Quantum Chemistry Analysis Of Collecting Performances Of Amine Collectors For The Flotation Process Of Silicate Minerals

Silicate minerals are a group of mineral populations with high research value.In the flotation practice of silicates,the key to success of the flotation process is whether it can effectively suppress or activate certain silicate minerals.The study of the flotation principle of silicate minerals is of great significance to silicate mineral collectors and properties.In this paper,molecular dynamics methods were used to study the adsorption behavior of amine collectors on muscovite(001)surface and quartz(100)surface under different conditions,and the adsorption process was calculated by quantum calculation.As a widely used tool,molecular dynamics can provide a more detailed basic understanding on the research of the solid/liquid interface involved in flotation,the atomic potentials of various molecules,and the floatability of minerals.The content and results of this study include the following:(1)The establishment of the system model.The CASTEP module was used to optimize the crystal structure,and the main parameters were: exchange/correlation function GGA-PBESOL,cut-off energy 360eV;DMol3 module was selected to optimize molecular structure,GGA-PW91 was choosed as exchange function.COMPASS was used to optimize the force field of crystal dissection and flotation,the optimization result is indistinguishable from literature.Using Bulid Layer tool,the collector/mineral surface model was obtained,and the COMPASS field was used for structural optimization and system energy calculation.Results show that total force and van der Waals force between collector and white mica/quatz were positive value(repulsion),the electrostatic force was negative(gravitational)and its absolute value is far greater than total force and van der Waals force,which indicated that the amine collector mainly adsorbs on the surface of white mica and quartz by electrostatic action.(2)The effect of the collector itself on the flotation process.By controlling the chain length and head group of the amine collector during the adsorption process,itcan be found that the chain length of the amine collector has little effect on the flotation process,but in actual production process,taking into account the solubility of the agent and the size of the hydrophobic capacity of the adsorbed secondary micelle groups,the carbon chain length is generally chosen to be between 12-18.Amine collectors as flotation agents;When the head group is changed by flotation calculation,the interaction energy of different head-based systems differs greatly.the absolute value size order is:(quaternary amine/mineral surface)>(tertiary amine/mineral surface)>(secondary amine/mineral surface)>(primary amine/mineral surface).This shows that in the calculation of single mineral flotation,the flotation effect of different head-based amine collectors is: quaternary amine>tertiary amine> secondary amine> primary amine,which is consistent with the prediction result based on the frontal orbital energy gap.(3)The effect of solution acid-base environment on the flotation process.White mica(001)formed water moleculer layer on surface,strong interaction exsited between the surface of mineral and water molecules,the adsorption between hydroxyl and white mica(001)in water molecules is far greater than that of amine cation and white mica(001).When flotation takes place,the flotation agent needs to pass through the water membrane,act on the water molecule layer on the mineral surface through the amine group,and use the hydrophobicity of the hydrocarbon chain to float out the mineral.By changing the acidity and alkalinity of the solution during flotation,it can be known that in the medium and strong acidic solutions,the amine collector shows floatability on the muscovite and inhibition on the quartz;amine collectors in neutral,weakly acidic and weakly alkaline solutions show buoyancy for both muscovite and quartz;both the muscovite and quartz show inhibition in medium alkali and strong alkali solutions.Therefore,when an amine collector is used for flotation separation of muscovite and quartz,the solution is strongly acidic.At the same time,for the single mineral flotation system,baed on the calculation of interaction energy,amine collector flotation effection of different head is:quaternary amine > tertiary amine > secondary amine > primary amine,which is consistent with the prediction of front-line orbital energy gap.