Study On The Effect Of Magnetite On The Flotation Of Fine-grained Hematite And Its Mechanism

Steel resources are one of important industrial raw materials in China.As the constant improvement of steel production,the demand for iron ore is increasing gradually.At present,the iron ore produced independently in our country is difficult to satisfy the demand of industrial production,which makes the quantity of imported iron ore increasing continuously.Therefore,it is essential to convert iron ore resources into iron ore supply capacity by technical means..There are abundant iron ore resources in China,which are difficult to separate.The main reasons are that the ore has fine grain size and low size fraction,the high content of sulfur,phosphorus and other impurity elements,and there is an interaction between useful minerals and gangue minerals,which makes small difference in separation and unsatisfactory beneficiation indexes.The theoretical and technological research on the separation of fine particle size hematite will be beneficial to improve the comprehensive utilization rate of iron ore resources.It has an important practical significance for the development and utilization of refractory iron ore.In this paper,the fine hematite,magnetite and quartz were studied systematically.Based on the study of three kinds of micro-size fraction pure minerals flotation behavior.the effects of different size fraction pure minerals on the flotation of-45?m size fraction hematite,magnetite and quartz were discussed.The magnetic agglomeration flotation technology of magnetite for micro-size fraction hematite was discussed in details.Finally,based on the theory of EDLVO,and by means of infrared spectroscopy,potentiodynamic measurement,microscopic analysis and laser particle size analyzer,the action mechanism of reagent on the flotation of fine hematite and the magnetic agglomeration flotation mechanism of magnetite on fine hematite are discussed.The flotability test results of fine pure minerals determined the flotation agent system:in the positive flotation system,the pH value is about 9,the sodium oleate dosage in hematite flotation is 280 mg/L,and the sodium oleate dosage in magnetite and quartz flotation is 200 mg/L.In reverse flotation system,the pH value is about 11.5,the dosage of starch is 90 mg/L,the dosage of calcium chloride is 125 mg/L,the dosage of sodium oleate in hematite flotation is 280 mg/L,and the dosage of sodium oleate in magnetite and quartz flotation is 200 mg/L.The binary system flotation aims to study the effects of different minerals on hematite,magnetite and quartz flotation.According to the results of fine-grain single mineral flotation,two flotation systems were determined:1 positive flotation system?pH is about 9,concentrate is foam product?;2 reverse flotation system,?pH about 11.5,concentrate is the bottom tank product?.The results show that in the positive flotation system,when flotation is used to recover fine-grained hematite,the addition of different grain size of quartz and coarse-grained magnetite will reduce the recovery of hematite.Adding fine-grained magnetite can improve recovery rate of hematite.;when flotation recovery fine-grained quartz,-45+18?m granular grade magnetite has no obvious effect on quartz flotation,other granular grade will increase the recovery rate of quartz;when adding different grain size of hematite flotation to recover fine-grained magnetite,the effect is similar to that of adding different grade magnetite to hematite flotation.;magnetized magnetite is not conducive to the positive flotation of iron ore.In the binary reverse flotation system,when flotation is used to recover fine-grained hematite,the addition of different grain size of quartz reduces the hematite recovery rate;when flotation recovers fine-grained quartz,the-18?m granular grade magnetite reduces the quartz recovery and the grade of SiO₂,the effect of others is not obvious;in the magnetite-hematite flotation system?magnetized and unmagnetized?,the recovery rate of hematite and magnetite in the concentrate?bottom tank product?is close to 100%.When flotation recovery fine-grained quartz,the addition of magnetized magnetite can increase the recovery of fine-grained quartz in the foam product.The magnetization of magnetite will facilitate the reverse flotation of iron ore.The results of mineral interaction in ternary system show that in sodium oleate system,fine-grained magnetite can improve the recovery of fine-grained hematite,but the effect of coarse-grained magnetite on fine-grained quartz is opposite,and magnetite has no obvious effect on fine-grained quartz.The actual hematite ore test verifies the results of the previous paper,adding fine-grained magnetite in the flotation process can improve the recovery of fine-grained hematite and improve the Fe grade of concentrate.In sodium oleate-starch-calcium chloride system,different size magnetite has no obvious effect on flotation of fine hematite,but adding magnetite will lead to higher recovery of quartz in concentrate,which is unfavorable to flotation;but adding a small amount of sodium silicate can reduce the recovery of quartz in concentrate,improve the grade Fe of iron in concentrate,and is beneficial to reverse flotation of fine hematite.The effects of different particle size magnetite on the flotation of micro-size fraction hematite in sodium oleate system by means of DLVO theoretical calculation,laser particle size analyzer,microscopic analysis and sedimentation test show that,in the sodium oleate system,the micro-size fraction magnetite can be agglomerated with micro-size fraction hematite,increasing the surface particle size of hematite and enhancing the adhesion possibility between hematite and bubble,thereby increasing the recovery of hematite.The research on the action mechanism of the agents by infrared spectroscopy and potentiodynamic analysis showed that sodium oleate did not adsorb with quartz,and it could adsorb with activated quartz by calcium ion.The addition of a small amount of sodium silicate did not affect the adsorption of sodium oleate on the activated quartz surface.