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Applications of thermoanalytical methods to studies of flash smelting reactions
115
ThermochimicaAcfa, 85 (1985) 115-118 Elsevier Science Publishers B.V., Amsterdam
APPLICATIONS
OF THERMOANALYTICAL
-Printed
METHODS
in The Netherlands
TO STUDIES OF FLASH SMELTING
REACTIONS
J C CbNN1 and S A A JAYAWEERA2 1 School of Applied Chemistry, liAIT, Kent St, Perth, Western Australia 2 Department of Environmental Sciences, Plymouth Polytechnic, Plymouth,
6132 Devon UK
A6STRACT DTA and TG techniques extents
of reaction
smelting
chosen.
concentrates ignition
from different
the ignition
concentrates
Under standardisad
temperatures
of about 20%.
sulphide
The values obtained
processes.
conditions
were used to measure
of nickel
were dependent
procedures,
properties
and indicated
and differences
These values are significant
and in flash
on the experimental
the thermal
sources were measured,
in the range 23-30°C
temperatures
used as feedstock
of
differences
in
in extent ofreaction
in terms of smelter
operations.
INTRODUCTION There are many examples eral sulphide
oxidation
ine the stepwise formed during ignition appears
oxidation
reaction.
reactions
in the literature
studies carried sequence
However,
in pyrotechnic
of the various mineral
although systems
ignition
reactions
of mineral
sulphides,
ref 1) of min-
designed
to exam-
phases present
or
DTA and TG have been used to study (2) and coal
to be the first in which the correct
trates typical
(see for example,
out under conditions
(3), this present
conditions
specifically
of those used in flash smelting
paper
are used to study the
nickel
sulphide
concen-
processes.
EXPERIF'IENTAL Nickel Western
sulphide
Australia
concentrates
pyrrhotile,
All DTA experiments
RESULTS
pentlandite
were performed
with a high temperature
used as an inert reference TG experiments
by the Kalgoorlie
and were tested as received.
present were pyrite,
equipped
were provided
The major
Nickel Smelter,
sulyhide
phases
and violarite.
using a DuPont 1090 Thermal
(1600°C) DTA cell.
Refractory
Analyser
alumina
was
material.
were performed
on a Stanton
Redcroft
TG 750 thermobalance.
AND DISCUSSION
DTA Investigations Figure 1 shows a DTA record of the same nickel
0040-6031/85/$03.30
0 Elsevier Science
Publishers
B.V.
sulphide
concentrate
heated
116 under different heating
experimental
rate of 10 degrees
atmosphere.
These conditions
phases present,
and oxidation
iron-nickel
not complete
Using the more vigorous a 15 mg sample,
producing
No further
The reaction
conditions
of a heating
and an oxygen atmosphere
was detected
be incorrect
from the non-ignition
the ignition
temperature
the ignition
DTA curve,
oxidation
(4)
is complex
the sulphide
over a temperature
per to ignite,
range of
record was also apparent.
sulphide
concentrate
to derive any information
since this is evidently phase which reaction.
of the ignition
temperature
DTA peak, which
had a value of 475°C.
under
on ignition
It would also be incorrect
as the first exothermic
on the ignition
rate of 20 degrees
(mid
experiment.
of a minor sulphide
icant effect
oxid-
scheme
by the DTA above 500°C.
DTA traces of the oxidation of nickel and non-ignition conditions.
It would obviously
air
of the individual
of the sequential
caused
of the temperature
TIME
Fig. 1. ignition
at a
until 800°C.
A perturbation
reaction
reaction
peaks are evidence
sulphides.
a very intense DTA peak which occurred
30°C (Figure 1).
actions
The lower trace was obtained
favour the stepwise
and the exothermic
ation of various
minute,
conditions.
per minute with 5 mg of sample and a flowing
deviation
from the baseline
the exothermic
Hence the only correct
had no signif-
interpretation
onset temperature
of the main
TG Investigations Thermogravimetric
studies on the oxidation
of nickel
in
peak from the
under these conditions
is the extrapolated
re-
to take
sulphide
concentrate
117 under ignition
and non-ignition
Under non-ignition iron and nickel and oxidative
conditions
sulphates
were evident
decomposition
itions, the sulphation
conditions significant
followed
of the remaining
reaction
over a much smaller temperature The thermobalance
have been previously weight
This technique
by heating
the furnace
determined
by the dynamic TG method
cond-
occurred
These characteristics
gain due to sulphation
enabled
in the sample crucible, before raising
could be used to determine
and
it around
the -1 min were
the ignition temperature,
below the ignition
temperature
and then raising the furnace around the
was repeated
Below the ignition
which
very fast heat-
rates of between 4000-5000°C
to a set temperature
This procedure
(See Figure 2).
(6).
temperature
that heating
attained.
sample.
and the oxidation
The sample was placed
to a specific
It was calculated
sample.
of
range and at a much lower temperature.
to be used in a novel manner which permitted
preheated
(5).
of sulphates
Under' ignition
used in this work has a small water cooled furnace
ing rates to be achieved. the furnace
by decomposition
sulphides.
was much reduced,
is raised around the sample on a cam shaft the thermobalance
reported
gains due to the formation
on fresh samples until ignition occurred temperature
but above the ignition
the only change was a weight
temperature
a very rapid weight
loss occurred.
I
FIGURE 3.
FIGURE 2. 700i
n . ;
* 60
A MIXTURE
A
#
I3
TEMPERATURE TIME
(%I
(min)
Fig. 2. TG trace of the cxidation isothermal technique. Fig. 3. Extents temperature.
MIXTURE
of reaction
of nickel
for nickel
sulphide
sulphide
concentrates
concentrate
using an
as a function
of
118 Generally
the ignition
than those determined
temperatures
determined
by either conventional
were lower only by about 30 degrees at a maximum the 230 times
increase
has been reached
sufficient
rate have a relatively Some ignition in Table TABLE
in heating
rate.
by this approach
DTA or TG, although
and were not in proportion
This suggests
to cause ignition
were lower
the values
that once a heating
then further
increments
to rate
in heating
small effect.
temperature
values determined
by the three methods
are given
1.
1
Ignition
temperatures
determined
by thermoanalytical
methods.
Ignition Temperature
"C
Samole
I 1
DTA
Nickel Sulphide Concentrate
The weight
loss at any particular
extent of oxidation possible
475
weight
can be obtained
at that temperature.
extents
of reaction
various
air pre-heat
mixture
A is much more reactive
reaction
(
470
is directly
proportional
Hence by determining extent of reaction
temperatures.
nickel concentrates
to the
the maximum
against
These plots give an indication
for different
at 500°C compared
1 lsot;;rma’
500
temperature
loss, plots of percentage (see Figure 3).
TG
/
temperature
of relative
or concentrate
blends at
In the example shown, it is evident that the
than mixture
B, the former having achieved
with only 63% reaction
at the same temperature
85% for
the latter. CONCLUSION DTA and TG techniquescan ions to compare sulphide
the ignition
concentrates
be used under well controlled temperatures
and mixtures.
and extents
This information
standardised
of reactions
condit-
of nickel
is of value to efficient
flash smelter management. REFERENCES 1 2 3 4
65
E.#. Bollin, Chalcogenides, in R.C. Mackenzie (Ed.), Differential Thermal Analysis, Vol 1, Academic Press, London, 1970, Chapter 7. E.L. Charsley and Chieh-Hua Chen, Thermochim. Acta, 35 (1980) 141. L.S. flerril, Fuel, 52 (1973) 61. J.G. Dunn and C.S. Kelly, J Therm. Anal., 18 (1980) 147. J.C. Dunn and S.A.A. Jayweera, Thermochim Acta, 61 (1983) 313. E.L. Charsley and A.C.F. Kamp, J. Therm. Anal., 7 (1975) 173.
ThermochimicaAcfa, 85 (1985) 115-118 Elsevier Science Publishers B.V., Amsterdam
APPLICATIONS
OF THERMOANALYTICAL
-Printed
METHODS
in The Netherlands
TO STUDIES OF FLASH SMELTING
REACTIONS
J C CbNN1 and S A A JAYAWEERA2 1 School of Applied Chemistry, liAIT, Kent St, Perth, Western Australia 2 Department of Environmental Sciences, Plymouth Polytechnic, Plymouth,
6132 Devon UK
A6STRACT DTA and TG techniques extents
of reaction
smelting
chosen.
concentrates ignition
from different
the ignition
concentrates
Under standardisad
temperatures
of about 20%.
sulphide
The values obtained
processes.
conditions
were used to measure
of nickel
were dependent
procedures,
properties
and indicated
and differences
These values are significant
and in flash
on the experimental
the thermal
sources were measured,
in the range 23-30°C
temperatures
used as feedstock
of
differences
in
in extent ofreaction
in terms of smelter
operations.
INTRODUCTION There are many examples eral sulphide
oxidation
ine the stepwise formed during ignition appears
oxidation
reaction.
reactions
in the literature
studies carried sequence
However,
in pyrotechnic
of the various mineral
although systems
ignition
reactions
of mineral
sulphides,
ref 1) of min-
designed
to exam-
phases present
or
DTA and TG have been used to study (2) and coal
to be the first in which the correct
trates typical
(see for example,
out under conditions
(3), this present
conditions
specifically
of those used in flash smelting
paper
are used to study the
nickel
sulphide
concen-
processes.
EXPERIF'IENTAL Nickel Western
sulphide
Australia
concentrates
pyrrhotile,
All DTA experiments
RESULTS
pentlandite
were performed
with a high temperature
used as an inert reference TG experiments
by the Kalgoorlie
and were tested as received.
present were pyrite,
equipped
were provided
The major
Nickel Smelter,
sulyhide
phases
and violarite.
using a DuPont 1090 Thermal
(1600°C) DTA cell.
Refractory
Analyser
alumina
was
material.
were performed
on a Stanton
Redcroft
TG 750 thermobalance.
AND DISCUSSION
DTA Investigations Figure 1 shows a DTA record of the same nickel
0040-6031/85/$03.30
0 Elsevier Science
Publishers
B.V.
sulphide
concentrate
heated
116 under different heating
experimental
rate of 10 degrees
atmosphere.
These conditions
phases present,
and oxidation
iron-nickel
not complete
Using the more vigorous a 15 mg sample,
producing
No further
The reaction
conditions
of a heating
and an oxygen atmosphere
was detected
be incorrect
from the non-ignition
the ignition
temperature
the ignition
DTA curve,
oxidation
(4)
is complex
the sulphide
over a temperature
per to ignite,
range of
record was also apparent.
sulphide
concentrate
to derive any information
since this is evidently phase which reaction.
of the ignition
temperature
DTA peak, which
had a value of 475°C.
under
on ignition
It would also be incorrect
as the first exothermic
on the ignition
rate of 20 degrees
(mid
experiment.
of a minor sulphide
icant effect
oxid-
scheme
by the DTA above 500°C.
DTA traces of the oxidation of nickel and non-ignition conditions.
It would obviously
air
of the individual
of the sequential
caused
of the temperature
TIME
Fig. 1. ignition
at a
until 800°C.
A perturbation
reaction
reaction
peaks are evidence
sulphides.
a very intense DTA peak which occurred
30°C (Figure 1).
actions
The lower trace was obtained
favour the stepwise
and the exothermic
ation of various
minute,
conditions.
per minute with 5 mg of sample and a flowing
deviation
from the baseline
the exothermic
Hence the only correct
had no signif-
interpretation
onset temperature
of the main
TG Investigations Thermogravimetric
studies on the oxidation
of nickel
in
peak from the
under these conditions
is the extrapolated
re-
to take
sulphide
concentrate
117 under ignition
and non-ignition
Under non-ignition iron and nickel and oxidative
conditions
sulphates
were evident
decomposition
itions, the sulphation
conditions significant
followed
of the remaining
reaction
over a much smaller temperature The thermobalance
have been previously weight
This technique
by heating
the furnace
determined
by the dynamic TG method
cond-
occurred
These characteristics
gain due to sulphation
enabled
in the sample crucible, before raising
could be used to determine
and
it around
the -1 min were
the ignition temperature,
below the ignition
temperature
and then raising the furnace around the
was repeated
Below the ignition
which
very fast heat-
rates of between 4000-5000°C
to a set temperature
This procedure
(See Figure 2).
(6).
temperature
that heating
attained.
sample.
and the oxidation
The sample was placed
to a specific
It was calculated
sample.
of
range and at a much lower temperature.
to be used in a novel manner which permitted
preheated
(5).
of sulphates
Under' ignition
used in this work has a small water cooled furnace
ing rates to be achieved. the furnace
by decomposition
sulphides.
was much reduced,
is raised around the sample on a cam shaft the thermobalance
reported
gains due to the formation
on fresh samples until ignition occurred temperature
but above the ignition
the only change was a weight
temperature
a very rapid weight
loss occurred.
I
FIGURE 3.
FIGURE 2. 700i
n . ;
* 60
A MIXTURE
A
#
I3
TEMPERATURE TIME
(%I
(min)
Fig. 2. TG trace of the cxidation isothermal technique. Fig. 3. Extents temperature.
MIXTURE
of reaction
of nickel
for nickel
sulphide
sulphide
concentrates
concentrate
using an
as a function
of
118 Generally
the ignition
than those determined
temperatures
determined
by either conventional
were lower only by about 30 degrees at a maximum the 230 times
increase
has been reached
sufficient
rate have a relatively Some ignition in Table TABLE
in heating
rate.
by this approach
DTA or TG, although
and were not in proportion
This suggests
to cause ignition
were lower
the values
that once a heating
then further
increments
to rate
in heating
small effect.
temperature
values determined
by the three methods
are given
1.
1
Ignition
temperatures
determined
by thermoanalytical
methods.
Ignition Temperature
"C
Samole
I 1
DTA
Nickel Sulphide Concentrate
The weight
loss at any particular
extent of oxidation possible
475
weight
can be obtained
at that temperature.
extents
of reaction
various
air pre-heat
mixture
A is much more reactive
reaction
(
470
is directly
proportional
Hence by determining extent of reaction
temperatures.
nickel concentrates
to the
the maximum
against
These plots give an indication
for different
at 500°C compared
1 lsot;;rma’
500
temperature
loss, plots of percentage (see Figure 3).
TG
/
temperature
of relative
or concentrate
blends at
In the example shown, it is evident that the
than mixture
B, the former having achieved
with only 63% reaction
at the same temperature
85% for
the latter. CONCLUSION DTA and TG techniquescan ions to compare sulphide
the ignition
concentrates
be used under well controlled temperatures
and mixtures.
and extents
This information
standardised
of reactions
condit-
of nickel
is of value to efficient
flash smelter management. REFERENCES 1 2 3 4
65
E.#. Bollin, Chalcogenides, in R.C. Mackenzie (Ed.), Differential Thermal Analysis, Vol 1, Academic Press, London, 1970, Chapter 7. E.L. Charsley and Chieh-Hua Chen, Thermochim. Acta, 35 (1980) 141. L.S. flerril, Fuel, 52 (1973) 61. J.G. Dunn and C.S. Kelly, J Therm. Anal., 18 (1980) 147. J.C. Dunn and S.A.A. Jayweera, Thermochim Acta, 61 (1983) 313. E.L. Charsley and A.C.F. Kamp, J. Therm. Anal., 7 (1975) 173.