Enhanced efficacy of sodium dodecyl sulfonate in the reverse flotation of hematite with dodecylamine as the collector

The cationic reverse flotation of fine iron ore faces the issue of foam stability, which negatively impacts the flotation performance. The effects of single collectors, dodecylamine (DDA) and sodium dodecyl sulfonate (SDS), as well as their combination (DDA + SDS), on the flotation of quartz and hematite were thoroughly examined through micro-flotation and froth stability experiments. The interactions between DDA and SDS, along with the enhanced performance of SDS in the reverse flotation of hematite with DDA, were analyzed using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and zeta-potential analysis. The findings indicated that adding SDS to DDA in a specific ratio alleviated the excessive froth stability associated with DDA and improved flotation performance. At pH 7, negatively charged SDS could not adsorb onto mineral surfaces when used alone but could co-adsorb with DDA due to their strong interaction. While SDS co-adsorbed on both minerals, it had minimal impact on DDA adsorption on quartz but significantly reduced it on hematite, leading to differing flotation recoveries. This discrepancy was explained by the difference in charge amounts on the quartz and hematite surfaces, as well as the subsequent adsorption processes.