Basic Research On Surface Magnetic Seed And Magnetic Separation Of Specularite In JISCO

China's weakly magnetic oxide iron ore has the characteristics of low grade,multi-component dense symbiosis and fine disseminated particle size.It needs fine grinding to dissociate it from gangue minerals.The fine-grained weakly magnetic oxide iron ore after fine grinding has the characteristics of small particle size,large specific surface area and low specific magnetic susceptibility.Conventional beneficiation methods are often difficult to collect and have low recovery,and it is difficult to achieve ideal separation with gangue minerals Separation effect.Although the commonly used magnetization roasting method can improve the magnetic properties of minerals,there are still some problems in the industrial production,such as the difficulty of equipment maintenance,uneven magnetization quality,high production cost and related environmental problems.In contrast,the surface magnetization method aims to selectively adsorb magnetic species on the surface of weak magnetic iron minerals by adding magnetic species to the pulp,expand the magnetic difference between them and gangue minerals,and then realize effective recovery of weakly magnetic oxide iron ores by magnetic separation,and greatly simplify the process flow.Based on the analysis and summary of a large number of literatures at home and abroad,this paper takes the Specularite of Jiuquan Iron and Steel Co,which mainly contains iron minerals such as Specularite,limonite and siderite,and the main gangue minerals such as quartz and dolomite,as the object.By adding magnetic seeds under different slurry conditions,the magnetic seeds can selectively agglomerate with weak magnetic oxide iron ore,and then recover the oxide iron ore through magnetic separation,The magnetization effect of magnetic seed is judged by magnetic separation concentrate index,scanning electron microscope(SEM)and sample vibrating magnetometer(VSM),and the main conclusions are as follows:1.With the increase of the concentration of sodium hexametaphosphate in the slurry,the negative surface potential of each mineral increases,and the dispersibility increases.When the concentration of sodium hexametaphosphate is 35mg/L,the difficulty degree of magnetic seed adsorption on the surface of each mineral is in the order of siderite>Specularite>dolomite>limonite>quartz.Because dolomite and quartz are non-magnetic minerals,and the saturation mass magnetization is Specularite>limonite>siderite,when the pulp p H is 7,the dosage of sodium hexametaphosphate is 25mg/L,and the dosage of magnetic seed is 3%,the order of magnetic separation recovery is Specularite>siderite>limonite>dolomite>quartz.2.When the concentration of sodium oleate is 100mg/L and the dosage of magnetic seed is 3%,the order of magnetization effect is as follows:Specularite>limonite>siderite>dolomite>quartz.At this time,the saturation mass magnetization of siderite,limonite and Specularite increased from 0.55A·m²·kg^-1?0.86A·m²·kg^-1?1.53A·m²·kg^-1to 11.64 A·m²·kg^-1?12.68A·m²·kg^-1?29.57A·m²·kg^-1,respectively,achieving good magnetization effect.With the increase of PAM concentration,the agglomeration phenomenon in the pulp becomes more obvious,the agglomeration between the magnetic seed and the minerals becomes closer,and the recovery of the minerals increases obviously.3.The qualified iron concentrate with iron grade of 47.27%(54.21%after burning)and total recovery of 77.12%can be obtained after medium high intensity magnetic preconcentration sodium hexametaphosphate and sodium oleate composite agglomeration magnetic seed magnetic separation,in which the high intensity magnetic field intensity is 480k A/m and the magnetic separation magnetic field intensity after seed magnetization is 320k A/m.The concentration of sodium hexametaphosphate was 100mg/L,the concentration of sodium oleate was 80mg/L,and the dosage of magnetic seed was 3%.Compared with the concentrate index of45.5%iron grade(52.44%after burning)and 65.7%metal recovery obtained by high intensity magnetic separation process in JISCO,the iron grade and recovery of the concentrate have been improved.