| 1. |
- Isaksson, Jenny, et al.
(författare)
-
Improved Settling Mechanisms of an Industrial Copper Smelting Slag by CaO Modification
- 2023
-
Ingår i: Journal of Sustainable Metallurgy. - : Springer Nature. - 2199-3823 .- 2199-3831. ; 9:3, s. 1378-1389
-
Tidskriftsartikel (refereegranskat)abstract
- A significant source of copper losses from pyrometallurgical copper extraction is attributed to dissolved and entrained copper in discarded slag. Entrained copper can be recovered via pyrometallurgical slag cleaning in a settling furnace, where the slag viscosity and copper droplet size distribution (CDSD) are critical parameters. Reduced copper losses suggest improved raw material efficiency, and the slag becomes a more environmentally safe byproduct. In this study, iron silicate slags from a smelting furnace are industrially CaO modified in a fuming furnace to contain a CaO content between 8 and 18 wt.%. The viscosity of slags with and without CaO modifications is evaluated in the temperature range from 1423 to 1723 K. The influences of the CaO modifications on the CDSD, slag matrix copper content, and total copper content were determined. The results show that the slag viscosity decreases with increasing CaO concentrations in the slag. In addition, the copper content decreases in the slag phase, and the CDSD shifts to contain relatively larger droplets. The effect of CaO slag modification reveals a linear relationship between the overall copper recovery and viscosity, which increased from 63 to 88% when the viscosity in the respective batch was 0.51 and 0.25 Pa·s.
|
|
| 2. |
- Isaksson, Jenny, et al.
(författare)
-
Improved Settling Properties of Iron Silicate Slag by CaO Modifications
- 2023
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- One of the most significant sources of copper losses from pyrometallurgical copper extraction is attributed to dissolved and entrained copper in the discarded slag. The entrained copper can be recovered via pyrometallurgical slag cleaning in a settling furnace. Reduced copper losses mean increased smelter profits by improved raw material efficiency, and, in addition, the slag will become a more environmentally safe by-product. One way to increase the copper recovery during the settling process is to modify the slag to improve the properties that decrease copper solubility and slag viscosity. In this study, iron silicate slag was modified using CaCO3 on an industrial scale to evaluate its effect on the settling process. More specifically, the changes in settling were related to the modifications and measurements of slag viscosity and copper droplet size distributions in the slag. The trial was evaluated by comparing the copper content in different batches, the size distribution of copper-containing droplets using automated scanning electron microscopy, and performing rheological studies using a high-temperature rheometer. The results showed that increasing the CaO content of the slag by modification with CaCO3 has a positive effect on the settling process and is thus a possible method to improve the industrial settling process of valuable metals in slag.
|
|
| 3. |
- Isaksson, Jenny, et al.
(författare)
-
Industrial Slag Cleaning of Reduced Iron Silicate Slag - Effect of Process Parameters and Slag Modification
- 2022
-
Ingår i: Proceedings of Copper 2022 international conference. ; , s. 22-40
-
Konferensbidrag (refereegranskat)abstract
- During primary copper sulfide smelting and converting, one of the main copper losses is to the slag, which decreases the overall copper recovery. To decrease the copper losses, which are mechanically entrained or dissolved, a slag cleaning route can be used. At the Boliden Rönnskär smelter in Sweden, the slag from the smelting furnace is treated under reducing conditions in a fuming furnace and then tapped into an electric settling furnace where the copper is separated from the slag under the action of gravity. A trial was conducted in the settling furnace at the Rönnskär smelter to increase the knowledge of the copper content in slag and how the process parameters temperature and settling time influence the final slag copper content. The slag was also modified with CaO, to enhance the slag properties for an increased settling velocity and thus decreased copper content. The trial was evaluated by collecting multiple samples of the ingoing and outgoing slag and then compare the slag copper content in the samples. The results showed that the copper content increased with increasing temperature and decreased when the slag was modified with CaO, both parameters had a more pronounced effect compared to the settling time. The slag was also characterized showing that copper was associated with spinels and bubbles, which hinders the settling.
|
|
| 4. |
- Isaksson, Jenny, et al.
(författare)
-
Settling of copper phases in lime modified iron silicate slag
- 2021
-
Ingår i: Metals. - : MDPI. - 2075-4701. ; 11:7
-
Tidskriftsartikel (refereegranskat)abstract
- Copper in discarded slag decreases the profits and copper recovery during the pyrometallurgical extraction processes. The copper losses to slag can be reduced by using a settling furnace, in which mechanically entrained copper droplets separate from the slag under the action of gravity. The settling rate of entrained droplets can be increased by modifying the slag composition and, thus, the slag properties, which are known to influence the settling rate. The knowledge of industrial CaO slag modification in a reduced iron silicate slag with a Fe/SiO2 ratio close to unity is limited. An industrial trial was thus conducted in an electric settling furnace, where the slag had been pretreated in a fuming furnace, to investigate the effect of CaO slag modification on the final slag copper content. Slag samples were collected from the ingoing and outgoing slag and from within the furnace of batches modified with CaO up to about 16 wt %. The trial was evaluated by comparing the final slag copper content and the copper recovery in the settling furnace. The results indicate that the settling becomes more efficient with the CaO modification as the final slag copper content decreased with increasing CaO content.
|
|
| 5. |
- Lotfian, Samira, et al.
(författare)
-
Plastic-containing materials as alternative reductants for base metal production
- 2019
-
Ingår i: Canadian metallurgical quarterly. - : Taylor & Francis. - 0008-4433 .- 1879-1395. ; 58:2, s. 164-176
-
Tidskriftsartikel (refereegranskat)abstract
- Shredder residue materials are produced after the removal of ferrous and non-ferrous fractions from end-of-life electronic equipment. Despite the high plastic content and metal value in the ash, high percentages of these materials are currently sent to landfills. In this study, the potential of utilising shredder residue material and other plastic-containing materials as reducing agents was studied. Plastic-containing materials were co-injected with coal into a zinc-fuming furnace in Boliden-Rönnskär smelter. The data obtained from the trial, such as the data from the chemical analysis of the slag and the steam production, are discussed. The observations indicate that plastic-containing material can replace up to 1 ton h−1 of coal without a significant decrease in the zinc reduction rate.
|
|
