Selection of flotation reagents in lithium ore flotation

Flotation is a selective, non-destructive material separation method based on the physical and chemical properties of the material surface, which can maintain the inherent structure of the material. More and more researchers are applying flotation method to the recovery and treatment of black matter.

Froth flotation is a separation technology based on differences in physical and chemical properties of mineral surfaces. It uses flotation agents and bubbles as carriers to selectively enrich required minerals at the solid-liquid-gas interface and separate them from gangue minerals. In the flotation separation process of spent lithium-ion batteries, flotation agents are mainly used to selectively adsorb on the surface of electrode materials, increase the wettability difference between positive and negative active materials, and achieve flotation separation. Typical flotation reagents include collectors, frothers and conditioners.

Collecting agents are reagents that can increase the hydrophobicity of mineral surfaces and are the most important reagents in mineral flotation. The collector interacts with active sites on the surface of the mineral, making it hydrophobic and attached to the surface of the bubbles, which then rise to the surface. Even if natural hydrophobic minerals such as graphite are used in the flotation of black matter, non-polar oil capture agents should be appropriately added to improve their floatability and separation efficiency. Common collectors include kerosene, diesel, xanthates, and amines.

The foaming agent has a hydrophilic polar group on one end and a hydrophobic non-polar group on the other end. In foam flotation, the foam agent is mainly adsorbed at the liquid-gas interface, with non-polar groups facing the gas phase and polar groups facing the liquid phase. They form a directional arrangement at the liquid-gas interface, reduce the surface tension of water, increase the dispersion of air in the slurry, change the size and movement of bubbles, and form stable and appropriately sized foam. The foaming agent is preferably a non-collecting agent to facilitate process control. Common foaming agents include pine oil, isoamyl alcohol, and methyl isobutyl carbinol (MIBC).

Regulators mainly include pH regulators, dispersants, inhibitors, flocculants, etc. In the flotation process, the pH value of the slurry is very important. Only under suitable pH conditions can various minerals be effectively flotated.

Dispersants are compounds that have both lipophilic and hydrophilic properties within their molecules. They can promote the uniform dispersion of material particles in the medium, or the uniform dispersion of solid particles that are difficult to dissolve in liquid, and can also prevent the settling and agglomeration of solid particles, which is necessary to form a stable suspension. The application of dispersants in froth flotation mainly involves two aspects. On the one hand, dispersants can improve the floatability of minerals by preventing slime (fine particles) from adhering to mineral particles. On the other hand, they can disperse fine particles in selective flocculation

The main function of the inhibitor is to selectively destroy or weaken the adsorption of certain minerals to the collector when several minerals have similar floatability, enhance the hydrophilicity of the surface of specific minerals, and achieve the goal of matching the target minerals with gangue minerals. of separation. Flocculants are molecular organic compounds with multi-functional groups that can be adsorbed at multiple points on the interface between mineral particles and water, causing flocculation. The application of selective flocculation in fine-grained mineral foam flotation involves changing the surface properties of the target mineral particles, appropriately increasing their particle size, and then flocculating and separating the sediment from the gangue minerals.