Evolution of ideas towards the implementation of nanoparticles as flotation reagents

Abstract

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.

Use of Polystyrene Nanoparticles as Collectors in the Flotation of Chalcopyrite

“…Therefore, this may produce chalcopyrite-nanoparticle agglomerates or lead to the hydration of the NP-coated mineral surfaces and then, making it hydrophilic when higher doses of NPs were used. Different authors argue that these increases in hydrodynamic diameter and particle size distribution as the pH increases are mainly associated with the occurrence of aggregation between nanoparticles, disfavoring the interaction with the mineral of interest [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. In addition, these aggregates can contribute to reducing the kinetic rates of attachment between NP-deposited chalcopyrite and bubbles, and it is well known that more hydrophobic materials have faster kinetic rates with bubbles than less hydrophobic materials [ 16 ].…”

“…There have been attempts to investigate hydrophobic nanoparticles as a new class of flotation collectors called “the core”, and to which functional groups are attached because of chemical reaction [ 6 , 9 , 11 , 12 , 13 , 14 ]. The functional nanostructures presented in the literature have cores that can be categorized in subgroups: polystyrene nanoparticles; cellulose nanocrystals/nanofibers and inorganic nanoparticles; and styrene and cellulose, which are distinguished by their ability to easily modify surface physicochemistry whilst inorganic nanoparticles are usually not chemically functionalized due to their structural nature [ 15 ].…”

A review of the application of nanoparticles as collectors in ion flotation

“…This can change their surface charge, affect the folding of peptide chains, and conflict with normal biological activity. Therefore, it is important to develop and use environmentally friendly and highly efficient surfactants for ion flotation (Mulligan 2009;Khoshdast et al, 2012;Li et al, 2013;Peng et al, 2019;Ziaee et al, 2021).…”

“…To achieve nearly complete removal of the colligend, the minimum appropriate concentration of the collector must be equal to or higher than the stoichiometric value and less than the critical micelle concentration. The benefits of using nanocollector to remove ions from wastewater include simple synthesis, low cost, high efficiency, stability in aqueous solutions, and collector consumption Legawiec and Polowczyk 2020).…”

Flotation of Smithsonite From Quartz Using Pyrophyllite Nanoparticles as the Natural Non-toxic Collector

“…So far, the adoption of natural hydrophobic mineral nanoparticles as flotation collectors is due to the electrostatic interaction (physical adsorption) between the floating minerals and NP. (Legawiec and Polowczyk, 2020). Therefore, controlling the pH of pulp is important based on its large effect on the surface charge of minerals.…”