Investigation of pullulan polysaccharide as a sphalerite depressant for chalcopyrite separation: Flotation behavior and interfacial adsorption mechanism

• Published in: Advanced powder technology : the international journal of the Society of Powder Technology, Japan Vol. 35; no. 10; p. 104621
• Main Authors: Zhai, Qilin, Hu, Yuwei, Liu, Runqing, Sun, Wei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2024
• Subjects: Chalcopyrite; Flotation; Green depressant; Separation; Sphalerite; Sphalerite; Flotation; Chalcopyrite; Separation; Green depressant
• ISSN: 0921-8831
• DOI: 10.1016/j.apt.2024.104621

[Display omitted] •Pullulan polysaccharide (PP) was used as sphalerite depressant for Cu–Zn separation.•PP can be chemisorbed onto the Zn sites on sphalerite surfaces via C−O−H groups.•PP effectively prevent the adsorption of the collector onto sphalerite surfaces.•The Fe sites on chalcopyrite surfaces can adsorb PP, but the Cu sites remain exposed.•PP cannot prevent the adsorption of the collector onto chalcopyrite surfaces. The remarkable differences in the metallurgical processes of copper and zinc require their host minerals to be separated as far as possible during beneficiation. For chalcopyrite and sphalerite, the primary host minerals of copper and zinc, their green and efficient separation in the beneficiation stage remains a great challenge. This work is the first to employ environmentally friendly pullulan polysaccharide (PP) as a sphalerite depressant to assist in the concentration of chalcopyrite. Flotation experiments have revealed that PP possesses a selective depression action on sphalerite without having a large influence on the recovery of chalcopyrite. Characterization analysis has revealed that PP can be adsorbed onto chalcopyrite and sphalerite surfaces, but with a different response to subsequent sorption collectors. PP adsorbs to the Zn atoms on sphalerite surfaces via its O atoms in the C−O−H group and thus prevents the adsorption of sodium butyl xanthate (BX). The Fe sites on the chalcopyrite surface can adsorb PP, but this process does not affect the BX adsorption as the Cu sites remain exposed. Hence, PP can enhance the hydrophilicity of sphalerite without interfering with the hydrophobicity of chalcopyrite, resulting in a desirable separation effect. Overall, this work offers a promising scheme for the concentration of chalcopyrite from sphalerite during beneficiation, thereby contributing to the efficient exploitation of copper and zinc resources.