Evolution of ideas towards the implementation of nanoparticles as flotation reagents

The paper discusses an idea of nanoparticles application to the flotation process. Due to the growing awareness of the environmental impact of industry and legal restrictions, the directions of research on new chemicals used in mineral processing, as well as in the other branches of industry are changing. The flotation reagents of the future should be, or are expected to be, readily biodegradable, but also their products should be harmless to the environment. A review of the works presented here presents an overview of the state-of-the-art application of nanostructures from early reported polystyrene nanoparticles to the most promising cellulose nanostructures which can be successfully adapted to the desired amphiphilicity parameters through simple functionalization. Limitations on the use of such nano-sized entities related to control aggregation in the flotation process and the ability to adsorb at interphase boundaries are also presented. Overall, nanoparticles can become universal flotation collectors and also an alternative to conventionally used hydrocarbon-based reagents

Rhamnolipids as Effective Green Agents in the Destabilisation of Dolomite Suspension

In this paper, we describe an application of mono- and dirhamnolipid homologue mixtures of a biosurfactant as a green agent for destabilisation of a dolomite suspension. Properties of the biosurfactant solution were characterised using surface tension and aggregate measurements to prove aggregation of rhamnolipids at concentrations much lower than the critical micelle concentration. Based on this information, the adsorption process of biosurfactant molecules on the surface of the carbonate mineral dolomite was investigated, and the adsorption mechanism was proposed. The stability of the dolomite suspension after rhamnolipid adsorption was investigated by turbidimetry. The critical concentration of rhamnolipid at which destabilisation of the suspension occurred most effectively was found to be 50 mg·dm−3. By analysing backscattering profiles, solid-phase migration velocities were calculated. With different amounts of biomolecules, this parameter can be modified from 6.66 to 20.29 mm·h−1. Our study indicates that the dolomite suspension is destabilised by hydrophobic coagulation, which was proved by examining the wetting angle of the mineral surface using the captive bubble technique. The relatively low amount of biosurfactant used to destabilise the system indicates the potential application of this technology for water treatment or modification of the hydrophobicity of mineral surfaces in mineral engineering