Experimental Research On Recovery Of Iron Contained In The Separation Tailings Of Anshan-type Iron Ore

With the great development and exploitation of iron ore resource in China, the amounts of iron ore resource increasingly decrease. As a secondary resource, tailings has been drawing an increasing attention. In China,the average grade of Fe in iron tailings was10%. It is a considerable amount of iron ore resource,which could be recovered from iron tailings.About60%of iron tailings comes from mineral separation of Anshan-type iron ore.Taking the most advantage of Anshan-type iron tailings is of great significance for sustainable development of mining.In this paper,the composite tailings of Qidashan concentration plant,which were composed of gravity concentration tailings,magnetic concentration tailings, reverse-floatation tailings, was chosen as the research object.On the foundation of technology mineralogy research, a experimental study on the recovery of iron in tailings was carried out systematacially. Through a variety of test plans and process flow sheet, the appropriate process flow sheet was confirmed,and great separation index had been achieved.Through the chemical multielement analysis and X-ray diffraction analysis of the composite tailings, it was found that elements can be recovered in tailings is mainly iron.The content of iron is11.10%and the harmful elements’is low,such as S and P. The iron minerals in tailings are mainly hematite and the main gangue minerals is quartz.The results of size analysis and microscopic observation showed that,in the tailings, the size of the gangue minerals (quartz) is clearly coarser than the iron minerals and the iron grade of the coarse is low. the iron minerals is mostly distributed in the fine.The results of shaking table separation test indicated that classification played an important role in improving the separation accuracy of gravity separation, and it is of great significance for improving the separation technology index. Adopting the classification-two stage shaking table separation flowsheet to separate the composite tailings,following results had been achieved:the productivity, iron grade,recovery of iron concentrate were2.58%,67.02%,15.60%.The results of spiral separation test indicated that qualified gravity concentrate could not be generated by using single spiral for the composite tailings. Adopting the classification-two stage spiral separation flowsheet to separate the tailings,it was obtained a concentrate with a productivity of0.68%and a iron grade of56.51%.Adopting the classifying-screening-spiral separation flowsheet to separate the tailings, it was obstained a concentrate with a productivity of only0.38%and a iron grade of66.46%.Adopting the classifying-screening-spiral rougher and shaking table cleaner separation flowsheet to separate the composite tailings, following results had been achieved:the productivity, iron grade,recovery of gravity concentrate were2.41%,65.90%,14.33%.Applying magnetic separation to the middings of gravity separation,a magnetic tailing with a productivity of47.38%,a iron grade of6.45%and a iron recovery of27.56%was obstained. Adopting rougher,three stage cleaner and scavenger reverse floatation flowsheet to separate the magnetic concentrate with a iron grade of31.10%, test results were as follows:the productivity, iron grade, iron recovery of flotation concentrate were4.58%,65.65%,27.14%.The appropriate process,classifying-screening-gravity separation-magnetic separation-reverse flotation,had been carried out to separate the composite tailings according to scientific test investigation, and following results had been achieved:the productivity,iron grade,iron recovery of iron concentrate were6.99%,65.74%,41.47%; the grade of the ultimate tailings was6.97%. The advantages of this process were highly targeted,realizing the separating on the narrow,and the same floating agent as dressing plant. So the research of this paper provided a valid technological process for the recovering of the low grade tailings in practice.Above-mentioned research results provided feasible program and theoretical basis for the recovering of the iron in the composite tailings of Qidashan concentration plant, and offered reference for Anshan-type iron ore tailings.