Page 20 - Mines and Minerals Reporter eMagazine - Volume December 2024

IRON ORE MINING

BANDED MAGNETITE QUARTZITE (BMQ)
FROM BELLARY, KARNATAKA

The grayish coloured hard and compact BMQ sample from
Bellary, Karnataka assayed 58.25 % Fe, 13.52 % SiO2, 6.75 %
FeO, 1.82 % Al2O3, 0.20 % P, 0.10 % S, 0.40 % LOI and contained
hematite [20 %], quartz [5 %], chlorite

No. Characteristics Data
1 Marine sands from Ratnagiri, [5]
Maharashtra
2 Physical Black fine sands D80 0.15mm

3 Chemical NA [*10 % Fe]
Quartz [70 %], magnetite [7
%], ilmenite [15 %], shell [8 %], Fig. 2 Manganese bearing iron ore psilomelane (Psi), hematite (He), clay (Cl)
4 Mineralogy
hematite, zircon, goethite and and goethite (Go) grains are seen in -65 ?200 mesh size fraction. (Reflected
martite[Tr] light, air, 910)
DAT: deslime, sink and float [3SG],
5 hand mag separation of sinks >62 % Fe concentrate
at -0.25 mm [15 %], martite [20 %], magnetite [40 %], apatite, clay, goethite,
pyrite[Tr]. The DAT produced[64 % Fe, 6.52 % SiO2, 16.75 %
Process: screening over 1.0 and
0.05 mm, tabling of -1 ? 0.05 mm >67 % Fe concentrate with 75 FeO, 0.82 % Al2O3, 0.50 % P, 0.10 % S, 0.20 % LOI concentrate
6 % iron oxide recovery at 6 % with 87 % Fe recovery at 75 wt% yield from the phosphorus
followed by WLIMS of gravity yield
concentrate and sulfur bearing high grade BMQ. The DAT indicated that
the sample is amenable to gravity and magnetic concentration
Table 2 Alluvial black sands containing iron oxide minerals
and flotation may be required to remove P, S and remnant
SiO2. The gravity and magnetic separation (WLIMS) test
No. Characteristics Data varying MOG yielded optimum results at -0.6 mm followed
by cleaner gravity and WLIMS after regrinding to -0.1 mm
1 M/s A.V.B.S. Ltd., Bellary [4]
yielded a concentrate assaying 65.65 % Fe, 4.02 % SiO2, 0.10
Hard compact grayish black % Al2O3, 0.75 % FeO, 0.03 % P, 0.03 % S, 0.42 % LOI with 75.7
2 Physical
lumps % meeting the pellet grade. The results are given in Table
58.25 % Fe, 13.52 % SiO2, 3. The grade was low at MOG coarser than 0.2 mm due to
6.75 % FeO, 1.82 % Al2O3,
3 Chemical interlocking and Fe recovery was low at size finer than 0.074
0.20 % P, 0.10 % S, 0.40 %
LOI mm due to slime constraints on gravity and WLIMS, leading to
Hematite [20 %], quartz [5 pre-concentration at coarse size followed by cleaner step after
%], chlorite [15 %], martite regrinding to -0.1 mm. The flotation of gangue minerals using
4 Mineralogy [20 %], magnetite [40 %], xanthate, oleate and amine sequentially from concentrate
apatite, clay, goethite, reduced the impurity level in non float significantly. The
pyrite[Tr] ganuge content and fine interlocking nature complicates the
>64 % Fe, 6.52 % SiO2, 16.75 process though the processing of BMQ appears simple. Haran
DAT: deslime, sink and float [3SG], % FeO, 0.82 % Al2O3, 0.50 % et al. [6] produced similar and better results employing dry
5 hand mag separation of sinks at P, 0.10 % S, 0.20 % LOI cobbing at coarse sizes of -6 mm, gravity and concentration at
-0.25 mm concentrate with 87 % Fe
recovery at 75 wt% yield -0.1 mm and inverse flotation to remove S and P after grinding
the concentrate to -0.075 mm.
>68 % Fe, 0.92 % SiO2, 19.75
% FeO, 0.22 % Al2O3, 0.05 %
Process: stage grind to -0.6 mm, P, 0.08 % S, 0.10 % LOI SOFT FRIABLE SILICEOUS IRON ORE FINES FROM
rougher WLIMS, tabling of non- CHITRADURGA, KARNATAKA
6 mag, 2 stages of HGLIMS cleaning concentrate with 62 % Fe
recovery at 52 wt% yield.
after grinding rougher mag Subsequent gangue flotation
concentrate to 0.07 mm.
significantly reduced the S, P, The soft friable siliceous blackish gray coloured iron ore fines
SiO2 values from Chitradurga, Karnataka assayed 59.60 % Fe, 9.06 % SiO2,
Table 3 Banded magnetite quartzite (BMQ) 1.06 % FeO, 1.09 % Al2O3, 0.05 % P, 0.03 % S, 4.02 % LOI and

18 MINES & MINERALS REPORTER / DECEMBER 2024