Research On The New Separation Technology And Mechanism Of Daxigou Iron Ore

Daxigou iron ore is the biggest siderite base in our country,which has a character of refractoryn low grade.fine-grain disseminated and complexity.In this paper,Daxigou iron ore was used as raw samples to set a new way to utilize efficiency and launch the research on process and mechanism of preliminary processing by high intensity magnetic-magnetization roasting-magnetic separation of the iron ore.The total iron grade of Daxigou iron ore is 26.08%,iron mainly exists in form of siderite and hematite-limonite,with distribution rate of 68.88%and 22.31%respectively,the gangue minerals are mainly quartz and muscovite which closely symbiosis with useful minerals,the main mineralogy factor of influencing on separation indexes is fine quartz and tiny distributed in iron minerals that makes the valuable single mineral difficult to liberate.Beneficiation experiments of twice high intensity magnetic separation were applied for Daxigou iron ore,and magnetic concentrate with total iron grade of 28.47%and recovery of 96.78%is obtained.,and production rate of discarding tailing is 8.10%.The total iron grade increase 2.39%,the useful minerals,such as siderite.limonite and magnetite,mainly enriched in the magnetic concentrate,but sulfide and silicate mainly lossed in the tailings,part of the gangue minerals and slime were thrown at the same time via high intensity magnetic separation.The total iron grade of magnetic tailings is 8.11%,the iron minerals were wrapped by quartz and muscovite lead part of them to loss in the tailings.Excellent indicator of total iron grade of 59.29%and recovery of 87.50%is obtained after the beneficiation experiments of preliminary processing by high intensity magnetic-magnetization roasting-magnetic separation were were applied for Daxigou iron ore,compared to the result of total iron grade of 57.09%and recovery of 89.87%is obtained by direct magnetization roasting-magnetic separation for Daxigou iron ore,though the recovery reduce 2.37%,the total iron grade of concentrate increase 2.2%.The two roasting products have similar properties with simple mineral composition>less mineral species,the major iron mineral is magnetite,and the gangue minerals are mainly quartz and muscovite,the result show that siderite and limonite of iron minerals in raw ore transformed into magnetite,but the gangue minerals are changed a little after roasting.Magnetic analysis results indicated that the unit mass magnetic distance and specific susceptibility increased significantly after roasting,low intensity magnetic was applied for roasting products in the following effective separation.The optical microscope show that single liberation degree of magnetite in roasting products is low,the content of body with gangue minerals is higher,so fine grinding should be taken for roasting products before low intensity magnetic separation.The mechanism research of siderite in the process of magnetization roasting shows that,FeO was generated at the beginning of the reaction,but the FeO is an intermediate phase and then continue to translate into Fe3O4 in a short time,it mainly reacts with FeCO3= 1/3Fe3O4+2/3 CO2+1/3CO on the magnetization of siderite under neutral atmosphere.The pyrolysis temperature of siderite start with about 410?,maximum pyrolysis rate around 510?,until the pyrolysis is end about 600?.With the increase of heating rate within a certain range,the higher reaction rate of siderite pyrolysis can be achieve easily in a relatively short time,and reduce the time required to complete the reaction.The non-isothermal kinetics indicated that,the mechanism functions on pyrolysis reaction of siderite are all F1 at different heating rates,as instantaneous nucleation and unidimensional growth mechanism,apparent activation energy and pre-exponential factor are reduced with the increase of heating rates.The result of phase and magnetic transformation of the siderite both before and after roasting indicated that,siderite transformed into magnetite,and the unit mass magnetic distance and specific susceptibility increased significantly after roasting.The research can provide the foundation for further exploitation and utilization the Daxigou iron ore,and can provide significant reference for the separation of similar refractory iron ore.