Adsorption Mechanism Of Collector On Apatite And Dolomite Surface

The selective adsorption of the collector on mineral surface is an important factor affecting flotation efficiency.Studying the adsorption mode and adsorption configuration of the agent on the mineral surface is of great significance for studying the flotation mechanism.In order to explore the adsorption mechanism of fatty acid collectors on the surface of fluorapatite and dolomite,sodium oleate(NaOL)was used as a collector in this paper.Calcium magnesium phosphate ore and fluorapatite and dolomite single minerals were used as research objects.X-ray diffraction(XRD),X-ray fluorescence spectrometer(XRF),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectrometer(FTIR),Zeta potential,microcalorimetry,total organic carbon analyzer(TOC)and other research methods were used to reveal the mechanism of NaOL on the surface of fluorapatite and dolomite from a macro perspective.The first-principles method based on density functional theory and the molecular dynamics method based on Newtonian mechanics were used to reveal the adsorption mechanism of oleic acid ions on the surface of fluorapatite and dolomite from a microscopic perspective.The adsorption model of NaOL on fluorapatite and dolomite was established by adsorption kinetics,adsorption thermodynamics and adsorption density,and the adsorption amount per unit area of NaOL on mineral surface was further analyzed.Through the above research methods and research methods,the adsorption mechanism of fatty acid collectors on the surface of fluorapatite and dolomite was revealed from the macro and micro perspectives.The main conclusions are as follows:In the process of reverse flotation of phosphate rock,HEDP can effectively inhibit fluorapatite.Under the condition of using hydroxyethylidene diphosphonic acid(HEDP)as an inhibitor,the adsorption rate on the surface of fluorapatite is greater than that on the surface of dolomite.The adsorption of NaOL on the surface of fluorapatite is monolayer adsorption.There are a certain number of metal active sites on the surface of fluorapatite and dolomite as adsorption centers.The adsorption of NaOL on the surface of fluorapatite and dolomite shows a dynamic equilibrium adsorption state of adsorption and desorption.The adsorption capacity of NaOL per unit area on dolomite surface is higher than that on fluorapatite surface.Under acidic conditions,HEDP can achieve selective separation of fluorapatite and dolomite.With the addition of HEDP,the Zeta potential of fluorapatite decreased significantly,and the Zeta potential of dolomite did not change much.The inhibition effect of HEDP on fluorapatite was stronger,and the effect on dolomite was smaller.XPS results show that the interaction of HEDP on the surface of fluorapatite is stronger than that on the surface of dolomite under acidic conditions.NaOL will adsorb on the surface of fluorapatite and dolomite,but the adsorption on the surface of dolomite is stronger.HEDP has a strong inhibitory effect on the adsorption of NaOL on the surface of fluorapatite,but HEDP has little effect on the adsorption of NaOL on the surface of dolomite.After crushing and grinding of fluorapatite,the(211)surface may be exposed.Molecular simulation studies have shown that the activity of the(001)and(211)surfaces of fluorapatite is different.When the(211)surface of fluorapatite is exposed,the difference in the interaction between the surface of fluorapatite and the surface of dolomite and the collector will be relatively reduced.The(001)surface is more hydrophilic than the(211)surface,and the hydrophilicity of the(001)surface is greater than that of the(211)surface.The inhibitor molecules are more likely to interact with the fluorapatite(001)surface.If the grinding process is selectively used to make the(001)surface more exposed,the floatability of fluorapatite will decrease in the reverse flotation of phosphate rock,so as to better realize the separation of fluorapatite and dolomite,and the flotation recovery rate will be further improved.The surface state density and Mulliken population analysis of dolomite(104)show that the reactivity of Ca atoms on dolomite surface is stronger than that of Mg atoms.The adsorption configuration of oleic acid ions on the surface of fluorapatite and dolomite is mainly bridge adsorption.The two O atoms in the oleic acid ions have chemical interactions with the corresponding Ca and Mg atoms on the dolomite surface.The results of molecular simulation show that the interaction strength between fluorapatite and water molecules is close to that between dolomite and water molecules when no reagent is added,and the effect of water molecules on the surface of dolomite is slightly stronger than that on the surface of fluorapatite.The hydrophilicity of dolomite is greater than that of fluorapatite.NaOL is easier to interact with fluorapatite;the interaction strength between HEDP and fluorapatite is significantly stronger than that between HEDP and dolomite.Oleate ions are adsorbed on the fluorapatite(001)surface and dolomite(104)surface at a certain inclination angle.The adsorption of oleic acid ions in the pore size of fluorapatite and dolomite is similar to that on the surface.The adsorption strength of oleic acid ions on the surface of fluorapatite is less than that on the surface of dolomite.When HEDP is not added,the adsorption strength of oleic acid ion on the surface of fluorapatite is greater than that on the surface of dolomite.HEDP will inhibit the adsorption of oleic acid ion on the surface of fluorapatite,resulting in the increase of the difference between fluorapatite and dolomite and collector,and the selective separation of fluorapatite and dolomite is realized.This study reveals the adsorption mechanism of fatty acid collectors on the surface of fluorapatite and dolomite,which lays a theoretical foundation for the flotation separation of fluorapatite and dolomite.