Characterization of ilmenite of Cox's Bazar heavy mineral deposit

Abstract

Ilmenite and l1ltile are natural sources of Ti02 and titanium metal. Rutile, naturally occuring pure Tin, i, prefen-ed to ilmenite as a raw materia!. Due to rapid decrease ;n sup1'l} of rutile, the necessity of alternate sources of rutile cannot be ov~relllpha,i7ed_ As a l'esult, investigatlOns are bcmg carried out throughout the world on the lIpgradation of low-gmde ilmenite 10 rutile. C()n.<equently, it has become necessary to identitY the best possible route for the upgradallon of ilmenite to what is known as sylllhclic rutile. Ilmenite m~y contam malll minerals like hematite, magnetite etc In it, structure. ).iaturai weathering of llmcnilc rcsull, in the inL,ea,e in the '] iO, content of ilmenite with incre •.,ing time of weathering, So detailed investigation into the exlent of weatberlng of ilmenlle of a parlicular placer deposit is essential nOI only for the qual itative assessment of tbe deposit but also to Improve the technique of produelion of ,yntbetie n'tilc. Samples of ilmenite containing 14.4 per cent FeO, 33.0 per cent Fe20J and 39,5 per cent Ti01 were collected from the Beach Sand Exploitalion Center, Kalalli, Cox's lla7.ar. The samples were tben subjected to magnetic and size Iractionation, The phases present in the dlllerent fractlOns (both magnetle and size) were idenlified by X-ray diffractions analysi:;, The chemical compositions oftlle dillcrent magnetic and :;ize fractions were determined by wet chemical analysis. The fractions were reduced lor 4 hour at I0500C by equal amounls of charma!. The exlent of reduction was followed by chemical analysis of the reduced mass for metallic iron. The ,results obtained were <upplemenled hy X-ray difti'action analysis and optical microscopy. Samples of the different magnelic fractions and ,ize fractions were oxidi7ed for two hour al 9000C and were reduced under otherwi,e identical conditions. The effects of the oxidalion on the extent of reduction were followed by tlle determination of mctalhc Iron content of the reduced samples. The efTeel of addilion of 10 per cenl • V[I N,'2CO, on lhe exlent of reduction of the diffcrent fractions (botb before and after o~idation) under otherwi,e idenlical conditions were also investigaled. from the chemical analysi.', il was found that Cox's Bazar ilmenite is characteri"lically "imilar to Moheskh~li ilmenite. l're,ence of aHeration productl; of ilm~nite, partlcularly pseudorutile, could nul be detected in the X_ray diffra~lion pallems of any ot the ,ix magnetic fraclion, of this deposit. Attempt, were al;o made / 10 delect the presence of waler and hence the presence of pseudorutilc by thermogra,imelri~ analysis. Thermogravimelric analy<is did not show any significant change of weight ncar about 600°C for any magnelie lr~ction. Mineralogical study has also been carried oul. The results of lhese investigations led to the conclusion that Cox's I3anr ilmenite ha, not u'ndergune alteration to any signitlcant extent This study ~Iso concentrated upon the reduetiun behavior of the different magnetic lhetions ~s well a, UPOllreduelion behavior of dillcrcnt size tractions. II has bem, concluded that separate reduclion procedures for the differenl fraclions (either magnetic or size) i, not n~~e"ary.