Effects of Na2O additions to copper slag on iron recovery and the generation of ceramics from the non-magnetic residue

A potential industrial waste–waste co-treatment process of utilizing waste SO2 gas and residue heat to recover Co, Ni, and Cu from copper smelting slag

“…Recently, secondary raw materials, e-waste, and other secondary sources for smelting have also brought other valuable metals into slag (Cui and Zhang, 2008;Shuva et al, 2016;Wan et al, 2018;Wan et al, 2020a); thus slag can be a significant resource for metals. According to the ICSG forecast (Meng et al, 2020), 40 million metric tons of copper smelting slag will be generated in 2020.…”

“…During the industrial flash smelting process, the slag and flue gas carry 16% and 29% of the heat from the reactions in the furnace, respectively (Kojo and Storch, 2006). If the slag output reaches 40 million metric tons in 2020 (Meng et al, 2020) and considering the specific heat of copper slag C ps =1100 J/kg• K (Sibarani et al, 2020;Xia et al, 2007), it can be calculated that the total thermal energy carried by molten slags is equivalent to the combustion heat of 3.3 Mt of standard coal, meanwhile the flue gas total thermal energy equals to 6.0 Mt of standard coal. With the theoretical recoveries 95.8% and 91.8%, and 81.6% of Ni, Co, and Cu respectively, J o u r n a l P r e -p r o o f using the contents in the smelting slag analyzed in this study, the amounts of these recovered metals can reach 0.39 Mt Cu, 0.019 Mt Ni and 0.022 Mt Co every year from the flash smelting slag.…”

Utilization of copper slag in the fabrication of silica refractory: Characteristics and performance evaluation

“…Magnetic separation and selective reduction combining magnetic separation 14,15 were attempted to extract iron which obtains relative low recoveries of 38.09% and 68.96% due to the existent of fayalite phase (Fe 2 SiO 4 ). Although addition of CaO and Na 2 O can improve the recovery of iron, [16][17][18] the grade of recovered magnetic products does not meet the requirements of ironmaking raw material. In addition, these above methods need high-temperature treatment and high production cost with energy consumption.…”

Carbothermal reduction of fayalite: Thermodynamic and non-isothermal kinetic analysis

“…In China, more than 80% of copper is produced from the copper ores through the pyrometallurgical route, where the copper slag is produced as a kind of by-products [2]. Typically, about 2.2~3.0 tons of copper slag are generated per ton matte produced [3]. Dumping and disposal are the traditional options to treat copper slag, which not only occupies a large amount of land, but also causes serious pollution.…”

“…Renewable resources of reductants have also been investigated, such as cooking oil [16,17], biochar [18,19] and diesel oil [20,21], which are cost-effective and eco-friendly. At temperature above 1200 ℃, it is easy to realize the separation of slag and iron while the smelting reduction takes place, and the additives, such as CaO, CaF2 and Na2O, can decrease the reaction temperature [3,18,22]. Furthermore, the components of the secondary waste slag after reduction are mainly SiO2, CaO, Al2O3 and MgO, which can be reused as raw materials for the cement and glass ceramics [23,24].…”