Effects of mineral species transformation driven by surface dielectric barrier discharge plasma modification on the flotation performances: Perspective of critical oxidation degree

Abstract

Surface dielectric barrier discharge (SDBD) plasma modification has been proven to be an effective pretreatment method for flotation separation pyrite from arsenopyrite. However, there is limited quantitative research on the relationship between the surface species transformation of different components to flotation performance, which hinders the understanding of the selective surface modification mechanism driven by low-temperature plasma. In this study, the concept of critical oxidation degree was introduced to establish a correlation between total and individual component oxidation degrees and flotation recovery for varying particle sizes of arsenopyrite and pyrite. The findings revealed that fine particles exhibited higher critical oxidation degrees and rates, rendering them more susceptible to being oxidized into a hydrophilic state. The highest critical oxidation degree on the arsenopyrite surface was observed at the Fe site, however, it was prone to easy oxidation to Fe(III)–O/OH. The deposition of iron hydroxyl compounds limited ion exchange and the stable adsorption of the collector, resulting in the formation of a high hydrophilicity “metal-deficient” surface. Due to the high reactivity of surface As and Fe sites, arsenopyrite showed greater susceptibility to plasma modification compared to pyrite, laying the foundation for SDBD plasma induced flotation separation of arsenopyrite and pyrite.