Abstract
The possibility of applying a combined concentration and metallurgical method for processing low-grade and refractory copper–nickel ores was considered. The resulting rougher and scavenger flotation concentrate contained 2.07% nickel and 0.881% copper at a recovery of 85.44% and 89.91%, respectively. The concentrate was then roasted with ammonium sulfate, followed by aqueous leaching of clinker to dissolve nickel and copper. The roasting temperature, the ratio of concentrate to (NH4)2SO4 in the mixture, and the temperature were varied. Based on the study findings, the following process conditions were found to be optimal: roasting temperature 400 °C, rougher concentrate to ammonium sulfate ratio 1:7, and grinding size −40 μm. A roasting temperature of 400 °C is significantly lower than the temperature applied in conventional pyrometallurgical processes. The possibility of collecting off-gases allows the reagent to be regenerated and makes the process even more cost-effective. End-to-end recovery into pregnant solution was 81.42% for nickel and 82.81% for copper. The resulting solutions can be processed by known hydrometallurgical methods.
Highlights
More than 400 copper–nickel ore deposits have been discovered worldwide, and the combined global reserves of copper and nickel are currently estimated at 1.6 billion tons and 210 million tons, respectively
Sulfide copper–nickel ore deposits account for 65% of the annual global nickel production, amounting to more than 2 million tons
The results showed that after roasting at 650 ◦C for 2 h, the recovery of non-ferrous metals into the solution after aqueous leaching of the clinker was 70% nickel, 89% cobalt, and 90% copper, while iron almost completely passed into iron oxides—magnetite and hematite
Summary
More than 400 copper–nickel ore deposits have been discovered worldwide, and the combined global reserves of copper and nickel are currently estimated at 1.6 billion tons and 210 million tons, respectively. Low-temperature roasting of a mixture of low-grade lateritic and mixed nickel ores with ammonium sulfate, followed by aqueous leaching of clinker, is considered a promising and environmentally safe process [14,15]. This process is characterized by a high degree of metal recovery, reaction selectivity, energy efficiency, and low cost. Roasting followed by subsequent leaching of the concentrate produced by rougher and scavenger flotation to concentrate sulfides will make it possible to achieve a higher recovery of non-ferrous metals. This was evidenced by the concentration performance of the flotation process flow—nickel recovery into the rougher concentrate (into the rougher and scavenger flotation froth) was ~10% higher than its recovery into the final concentrate (into the cleaner flotation froth)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
