Research On The New Technology And Mechanism Of The Redressing Of Iron Tailings In Shangchang, Yunnan

With the development of steel industry,the demand for iron ore in China is increasing gradually.However,the domestic iron ore resources are hard to meet the demand of development,which leads to the increasing degree of external dependence of iron ore in China.Due to the continuous progress of mineral processing process,the iron tailings discharged are of finer size and lower grade,and the discharge volume and the heap stock are increasing year by yea,which have caused a series of environmental problems.In order to solve the problem of massive accumulation of iron tailings and relieve the pressure of domestic iron demand,iron tailings re-concentration has gradually attracted people's attention.For the re-concentration,high magnetic selection,gravity separation and the combined process with flotation after grinding was adopted at present.Generally,the recovery index of these processes is low,and most of the processes are complex,which often consist of a variety of combinations of pre-separation,grinding,magnetic separation,gravity separation and flotation.In order to solve some problems existing in the existing re-concentration process,and in view of the difficulties in iron tailings re-concentration in Shangchang,Yunnan Province,according to the characteristics of the iron tailings'process mineralogy,a new process is put forward in this paper.The new process can effectively realize the recovery of iron from the iron tailings.That is,further fine grinding,medicament action,high impact and high gradient magnetic separation.The influence of main factors is studied,the related reasons are analyzed,and the mechanism of the new process is discussed.It provides an important reference for the reuse of iron tailings.In this paper,iron tailings in Kun Gang ShangChang were taken as the research object,by X-ray diffraction,EDS and other modern analytical instrument and chemical analysis method on the process mineralogy research,the results show that:the iron content of the raw ore is only 16.56%,of which 71.24%of the iron was in the form of weakly magnetic hematite,and 26.74%was the unrecoverable silicate iron ore.The gangue minerals are mainly talc,kaolinite,quartz and calcite,and the mineral hematite and gangue mineral are adjacent to the linings,or scattered with fine grain.The particle size of the raw ore is fine,and the proportion of-74?m is up to 91.98%,and the proportion of-45?m is 82.73%.Iron is mainly distributed in the grain fraction of-45?m,and the distribution rate of the medium iron is 86.34%.Due to the complex disseminated characteristics of hematite,the liberation degree of the monomer is only 38.47%.Totally,the raw ore belongs to fine grain and low grade iron tailings.According to the density and magnetic difference of gangue minerals and hematite,centrifugal reselection,magnetic roasting-weak magnetic separation,and high gradient magnetic separation exploration tests were conducted.The results show that the effect of high gradient magnetic separation in the three process flows is best,and in the process,fine grinding,dosing and increasing the number of shots can greatly increase the magnetic separation index.Based on this,and based on the mineralogical characteristics of the tailings,a new process of“Fine Grinding-Pharmaceutical Action-High Crushing and High Gradient Magnetic Separation”was proposed.In the new process experiment,the grinding fineness test is firstly carried out,and the degree of grinding can be increased to increase the dissociation degree of the monomer of hematite,and the optimum grinding fineness is 95%-45?m.Good pulp for fine grinding of"agents"?scattered selective flocculation?processing,scatter hematite and the gangue minerals,selective flocculation microgranular hematite particles,increase its size,increase in the subsequent stages of magnetic separation on hematite pellet strength,separation stage drug effect best conditions:mixing speed is 800 RPM,the mixing time of 6 min,the dosage of YL-1 is 800 g/t;To high impact has good flocculation pulp high gradient magnetic separation test,strong water flow,high speed can increase the washing of gangue mineral,suitable for the magnetic field strength,magnetic medium size increase adsorption amount of hematite in assembled magnetic medium,the best conditions for:water flow speed 6 L/min;Pulsating impulse 320times/min;The magnetic field intensity is 0.7 T and the second magnetic field intensity is 0.8 T.The polymagnetic media is 1.5 mm.Under the optimum condition of the new process,the iron grade reached59.46%and the recovery rate reached 50.13%.According to the study of YL-1 dispersion mechanism,The main dispersion of sodium silicate is SiO?OH?₃^-.The addition of ammonium sulfate can increase the concentration of SiO?OH?₃^-components in the solution.At the same time,ammonium sulfate has a certain dispersive effect on the slime,so the combination of the two can produce a positive synergistic dispersion effect.In addition,H⁺produced by nonionic polyacrylamide during hydrolysis can also promote the generation of SiO?OH?₃^-,so the YL-1 has a better dispersion effect.The results of the flocculation mechanism of YL-1 shows that the flocculation effect of yl-1 on granular hematite is better than that of quartz grain.YL-1 has little effect on the surface potential of the dispersed quartz,but it can significantly improve the surface potential of hematite,indicating that YL-1-1 has a strong selectivity for hematite.