Download The Technology of Getting Cryptocrystalline Graphite Having Low

Journal of Siberian Federal University. Engineering & Technologies 4 (2012 5) 419-432
~~~
УДК 621.742
The Technology of Getting Cryptocrystalline
Graphite Having Low Ash Content Mined
in the Deposits of Krasnoyarsk Territory
Tatyana R. Gilmanshina*,
Lyudmila I. Mamina and Galina А. Korolyova
Siberian federal University
79 Svobodny, Krasnoyarsk, 660041 Russia 1
Received 13.08.2012, received in revised form 20.08.2012, accepted 27.08.2012
There is studied the possibility of increasing the quality of cryptocrystalline graphite which is connected
with searching for more complete opening, the aggregates of graphite and ash admixtures. To achieve
this purpose, there was used mechanoactivation and microbiological processing. The developed
technology including mechanoactivation, sintering, chemical and microbiological processing, allows
to reduce the ash content of cryptocrystalline graphite from 20–25 down to 1–10 % depending on the
initial quality and the area of using graphite
Keywords: cryptocrystalline graphite, mechanoactivation, sintering, chemical processing,
microbiological processing, complex activation methods.
Introduction
Krasnoyarsk Territory is one of the regions which are especially rich in natural resources [1, 2
and others].
A great number of works are devoted to studying them. Practically all the reserves of
cryptocrystalline graphite in Russia are concentrated in Siberian federal Okrug (Krasnoyarsk territory,
Evenk autonomous okrug). The combined reserves of these graphites in the three, registered deposits of
Tungus basin (Noginskoye, Kureiskoye, Fatyanikhovskoye) and in some graphite manifestations have
been estimated to be hundreds of millions tons. This is undoubtedly a huge possession of Krasnoyarsk
territory, which has been used not in full extent up to now. From the technical and economical
viewpoint, another important fact is that although the volumes of the processed ores are the same, the
extraction of low ash content concentrates of cryptocrystalline graphite is much less than in case of
extracting crystalline concentrates.
The Noginskoye deposit was mined till 2004. At first there was mined the graphite marked as
GLS-1 and GLS-2. During the last ten years it was presented as type GLS-3. However, it didn’t find
wide application both in casting and other branches of industry. It was explained by the fact that it
contained high ash content impurities (to 25–30 %) and by the difficult dressability of graphitic ores.
*
1
Corresponding author E-mail address: [email protected]
© Siberian Federal University. All rights reserved
– 419 –
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
At present there is mined graphite at Kureickoye deposit. This graphite has the ash content of
8–15 % on the average. The mined graphite is delivered to the industry. As compared to the graphite
of Noginskoye deposit, the Kureika graphite is more perspective because its deposit has the reserves
of qualitative amorphous graphite. But to mine it efficiently, it is necessary to create and develop
the following industries in the region: transport, mining, processing. It is also necessary to have the
corresponding social infrastructure.
The graphite of the deposits of Krasnoyarsk territory is processed (which includes crushing,
drying, grinding and packing) at the factory «Krasnoyarskgraphit». As a result of this processing,
there are produced casting types. But they are far from meeting the requirements of the industry. Now
the situation in producing and using graphites in Krasnoyarsk territory is the following. Although
there are great reserves of cryptocrystalline graphites delivered in limited amounts to other regions,
the enterprises are in great need of a wide range of high-quality materials and products made from
these graphites.
The quality of Krasnoyarsk cryptocrystalline graphites is heterogeneous. According to the
research we conducted earlier, the graphites of Noginsk type GLS (N) and those of Kureika type
GLS-2 (K) belong to high-ash and hard-concentrated ones. The mineral composition of the ore, except
for the main component – graphite, was presented by quartz, calcite, feldspar, pyrite, copper pyrite,
montmorillonite and others [3].
The aim of our work is developing the technology of increasing the quality of the natural
cryptocrystalline graphite mined in the deposits of Krasnoyarsk territory.
The traditional scheme of concentrating the graphitic ore provides for crushing, grinding,
preliminary flotation, the final many-staged grinding of the preliminary concentrate with subsequent
flotation [4]. The best quality of the Noginsk graphite having the initial ash content of 20–25 %, is
reached according to the flotation scheme during the two-stage grinding, of the ore to 90 % of the type
of 0.07 mm with the intercycle flotation. By using this method, there was obtained the concentrate
containing 15–18 % of the ash residue. So the traditional method of concentrating the graphitic ore
does not provide obtaining low ash concentrates.
At the Open Joint Stock Company «Zalalyevck graphite plant» (Ukraine) which is the main supplier
of the crystalline graphite of industrial importance, there was developed a method of concentrating the
crystalline graphite. This includes sintering graphite with soda ash at 800–900 ºC, followed by water
leaching and chemical processing with acid solutions [5]. The application of the given technology for
the cryptocrystalline graphite turned out to be practically impossible because of the close intergrowth
of graphitic particles and nonmetallic minerals. The latter spread in the ore irregularly (from 5 to
40 %). The spreading is presented by the dispersed dissemination (the particle size is from 0,05 to
0,001 mm) as well as separate grains or aggregate formations, cutting the ore in all directions. The
sizes of the large extraction reach 0,2 mm.
The principal possibility of the further increase of the graphitic concentrates quality is
connected with searching for conditions of possibly more complete opening of aggregations of
graphitic particles and ash admixtures. To reach this, it was decided to use mechanoactivation as the
first stage of graphite concentration. During the mechanoactivation, there takes place not only the
grinding of the graphitic particles and the opening of the aggregations but also the increase of the
graphite reactivity [6].
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Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
The development of the mechanoactivation technology
of concentrating graphites
Ash content, %
The graphite activation was carried out in a planetary centrifugal mill AGO-2. With increasing
the activation time the ash content of the graphite of the type GLS-3 (N) increased by 5–7 %. During
the further activation, it did not change (Fig. 1). The observed phenomenon increasing the ash content
may be explained by a lighter grinding and releasing ash admixtures from the graphitic particles.
Under these conditions, the ash content of the graphite of the type GLS-2 (K) does not change
essentially.
Since the technology of concentrating the crystalline graphite, which was developed at the Open
Joint Stock «Zavalyesk graphite plant» and intended for the studied cryptocrystalline graphites did
not produce any positive results. It was decided to process the graphite of the type GLS-3 (N) during
its mechanoactivation with soda ash with subsequent chemical leaching. It was supposed that during
the process of activation, the admixed particles must actively react with the soda ash while the high
temperatures during the mechanoactivation, must replace the sintering process (Fig. 2).
22,5
21
19,5
18
16,5
Fig. 1. Dependence of graphite ash content for GLS-3 (N) and GLS-2 (K) on graphite activation time
Fig. 2. Dependence of graph
GLS-3 (N) and GLS-2 (K) on graphite activation
GLS-3 (N) on the time of g
Ash content, %
Fig. 1. Dependence of graphite ash content for
22,5
time
together with so
21
19,5
18
16,5
15
0
50
100
Activation time, min
150
Fig. 2. Dependence of graphite ash content for GLS-3 (N) on the time of graphite activation together with soda
ash
– 421 –
Fig. 3. Dependence of the ash content of graph-
Fig. 4. Dependence of the ash c
ite GLS-3 (N) on the activation time and sinter-
GLS-3 (N) on water content
GLS-3 (N) and GLS-2 (K) on graphite activation
time
GLS-3 (N) on the time of gra
together with soda
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
Fig. 3. Dependence of the ash content of graphite GLS-3 (N) on the activation time and sintering time (sintering
temperature is 860 ºC)
Fig. 3. Dependence of the ash content of graph-
Fig. 4. Dependence of the ash co
ite GLS-3 (N) on the activation time and sinter-
GLS-3 (N) on water content in
The obtained results show
that the
mechanoactivation
of is
the860
mixture
ash
ing time
(sintering
temperature
ºC) of graphite and soda
graphite–soda
ash – w
with the subsequent water leaching and chemical concentration, promote the stable decrease of ash
admixtures down to 16,5 %. Increasing the duration of this process (more than 120 min) is inexpedient
because it does not lead to the noticeable improving of the final product quality. The essential decrease
of the ash admixtures of the samples of GLS-3 (N), when they are processed in the planetary and
centrifugal mill, in the presence of the soda ash, is connected with the possibility of spot development
of high temperatures in the processed material. At the same time, there happens the solid phase of
sintering ash admixtures and soda ash without being influenced by external temperatures.
The possibility of the high-speed deformation of the material under the influence of great loads, as
well as the spot sintering of the mixture components lead to forming the silicates (Na2SiO3), aluminates
(NaAlO2), and ferrites (NaFeO2) – from the soda ash components – SiO2, Fe2O3, Al2O3 and soda ash.
The further water leaching of the obtained mixture for 60 min allows to remove their soluble
component – sodium silicate.
Ferrite and sodium aluminate are partially hydrolyzed in a light alkaline medium. As a result, there
are formed high-dispersed precipitates ((Al(OH)3 and Fe(OH)3) which impedes the pulp filtration.
To reach the maximum extraction of insoluble ash admixtures, the samples containing aluminium
hydroxide and iron hydroxide, calcium carbonate, magnesium carbonate – were treated with a 5 %
sulphuric acid solution. After that they were washed till getting the neutral medium. The interaction
between calcium carbonate and magnesium carbonate and the acid leads to forming sulphates being
soluble under these conditions. The graphite ash content during the considered chemical concentration
decreased from 22 down to 16 %.
As a method of concentrating the material, the mechanoactivation cannot completely replace the
sintering process. The variation of the conditions of the heat treatment of the mixture «graphite–soda
ash» shows that the optimum parameters of this process are the temperature of 700–900 ºC which is
kept during 60–120 min during the time of the mixture activation – 60–120 min (Fig. 3).
Decreasing the sintering temperature from 860 down to 740 ºC allowed to reduce a little the
graphite ash content of GLS-3 (N)– from 6 % (at 860 ºC) down to 5,5 % (at 740 ºC). The increase
of the temperature had to remove the silicon component of the ash residue. However the process is
– 422 –
N) and GLS-2 (K) on graphite activation
time
GLS-3 (N) on the time of graphite activation
together with soda ash
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
Fig. 4.
Dependence
of the Fig.
ash content
of graphiteofGLS-3
(N)content
on waterofcontent
in the mixture «graphite–soda
pendence of the ash
content
of graph4. Dependence
the ash
graphite
ash – water»
(N) on the activation time and sinter-
e (sintering temperature is 860 ºC)
GLS-3 (N) on water content in the mixture «
graphite–soda ash – water»
accompanied by burning the charge when coming into contact with oxygen. This is promoted by the
highly developed surface of the activated graphite as well as its increased chemical activity. Some
increase of the ash content is probably connected with more complete burn – out of the graphitic
mass.
The application of this technology for concentrating the graphite of the type GLS-2 (K) decreases
its ash content from 13,8 down to 2,2 %.
So, the preliminary combined activation of graphite and alkaline metal salt decreases the
temperature of heat treatment from 850–900 down to 700–750 ºC. Besides, it reduces the consumption
of the alkaline metal salt by 40–45 % per ton of the cryptocrystalline graphite (as compared to the
technology of concentrating the crystalline graphite).
In addition to the above – described method, there was used a method of the wet mixing of the
charge components (graphite + soda ash) when preparing it for sintering. The graphite is mixed in
the saturated soda solution and dried at a temperature of 350–450 ºC. In this case, there is reached a
more complete contact of the soda particles with the particles of ash admixtures. But there is required
a great energy consumption for drying the charge. The obtained data testify to the fact that the wet
mixing of graphite with the soda ash and the combined activation of these components allow the charge
components to come into reaction before the sintering process.
To study the further intensification of the interaction processes, there was investigated the
influence of the water content as a component, on the graphite ash content. It was carried out in the
mixture «graphite–soda ash–water» (Fig. 4). The research of the optimum ratio, during the combined
activation of the components of the mixture «graphite–soda ash–water» did not lead to decreasing the
ash content lower than 5 %.
The next stage was studying the influence of the mill type on the content of the admixtures in
the graphite during the activation. The grinding was carried out in the vibration mill RVM-45 and
in the planetary and centrifugal mill AGO-2. During the activation in the mill AGO-2, the graphite
ash content decreases down to 5,5 %, as regards the mill RVM-45 – down to 5 %. A slight difference
in the indexes testifies to the possibility of using the principally different devices on the condition of
optimizing the activation modes.
– 423 –
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
8
6
4
2
0
15
Ash content, %
Ash content, %
Ash content, %
Ash content, %
10
12
10
8
6
4
8,3
8,3
9
9,04
9,04
6
3
2
0
0 hydrochloric
sulphuric :
hydrochloric hydrochloric
sulphuric
(1 ::
hydrochloric
(1 :
1)
1) Acids
Acids
(acids concentration 5 %)
(acids concentration 5 %)
аа
15
12
Leaching time, min:
60 Leaching time, min:
90 60
90
9
6 9,12
9,12
3
0
9,12
9,12
8,6
12,3
12,3
8,6
hydrochloric
sulphuric :
hydrochloric hydrochloric
sulphuric
:
(1 : 1)
hydrochloric (1 : 1)
Acids
Acids
(acids concentration 5 %)
(acids concentration 5 %)
b b
а
b
Fig. 5.
of the
of theofgraphite
GLS-3GLS-3
(N) on(N)
the on
chemical
concentration
parameters:
Fig. Dependence
5. Dependence
of ash
the content
ash content
the graphite
the chemical
concentration
pa- а – the
Fig.«graphite–soda
5. Dependenceash»
of the
ash
content
of the graphite
GLS-3is(N)
on theb –
chemical
concentration
pamixture
(the
time
of leaching
with hot water
60 min);
activated
mixture «graphite–
rameters: а – the mixture «graphite–soda ash» (the time of leaching with hot water is 60 min);
soda ash» (the time of leaching with not water is 60 and 90 min)
rameters: а – the mixture «graphite–soda ash» (the time of leaching with hot water is 60 min);
b – activated mixture «graphite–soda ash» (the time of leaching with not water is 60 and 90 min)
b – activated mixture «graphite–soda ash» (the time of leaching with not water is 60 and 90 min)
Ash content, %
Ash content, %
Ash content, %
Ash content, %
A great role in the practice of mechanothermochemical concentration is played by the washing of
the charge and separating it from the soluble admixtures. A high milling fineness reached by grinding
14 in the mill-activator AGO-2 and the formation14
the charge
of the gel of silicic acid impedes the process
14
14
of washing
and
filtrating
the
sinter
with
cold
water,
hot
water
and the acids solutions.
12
12
12
To 12
optimize the chemical concentration, there were
10 studied the following dependences: the
10
influence10of the sulphuric acid concentration on the graphite
10 ash content; the possibility of using
8
8
hydrochloric acid for the concentration (Fig. 5); the possibility
8 of the combined application of 5 %
8
6 of the hydrochloric acid and the sulphuric acid. 6
solutions
6
6 out that the indicated parameters of the chemical
4
It 4turned
concentration (except for the sulphuric
4
0
10
20
30
40
acid concentration)
04
10do not essentially
20
30influence
40the graphite ash content. The content of the admixtures
0
10
20
30
40
of fluorohydrogen
0Concentration
10 turns
20out to be
30 a acid,
40
in the graphite
samples
minimum
one when the sulphuric acid concentration is
Concentration
of
fluorohydrogen,
%
Concentration of fluorohydrogen%
acid,
5–10 %.
Concentration of fluorohydrogen, %
%
Using the hydrochloric acid and the mixture of hydrochloric acid and sulphuric acid did not
produce any positive results.
The graphite ash content made up 8–9 %. b
а
that introducing
A high content of quartz
(SiO2) in the graphite samples allowed to suppose
а content
b
Fig. 6. Dependence of the ash
of non-activated graphite and activated graphite
GLS-3 (N) on
fluorine –
containing
compounds
into
the
system,
would
decrease
the
silicon
component. By
Fig. 6. Dependence
of the ash content
of non-activated
and activated
the concentration
and temperature
of thegraphite
fluorodydrogen
acid:graphite GLS-3 (N) on
adding the soluble saltthe
ofconcentration
ammonium and
fluoride
into the
mixture, acid:
we could decrease the
temperature
of reaction
the fluorodydrogen
а – initial graphite; b – activated graphite; Δ – without heating; ● – with heating
admixtures content in the graphite by 5 % (from 21,4 down to 16,1 %). And the processing of the
а – initial graphite; b – activated graphite; Δ – without heating; ● – with heating
samples with 8 % fluorohydrogen acid by heating it to 50 °C during 120 min decreased the ash
content down to 5 % (Fig. 6). The further increase of the acid concentration did not produce any
positive results.
It should be noted that fluorohydrogen acid is a specific chemical reagent and it requires using not
simple equipment.
So, as a result of the conducted research there was developed the mechanothermochemical way
of concentrating cryptocrystalline graphite of the deposits of Krasnoyarsk territory. This includes
activating graphite with soda ash, sintering the activated mixture with the subsequent water leaching
and chemical processing.
– 424 –
rameters:
rameters:
а – the
а – mixture
the mixture
«graphite–soda
«graphite–soda
ash»ash»
(the (the
timetime
of leaching
of leaching
withwith
hot water
hot water
is 60ismin);
60 min);
b – activated
b – activated
mixture
mixture
«graphite–soda
«graphite–soda
ash»ash»
(the (the
timetime
of leaching
of leaching
withwith
not water
not water
is 60isand
60 and
90 min)
90 min)
8
6
6
4
4
12 12
10 10
0
14 14
Ash content, %
8
Ash content, %
14 14
Ash content, %
Ash content, %
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
8
8
6
6
12 12
10 10
4
4
0
0
10 10 20 20 30 30 40 40
Concentration
Concentration
of fluorohydrogen
of fluorohydrogen
acid,acid,
% %
0
10 10
20 20
30 30
40 40
Concentration
Concentration
of fluorohydrogen,
of fluorohydrogen,
% %
а
b
Fig. 6. Dependence of theаashаcontent of non-activated graphite and activated bgraphite
b GLS-3 (N) on the concentration and temperature of the fluorodydrogen acid: а – initial graphite; b – activated graphite; ∆ – without
Fig. Fig.
6. ● –
Dependence
6.with
Dependence
of the
of ash
the content
ash content
of non-activated
of non-activated
graphite
graphite
and and
activated
activated
graphite
graphite
GLS-3
GLS-3
(N) on
(N) on
heating;
heating
the concentration
the concentration
and and
temperature
temperature
of the
of fluorodydrogen
the fluorodydrogen
acid:acid:
Content, %
а – initial
а – initial
graphite;
graphite;
b – activated
b – activated
graphite;
graphite;
Δ – without
Δ – without
heating;
heating;
● – ●with
– with
heating
heating
7
6
GLS-3 (N), А = 20 %
5
GLS-0 (N)а, А = 5,5 %
4
3
2
1
0
Fe
S
Al
Ca
K
Mn
Ti
Mg
Si
Element
Fig. 7. Element composition of graphite GLS-3 (N) (А – ash content)
Fig. 7. Element composition of graphite GLS-3 (N) (А – ash content)
Content, %
6
GLS-2 (К), А = 15 %
Using this method
5 allowed to reduce the ash content of Noginsk graphite from 20–25 % (graphite
(К)а,GLS-0
А = 2 (N)
% a), for Kureika graphite – from
of the type GLS-3 (N)) down to 4–6 % (graphiteGLS-0
of the type
4
10–15 % (graphite of the type GLS-2 (K)) down to 2–4 % (graphite of the type GLS-0 (K)a).
The data on the3 element composition (Fig. 7–8) show the decrease of the components of iron
in Kureika graphite –
2 from 5,6 down to 0,25 %, the components of aluminium – from 1,1 down to
0,2 %, the components of calcium – from 2,2 down to 0,5 %. As regards Noginsk graphite, there was
1
a decrease of iron – from 4,2 down to 1,5 %, calcium – from 2,5 down to 1 %, potassium – from 0,8
0
down to 0,3 % and magnesium –
from 0,9 down to 0,5 %.
Fe of the
S samples
Al
Zn
K
Mngraphite
Ti Mg
The phase composition
of theCaconcentrated
GLS-3 Si
(N) and GLS-2 (K)
Element
showed a slight (to 1 %) content of admixture phases (calcite, montmorllonite, kaolinite and others)
(Fig. 9–12). Quartz
being thecomposition
least reactive
is removed
Fig. 8.asElement
ofcomponent,
graphite GLS-2
(K) (Аfrom
– ashgraphite
content)not completely. It
is ground not so easily and it is chemically inert.
– 425 –
0
Fe
S
Al
Ca
K
Mn
Ti
Mg
Si
Element
Content, %
Tatyana R. Gilmanshina,
I. Mamina…
TheofTechnology
of Getting
Fig. Lyudmila
7. Element
composition
graphite GLS-3
(N) Cryptocrystalline
(А – ash content)Graphite Having Low…
6
GLS-2 (К), А = 15 %
GLS-0 (К)а, А = 2 %
5
4
3
2
1
0
Fe
S
Al
Zn
Ca
K
Mn
Ti
Mg Si
Element
Fig. 8. Element composition of graphite GLS-2 (K) (А – ash content)
Fig. 8. Element composition of graphite GLS-2 (K) (А – ash content)
Fig. 9. Phase composition of graphite GLS-3 (N):
Fig. 9. Phase composition of graphite GLS-3 (N):
Fig. 9. Phase composition of graphite GLS-3 (N)
The development of microbiological and complex technologies
for getting low ash content cryptocrystalline graphite
At present there are well-known microbiological methods of removingsilicon oxide, aluminium
oxide, iron oxide from the mineral raw material with the cultures A.niger, Hyphomicrobium sp. [7].
Especially effectively the concentration takes place when separating the processes of creating the
reagent – the cultural liquid containing organic acids and the products of metabolism of microorganisms.
Another thing that accompanies this is removing admixture minerals from the initial substance [7].
In the series of the model experiments on reducing the ash content of Noginsk graphite of the
types GLS-3 (N), GLS-3 (N)a and GLS-0 (N)a, there was used the solution imitating the cultural
medium of the microorganism A.niger. the time of processing the graphite was 48 and 96 hr and the
temperature – 20 and 80 ºC.
The scheme of processing the graphite included preparing a leaching solution (cultural liquid) and
introducing admixture components into it.
– 426 –
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
Fig. 10. Phase composition of the processed Noginsk graphite GLS-0 (N)a:
Fig. 10. Phase composition of the processed Noginsk graphite GLS-0 (N)a:
Fig. 10. Phase composition of the processed Noginsk graphite GLS-0 (N)a
Fig. 11. Phase composition of graphite GLS-2 (K):
Fig. 11. Phase composition of graphite GLS-2 (K):
Fig. 11. Phase composition of graphite GLS-2 (K)
The solution imitating the cultural medium was prepared by getting the solution of oxalic acid
with the concentration of 100 g/l using a mixture of sulphuric acid and hydrochloric acid (2 : 1) to pH
0,5. On finishing the incubation the cultural liquid was separated from mycelium by filtration. Then it
was diluted by water and acidified again to the hydrochloric acid pH 0,5.
Fig. 12. Phase composition of the processed Kureika graphite GLS-0 (K):
As it was turned out, increasing the time for microbiological processing of graphite from 48 hr to
72 hr (Fig. 13) didn’t
provide
decrease of
of the
ashprocessed
content. The
growth
of temperature
to 80 ºC leads to
Fig. 12.
Phase the
composition
Kureika
graphite
GLS-0 (K):
increasing the activity of microorganisms of this type oxidizing carbon alongside with admixtures.
By using the X-ray spectrometry (Fig. 14), there was proved the removing of iron and potassium
from graphite which was the result of microbiological processing. The content of the elements of
– 427 –
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
Fig. 12. Phase composition of the processed Kureika graphite GLS-0 (K):
Ash comtent, %
Fig. 12. Phase composition of the processed Kureika graphite GLS-0 (K)
Treatment temperature, оС:
20
80
24
20
16
12
8
4
0
GLS-3 (N)
48
72
Treatment time, hr
Fig. 13. Influence of microbiological
treatment
temperature ontreatment
the ash content
of graphite GLS-3 (N)
Fig. 13. Influence
of microbiological
temperature
on the ash content of graphite GLS-3 (N)
Content of element, %
time, ishr:finely disseminated into the
8 practically does not change.Processing
titanium, calcium and sulphur
Quartz which
GLS-3 (N)
7
scales of graphite is oxidized
48
6 by microorganisms.
The graphite processed
48 hr at 80 ºC as it was shown by the phase
5 by the cultural liquid during72
4
analysis, contained a new phase vevelite (CaC2O4). Its appearance is connected with forming gaseous
3
products CO and CO2 during
2 oxidizing the graphite in the air. It is known [8] that the edge places of
graphite particles may contain
1 carbon atoms, forming radicals CO – and CO2– with oxygen atoms.
0
The formation of the oxalate
ion, which is present in the phase of vevelite is possible through the
Fe
S
Si the
Al viewpoint
Ca
Kof valency
Cl
Ti it may react with another
–
radical CO
whose carbon is not saturated
from
and
– 2
through the radical CO2 whose carbon is not saturated from the viewpoint of valency
and it element
Chemical
similar
react with another
similarradical:
radical:
О = С − О−
О = С − О−
→ [С2О4 ] .
2−
а
Content of element, %
The microorganismsThe
A.niger
used during the8A.niger
concentration,
leach aluminium
and iron,
Processing
time,leach
hr: aluminium and iron, moving
microorganisms
used during
the concentration,
GLS-3 (N)
7
them info the solution. As for calcium, interacting with the oxalate ion, it forms the phase of
48
6
vevelite.
72
5
The composition of the
4 samples of graphite GLS-3 (N) treated by the cultural liquid at various
temperatures, shows that the
3 increasing of the time for processing graphite to 72 hr, does not influence
2
greatly on the content of admixture
phases (that is of quartz, vevelite and clayey minerals).
1
0
– 428 –
Fe
S
Si
Al
b
Ca
K
Cl
Ti
Chemical element
GLS-3 (N)
48
72
Treatment
time, hr
Treatment time, hr
Fig.
treatment temperature
temperature
Fig.13.
13.Influence
Influenceof
ofmicrobiological
microbiological treatment
on
GLS-3 (N)
(N)
onthe
theash
ashcontent
content of
of graphite
graphite GLS-3
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
Processingtime,
time,hr:
hr:
Processing
GLS-3 (N)
(N)
GLS-3
48
72
Content of element, %
Content of element, %
88
77
66
55
44
33
22
11
00
Fe
Fe
SS
Si
Si
Al
Al
Ca
Ca
K
Cl
K
Cl Ti
Ti
Chemical
element
Chemical element
а
аа
Processing time, hr:
Processing time, hr:
GLS-3 (N)
GLS-3 (N)
48
48
72
72
Content of element, %
Content of element, %
8
8
7
7
6
6
5
5
4
43
32
21
10
0
Fe
Fe
S
S
Si
Si
Al
Al
b
Ca
Ca
K
Cl
Ti
Chemical
K
Cl element
Ti
Chemical element
b
Fig. 14. Dependence of the element composition of the ash admixtures of Noginsk graphite GLS-3 (N), on the
bof the ash admixtures of Noginsk graphite GLS-3
Fig.and
14.temperature
Dependence
the element
composition
time
of of
processing
(а – 20
°С; b – 80 °С)
Fig. 14. Dependence
of the
the time
element
the ash admixtures
(N), on
and composition
temperature ofofprocessing
(а – 20 °С;ofbNoginsk
– 80 °С) graphite GLS-3
(N), on the time and temperature of processing (а – 20 °С; b – 80 °С)
So the optimum conditions for microbiological processing cryptocrystalline graphite with
microorganisms A.niger are the following: time – 48 hr and the temperature – 20 ºC. Using this method
of concentration allows to obtain graphite with the ash content less than 10 %.
The efficiency of the suggested method concentration to a great extent depends of the sizes and
activity of the particles of the initial mineral raw materials. The polydispersity of the graphite of
the type GLS-3 (N) and the close intergrowth of graphitic and ash particles lead to the fact, that the
microorganisms do not leach sufficiently completely the admixture components.
Then there were studied the preliminarily mechanoactivated samples of graphite GLS-3 (N)a.
The processing of graphite GLS-3 (N)a with microorganisms A.niger was carried out under the same
conditions as for the natural graphite (see the table).
The optimum temperature of leaching admixture compounds makes up 20 ºC. The ash content
of graphite decreases from 22 down to 14 % (when it is activated in the planetary and centrifugal
mill) and down to 7 % (when activated in the vibratory mill). The obtained results are explained by
the fact that in the mill of both types, under the action of great loads, there appears the possibility of
high-speed deforming the graphite. As a result, there are opened the aggregations of the graphite and
– 429 –
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
Table. Element composition of graphite GLS-3 (N)a after the microbiological processing
Mechanoactivation
Chemical element, %
mill
time,
min
Temperature
of microbiological
processing, °С
Ash content, %
Fe
S
Si
Al
Ca
K
Cl
Ti
–
–
–
20,50
4,20
1,00
5,5
1,4
2,5
0,8
0,40
0,25
15
RVM-45
120
Element content, %
AGO-2
20
14,47
0,85
1,00
6,5
1,9
1,9
0,5
0,35
0,30
80
16,85
0,80
0,75
8,5
1,3
4,0
0,6
0,50
0,40
20
6,77
0,75
0,80
7,5
1,2
2,4
0,4
0,40
0,35
80
13,6
0,65
0,75
7,3
1,1
2,3
0,5
0,55
0,35
7
6
5
4
3
2
1
0
GLS-3 (N)
48 hr
96 hr
Fe
S
Si
Al
Ca
K
Cl
Ti
Chemical element
Fig. 15. Dependence of the element composition of graphite GLS-0 (N)a on the processing time
Fig. 15. Dependence of the element composition of graphite GLS-0 (N)a
on the processing time
– main
ash admixtures. During the activation in the vibratory mill, the release of the
ashoperation;
admixtures from the
– auxiliary operation.
graphite particles takes place more intensively, which
leads to the more essential reduction of the ash
GLS-2(3)
content.
For the purpose Mechanoactivation
of the furtherwith
increase
of efficiency
of concentrating
graphite GLS-3 (N)a, there
surface active
substanoes (schemes
А, B, C)
or without surface active substances (schemes D, E)
was added the microbiological leaching as a stage of mechanothermochemical way of clearing the
graphite. For this, graphite, processed according to theThermorefining
mechanothermochemical technology, was
subjected to the additional microbiological processing for 48 and 96 hr at a temperature of 20 ºC
Circulating
B, C
А
Circulating
(Fig. 15).
water
water
Water leaching
As a result of the research the ash content of graphite
GLS-0 (N)a made up 3 %. By using X-ray
E that
D Cthe iron content decreases down to 0,4 % and the calcium
spectrometry, it was found out
content –
Neutralization
and
clearing of the
Neutralization and
down
Microbiological
Chemical dressing
worked waters
clearingtoof0,5 %.
the
processing
worked waters
As a result of the conducted research, there were developed
some
separate
and
complex
technologies
А,
B
C
C, D, E
Separating
of concentrating cryptocrystalline graphites of the deposits in Krasnoyarsk alkaline
territory
water(Fig. 16).
The developed technologies allow to reduce
Separating
Drying the ash content of cryptocrystalline graphites from
acidic water
20–25 down to 1–10 % depending on the area of its application.
Final grinding
Schemes А – GLS-1а (ash content 12 %)
Schemes B – GLS-0а (ash content 4–6 %)
Schemes C – GLS-0а (ash content 3–5 %)
Schemes D – GLS-0а and GLS-1а (ash content 6–12 %)
Schemes E – GLS-1а (ash content 11–13 %)
Mechanoactivation
Separating
acidic water
Schemes А – GLS-1аМ
Schemes B – GLS-0аМ
Schemes C – GLS-0аМ
Schemes D – GLS-0а and GLS-1а
Schemes E – GLS-1аМ
Рис. 16. Schemes of dressing cryptocrystalline graphites
Chemical element
Fig. 15. Dependence of the element composition of graphite GLS-0 (N)a
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
on the processing time
– main operation;
– auxiliary operation.
GLS-2(3)
Mechanoactivation with surface active substanoes (schemes А, B, C)
or without surface active substances (schemes D, E)
Thermorefining
B, C
Circulating
water
Water leaching
E
Neutralization and
clearing of the
worked waters
Circulating
water
А
D C
Microbiological
processing
Chemical dressing
C
C, D, E
Separating
acidic water
Neutralization and
clearing of the
worked waters
А, B
Separating
alkaline water
Drying
Final grinding
Mechanoactivation
Schemes А – GLS-1а (ash content 12 %)
Schemes B – GLS-0а (ash content 4–6 %)
Schemes C – GLS-0а (ash content 3–5 %)
Schemes D – GLS-0а and GLS-1а (ash content 6–12 %)
Schemes E – GLS-1а (ash content 11–13 %)
Separating
acidic water
Schemes А – GLS-1аМ
Schemes B – GLS-0аМ
Schemes C – GLS-0аМ
Schemes D – GLS-0а and GLS-1а
Schemes E – GLS-1аМ
Рис. 16.
Schemes of dressing
cryptocrystalline graphites
Fig. 16. Schemes of dressing
cryptocrystalline
graphites
Conclusions
1. There is grounded the possibility of increasing the quality of cryptocrystalline graphites at
the expense of reducing the ash content by means of using such methods of processing as mechanical
activation, sintering, chemical and microbiological dressing.
2. It is determined, that the mechanical activation considerably intensifies all the subsequent
processes of concentrating the cryptocrystalline graphite more completely releasing ash admixtures
from its particles. This allows to recommend this way as a method of preliminary processing the
graphites.
3. Using the preliminary mechanoactivation during applying the mechanoactivation method of
concentrating graphites with soda ash, allows to decrease the consumption of the salt of the alkaline
metal by 40–50 % and the sintering temperature – by 100–150 ºC.
4. There is shown the effectiveness of using complex activation methods (such as mechanochemical,
mechanothermochemical, mechanomicrobiolothermochemical).
These allow to reduce the graphite ash content down to 1–10 % depending on the initial quality
and the field of the further application of graphite. This also allows to obtain the activated graphites of
the type GLS-2, GLS-1 of a higher quality.
Tatyana R. Gilmanshina, Lyudmila I. Mamina… The Technology of Getting Cryptocrystalline Graphite Having Low…
Reperences
[1] Nikitin А. // Jornal of Siberian university. Series: Machines and technologies. 2009. – V. 2. N
4. P. 368–375.
[2] Kuznetsov P. Magazine of Siberian federal university. Series: Machines and technologies.
2008. V. 1. N 2. P. 168–180.
[3] Zatkhei R.A. Account. Krasnoyarsk. 1970.
[4] Bragina V.I. Processing non-metallic minerals : textbook [Text] / V. I. Bragina, V. I. Bragin.
Krasnoyarsk: State Academy of Non-Ferrous metals and gold, 1990 – 100 p.
[5] Shokin V.N. and othes // Graphites and their application in industry : proceedings of scientific
pfpers.
[6] Khasiyev D.R., Korolyova Y.A. [and othes] // Perspective materials, technologies, constructions.
Krasnoyarsk: State Academy of Non-Ferrous metals and gold, 1999. P. 24
[7] Korobuchkina, E. D. Microbiology [Text]. – 45. – 3. – 1976. – P. 535.
[9] Baranov, V. N. Activation of graphite of various crystalline chemical for refractory products
and paints is casting [Text] / V. N. Baranov // Author’s abstract for getting the scientific degree of the
Candidate of technical sciences if speciality 08/16/04 – Casting – Krasnoyarsk, 2005. – 26 p.
Технологии получения низкозольного
скрытокристаллического графита
месторождений Красноярского края
Т.Р. Гильманшина,
Л.И. Мамина, Г.А. Королёва
Сибирский федеральный университет
Россия 660041, Красноярск, пр. Свободный, 79
С целью повышения качества скрытокристаллического графита месторождений
Красноярского края исследована возможность поиска условий более полного раскрытия
сростков графита и зольных примесей. Для достижения этой цели и применяли комплексные
технологии, основанные на использовании механоактивации, спекания, химической
и микробиологической. Комплексная технология, включающая механоактивацию,
спекание, химическое и микробиологическое обогащение, позволяет снижать зольность
скрытокристаллического графита с 20-25 до 1-10 % в зависимости от исходного качества
и области применения графита.
Ключевые слова: скрытокристаллический графит, механоактивация, спекание, химическое
обогащение, микробиологическое обогащение, комплексные методы активации.