residual concentration of copper in the waste slag. Together, it is possible to make an increase in the complexity of the use of raw materials with the organization and implementation of low-waste technology.
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.