Research On A New Process Of Separating Fine-grained Ilmenite And Hematite Based On Centrifugal High-gradient Magnetic Separation Technology

China is rich in weakly magnetic ores;for instance,titanium and tungsten resources rank first in the world,and account for 27.78%and 58%of global reserves,respectively.However,most of the weakly magnetic resources in China are not well recycled.Taking ilmenite and hematite as examples,at present,most of the resources in China have low grade,complicated and lengthy production process,low separation efficiency and low recovery rate.Therefore,it will be an effective way to develop and utilize this kind of mineral resources in China to form a short-new flow process making use of the efficient and selective separation technology.At present,high gradient magnetic separation（HGMS）is one of the effective methods for the separation of weakly magnetic minerals.Although the existing HGMS method can achieve high recovery rate,but there is still a technical problem of low selectivity.Centrifugal high gradient magnetic separation（CHGMS）method is a new separation method based on the new compound force field-centrifugal high gradient magnetic field.Plenty of experimental studies show that this method has the advantages of high separation accuracy and better capture selectivity.On the basis of CHGMS method,this research explores a short-new flow process for the separation of ilmenite and hematite,two typical weak magnetic minerals in China.The main conclusions are as follows:The results of the short-new process for the tailings of ilmenite from panzhihua iron and steel group co.LTD show that TiO₂ concentrate with a grade of 46.62%and a recovery of 40.42%can be obtained by the new process of "PHGMS roughing-CHGMS cleaning-flotation cleaning".In the new process,PHGMS discarded 64.46%tailings by one roughing,and increased the TiO₂ concentrate grade from 6.32%to 13.44%.The CHGMS process further reduced the TiO₂ concentrate yeild rate by 20.23%,improved the grade to 27.62%,and the recovery reached55.76%.Through the "one roughing four cleaning two scavenging"flotation processes,the TiO₂ concentrate grade of 46.62%and recovery rate of 40.42%were obtained.Compared with the current separation process "PHGMS roughing-flotation cleaning",the CHGMS process is inserted in the new separation process,making the concentrate grade higher and the yield lower under the premise of ensuring the recovery rate of magnetic separation concentrate.This process greatly reduces the amount of ore feeding in subsequent flotation separation operations,improves the flotation feed grade,thus reducing the dosage of flotation reagents,shortening the flotation process,and achieving energy saving,consumption reduction and the improvement of the separation index.The samples used in the hematite test were raw ore from dahongshan iron ore processing plant of Kunming iron and steel group.In the magnetic experimental study of hematite,the test flow of "PHGMS roughing-CHGMS one roughing and one scavenging"was determined.Under the optimal separation conditions of this process,the yield,grade and recovery of magnetic concentrate were 47.09%,58.81%and77.70%respectively.Comparing with the magnetic concentrate obtained by the test flow of "PHGMS one roughing and one cleaning",the yield decreased by 17.74%,the grade increased by 8.44%,and the recovery decreased by 9.68%.In the process test of "HGMS-gravity separation",the test flow of "PHGMS roughing-CHGMS one cleaning one scavenging-centrifuge gravity cleaning separation"and the optimum separation conditions for each operation were determined.Under this process and the optimal separation conditions,the final concentrate index of Fe concentrate grade 60.80%and recovery 76.24%was obtained.In the process test of "HGMS-flotation",the test flow of "PHGMS roughing-CHGMS one cleaning one scavenging-reverse flotation one roughing,one cleaning one scavenging"and the optimum separation conditions for each operation were determined.Under the experimental process and optimal separation conditions,the separation index of Fe concentrate grade was 61.90%and recovery was 73.53%.To sum up,the separation process based on CHGMS technology can effectively separate ilmenite and hematite,two typical weakly magnetic ores in China.Compared with the traditional process,this process has better separation selectivity and low cost,what’s more,the new process can greatly reduces the ore feed of the subsequent separation operation to simplify the operation process of the gravity separation or flotation at the back end.The new process has better economic benefits,and realizes the improvement of energy saving,consumption reduction and separation index.This provides a new technical approach to improve the development and utilization of weakly magnetic mineral resources in China.