FLUORSPAR IN RAJASTHAN
Introduction:
Fluorite or fluorspar is the name given to a mineral having the chemical
composition of calcium fluorite (CaF2). The mineral fluorite in its pure form
contains 51.1 % Ca (Calcium) and 48.9% (Fluorine). It usually occurs as crystals of
cubic habit, but octahedral forms are also noted. It has a hardness of 4, specific
gravity 3.01 to 3.25 and display a wide range of colours varying from colourless to
white, yellow, violet, purple, blue & green. The phenomena of fluorescene derives
its name from fluorspar because of its property to fluoresce, "to glow", when
subjected to external source of energy. It often shows bluish fluorescence.
Fluorspar deposits usually occur in the form of veins deposited from hot
solutions in both sedimentary and igneous rocks. It occurs as fissure-filling veins
and as replacement veins in various types of country rocks such as limestone,
dolomite, granite, nepheline syenite and volcanic rocks.
The total known fluorite reserves in country are about 2.9 million tonnes.
Fluorite is mined in the country from Gujarat, Rajasthan & Maharashtra only.
Rajasthan is the largest producer of graded (hand sorted) fluorspar in the country.
Gujarat is the largest producer of beneficiated (concentrated) fluorite in the country.
Beneficiation of fluorspar is not being carried out in Rajasthan & Maharashtra.
Occurrences in Rajasthan :
Rajasthan is the principal fluorite producing state in the country. There are
18 mining leases for fluorite in the state and about 11052 tonnes was produced
during the year 1998-99. The description of the deposits in Rajasthan is given
below.
Dungarpur district :
(I) Mando-Ki-Pal: The largest fluorite deposits in the state are located in
Mando-Ki-Pal area in this district.
The ares is located about 35 km. from Dungarpur and 150 km. from
Udaipur. Fluorite mineralisation is widely distributed in an area covering 190 sq.
kms. lying between Hathi-Ki-Dhani in north, Kahila in South, Matatiba in west and
beyond Lihata Bunali in east. Fluorite mineralisation occurs as fracture and fissure
fillings along shear zones. The fluorite veins show variation in thickness, attaining
maximum thickness of 30 cm. The mineralisation is seen in variety of rocks viz.
mylonite, pegmatites, aplites and porphyroblastic gneisses. The width of mineralise
zone varies between 1 to 7 metres.
The state department has estimated 0.203 million tonnes of reserves having
8% to 23% CaF2 content in the seven blocks namely (1) Ramore hill (2) Mata hill
(3) Bhagal hill (4) Rehatwali hill (5) Thorwali hill (6) Umaria hill (7) Singhwali
hill. Besides above, in the area between Umaria & Singhwali, Basdighati, Punawali
and Umri reserves of 0.131 million tonnes have also been estimated having 30 to
40% CaF2.
(II) Kahila area: The area is situated about 8 km. from Varda village which
is 30 km. from Dungarpur on Banswara road. Fluorite mineralisation is seen in
Dhadka hill, Baska hill and in Forest Chowki area. The mineralisation is traceable
over 1.2 km strike lengh Fluorite mineralisation occurs in Aravali quartzites as
veins along shear zones. The thickness of individual fluorite vein is up to 15 cms.
The width of mineralised zone varies from 1m. to 5 m. Reserves of 0.246 million
tonnes with average 29% CaF2 has been estimated by state department. In the
vicinity of Kahila, mineralisation is also found in Rekha hill which is in forest area.
Jalore district:
Karda area: The state department has located a fairly large deposit of
fluorite near village Karda which is 24 km. south west of Bhinmal town (tehsil
H.Q.) in Jalore district.
The mineralisation occur within 10 sq. km. area, the important localities are
Rekha hill, Krishna hill, Pushi hill, Campwali hill, Vita-Ki-Tak, Nagara Magra,
Ada-Magra, Betak-Ki-Magri, Bhanwaria-Ki-Bhit, Dharma hill, Pillas hill, etc. near
village Karda. The mineralisation of fluorspar is found along Shear zones and
fracture planes in Agglolnerates, Trachyte, Basalt and as cavity fillings.
The total reserves of fluorspar of the Karda deposit are estimated by the
state department at 0.173 million tonnes of 51.92% CaF2 content. Out of which
about 70,000 tonnes are of 80-95% CaF2 content.
Sikar district:
(1) Salwari (Chowkri) area: Fluorite mineralisation occurs near Salwari
hutment about 2 km. west of Chowkri village and 7 km. east of main bus route from
Khandela to Udaipurwati in Sikar district. Fluorspar mineralisation occurs along
shear fracture zones, joints planes and at the contact of host rock and vein quartz.
Mineralisation is localised in post Delhi intrusives of tonalite in Khanwali hill and
in hornblendite and vein quartz.
The state department has prospected this area and a reserves of 0.35 million
tonnes containing 8 to 21.9% CaF2 has been estimated.
Jhunjhunu district:
Chapoli area: Fluorite mineralisation occurs about 2 km. south east of
Chapoli village. Mineralisation occurs as joints and fissure fillings, replacement,
cavity filling and as dissemination in Ajabgarh felspathic quartzite and also applites
of younger age intruded in these quartzites.
The state department has prospected this area and estimated reserves of 0.13 million
tonnes containing 11 to 14.5 CaF2.
Bhilwara district:
(1) Asind area: Asind in Bhilwara district is located about 48 km. north west of
Mandal Railway Station. Fluorite occurrences have been reported near Dantra,
Udalpura, Barukhera, Shikarwadi and Baratpura. The area was prospected by the
state department but no significant reserves could be proved.
Udaipur district:
Fluorite occurrences were located near Jhalara about 10 km. south of
Salumber and Kala Magra, Paira, Mandli, Camera, Kaliana, Sagot, Bhabrana,
Matasola & Bhimroda.
Fluorite mineralisation occurs in quartzite aplites and porphyroblastic
gneisses as cavity fillings and also as disseminations along joints & frctdures.
A reserves of 0.168 million tonnes containing 17.18% CaF2 have been
estimated by the state department at Kala Magra and Jhalara.
Ajrner district:
(1) Richhmaliyan area: The state department has located a fluorite mineralisation
near village Richhmaliyan in district Ajmer in the year 1989. It is about 45 km.
from Ajmer. Fluorite mineralisation has been traced over 5 km. strike length from
Richhmaliyan in the north east to Sewaria (Pali district) in the southwest. Rich
mineralisation has been located along a shear zone in 600 metres length having 50
metres wide mineralised zone. Length of individual veins ranges from 5 to 100 m.
and width from 10 cm. to 1.5 m. The mineralisation is confined to Rhyalitic flows
surrounded by granite. A reserves of 986.6 tonnes with average CaF2 values 29%
were estimated.
Occurrences of Fluorite also reposted from Barla and Khajrot area, Mundoli
area and Tilora area of the district.
Sirohi district:
Balda-Badabera area: The village Balda is located about 6 kms. from
Sirohi town on Sirohi-Abu tar road. The occurrences of fluorite is reported from
Balda in south-west to Bada Bera in north-east for a strike length of about 12 kms.
The area belongs to the Delhi Supergroup of rocks namely mica schist, quartzite,
cale silicate intruded by Erinpura granite and quartz veins.
The fluorite bearing quartz veins are confined to Shear zone and occur in the
form of veinlets and disseminations within and at the contact of granite and
pegmatite.
During the course of investigation for tungesten, G.S.I. have proved 50,000
tonnes of fluorite having 40% CaF2 in sheared zone upto 25 m. depth. Minor
occurrences of fluorite also reported from Mirpur, Sibagaon and Khejuri van and
Mundwara area of the district.
Jaipur district:
(1) Ladera area: Ladera area is located 5 kms. northeast of Mundoti area of
Ajmer district. Fluorite of violet and whitish colour occurs in an area of 300 x 275
sq. mts. and 80 x 40 sq. mts. separated by barran rocks. The country rocks are
aplites and granite gneisses. Small veins up to 1.2 m. length and 10 cm. Width were
observed along fractures. Disseminations are also observed in aplite rocks. The
surface samples indicated 92.6% CaF2 contant. The occurrence is sporadic and
depth persistance is negligible.
Industrial Application:
Fluorspar is considered as a mineral of great industrial importance and
utility, as without this mineral, many manufacturing industries and some of the
industrial processes would not be implemented. The importance of fluorspar is
keenly felt in many countries and it has become absolutely indispensable to many
basic industries, such as open hearth steel plants, metallic aluminium, in the refining
of uranium ores, chemicals, ceramic products, glass, enamel, for hydrofluoric acid
manufacture and other fluorine compounds.
Fluorspar is marketed in three grades according to end use. These are acid
grade, metallurgical grade and the ceramic grade. Fluorspar has many direct and
indirect uses, the chief uses are given here under :
(a) Metallurgical uses:
It is used as a flux in the production of steel by the open hearth, electric arc
and basic oxygen (BOF) processes, and also in the electro-slag refining process for
making high grade steel and certain alloys. Fluorspar is also used in the production
of ferroalloys,
iron castings, as a flux in magnesium reduction and in zinc smelting. Minor amount
of fluorite is used as flux in smelting and refining of antimony, copper-chromiumsilver and lead ores, gold, nickel and tin.
(b) Ceramic uses:
The glass industry is a stable consumer of fluorspar. The spar is used as a
flux and opacifier for the manufacture of glass and for enamel coatings on sinks,
bathroom fixtures, stoves, refrigerators, signs and the like. Examples of opal glass.
are lamp bulbs, globes, shades, toilet and medicinal containers, and many other
items. Clear glass has the least amount of fluorspar in its formulations, whereas opal
glass and coloured glass demand a larger quantity to obtain opaqueness.
(c) Chemical uses:
The principal uses of fluorspar are in the manufacture of fluorine chemicals,
chiefly hydrofluoric acid (HF). Hydrofluoric acid is an essential raw material
required for producing synthetic cryolite (Na3 AIF6) and aluminium fluoride
(AIF3), which are used as fluxes and electrolytes in the production of primary
aluminium. Another important use is in the manufacture of fluorcarbons, for
preparation of aerosol propellants, plastics, refrigerants (arcton and freon gases),
blowing agents for urethane foams, polymers and fire extingushing gases. The acid
is also used as a catalyst in petroleum alkylation, in steel pickting, enamel stripping
and in various electroplating operations. Fluorine chemicals are useful in
production of uranium tetrafluoride (UF4 & UF6) which is used in the separation of
uranium isotopes in development of atomic energy. Fluorides are used as
insecticides, fungicides, medicinals, preservatives, antiseptics, in electroplating
solutions, water fluoridation and rocket and missile fuels.
(d) Miscellaneous uses:
Fluorspar is used also in making mineral wool/ glass fibre, as a bonding
material in abrasive wheels and carbon electrodes, in portland cement industry and
in brick making to prevent staining. For optical purposes, colourless or nearly
colourless crystals of fluorite free from flaws are used. Attractive coloured varieties
are also used in the manufacture of vases, ashtrays, other decorative objects and as
semiprecious stone. Recently fluorspar is being successfully used by mixing oxygen
with fluorspar in order to make a very hot cutting flame for welding purpose instead
of the traditional oxy-acetalane flame.
Specification:
Fluorspar is mined and marketed usually after beneficiation in three grades
(i) metallurgical (ii) ceralnic and (iii) acid.
The I.S.I. (IS 4574-1981) has prescribed the following specifications for
metallurgical grade fluorspar:
Constituents
Grade-I
For
Aluminium
Requiremenf %
Grade-Il . For
Steel Industry
Grade-III
Calcium
Fluoride
97
85
80
1
6
8
-
70
60
1
3
3
1.5
3.5
3.5
Sulphur max.
0.1
0.3
0.3
Lead max.
-
0.3
0.3
(CaF2) min.
Sillica
Max
(Sio2)
Effective Cal.
Fluorite
(CaF2) min.
Calcium
Carbonate
(CaCo3) max.
Mixed Oxide
(R2O3) max.
Note: The "effective" percentage is calculated by multiplying the silica
percentage in the analysis y 2.5 and subtracting this number from the CaF2
percentage in the analysis.
The GMDC markets metallurgical grade fluoride having the composition
CaF2 85 % (min), CaCO3-3 %
(max), SiO2 4.5% (max), Fe2O3 + Al2O3 - 3.50 % (max), P2O5 1% (max); BaSO4
0.50% (max).
According to GMDC this grade of concentrate has been widely accepted by the
industry.
As per the Rajasthan State Mineral Development Corpn. fluorite to be used
as a flux for making special steel would have 80-85% CaF2 and in ordinary steel it
would have 70-75% CaF2.
Chemical Grade: (ISI - 8587-1977)
Constituents
Percentage
Free Moistue
10
CaF2 Min. percent by mass
96
SiO2 max.
1
Calcium (as CaCO3) max; percent by
1.2
mass
Sulphur (as S) max by mass
0.08
Barium (as BaSO 4) by mass
0.05
Phosphorous (as P2O5) max. by mass
0.20
Mixed Oxide (as R2O3) max. by mass
1.5
Organic matter
0.25
Chlorite to pass the test
Berylium to pass the test.
Size (1) Retained on 500 micron
-nill mass
sieve
(2) Retained on 212 micron sieve
10 %
(3) Retained on 75 micron sieve
25 % wmax
The GMDC markets the following two acid grade:
Acid Grade 'A'
Acid Grade 'B'
CaF
96 % and above
93 % to 95 %
CaF
96 % (min.)
93 % (min.)
CaCO3
1.20 % (max.)
1.50 % (max.)
SiO2
1.0 % (max.)
1.5 % (max.)
Fe2O3 + Al2O3
1.5 % (max.)
1.6 % (max.)
P2 O5
0.20 % (max.)
0.6. % (max.)
BaSO4
0.20 % (max.)
0.30 % (max.)
According to the GMDC, to meet the specifications set up by the aluminium
industries for manufacturing aluminium fluoride, acid grade 'A' has been used all
along in a suitable blend with the imported concentrates. However, acid grade 'A' as
well as acid grade 'B' as mentioned above have been fully accepted by other
chemical industries such as synthetic cryolite, referigerent gases, stainless steel etc.
According to RSMDC, fluorite would have 90-95 % CaF2 and above for
chemical industries for making acids, synthetic cryolite and aluminium fluorite.
Ceramic Grade:
There is no ISI specifications for this grade. The specifications prescribed
by user industries is that tluorspar should contain CaF2 – 95 % (min.), SiO2 2.5 %
max., Fe2O3 0.12 % max. while CaCO3 be 1% max.
Glass:
ISI has not prescribed any specification for this industry. However, based on
user industries CaF2 should be (a) from 90 to 98 % pure (b) 65 to 80 % with size 75
to 150 mesh in most cases.
Mill Head Grade:
In order to produce the grades reported by GMDC, it is necessary to have
the following head grade for the plant.
Mineral Constituent
%
CF2
24 % ± 5 %
CaCO3
4.0 % ± 1 %
P2O5
1.2 % ± 0.5 %
SiO2
60 % ± 5 %
Year
Statistical Information for Fluorite in Rajasthan
Production
(000"
Revenue (Rs.
Tonnes)
000")
in
No.
Leases
199495
1.49
503.000
17
199596
1.69
488.000
18
of
199697
15.740
333.050
18
199798
1.403
648.240
19
199899
11.052
969.610
18
District-wise Production of Fluorite (Year: 1998-99)
District
Dungarpur
Jalore
Sirohi
Total of Rajasthan
Production
Tonnes)
0.491
10.561
0.000
11.052
(000"
Leases
11
6
1
18