Journal of Minerals & Materials Characterization & Engineering, Vol. 9, No.3, pp.247-262, 2010 Printed in the USA. All rights reserved
Applied Mineralogical Studies on Iranian Hard Rock Titanium Deposit
A. Mehdilo and M. Irannajad*
Department of Mining and Metallurgical Eng., Amirkabir University of Technology, Tehran,
*E* Corresponding Author:, Phone: 0098-21-66419729
The Qara-aghaj hard rock titanium deposit has been located in the 36 Km at the North-West of
Euromieh, Iran. Mineralogical studies performed by XRD, XRF, Optical microscopy and SEM
studies indicated that ilmenite, magnetite and apatite are main valuable minerals. The gangue
minerals consist of the silicate minerals such as pyroxene, olivine, plagioclase and some
secondary minerals. Ilmenite in Qara-aghaj ore occurs in three forms: ilmenite grains, exsolved
ilmenite lamellae in magnetite and ilmenite particles disseminated in silicate minerals. The grain
forms liberated in 150µm are only recoverable by physical methods. The maximum content of
TiO2 in ilmenite lattice is determined 48% by EDX. Although the ore has 8.8% average grade of
TiO2, the recoverable TiO2 is only about 6.72% the studied sample contained 18.3% ilmenite and
the amount of recoverable ilmenite is only about 14% (6.72% TiO2). This is due to the ilmenite
exsolutions and inclusions in the magnetite and silicate minerals, and the TiO2 in solid solution
in the lattices of these minerals. In fact, about 77% of whole ilmenite content of the ore will be
recoverable. EDX analysis showed that Fe is substituted partially in ilmenite by Mn and Mg.
Some narrow lamellae of hematite are formed inside ilmenite. By analyzing of magnetite, it was
found that the V2O5 content is up to 1%. V3+ is found in magnetite lattices by replacing Fe3+.
Analyzing of clinopyroxenes indicated that augite, containing Ti, is the main form of this group.
Ilmenite, apatite and magnetite are valuable minerals for production of TiO2, P2O5 and Fe,
respectively and the V2O5 can be extracted from magnetite as a by-product.
Key Words: Applied Mineralogy, Titanomagnetite, Ilmenite, Magnetite, Apatite, Hard Rock
248 A. Mehdilo and M. Irannajad Vol.9, No.3
Titanium is widely used as titanium dioxide (TiO2) for production of white pigment [1]. Ilmenite
(FeTiO3, 52.6% TiO2 and 47.4% FeO) is the most common source of titanium dioxide [2]. The
term ilmenite, as used in the titanium industry, commonly covers the entire range from
unweathered ilmenite with TiO2 contents below 50% to altered ilmenite containing more than
60% TiO2 [3]. All economically exploitable ilmenite occur as hard-rock resources and beach
sands. The hard-rock titanium deposits have complicated mineralogical characteristics whose
identification is the most important from processing viewpoint. The amenability of various iron-
titanium deposits to beneficiation is controlled by mineralogical and textural characteristics. In
the evaluation of the mineralization and in the design of procedures of mineral dressing, the
distribution of the valuable material is a matter of immediate importance. It is necessary to
determine whether a given element is occurring in one mineral or several [3]. Considering the
magmatic titanium deposits, the majority of the worlds economic rock deposits of titanium
minerals are restricted to massive or disseminated anorthositic or gabbroic rocks. They are
classified as ilmenite-magnetite deposits, ilmenite-hematite deposits and ilmenite-rutile deposits
Tellnes [4] and Bjerkreim-Sokndal [5] in Norway, Kauhajärvi [6], Lumikangas [7],
Koivusaarenneva [3,8], Iso-Kisko [9], Otanmäki [10] and Kalviä [11] in Finland, Sinarsuk V-Ti
project in West Greenland [12], the Sept– Iles project in Canada [13], Navaladi and Surungudi
area in southern India [14] and Kahnoj beach sands in Iran [15] are some of the most important
titanium deposits which have been investigated from applied mineralogical viewpoint.
The Qara-aghaj hard rock titanium deposit which is studied in this paper is located in the 36 Km
at the North-West of Euromieh in Azarbayejan province, Iran (Fig.1). This deposit has been
identified as a titanium-phosphorus resource. Based on the geological and petrological studies at
the region, the most important rock massif formation that have caused titanium and phosphate
mineralization, is the intrusive igneous rocks named as the Qara-aghaj mafic-ultramafic intrusive
mass. This mass has formed of three portions: the ultramafic zones have been formed by wherlite
and pyroxenite; the mafic zones are compound of the gabbro, gabbro-norite and gabbro-diorite;
and the intermediate portion has formed of the diorite, some tonalite and a little quartz-feldspar
veins. This formation has chemical properties of the intermediate alkali magma, which have
injected into crust rocks and then have caused the magmatic phenomenon and metallization. At
the preliminary exploration, some 1590 meters trenches have excavated throughout in the
outcrop of the deposit. In addition, four exploration faces and two boreholes with overall length
about 155 m have been excavated in this stage. The exploration studies show an estimated
reserve of 209 Mt. with an average grade of 8.5% TiO2 [16, 17, 18 and 19].
Vol.9, No.3 Applied Mineralogical Studies on Iranian Hard Rock Titanium Deposit 249
Fig. 1. Location map of Qara-aghaj deposit.
Four representative samples from exploration faces (F, G, C and H) and two drill core samples
from two boreholes (BH1 and BH2) with overall length about 155 m were collected. The
crushing of the samples less than 2 mm was done by laboratory jaw, cone and roller crushers.
The rod and ball mills were used for grinding of samples. The corresponding polished thin
sections were studied for ore and rock-forming minerals and their textural relationships by
reflected and transmitted light microscopy. The chemical and mineralogical composition of
different samples carried out by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The
Philips scanning electron microscopy (model: XL30) was used for description of inclusion,
exsolution and other textural relationships. The EDX DX-series PV 9462/30 (model: NEW
XL30 144-10) was also used for probe analysis. The Merck clerici solution (SG=4, Art No.
=8136) and Aldrich methylene iodide (SG=3.3) were employed in heavy liquid tests.
3.1. Chemical and Mineralogical Composition
According to the X-Ray diffractography, the main valuable minerals consist of the ilmenite and
magnetite. The other minerals present in the samples are olivine, pyroxene, plagioclase,
hornblende, apatite and secondary minerals such as chlorite. The chemical composition of six
250 A. Mehdilo and M. Irannajad Vol.9, No.3
representative samples is shown in Table 1. The collected drill core sub samples were also
analyzed. TiO2, Fe2O3 and P2O5 are correlated very closely as shown in Fig. 2.
Table 1. The chemical composition of six representative samples
TiO2 9.1 9.2 9.0 8.4 7.1 7.4
Fe2O3 33.0 36.7 36.5 32.9 28.8 31.7
SiO2 30.4 27.7 23.2 25.1 30.1 27.1
17.7 14.0 11.9 13.6 12.2 13.4
CaO 3.0 6.3 8.2 8.9 8.3 8.5
Al2O3 3.61 2.45 2.7 3.0 6.5 4.6
P2O5 0.42 2.4 5.8 5.6 4 4.9
MnO 0.35 0.44 0.48 0.41 0.37 0.42
V2O5 0.16 0.13 0.12 0.13 0.09 0.1
Na2O 0.18 0.22 0.36 0.32 1.1 0.81
K2O 0.027 0.024 0.039 0.047 0.15 0.11
S - - - - 0.42 0.66
SO3 0.077 0.067 0.088 0.067 - -
Cl 0.034 0.040 0.047 0.057 0.072 0.054
L.O.I 1.88 0.01 0 0.42 0.68 0
Total 99.9 99.7 98.4 99.0 99.9 99.7
3.2. Ore Microscopy
Based on the results obtained from transmitted-light microscopy studies, the gangue minerals
filling the interstices between the ore minerals are pyroxene (clinopyroxene and orthopyroxene),
olivine, plagioclase, hornblende, apatite, minor constitutes of quartz, Na-feldspars and secondary
minerals such as chlorite, antigorite and serpentine probably derived from alteration of
clinopyroxene and olivine (Fig. 3). The large amount and coarse grains mineralization has
mainly occurred in where the content of olivine and pyroxene is high (Fig. 3a, b, c and e). By
increasing the content of plagioclase the volume and size of ore minerals is decreased strongly
(Fig. 3d and f). Based on the study of 42 polished sections by reflected-light microscopy, the ore
mineral assemblage, in average, includes about 3-22 Vol % ilmenite, 3-20 Vol % magnetite and
small amount (max 5 Vol %) of sulphide minerals such as pyrite, pyrrhotite and chalcopyrite and
trace amount of hematite. The ilmenite is found in granules form (Fig. 4a, 4c and 4d), but some
lamellae of the ilmenite are found inside the magnetite (Fig. 4b). Inclusions of apatite in the ore
minerals and in silicates are the most typical texture (Fig. 4a and c). The sulphide minerals such
as pyrite, chalcopyrite and pyrotite appear in the inclusion form inside the ilmenite and magnetite
or associated with gangue minerals (Fig. 4c and d). The quantity of the sulphide minerals are
very low in the face sample, its quantity is higher when the depth is increased.
Vol.9, No.3 Applied Mineralogical Studies on Iranian Hard Rock Titanium Deposit 251
A large amount of ilmenite and magnetite are in crystalline form but commonly have filled the
interstices between the silicate minerals.
0510 15 20 25 30 35 40 45505560 65 70 75 80 85
Depth (m)
Percentage (%)
TiO2P2O5 Fe2O3
0510 1520 25 30 35 40 45 50 5560 65 70 75
Depth (m)
Percentage (%)
TiO2 P2O5 Fe2O3
Fig. 2. Variation of titanium, phosphorous and iron in two drill holes BH1 and BH2.
252 A. Mehdilo and M. Irannajad Vol.9, No.3
a b
c d
e f
Fig. 3. Study of different samples by transmitted light microscopy. a) and b): Interlocking of ore
and gangue minerals in the wherlitic or mineralization zone (Sample G). The plagioclases
quantity is very low and the olivine and the clinopyroxene are altering into the secondary
minerals such as amphibole and chlorite. c): Interlocking of the minerals in the mineralization
zone, coarse grains mineralization accompanying with clinopyroxene (Sample F). d):
mineralization in dioritic zone is low and fine and mainly has been formed by plagioclase
(Sample F). e): clinopyroxenes and orthopyroxenes associated with the ore minerals in
mineralization zone ((29 m depth of BH1). f): plagioclase and quartz in dioritic zone. Ore
minerals are very low and fine (69.5 m depth of BH1). ( Opy: orthopyroxene; Cpy:
clinopyroxene; Ol: olivine; Pl: plagioclase).
Vol.9, No.3 Applied Mineralogical Studies on Iranian Hard Rock Titanium Deposit 253
Fig. 4. Study of different samples by reflected light microscopy.
a: Ilmenite and magnetite filling the interstices between silicate minerals (sample H)
b: Ilmenite in the form of exsolved lamellae in magnetite (head sample after crushing under 2
c: an ilmenite grain in contact with magnetite, pyrite and apatite (sample from 47 m depth of
d: a chalcopyrite inclusion inside an ilmenite grain surrounding by silicate minerals (47 m depth
of BH2)
( IL: Ilmenite, Ma: Magnetite, Py: pyrite, Ap: apatite, Cp: Chalcopyrite, TM: Titanomagnetite)
254 A. Mehdilo and M. Irannajad Vol.9, No.3
3.3. Scanning Electron Microscopy
The studies of samples by SEM (Fig. 5) and EDX analysis (Table 2) were performed for two
main purposes: 1) Study of exsolution and inclusion texture in minerals, 2) to determine the
minor element constituents in ilmenite and magnetite and to distinguish the type of different
lamellae inside them.
Some lamellae of ilmenite have been occurred as exsolution textures inside magnetite grains,
where the magnetite here can be referred to as ilmenomagnetite or titanomagnetite (Fig. 5a and
5b). These lamellae are very narrow (have a thickness between 0.5-20 µm) and so unrecoverable
by the physical methods. Some of the ilmenite lamellae contain exsolved lamellae of spinel (Fig.
5c and 5d) which are also evidenced by analysis using EDX (Table 2 and Fig 5e, Mapping of Ti
and 5f, Mapping of Al). Al is indicator for presence of spinel.
Some exsolved lamellae of the hematite, range in size 0.1 to 1 µm, are also observed inside the
ilmenite (Fig. 6a). The analysis of these lamellae by EDX (table 2, rows 18 to 21) indicated that
these lamellae could be hemoilmenite.
Average analysis of different phases of samples performed by EDX is given in Table 2. The
TiO2 content of ilmenite (41.6-48.0 %) is lower than the theoretical ilmenite composition which
indicates that there is no ilmenite alteration. The MgO and MnO contents of ilmenite (both grains
and lamellae) are 0.74-1.48 % and 0.38-2.4 % respectively which are relatively high. The MnO
content of ilmenite lamellae exsolved magnetite is higher than primary ilmenite or ilmenite
The TiO2 content in the magnetite lattices is considerably low (0.76-1.23 %) while it’s content in
titanomagnetite part is relatively high (5.19-11.73%). Vanadium in magnetite is relatively high
(V2O5= 1.12-1.46 %) but its content in ilmenite lattices is constant and low (0.24-0.45 %). The
Cr2O3 content in the magnetite and ilmenite is in the same range, approximately.
Apatite and pyrite minerals are usually as inclusion form inside ilmenite (Fig.6b, 6c and 6d),
however some of which were observed in magnetite and silicates. The size of apatite mineral is
mainly lower than 50 µm. According to the analysis of apatite by EDX, the fluorine content
(2.14-2.71 wt %) is indicative of fluor-apatite composition. The P2O5 content is lower than
theoretical chlor-apatite composition while the CaO content is higher than it. The analyzed
gangue minerals seem to be augite or ferroaugite containing Ti.
The SEM studies also indicated that some of ore minerals have been disseminated in silicate
minerals (Fig.6e and 6 f). Recovery of this type of ore minerals by physical methods is very
Vol.9, No.3 Applied Mineralogical Studies on Iranian Hard Rock Titanium Deposit 255
a b
c d
e f
Fig. 5. Study of samples by SEM
a, b: Ilmenite in the form of exsolved lamellae in magnetite (titanomagnetite texture)
c, d: lamellae of ilmenite exsolved in magnetite containing spinel lamellae (dark parts)
e: X-Ray mapping of Ti in ilmenite lamella containing spinel shown in Fig. 5d.
f: X-Ray mapping of Al in ilmenite lamella containing spinel shown in Fig. 5d.
256 A. Mehdilo and M. Irannajad Vol.9, No.3
a b
c d
e f
Fig. 6. Study of samples by SEM.
a: very narrow hematite lamellae exsolved in ilmenite (hemo-ilmenite texture)
b: Apatite and pyrite as inclusion form in ilmenite
c: X-Ray mapping of phosphorus as indicator of apatite in Fig. 6b.
d: X-Ray mapping of sulfurous as indicator of pyrite in Fig. 6b.
e, f: disseminated form of ore minerals in silicate minerals
Vol.9, No.3 Applied Mineralogical Studies on Iranian Hard Rock Titanium Deposit 257
Table 2. Selected EDX analysis of ilmenite, magnetite, apatite, some silicate minerals and other
TiO2 Fe2O3MnO V2O5P2O5CaOMgO SiO2Al2O3 Cr2O3 Cl Total
1 Ilmenite lamellae 43.45 50.97 1.48 0.36- - 0.59 1.15 1.28 0.42 - 99.7
2 Ilmenite 41.6 47.15 1.13 0.380.92 0.22 2.06 2.51 2.92 0.55 - 99.44
3 Ilmenite 47.34 48.08 0.85 0.400.35 0.2 0.75 0.98 0.61 - - 99.56
4 Ilmenite 48.0 49.09 0.95 0.450.21 0.09 - 0.96 - - - 99.85
5 Ilmenite 45.42 47.58 1.19 0.371.31 0.28 0.56 1.15 0.68 0.21 - 98.75
6 Ilmenite 42.28 50.75 1.15 0.420.21 0.36 2.4 1.16 0.95 0.24 - 99.92
7 Ilmenite 42.5 48.49 1.25 0.350.31 0.39 2.41 2.15 1.9 0.23 - 99.98
8 Ilmenite 45.47 48.75 1.14 0.420.38 0.34 0.91 1.19 0.55 0.27 - 99.42
9 Ilmenite 46.51 49.96 0.74 0.420.25 0.16 0.56 0.89 0.47 - - 99.96
10 Ilmenite 46.53 49.92 1.02 0.39- 0.06 0.38 0.97 0.37 - - 99.64
11 Ilmenite 46.21 49.25 1.42 0.38- 0.08 0.65 0.92 0.78 - - 99.69
12 Ilmenite 46.76 49.44 1.38 0.35- 0.27 - 1 0.41 0.22 - 99.83
13 Ilmenite 46.06 48.89 1.19 0.440.08 0.26 1.49 0.77 0. 66 0.16 - 99.34
14 Ilmenite 46.29 47.67 1.3 0.33- 0.2 1.62 1.21 0.9 0.11 - 99.63
15 Ilmenite 41.75 53.29 1.32 0.240.14 0.4 0.75 1.18 0.66 - 99.73
16 Hemo-Ilmenite (light
lamellae) 33.7 58.42 1.15 0.781.08 0.37 0.91 1.49 1.4 - 99.40
17 Hemo-Ilmenite (light
grains) 28.86 68.07 1.2 0.69- 0.42 - 0.55 - 0.18 - 99.97
18 Ilmenohematite 35.58 58.52 1.15 1.07- 0.27 1.18 1.36 0.52 0.28 99.93
19 Ilmenohematite
Lamellae 31.29 59.55 0.82 0.980.24 0.35 2.25 2.62 1.45 0.35 - 99.86
20 Magnetite 0.93 91.27 0.39 1.2 3.73 0.2 - 1.34 0.63 0.3 - 99.99
21 Magnetite 0.98 92.08 0.55 1.121.13 0.1 0.52 1.43 1.15 0.4 - 99.46
22 Magnetite 0.76 95.83 0.6 1.130.25 - - 0.99 - 0.42 - 99.98
23 Magnetite 1.23 90.52 0.63 1.46- - - 2.21 2.95 0.45 - 99.45
24 Spinel (dark grain) 1.4 58.99 0.34 0.853.86 0.21 4.89 1.08 27.9 0.43 - 99.95
25 Dark parts in Ilmenite
lamellae (Fig. 5b) 15.92 34.25 0.76 0.45- - 7.8 1.81 38.56 0.44 - 99.99
26 Titanomagnetite 9.41 86.92 0.77 1.15- 0.32 0.37 0.72 - 0.28 - 99.94
27 Titanomagnetite 10.99 80.15 0.78 1.022 0.24 1.51 1.03 1.79 0.45 - 99.96
28 Titanomagnetite 5.19 87.63 0.77 1.182.08 0.15 1.04 0.78 0.81 0.32 - 99.95
29 Titanomagnetite
lamellae 11.73 76.1 1.01 1.213.75 - 0.64 0.37 4.59 0.52 - 99.92
30 Apatite 0.39 1.26 - 0.1939.8 54.1 - 1.48 - - 2.7199.93
31 Apatite 0.29 0.94 0.37 0.3240.3 53.070.96 1.03 0.54 - 2.1499.96
32 Gangue 0.2 40.22 - - - 0.21 18.8537.093.42 - - 99.99
33 Gangue 0.22 40.66 - - - 0.1 21.3734.333.21 - - 99.89
34 Gangue 0.32 40.8 - - - 1.41 19.7234.0 3.52 - - 99.77
258 A. Mehdilo and M. Irannajad Vol.9, No.3
By mixing the six crushed samples (-2 mm) proportionate with their weight in the reserve, the
head sample containing 8.81% TiO2, 0.13% V2O5 and 2.9% P2O5 was obtained. The ilmenite and
magnetite liberation degree was determined 150 µm by using grain counting and heavy liquid
methods. The separation tests were performed on the head sample which the procedure and
results are presented in Fig.7. The magnetic product is a titanomagnetite concentrate with 18.5%
TiO2 grade by containing 24.6% (Recovery) of titanium dioxide. By regrinding of this
concentrate under 75 µm and re-separation by LIWMS (Low Intensity Wet Magnetic
Separation), with a little decrease in TiO2 content (from 43.52 to 43.2% TiO2) , the recovery is
increased about 7% in ilmenite concentrate (from 59.7 to 66.6%). According to Figure 7, the
magnetic product of second LIWMS is a titanomagnetite concentrate by grading 15.3% TiO2.
Approximately the source of whole TiO2 content of this concentrate could be the exsolved
ilmenite lamellae in magnetite. The titanomagnetite concentrate has also 0.73% V2O5 which
contains 57% of feed V2O5 content. The floated product of clerici solution is a final tailing which
contains about 4% P2O5.
According to Figure 2 and ore microscopically results, the mineralization of ilmenite, magnetite
and apatite have been mainly occurred in wherlitic parts of Qara-aghaj massive intrusion. The
main silicate minerals in this part are olivine and pyroxene (clinopyroxene and orthopyroxene).
The content of mineralization in mafic part with pyroxenite-gabbro component is lower than
wherlitic zone. The mineralization in the dioritic zone, has been mainly formed by plagioclase, is
very low with very fine grains. In terms of oxide mineral association, textural relationships and
nature of the host rock, the Qara-aghaj deposit can be classified as massive to disseminated
ilmenite–titanomagnetite occurrence. The ore minerals usually occur filling the interstices
between silicate minerals with simple boundaries.
Qara-aghaj titanium ore by average grading of 8.8% TiO2 which implies about 18.3% ilmenite
(by considering 48% TiO2 for ilmenite, based on EDX analysis results) is one of the low grade
deposits in the world. However the TiO2 content of Qara-aghaj deposit is lower than Tellnes (up
to 18% TiO2 and 35% ilmenite) [3] and Otanmäki (up to 14% TiO2 and 28% ilmenite) [3] ores
but it is comparable with these ores from reserve viewpoint. Qara-aghaj deposit is also
comparable with Kalviä and Sept–Iles deposits from viewpoint of TiO2 or ilmenite content.
The ilmenite in Qara-aghaj ore is in three forms: ilmenite grains, exsolved ilmenite lamellae in
magnetite and ilmenite fine particles disseminated in silicates. Based on TiO2 content of
titanomagnetite concentrate (Fig.7), the amount of lamellae form of ilmenite which is
unrecoverable by physical methods is estimated maximum 3.3%. The much of the ilmenite
Vol.9, No.3 Applied Mineralogical Studies on Iranian Hard Rock Titanium Deposit 259
disseminated in silicate minerals are unrecoverable by physical methods too. On the other hand,
the mineralogical source of TiO2 is not only ilmenite but also the titanium in lattices of silicate
minerals such as augite. So, the TiO2 content of the ore which is usually determined by chemical
analysis is not totally recoverable. Consequently, the recoverable ilmenite content of the rock is
not exceeding 14%.
Fig. 7. Schematic diagram of gravity - LIWMS combination test on the head sample
Head sample
(After crushing)
-150 µm
(Final tailing)
Clerici solution
First Ilmenite Concentrate
2.9 0.13 8.81
100 100 100
Sliming -30 µm
P2O5% V2O5% TiO2% Wt
P2O5 Recovery V2O5 Recovery TiO2Recovery
1.96 0.07 4.2
6.5 5.4 4.6
+30 µm
3.0 0.136 9.3
93.5 94.6 95.4
3.85 0.042 1.47
88.7 21.4 11.1
0.52 0.16 43.52
2.2 14.7 59.7 LIWMS
Magnetite Concentrate
0.68 0.75 15.3
2.3 57.1 17.7
Second Ilmenite Concentrate
0.53 0.13 40.3
0.3 1.4 6.9
0.66 0.65 18.5
2.6 58.5 24.6
Final Ilmenite Concentrate
0.521 0.157 43.2
2.5 16.1 66.6
Regrinding by ball mill
-75 µm
0.59 0.40 31.21
4.8 73.2 84.3
Rod mill
-2000 µm
260 A. Mehdilo and M. Irannajad Vol.9, No.3
The higher content of Fe2O3 in ilmenite lattice can be due to presence of hematite in solid
solution or as fine exsolution lamellae in ilmenite. The quality of ilmenite concentrate can be
affected by exsolved hemo-ilmenite lamellae or hematite solid solution in ilmenite and by the
abundance of elements in the ilmenite lattice. Presence of Mn and Mg can affect the pigment
production process. The quantity of V and Cr in the ilmenite is low however their presence may
reduce the value of concentrate as pigment production feed.
Vanadium is concentrated and uniformly distributed in magnetite rather than ilmenite. The
higher content of V2O5 in magnetite lattice can be due to replacing of Fe3+ by V3+. So, by
comparison of this concentrate with some vanadium extraction process feeds in the world from
V2O5 content viewpoint, this concentrate can be a suitable resource for vanadium production.
The apatite, as an accessory mineral, has been occurred mainly interlocking with ore minerals
but a large amount of it is liberated by grinding the ore under 150µm. The liberated particles of
apatite and the apatite grains interlocking with silicate minerals are concentrated in final tailing
of gravity separation. The recovery of apatite from tailing will be possible by flotation method.
The content of sulphide minerals are negligible and will not have any significant effect on
processing circuits. In spite of complicated mineralogical features of studied ore, it is predicted
that by combination of gravity methods such as tabling and Humphrey spiral and low intensity
wet magnetic separation, the concentration and production of commercial ilmenite concentrate
from Qara-aghaj deposit will be possible.
Based on this study, the Qara-aghaj deposit can be classified as massive to disseminated
ilmenite–titaniferous magnetite occurrence composed mainly of ilmenite and ilmenomagnetite.
The ore minerals mainly occur as filling the interstices between silicate minerals with usually
simple boundaries. However some of primary silicates such as pyroxene and olivine have been
altered to secondary minerals but there isn’t practically any alteration of ore minerals.
Titanium occurs mainly in the form of ilmenite partly as separate grains, exsolved lamellae in
magnetite and dissemination in silicate minerals. The maximum amount of TiO2 in ilmenite
lattice is 48% (lower than the theoretical amount, 52.6%). Considering the given contents of
MnO and MgO, the ilmenite has more of pyrophanite and Geikielite component.
Considering the abundance of ilmenite lamellae in magnetite and dissemination of ilmenite in
silicates, the recoverable TiO2 content is lower than what the whole ore chemical analysis
usually determines. So, with a maximum of 14% ilmenite content, the ore is classified as low
grade. The fine exsolved lamellae of hematite in ilmenite and the presence of Mn and Mg in
illmenite lattice can be affect the quality of concentrate and pigment production process. In spite
of these difficulties, Qara-aghaj deposit can be considered from economical viewpoint.
Vol.9, No.3 Applied Mineralogical Studies on Iranian Hard Rock Titanium Deposit 261
Production of a commercial ilmenite concentrate is possible by combination of gravity and
magnetic separation. In addition, the P2O5 and V2O5 could be produced in the process. The P2O5
is obtained from apatite concentrate which can be recovered by flotation of tailings of gravity
separation while the V2O5 could be obtained as by-product by hydrometallurgical processing on
magnetite concentrate.
[1] Colin J Douch, 2001;”Ilmenite, Titanium Dioxide and Titanium”; New Zealand Mining, Vol.
30; pp. 30 – 37.
[2] Chernet Tegist, 1999;”Applied Mineralogical Studies on Australian Sand Ilmenite
Concentrate with Special Reference to Its Behavior in the Sulphate Process”; Minerals
Engineering, Vol. 12, No. 5; pp. 485 – 495.
[3] Chernet Tegist; 1994; “Ore Microscopic Investigation of Selected Fe - Ti Oxides
Samples from Konusaarenneva Mineralization and other Localities in South Western
Finland”; Geological Survey of Finland, Department of Mineral Resources, Section for
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