1、Magnetic separation studies for a low grade siliceous iron ore sampleDwari Ranjan Kumar,Rao Danda Srinivas,Reddy Palli Sita RamCSIR-Institute of Minerals and Materials Technology,Council of Scientific and Industrial Research,Bhubaneswar 751 013,Indiaa r t i c l ei n f oArticle history:Received 2 May
2、 2012Received in revised form 3 June 2012Accepted 1 July 2012Available online 8 February 2013Keywords:Iron oreMagnetiteCharacterizationDry and wet magnetic separationa b s t r a c tInvestigations were carried out,on a low grade siliceous iron ore sample by magnetic separation,toestablish its amenabi
3、lity for physical beneficiation.Mineralogical studies revealed that the sample con-sists of magnetite,hematite and goethite as major opaque oxide minerals where as silicates as well ascarbonates form the gangue minerals in the sample.Processes involving combination of classification,dry magnetic sep
4、aration and wet magnetic separation were carried out to upgrade the low grade sili-ceous iron ore sample to make it suitable as a marketable product.The sample was first ground and eachclosed size sieve fractions were subjected to dry magnetic separation and it was observed that limitedupgradation i
5、s possible.The ground sample was subjected to different finer sizes and separated by wetlow intensity magnetic separator.It was possible to obtain a magnetic concentrate of 67%Fe by recover-ing 90%of iron values at below 200lm size.?2013 Published by Elsevier B.V.on behalf of China University of Min
6、ing&Technology.1.IntroductionMagnetic separation is an important beneficiation process andis usually adopted for ores of manganese,phosphate,titanium,chrome,tungsten,molybdenum,nickel,bauxite and niobium-tan-talum ores in addition to iron ores 115.Magnetic separationmethods were also carried out for
7、 the ferrochrome industry wastessuch as the flue dust to find out the possibilities of partial recyclingand or for the recovery of metal and chromite of significant value16.Magnetic separation is a simple,inexpensive,non-destructiveand rapid means of concentrating iron-bearing minerals to nearlymono
8、mineralic levels,particularly those present in different pro-portions in clays.The use of variable magnetic flux density furtherallows sub-fractionation of the iron-bearing minerals 17.Theselection of magnetic separation techniques depends on many pro-cessing factors,such as assemblage of minerals,t
9、heir liberationsize,and their corresponding magnetic susceptibility in additionto production,marketing and environmentally friendly issues.Magnetic treatment of ores and industrial minerals is conductedin both wet and dry modes.The dry magnetic separation processonly enables purification where as in
10、 the wet process the end prod-uct results in the form of slurry.The former especially applieswhen dealing with material with finer particle sizes.Many mineralprocessing industries want to purify the magnetic minerals fromthe non-magnetic portions by using the dry magnetic separationtechniques.The we
11、t and dry magnetic separation process has spe-cific advantages as well as disadvantages.Questions are oftenraised about which separation technique is most appropriate fora particular ore type or operation.The most suitable solution iscommonly determined by the required specifications of the endprodu
12、ct or a clean marketable product.The dry magnetic separa-tion techniques applied based on a number of reasons such as(i)local availability of water,(ii)cost of drying,(iii)demands of theend customer and(iv)ever changing environmental issues.Withdry methods care must also be taken to ensure control o
13、f dust haz-ard,an expensive precaution both in capital and operating costs.Furthermore,dry separators have considerably lower throughputsthan wet machines.Dry separators frequently yield excellent sep-aration of materials coarser than 75lm.On the other hand,on anunsized material containing large por
14、tions of fines,the wet processis the only acceptable one.Generally,dry magnetic separation isused when relatively large volume of non-magnetic substances isusually the commercial products and the amount of magneticmaterials removed is quiet small.Considerable advantages must,therefore,be offered by
15、dry separation techniques to justify itsuse in preference to wet process.This present paper discusses boththe dry and wet magnetic separation techniques used for process-ing of a low grade siliceous iron ore sample.2.Materials and methodsAbout 500 kg of a low grade siliceous iron ore sample wascrush
16、ed to below 10 mm size by using jaw crusher.The crushedsample was thoroughly mixed and subjected for sampling by con-ing and quartering technique to prepare representative samples.These representative samples were used for different laboratoryinvestigations.Dry magnetic separation method was adopted2095-2686/$-see front matter?2013 Published by Elsevier B.V.on behalf of China University of Mining&Technology.http:/dx.doi.org/10.1016/j.ijmst.2013.01.001Corresponding author.Tel.:+91 6742379476.E-ma
