Research And Mechanism Analysis On Polystyrene Nanoparticles As New Collector In Coal Flotation

Flotation is a critical operation in the isolation of valuable minerals from natural ore and the first step to achieve clean utilization of coal. It is widely used in coal slime separation process. Typical hydrocarbon oil collector in the flotation process is difficult to obtain ideal results with the reason to so many kinds of factors such as reduction of high quality coal resources in our country, fine coal slime increases, the drop of selected raw coal floatability and shortage of fossil resources. In view of this fact, the mining industry has shown a strong interest in searching for new alternatives to improve the process of coal washing, as well as more effective reagents to improve the process and reduce operating costs.Two kinds of polystyrene nanoparticles( latex), cationic polystyrene nanoparticles St-01-61 and anionic polystyrene nanoparticles St-02-53,synthesized by emulsion polymerization was used as flotation collectors for different rank coal flotation, and was compared with kerosene collecting performance in paper. The action mode between polystyrene nanoparticles and coal particles was calculated and analysis with the EDLVO theory. The contact Angle of coal samples under different conditions was measured. The influences of the nanoparticle adsorption on roughness, hydrophobic property, the surface energy were studied. Scanning electron microscopy(SEM) method was used to study the mechanism of action. This paper proposed a new way for the design of the coal collector and opened oriented design and synthesis of new areas. In this paper, main conclusions are as follows:1. The polystyrene nanoparticles latex as collector is completely feasible, it has good collecting ability and selectivity. It showed good generality for the three coal samples. However, its specific flotation effect is closely related to the properties of the coal sample. The flotation result in the presence of Cationic collector St- 01-61 was better than that of anionic St- 02-53 collector.2. The EDLVO total potential energy between coal particles and the polystyrene nanoparticles are negative, indicating that the polystyrene nanoparticles can adhere to coal surfaces successfully. Compared with DLVO potential energy curve, hydrophobic forces played a dominant role in the adsorption. Hydrophobic force increases quickly with the decrease of the spacing when distance between coal particles and the polystyrene nanoparticles is less than 25 nm, which enhance the adhering. It revealed cationic polystyrene nanoparticles can adhere to the surface of coal particles more easily.3. The contact Angle increased after conditioned with collector. The surface energy decreased caused by the adhering of collectors especially for the cationic polystyrene nanoparticles St- 01-61 based on the contact Angle. The hydrophobicity of coal is improved and collector can adhere to coal surface more easily. Leading to the formation of the bubbles-coal aggregate, which improved flotation behavior.4. Wetting heat measurement result showed that more heat was wetted out during the interaction of kerosene and coal which was previously conditioned with polystyrene nanoparticles. More heat will be wetted out in the presence of cationic polystyrene nanoparticles compared with anionic polystyrene nanoparticles.5. SEM measurement showed that the polystyrene nanoparticles collector can adhere to coal surface. What makes polystyrene nanoparticles different from traditional oil collector is that traditional oil collector formed hydrophobic oil slick on the coal surface to improve hydrophobicity of coal. But polystyrene nanoparticles loaded on the coal surface to micro-roughening the coal surface. Enlarge hydrophobicity of the coal surface, so as to achieve its floatability.