title: Co-treatment of waste smelting slags and gypsum wastes via reductive-sulfurizing smelting for valuable metals recovery.
abstract: In this work, a new innovative slag cleaning technique was presented to economically and environmentally friendly recover valuable metals from cobalt-bearing copper smelter slag. CaSO4-rich gypsum waste was used as sulfurizing agent to efficiently and selectively sulfurize and recover valuable metals lost in the slag at reductive atmosphere. Thermodynamic analysis and laboratory experiments were carried out to determine the feasibility and reliability of this new process. The optimum slag cleaning conditions were determined as follow: reductive agent coke dosage of 12%, 20% CaSO4addition of smelter slag weight, smelting at 1350°C for 3h. Under the optimum conditions, 92.04% Cu and 95.62% Co were enriched and recovered in copper-cobalt matte. The contents of Cu and Co in cleaned slag dropped to levels lower than 0.2% and 0.045% respectively. Selectivity recovery ratio of Cu/Fe and Co/Fe can reach 6.00 and 6.24 respectively. Calcium-rich and iron-poor cleaned slag property was more beneficial for minimizing cobalt and copper losses in slag. The products were characterized by XRD and SEM-EDS techniques. The Cu-Co matte primarily comprised iron sulphide (FeS), geerite (Cu8S5), iron cobalt sulphide (Fe0.92Co0.08S), independent cobalt sulphide (CoS) and some metallic Cu, Co and Fe. Copper and cobalt in resultant matte attended to appear separately in different mineral phases. The cleaned slag mainly contained fayalite (Fe2SiO4), hedenbergite (CaFeSi2O6) and magnetite (Fe3O4).
authors: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, PR China.
authors: Yun
authors: Y
authors: Li
authors: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, PR China. Electronic address: csuchenyongming@163.com.
authors: Yongming
authors: Y
authors: Chen
authors: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, PR China. Electronic address: chaobotang@163.com.
authors: Chaobo
authors: C
authors: Tang
authors: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, PR China.
authors: Shenghai
authors: S
authors: Yang
authors: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, PR China.
authors: Jing
authors: J
authors: He
authors: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, PR China.
authors: Motang
authors: M
authors: Tang
keywords: Gypsum waste; Recovery of Cu and Co; Reductive-sulfurizing smelting; Slag cleaning; Sulfurizing agent