Study On The Mechanism Of Selective Flotation Separation Of Magnetite And Quart

China’s iron ore resource reserves rank among the top in the world,but the characteristics of iron ore have gradually become poor,fine,and miscellaneous,and the co associated relationships are complex and variable.The difficulty of selecting high-grade iron concentrates from them has also gradually increased.Silicon is a typical harmful impurity in iron ore,and the excessive content of silicon element in iron concentrate can have serious adverse effects on subsequent metallurgical operations.Therefore,during smelting,it is necessary to remove harmful silicon elements from the iron concentrate as much as possible in advance,improve the quality of the smelting products,and reduce smelting costs.This paper takes magnetite and pure quartz minerals as the research object,uses sodium oleate collector,starch inhibitor,and calcium ion activator to carry out flotation test research,combined with the joint characterization of a variety of detection methods,conducts research on the mechanism of selective flotation separation of magnetite and quartz,and reveals the internal law of flotation separation between the two,The final prototype of the calcium ion hydrophobic complex activation anionic reverse flotation technology for iron and silicon removal was formed,providing theoretical basis and technical support for the practical application of this technology.The pure mineral flotation results indicate that at a pH of 12.5 in the slurry,calcium chloride is used as an activator with a dosage of 2.5×10^-4 mol/L,sodium oleate as a collector,with a dosage of 5×10^-4 mol/L,soluble starch as inhibitor,the dosage is 20 mg/L,the recovery rate of quartz is78.05%,and the loss rate of magnetite is 22.96%;At the same dosage of reagents,when calcium ions and sodium oleate are pre mixed and added,the recovery rate of quartz is 85.69%,and its flotation performance index is better than the flotation index of adding calcium ions first and then adding sodium oleate sequentially.Activated by calcium ion/calcium ion hydrophobic complex,the surface of quartz greatly promotes the adsorption of sodium oleate,while soluble starch can selectively inhibit magnetite,which lays a good foundation for the flotation separation of quartz and magnetite.In the flotation separation test of binary artificial mixed ore,after adopting the optimal reagent dosage determined in pure mineral flotation and the flotation process of"one roughing and one sweeping",the effective separation of quartz and magnetite was achieved,with a desilication rate of about 65%and an iron recovery rate of 81.96%.In the quartz sodium oleate system,the Zeta potential on the surface of quartz remains basically unchanged compared to that of blank quartz,and no absorption characteristic peak of sodium oleate is observed on the surface of quartz;After the pre selection and addition of calcium ions and sodium oleate,the surface potential of quartz Zeta significantly decreased,and absorption characteristic peaks of-COO^-and-CH₂^-sodium oleate were observed on the quartz surface.The Zeta potential on the surface of magnetite decreased significantly after the addition of soluble starch,an inhibitor.The absorption characteristic peaks of C-O and-CH₂^-starch were observed on the surface of magnetite.Zeta potential and infrared spectrum（IR）results show that sodium oleate can chemisorb on the surface of quartz activated by calcium ion,but not on the surface of quartz not activated.Soluble starch has obvious adsorption on the surface of magnetite.The X-ray photoelectron spectroscopy（XPS）results showed that the pre mixed addition of calcium ions and sodium oleate resulted in an increase in the C-O and-COO^-contents in the fitting spectrum of C1s on the quartz surface compared to the single addition of sodium oleate.Compared to adding only calcium ions,the pre mixed addition of calcium ions and sodium oleate increased the content of Ca atoms on the quartz surface,and Ca（OH）⁺and hydrophobic species Ca-OOCR were observed in the fitting spectrum of Ca2p on the quartz surface.Under the pre mixed dosing method,calcium ions and sodium oleate first form a Ca-OOCR component（calcium ion hydrophobic complex）in the solution.Through liquid-solid migration,Ca-OOCR adsorbs on the surface of quartz and causes mineral hydrophobic floatation.Before and after adding inhibitors,the content of C1s on the surface of magnetite increased from 28.72%to 36.85%,and the position of Fe2p binding energy shifted.The content of Fe-OH component in the O1s fitting spectrum was 39.86%,and the new hydroxy iron component increased the hydrophilicity of the surface of magnetite.Inductively coupled plasma spectrometry（ICP）and Total organic carbon（TOC）detection showed that;The pre mixed dosing method can promote the adsorption of calcium ions and sodium oleate on the surface of quartz,revealing the dominant activation mechanism of the pre formed Ca-OOCR colloidal precipitation in the solution and then migrating to the surface of quartz.Atomic Force Microscopy（AFM）detection showed that the surface roughness of quartz after calcium ion interaction was 326.6 nm,and the roughness of quartz surface increased to 382.2 nm after calcium ion/sodium oleate interaction.The quartz surface has strong adsorption ability for calcium ions,and calcium ion/sodium oleate promotes the adsorption of Ca-OOCR colloidal precipitation on the quartz surface in solution.in summary;In sodium oleate system,calcium ion activated quartz is mainly due to the combination of the increase of calcium active site on quartz surface and the adsorption of Ca-OOCR colloidal precipitation.In the pre mixed dosing mode,calcium ion hydrophobic complex is conducive to the adsorption of Ca-OOCR colloidal precipitation on quartz surface,improving the flotation performance of quartz;Soluble starch has a weak effect on the interaction between calcium ion activated quartz surface and sodium oleate,while it has a strong inhibition on magnetite,which is the main reason for the effective flotation of quartz and its selective separation from magnetite.