Co-treatment of waste smelting slags and gypsum wastes via reductive-sulfurizing smelting for valuable metals recovery

Release time:2021-03-04

Impact Factor:9.038

DOI number:10.1016/j.jhazmat.2016.10.028

Journal:Journal of Hazardous Materials

Key Words:Slag cleaning, Reductive-sulfurizing smelting, Gypsum waste, Sulfurizing agent, Recovery of Cu and Co

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% CaSO4 addition of smelter slag weight, smelting at 1350 degrees C for 3 h. 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). (C) 2016 Elsevier B.V. All rights reserved.

Indexed by:Journal paper

Discipline:Engineering

First-Level Discipline:Metallurgical Engineering

Document Type:J

Volume:322

Page Number:402-412

Translation or Not:no

Date of Publication:2017-01-15

Included Journals:SCI