Copper Content In Slag Research Articles

Control of Copper Content in Flash Smelting Slag and the Recovery of Valuable Metals from Slag—A Thermodynamic Consideration

To determine slag properties and the factors influencing these properties for optimization of operating conditions in the copper flash smelting process, the composition and microstructures of the quenched smelting and converting slags have been analyzed. Thermodynamic software FactSage 8.2 has been used to investigate the effects of matte grade, SO2 partial pressure, and the Fe/SiO2 ratio on the liquidus temperature and the copper content of the smelting slag. The possibility to recover valuable metals from the smelting and converting slags through pyrometallurgical reduction by carbon is also discussed. It was found that the flash smelting slag temperature is usually higher than its liquidus temperature and the copper (1.2% Cu) is mainly present in the slag as dissolved copper. In the copper flash smelting process, the copper content in the slag can be decreased by decreasing the Fe/SiO2 ratio and temperature. In pyrometallurgical slag reduction, most Cu, Mo, and Ni can be recovered as an alloy. The conditions of recovery such as the ratio of smelting slag to converting slag, temperature, and reduction extent have been discussed.

Influence of Process Parameters on Copper Content in Reduced Iron Silicate Slag in a Settling Furnace

During the pyrometallurgical extraction of copper, a significant fraction of this metal is lost with discard slag, which decreases profits and overall copper recovery. These copper losses can be reduced by using a settling furnace, in which suspended droplets containing copper separate from slag under the influence of gravity. An industrial trial was conducted in a settling furnace to increase the knowledge of the effect of temperature and settling time on the copper content of slag, and thus enhance the settling process to increase copper recovery. Slag samples were collected from four sample points: the ingoing and outgoing slag stream, within the furnace during settling, and the granulated slag. The chemical composition of the slag samples was analyzed and compared between batches with different temperatures and settling times. The appearance of copper and its associated phases were analyzed using a scanning electron microscope with an energy-dispersive X-ray spectroscopy detector (SEM-EDS). The results indicated that the outgoing slag copper content increased with an increase in temperature, and it was also concluded to be influenced by the attachment of copper to spinels and gas bubbles. The results indicate that regulating the settling furnace temperature to a lower interval could increase copper recovery.

Matte separated behavior from slag during the cleaning process by using waste cooking oil as carbon neutral reductant

As a waste resource, waste cooking oil (WCO) has not been widely used. Based on the characteristics of WCO cracking, this study proposed to replace fossil-based reductant with WCO for copper slag cleaning, to solve the problem of carbon neutralization in this process. Copper slag cleaning experiments were carried out in a lab-scale electric furnace. The matte separated behavior from slag and the distribution of matte in slag were studied. The results showed that the Fe3O4 content decreases from 12.9 to 3.5 wt.% by injecting 2.2 mL of WCO into 300 g copper slag at 1250?C. The distribution of copper content in slag is gradient along the vertical direction. In the reduction stage, the excessive Fe3O4 is reduced and the fluidity of slag is improved. When the precipitation time is above 60 minutes, the copper content in the middle and upper slag is reduced to 0.57 wt.%, which realizes the copper slag cleaning by using WCO.

Relationship between copper content of slag and matte in the SKS copper smelting process

In the newly developed oxygen-enriched bottom-blowing copper smelting process (also known as the SKS copper smelting process), Cu loss in slag is one of the most concerning issues. This paper presents our research results concerning the relationship between the Cu content of the matte and slag in the SKS process; the results are based on actual industrial production in the Dongying Fangyuan copper smelter. The results show that the matte grade strongly influences Cu losses in slag. The dissolved and entrained losses account for 10%–20% and 80%–90% of the total SKS industrial Cu losses in slag, respectively. With increasing matte grade, the dissolved and entrained Cu losses in the SKS slag both increase continuously. When the matte grade is greater than 68%, the content of Cu in the smelting slag increases much more dramatically. To obtain a high direct recovery of copper, the matte grade should be less than 75% in industrial SKS copper production.

Deparation of dump slags at the Balkhash copper smelting plant

The purpose of this work is to determine the regularities of reducing the losses of valuable metals with waste slag of copper smelting in the conditions of the Balkhash copper smelter. The change in the raw material base, the introduction of low-quality copper concentrates in the Balkhash copper smelter (BCS) on the VF-1 and VF-2 (Vanyukov furnaces), are accompanied by the production of waste slag containing increased copper content, which requires additional technological operations for their depletion. Smelting in optimal conditions can exclude the organization of separate processing waste slag. Ways to improve the autogenous smelting of copper concentrates at BCS are the following: strict adjustment of the charge composition by basic metals and silicon dioxide, temperature regime, maintaining the heat balance with the possibility of using fuel, optimal operation of the electric mixer. A study of the dependences between the copper content in charge and slag on furnaces VF-1 and VF-2 of BCS allows establishing that the amount of slag increases 1.5-2 times with a decrease of the copper content in the charge 2 times. Reducing the copper content in the feed increases the losses of copper in the slag. The dependences of the copper content in waste slag on content of magnetite and zinc indicate that an increase of the magnetite content from 8 up to 11 % leads to an increase of the copper content in the slag for 0.4-0.5 %. An increase of the zinc content from 4 up to 6 % leads to increase for 0.3-0.5 % of copper content in the slag. Thermal studying of samples of dump slag, produced on furnaces VF-1 and VF-2 showed that the temperature of the slag at the outlet of the electric mixer should be at least 1300 °C. This temperature is difficult to reach by autogenous smelting regime. To solve the problem of complete separation of slag and matte, it is necessary to overheat slag for 70-80 0С, which will realise at electric energy consumption 80 kWt·h/t of slag and allows obtaining waste slag of the optimal composition.

Effect of Iron Phase Evolution on Copper Separation from Slag Via Coal-Based Reduction

Copper slag, a by-product of copper pyrometallurgy, inevitably contains a certain amount of copper. Oxygen-enriched smelting technologies increase the copper content in slag indirectly because of the production of higher-grade matte. The effect of iron phase evolution on the copper content in slag during the slag cleaning process in an electric furnace was investigated using the method of combining theory with experiments. Based on the analysis, the main factors that impede the separation of slag and copper/matte were determined. Subsequently, the properties of slag were analyzed after decreasing the magnetite content within the slag. The experimental results showed that decreases in magnetite content were beneficial for the separation of copper and slag because of the decrease of slag viscosity. Nevertheless, Cu-Fe alloys formed when magnetite was completely reduced to metallic iron, and the foaming slag was formed at 1250 °C. Furthermore, the distribution of copper in the reduced slags was studied in detail.

Thermodynamic Modeling and Optimization of the Copper Flash Converting Process Using the Equilibrium Constant Method

Based on the principle of multiphase equilibrium, a mathematical model of the copper flash converting process was established by the equilibrium constant method, and a computational system was developed with the use of MetCal software platform. The mathematical model was validated by comparing simulated outputs, industrial data, and published data. To obtain high-quality blister copper, a low copper content in slag, and increased impurity removal rate, the model was then applied to investigate the effects of the operational parameters [oxygen/feed ratio (ROF), flux rate (RF), and converting temperature (T)] on the product weights, compositions, and the distribution behaviors of impurity elements. The optimized results showed that ROF, RF, and T should be controlled at approximately 156 Nm3/t, within 3.0 pct, and at approximately 1523 K (1250 °C), respectively.

Distribution Equilibria of Arsenic and Antimony between Na<SUB>2</SUB>CO<SUB>3</SUB>–Na<SUB>2</SUB>O–SiO<SUB>2</SUB> Melts and Liquid Copper

Following the previous report on phase equilibria between Na2CO3–Na2O–SiO2 melts and liquid copper, the distribution equilibria of arsenic and antimony have been investigated at 1523 K to investigate the optimum conditions for removal of these detrimental elements from copper by use of soda flux. The obtained results were explained by the terms of oxygen potential and soda-ratio in slag, and iso-bars of the distribution ratios were illustrated on the ternary diagram of (Na2CO3+Na2O)–SiO2–Cu2O. The increase in oxygen potential or in basicity of slag results in high removability of these elements. Tri-valent arsenic or antimony is common in the slag with low soda ratio, but penta-valent becomes predominant as the basicity of slag or oxygen potential increases. Pentavalent is more stable for arsenic than for antimony, and bring about drastic variations in the distribution ratio. Sodium carbonate melt under high oxygen potential represents high removability of arsenic and antimony with rather small dissolution of copper. Basic sodium silicate slag has also high removability of these detrimental elements, but copper content in slag is too high under high oxygen potential. High distribution ratio of arsenic and antimony is also observed for Cu2O slag containing 10 to 20% Na2O.

粗銅-白カワと平衡するシリカ飽和スラグへの銅の溶解について

Solubilities of copper in the silica-saturated iron-silicate slag coexisting with liquid copper (orCu-Agalloy) and white metal were measured under a controlled partial pressure of sulfur dioxide gas at temperatures of 1200°-1300°C. The quenched samples equilibrated in silica crucible were analysed by chemical, microscopic and EPMA methods. The obtained results are summerized as follows:(1) Bythe careful treatment of melting and sampling, only dissolved copper in slag can be analysed withoutany disturbance with suspended particles of metal and/or white metal.(2) Copper content in the slag equilibrated with Cu-Ag alloy is directly proportional toαcuat the fixed Pso2.(3) Copper content in the slag equilibrated with pure Cu increase with increasing.Pso2.(4) After the conversion of Pso2to Po2, copper content of slag is directly proportional to Po21/4The solubility of copper at the samePo2decrease with increasing temperature.(5) In a general trends, the results agree with the previous papers obtained for copper-slag-gas systems.