New insights into the aggregation and disaggregation between serpentine and pyrite in the xanthate flotation system

Guangsheng Zeng; Wei Chen; Sheng Liu; Guangyi Liu

doi:10.1016/j.jcis.2022.11.123

New insights into the aggregation and disaggregation between serpentine and pyrite in the xanthate flotation system

J Colloid Interface Sci. 2023 Mar:633:243-253. doi: 10.1016/j.jcis.2022.11.123. Epub 2022 Nov 25.

Authors

Guangsheng Zeng¹, Wei Chen², Sheng Liu¹, Guangyi Liu³

Affiliations

¹ College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
² College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. Electronic address: csuchenwei@csu.edu.cn.
³ College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. Electronic address: guangyiliu@csu.edu.cn.

PMID: 36459931
DOI: 10.1016/j.jcis.2022.11.123

Abstract

Hypothesis: In xanthate flotation system, the aggregation of serpentine on sulfide minerals significantly weakened their floatability. And it was generally assumed that the electrostatic attraction was of the dominant driver for coating of serpentine slimes. In this paper, the hydrophobic interaction between the "talc-like" cleavage plane of serpentine and the xanthate-hydrophobized surface of sulfide minerals was proposed as the dominated driver.

Experiments: To evaluate the aggregation of serpentine on pyrite surface, a novel experimental protocol was designed, and the aggregation behavior and mechanism in the absence and presence of sodium isobutyl xanthate (SIBX) were explored through in situ optical microscope, micro-flotation, contact angle, zeta potential and FT-IR. Afterwards, the disaggregation mechanism of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) to the aggregates of serpentine on pyrite surface was revealed.

Findings: The electrostatic attraction facilitated the slight aggregation of serpentine slimes on bare pyrite surface. The hydrophobic interaction between the "talc-like" plane of serpentine and SIBX-covered pyrite significantly promoted the aggregation between them, which remarkably weakened the floatability of pyrite. The attendance of HEDP anions reversed the surface potential of the octahedral Mg-O layers of serpentine from the positive into the negative, thus to prevent the aggregation of the HEDP-anchored serpentine with the SIBX-covered pyrite via the strong electrostatic repulsion between them. As a result, the disaggregation as well as SIBX flotation separation of pyrite from serpentine was realized. This investigation also provided new insights into the aggregation and disaggregation between serpentine and sulfide minerals during froth flotation.

Keywords: Aggregation; Disaggregation; Electrostatic repulsion; Hydrophobic attraction; Pyrite; Serpentine.