Properties and potential application of ozone-oxidized starch for enhanced reverse flotation of fine hematite

Authors：Zhang, Ming; Xu, Zeping; Zhang, Qin^*; Dan, Zusu; Fu, Hongqi; Yao, Wei^*

Source：Minerals Engineering, 2023, 198: 108084.

DOI：10.1016/j.mineng.2023.108084

• Starch oxidation
• Ozone
• Flotation
• Hematite
• Depressant

In this study, ozone as an eco-friendly oxidant was employed to improve the depressive performance of starch in the reverse flotation of fine hematite. Micro-flotation results showed that ozone-oxidized starch (OS) better depressed hematite flotation as compared to the native starch (NS). Particle surface wettability and size distri-bution analysis suggested that OS rendered the hematite surface more hydrophilic in the presence of an amine collector while maintaining a comparable flocculation performance to that of NS. Solubility, rheology, carbonyl and carboxyl content measurements, together with atomic force microscopy (AFM) imaging were performed to examine the variations in the structure and properties of starch upon ozonation and their correlation with the depressive performance of starch. It was found that ozone treatment not only increased starch acidity and sol-ubility, but also concurrently depolymerized starch with the yield of low molecular weight derivatives. These favorable changes appeared to be responsible for the superior performance of OS. Furthermore, the stronger interaction of OS with hematite was verified by X-ray photoelectron spectroscopy (XPS).