A Novel Technology for the Recovery and Separation of Cassiterite- and Iron-Containing Minerals from Tin-Containing Tailing

Abstract

Tin-containing tailing is classified as a solid waste, but it possesses valuable resources such as tin and iron. Tin-containing tailing exhibits a fine distribution and compact symbiosis of cassiterite- and iron-containing minerals. Therefore, it is difficult to recover and separate cassiterite- and iron-containing minerals using traditional mineral processing methods. The study proposed a novel technology involving pre-concentration, reduction roasting, and magnetic separation for the treatment of tin-containing tailings with a tin grade of 0.14% and an iron grade of 12.79%. The classification pre-concentration method was achieved using a combination of shaking tables, suspension vibration cone separators, and high-gradient magnetic separation with a magnetic field strength of 1.4 T. The discarded tailings ratio reached 73.56%. The gravity pre-enriched concentrates and magnetic pre-enriched concentrates underwent reduction roasting to facilitate the conversion of hematite and goethite into magnetite, respectively. The optimal conditions for reduction roasting of the gravity pre-enriched concentrate were a 10% lignite dosage, a roasting temperature of 650 °C, and a holding time of 80 min. The optimal conditions for reduction roasting of the magnetic pre-enriched concentrate were a 8% lignite dosage, a roasting temperature of 750 °C, and a holding time of 100 min. The reduction roasted products were treated using magnetic separation with a magnetic field strength of 0.16 T. Finally, a tin-rich middling with a tin grade of 2.93% and a recovery ratio of 70.88%, as well as an iron concentrate with an iron grade of 61.95% and a recovery ratio of 68.08% were obtained. The study achieved efficient recoveries of tin and iron from tin tailings, thereby presenting a novel approach for the utilization of resources in the tailing.