NZ631479B2 - Method and apparatus for controlling the flotation process of pyrite - containing sulphide ores - Google Patents
Method and apparatus for controlling the flotation process of pyrite - containing sulphide ores Download PDFInfo
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- NZ631479B2 NZ631479B2 NZ631479A NZ63147912A NZ631479B2 NZ 631479 B2 NZ631479 B2 NZ 631479B2 NZ 631479 A NZ631479 A NZ 631479A NZ 63147912 A NZ63147912 A NZ 63147912A NZ 631479 B2 NZ631479 B2 NZ 631479B2
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- New Zealand
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- slurry
- electrode potential
- molybdenum electrode
- lime
- molybdenum
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- 238000005188 flotation Methods 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 title claims abstract description 31
- 229910052683 pyrite Inorganic materials 0.000 title claims abstract description 31
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 title claims abstract description 31
- 239000011028 pyrite Substances 0.000 title claims abstract description 31
- UCKMPCXJQFINFW-UHFFFAOYSA-N sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 title claims abstract description 26
- 230000001276 controlling effect Effects 0.000 title claims abstract description 20
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 56
- ZOKXTWBITQBERF-UHFFFAOYSA-N molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims abstract description 55
- 239000011733 molybdenum Substances 0.000 claims abstract description 55
- 239000002002 slurry Substances 0.000 claims abstract description 50
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims abstract description 28
- 235000015450 Tilia cordata Nutrition 0.000 claims abstract description 28
- 235000011941 Tilia x europaea Nutrition 0.000 claims abstract description 28
- 239000004571 lime Substances 0.000 claims abstract description 28
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 22
- 239000011707 mineral Substances 0.000 claims abstract description 22
- 238000000926 separation method Methods 0.000 claims abstract description 17
- 150000002500 ions Chemical class 0.000 claims description 13
- 235000016768 molybdenum Nutrition 0.000 description 35
- 239000010949 copper Substances 0.000 description 34
- 229940108928 Copper Drugs 0.000 description 29
- 229910052802 copper Inorganic materials 0.000 description 29
- RYGMFSIKBFXOCR-UHFFFAOYSA-N copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 28
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium monoxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 22
- 235000010755 mineral Nutrition 0.000 description 19
- 241000196324 Embryophyta Species 0.000 description 12
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 12
- 239000012141 concentrate Substances 0.000 description 11
- 235000008504 concentrate Nutrition 0.000 description 11
- 238000005259 measurement Methods 0.000 description 9
- 239000011133 lead Substances 0.000 description 8
- 230000003334 potential Effects 0.000 description 7
- 239000000203 mixture Substances 0.000 description 6
- 229910052697 platinum Inorganic materials 0.000 description 6
- AXCZMVOFGPJBDE-UHFFFAOYSA-L Calcium hydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 5
- ZOOODBUHSVUZEM-UHFFFAOYSA-N ethoxymethanedithioic acid Chemical compound CCOC(S)=S ZOOODBUHSVUZEM-UHFFFAOYSA-N 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 239000011701 zinc Substances 0.000 description 5
- 239000011521 glass Substances 0.000 description 4
- 230000001537 neural Effects 0.000 description 4
- 238000003062 neural network model Methods 0.000 description 4
- 238000004886 process control Methods 0.000 description 4
- 229910017518 Cu Zn Inorganic materials 0.000 description 3
- 229910017752 Cu-Zn Inorganic materials 0.000 description 3
- 229910017943 Cu—Zn Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000000920 calcium hydroxide Substances 0.000 description 3
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 3
- 235000011116 calcium hydroxide Nutrition 0.000 description 3
- 229910001779 copper mineral Inorganic materials 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000005755 formation reaction Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- -1 copper-zinc Chemical compound 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 241000272168 Laridae Species 0.000 description 1
- HKZLPVFGJNLROG-UHFFFAOYSA-M Silver chloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- HRPVXLWXLXDGHG-UHFFFAOYSA-N acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- 235000014987 copper Nutrition 0.000 description 1
- 230000003247 decreasing Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002848 electrochemical method Methods 0.000 description 1
- 238000003487 electrochemical reaction Methods 0.000 description 1
- 230000005518 electrochemistry Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 230000036647 reaction Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 229910052950 sphalerite Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Abstract
Method and apparatus for controlling the flotation process of sulphide ores including separation of sulphide minerals from pyrite in an alkaline environment created by lime. The method comprises measuring the molybdenum electrode potential of an aqueous slurry of the ore and adjusting the addition of lime based on the measured molybdenum electrode potential to maintain the molybdenum electrode potential of the slurry in a preselected range. The apparatus comprises means (6) for measuring the molybdenum electrode potential and a control unit (7) for controlling the addition of lime to the slurry based on the measured molybdenum electrode potential of the slurry. of lime based on the measured molybdenum electrode potential to maintain the molybdenum electrode potential of the slurry in a preselected range. The apparatus comprises means (6) for measuring the molybdenum electrode potential and a control unit (7) for controlling the addition of lime to the slurry based on the measured molybdenum electrode potential of the slurry.
Description
ANDAPPARATUSFORCONTROLUNGTHEFLOTAHON
PROCESS OF PYRITE - CONTAINING SULPHIDE ORES
FIELD OF THE INVENTION
The invention relates to a method for con—
trolling the flotation process of sulphide ores in—
cluding separation of sulphide minerals from pyrite in
an ne environment created by lime. The invention
also relates to an apparatus for controlling such (lo—
tation process.
BACKGROUND OF THE INVENTION
ion process which includes separation
of sulphide minerals from pyrite by adjusting limo
(CaO) dosage is one of the most common ses used
in concentration plants throughout the world. The pro—
cess is used, for instance, in beneficiation of cop-
per, copper-zinc, —nickel, copper-molybdenum,
and complex ores.
Each flotation process has an l elec~
trochemical state that leads to the best possible met—
allurgical performance. In ion practice, methods
are known for controlling the feed of sulphidizinq
agent (e.g. NaZS) based on the measurement of electro—'
al potential (Eh) of an s ore slurry with
the help of a platinum electrode. Examples of such
methods are disclosed, for instance, in patent docu~
ments US 4011072 A and US 3883421 A. These methods rc—
late to flotation processes aiming at sulphidizinq ox—
idized forms of copper minerals. Such methods cannot
be directly applied to flotation separation of sul—
phide minerals from pyrite, since N825 applied in
those methods would result in activation of pyrite
flotation.
Lime addition in selective flotation of sul—
phide minerals from pyrite is usually controlled based
W0 2013/169140
on hydrogen ion concentration measured from the slur—
ry, or based on the conductivity of the slurry. in
spite of the high importance of separation of de
minerals from pyrite, there are no examples of relia—
ble implementation of such flotation control systems
in industrial conditions. The reasons for this will be
discussed in the ing.
Low ivity of glass electrodes with
highly alkaline slurry is one of the problems. Selec—
lO tive flotation of ~containing de ores is
usually carried out at a pH of about 12.0-12.2.
Fouling of ode surface with films of
Ca(OH)2 and mineral particles of the processed ore is
another problem. Attempts have been made to clean the
electrode surface mechanically or by washing with wa-
ter or acid. These procedures significantly complicate
the design of the measurement sensor. Still, they do
not ensure reliable operation of the pyrite separation
process.
The feasibility of eliminating sensor fouling
by means of natural peeling of the sensor surface with
the slurry flow is excluded because a glass electrode
would break in such treatment.
High sensor nce (over lOOO MOhm) re-
quires special ionometers with a esistance input
and protection of connecting cables and connectors
from the influence of electromagnetic fields of motors
installed in the flotation building, as well as taking
measures to prevent the ingress of moisture, vapours
and steam condensation into the fixture with the help
of which the sensor is installed into the slurry.
A glass electrode does not react on changes
in the redox—potential of the slurry.
Special researches conducted in a concentra—
tion plant beneficiating Cu—Zn ore confirmed the unre—
liability of using conventional s control with a
pH sensor during the separation of copper minerals
2012/000398
from pyrite. The measurement results of the industrial
sensor installed directly in a flotation cell and the
measurement results of a pH sensor installed in a test
flow—through cuvette were compared. The trend of the
sensor installed in the flotation cell demonstrated
first a gradual decrease of pH values and then a total
failure of the pH control system. Thus there is a
great risk that the pH sensor installed directly in
the flotation cell misinforms the process l op—
erator.
instability and low efficiency ot pH based
control of flotation s during separation of sul—
phide minerals front pyrite has also been discovered
when analysing the operation of another industrial
concentration plant treating complex ore.
A second industrially ented way of con-
trolling the ion separation of sulphide minerals
from pyrite is to adjust the CaO dosage according to
the slurry conductivity value. Taking into t the
particularities of the ionic composition of flotation
slurries, this method has numerous disadvantages.
Apart from the residual concentration of CaO, the con—
ductivity of the slurry is also considerably influ-
enced by the amount of ZnSOa electrolyte dosage into
the slurry, which is widely used, especially when
treating Zn~containing ores, as well as by any dosage
of other reagents. Apart from HP and OH” .ions, the
slurry conductivity is also influenced by the e
components of the processed ore and the composition of
circulation water, which may contain Na+, K‘, Cl‘, 323
SOf', szof‘, SqOJ', 80f- and many other ions. A close
correlation can be observed in an industrial —
trator plant between the slurry conductivity and the
electrochemical potential within short time periods,
but this correlation falls almost to zero within a
couple of days.
In a Finnish industrial concentration plant,
in order to l the operation of a conductometric
analyser, manual slurry pH control of the industrial
slurry is performed daily every 3—4 hours in the la—
boratory. Hence the control method is ous.
A control method based on conductometric mon—
itoring of the residual CaO concentration does not
ate the disadvantage of sensor element fouling
with films of Ca(OH)2 and mineral particles ot the
processed ore.
tes are often used as collectors in
flotation of sulphide ores. entation of a KloLa—
tion method comprising pyrite depression by means 01
lime provides for preventing the oxidation oi xanthate
ions into dixanthoqenide, which is a pyrite collector:
ZX' a X2 + 2e“ (1)
In other words, the pyrite depression process
also depends on the electrochemical potential of the
slurry, the value of which should be aimed at shifting
the on (1) to the left side. This fact is not
taken into account when implementing the present py-
rite separation process control, which is realised in
practice only by controlling the tration of EV
ions in the slurry based on a selective glass elec—
trode for gfii measurement. This can be considered as
the main technological drawback of the current process
of separating sulphide minerals from pyrite. This fact
has also been verified in practice. During different
operation periods in an rial concentration
plant, with the same “optimum” pH value 12.0—12.5,
ochemical potential values of different heights
were registered. Higher electrochemical potentials
were found to result in higher pyrite floatability and
disruption of flotation selectivity.
The object of the present invention is to me the
problems faced in the prior art.
More precisely, the object of the present invention is
to improve the control of conditions in a flotation process that
comprises selective separation of sulphide minerals from pyrite
in an alkaline environment created by addition of lime.
The ing objects are to be read ctively
with the object of at least providing the public with a useful
alternative.
SUMMARY
According to the present invention, a method for
controlling the flotation. process of sulphide ores including
separation of sulphide minerals from pyrite in an alkaline
environment created by lime comprises measuring the molybdenum
electrode potential of an aqueous slurry of the ore and
adjusting the addition of lime based on the measured molybdenum
electrode potential to maintain the molybdenum electrode
potential of the slurry in a preselected range.
Preferably, the molybdenum ode and a reference
electrode (Ag/AgCl) are placed at a point where the slurry is in
flow, for instance, in a feed line or in an intensively agitated
section of a flotation cell. This prevents fouling of the
electrode surface with Ca(OH)2 films and mineral particles of the
processed .
Reliability of electric ements can be increased
by' using' a low—resistance electrode, preferably‘ one having a
resistance below 1.0 ohm.
The optimum range for the molybdenum ode
potential, which is used as the preselected range in an
automatic control loop, can be defined experimentally in each
case.
According to the present invention, an apparatus for
controlling the flotation process of sulphide ores including
separation of sulphide ls from pyrite in an alkaline
environment created by lime comprises means for
measuring the molybdenum electrode
potential of an aqueous slurry and means for control-
ling the addition of lime based on the ed molyb—
denum electrode potential to maintain the molybdenum
electrode potential of the slurry in a ected
range.
Preferably, the means for controlling the ad—
dition of lime comprise means for comparing the meas—
ured enum electrode potential with the prese—
lected range and means for changing the feed rate of
lO lime to the slurry if the Heasured molybdenum elec—
trode ial deviates from the preselected range.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following the principles of the inven-
tion are ned with reference to the appended
drawings, where:
Fig. l is a schematic representation of a
control system. for a flotation process according to
the present invention.
Fig. 2 is a diagram illustrating three—
dimensionally lead losses with tailings as a function
of pH and molybdenum electrode potential.
Fig. 3 is a diagram illustrating copper con-
centrate grade and copper losses with tailings as a
on of enum electrode potential.
Fig. 4 is a diagram illustrating the final
copper concentrate grade in the form of isolines as a
function of molybdenum electrode potential and pH.
DETAILED DESCRIPTION OF THE INVENTION
Stemming from the physical-chemical nature of
the flotation process in separating de minerals
from pyrite, the new control method comprises adjust—
ing lime dosage based on the molybdenum electrode po—
tential ed from the ore slurry. The possibility
of pH control using metal—oxide electrodes is well—
W0 2013/169140
known from the theory of electrochemistry, but it has
not before been used in the t context.
Formation of molybdenum electrode potential
is determined by an electrochemical reaction:
M002 + H20 = M003 +2H+ + 2e" (2).
Since H? ion participates in the on
(2), the molybdenum electrode potential simultaneously
controls the pH and the redox potential of the slurry.
Redox potential measurement indicates the re—
duction/oxidation potential of a solution. Redox po—
tential is obtained by ing the electrode poten—
tial of a redox ode against 51 reference elec—
l5 trode. Usually, a platinum electrode is used in the
ement. However, platinum electrode is very un-
stable in terms of slurry composition; for instance, a
platinum electrode is influenced by the concentration
of oxygen and hydrogen in the slurry. um elec—
'trode is very sensitive to ions of bivalent iron,
which often appear in ore slurries. The instability of
the properties of platinum electrode is associated
with the method of its manufacture: presence of atomic
impurities from other metals in platinum,' electrode
shape, method of its surface processing.
In a flotation system for pyrite—containinq
copper ores, the ore is first d and ground with
lime usually added as an aqueous solution to depress
pyrite. The ore is then treated in a primary ELotation
3O circuit after a suitable copper collector and frother
have been added. The copper rougher trate thus
obtained contains most of the copper of the ore. This
copper rougher concentrate is then subjected to sever—
al stages of cleaner flotation, usually' after a re—
qrind operation, to produce a finished copper concen—
trate. The new control method can be used at any stage
of a flotation process used for separation of copper,
W0 2013/169140
or any other valuable sulphide minerals, such as Zn,
Pb, Mo, Ni, from pyrite in an alkaline environment
created by lime.
The principles of the ion process and
‘5 the control system according to the present invention
are illustrated in Fig. 1. An aqueous ore slurry is
fed to a flotation cell 1 via a slurry feed Line 2.
Lime or lime milk is added to the slurry via a lime,
feed line 3 in an ore mill (not shown), in a condi—
lO tioner (not shown) and/or in the flotation cell 1. The
goal of flotation is to separate valuable sulphide
minerals from pyrite and gangue minerals such that the
former are transferred to trate 4 and the latter
are transferred to tailings 5.
The redox~potential of the slurry is measured
by measuring means 6 which comprise, among other
, a nmlybdenum electrode and a reference elec-
trode, preferably an Ag/AgCl-electrode. Both elec—
trodes are placed either in the slurry feed Line ? or
in the flotation cell 1. It is important the elec—
trodes are placed at a point where the slurry is in
motion.
The measuring means 6 provide a ement
signal, which is transmitted to a control unit 7. The
control unit 7 compares the measured molybdenum elec—
trode potential with a preselected range given to the
molybdenum ode potential. If the ed value
is not within the preselected range, the control unit
7 transmits a l signal to an actuator 8 control—
ling the lime feed.
ageously, the optimum range for molyb-
denum electrode potential to be used as the preselect—
ed range in the control system should be defined ex—
perimentally in each case.
L0 (_fi The invention is further illustrated below by
reference to specific examples. However, the scope of
W0 2013/169140
the t invention is not limited to these exam-
ples.
EXAMPLE 1
A comparative evaluation of three different
control methods that can be used in selective flota-
tion separation of sulphide minerals from pyrite in a
lime environment was carried out in an rial con—
centration plant with the help of neural k mod—
cling. The concentration plant in question benefi-
clates Cu—Zn ore. Neural networks, with their remarka—
ble ability to derive meaning from complicated or im—
precise data, are a feasible tool for extracting pat—
terns and detecting trends that are too complex to be
noticed by either humans or other computer techniques.
The evaluated three methods comprise control—
ling the conditions in flotation process based on: pH
control, conductemetric , and redbx—potential
(Eh). Measurements of redox-potential and pH were per—
formed by installing the respective electrodes ln a
flow—through cell in a Chena® system installed in the
slurry flow fed into a rougher copper flotation. These
results were ed with results of conductometric
measurement system which was led at the same
process point. Information on metal content, section
lead and reagent dosage was received from Outotec Pro~
scon® automation system during the period of conduct—
ing the tests.
The results of the neural network modeling of
the sensitivity of each process control method are
given in Tables 1—3. In each table, s load pre-
sents the load of the observed process stage in terms
of tons of ore per hour. Fe in feed (or Cu, Zn, Pb, S
in feed) presents the iron content (or copper, zinc,
lead, r t) in the incoming ore. Xanthate
consumed (or ZnSOq, CaO consumed) presents the amount
of xanthate (or ZnSOa, CaO) consumed in the ore mill.
W0 2013/169140
Table 1 shows the neural network model for pH
control, Table 2 shows the neural network model for
conductometric method and Table 3 shows the neural
network model for redox potential (Eh) based control
system.
As expected, the method ing process
control based on pH (Table l) responds to CaO consump»
tion and copper content of the ore in the first place
and to other changes in the composition of the pro~
lO cessed ore in the last place.
The method employing process control based on
tometric method (Table 2) responds to ZnSOa feed
and to zinc and copper contents of the ore in the
first place.
The s control based on the redox poten—
tial (Table 3) responds to the composition of the pro—
cessed raw als in the first place. This explains
the reason of the optimality' of this parameter~ when
implementing the control method according to the pre—
sent ion.
The neural network model for Eh parameter is
noted for its better appropriateness for the discussed
site. The correlation factor for the model is evaluat—
ed as R = 0.947. For the flotation process control
based on pH the model appropriateness is ted as
R 2 0.657. When using a conductometric method, the
value of R is 0.889.
EXAMPLE 2
The optimality of using molybdenum electrode
potential in flotation control was further confirmed
by comparative tests with molybdenum. and pH elec—
trodes. The tests were performed in a 1concentration
plant treating polymetal ores. Fig. 2 shows the re—
sponse of an output function — lead losses with tail—
ings (8(Pbll - during neural network modeling against
the change of the slurry pH and the electrochemical
potential measured using a molybdenum electrode. From
Fig. 2 one can clearly see the availability of an op-
timum molybdenum ode potential at which lead
losses with tailings are minimal, whereas this is not
the case with pH values. On the shown se surface
there is almost no influence of pH value variation, or
there is a linear dependency necessitating reduction
of pH value in order to decrease the loss of Lead with
tailings, in which case increased pyrite floatabiiity
is inevitable.
EXAMPLE 3
The method according to the present ion
was tested during the treatment of Cu—Zn pyrite ore in
an industrial concentration plant in a copper flota—
tion circuit where CaO is fed into ore mills. Apart
from CaO, Zn804 is also fed into the ore mills for
sphalerite sion, and xanthate is used as a col—
lector for copper minerals. ation of molybdenum
electrode potential with the produced copper concen—
trate grade B(Cu) and copper losses with the circuit
tailings 6(Cu) is presented in Fig. 3. The figure re—
veals an optimum of molybdenum electrode potentials at
an area around -325 mV, where the highest copper con—
centrate grade and the minimum copper losses with
tailings are achieved. When the molybdenum eLectrode
potential is higher than the optimum, process parame—
ters are lly lower due to the shift of the reac—
tion (1) balance to the right side. According to the
present invention, high molybdenum electrode potential
necessitates increased CaO addition. Process paramew
ters are decreased as well with low molybdenum elec—
trode potentials, which is explained by the Formation
of complex nds of type )Xfl' in this area.
Formation of said complex has been confirmed by spe—
cial electrochemical measurements in rougher copper
flotation. se of the activity of the ionic form
W0 2013/169140
of xanthate is a reason for the increase of copper
losses with section tailings.
The advantage of controlling the molybdenum
ode potentials in the implementation of the pre—
sent method compared to controlling the pH parameter
is further med by Fig. 4. The figure shows a
plane in the coordinate system of molybdenum electrode
potential and pH in which isolines of the final copper
concentrate grade are plotted. A clear dependence 0L
copper concentrate grade and molybdenum electrode po—
tential variation can be observed. The dependence of
copper concentrate grade and pH is much weaker.
EXAMPLE 4
The l method according to the t
invention was tested during treatment of pyrite-
containing copper ore in an industrial concentration
plant in the coarse copper concentrate cleaner cir—
cuit, where CaO is fed into a d mill.
The correlation of process parameters - pro~
duced copper concentrate grade B(Cu) and copper losses
in the circuit tailings 6(Cu) - and molybdenum elec—
trode ials followed a similar pattern as in Fig.
3. The area of optimum values of molybdenum electrode
ials was found to be close to the area of opti—
mum values of molybdenum electrode potentials discov—
ered in Example 3. Control measurements of hydrogen
parameter value in that area pond to pH = 12.2.
The above results indicate that it is possi—
ble to optimize the selective flotation of sulphide
minerals from pyrite by measuring the molybdenum elec-
trode potential and by adjusting the lime addition
based on the measured electrode potential.
it is evident that the optimum molybdenum
electrode potential may vary in different concentra—
tion plants based on the differences in the ore compo—
sition and other process conditions. That is why the
W0 2013/169140
optimum range of molybdenum electrode potential shouid
be separately defined for each individual case.
It is obvious to a person skilled in the art
that with the ement of technology, the basic
idea of the invention may be implemented in various
ways. The invention and its embodiments are thus not
limited to the examples bed above; instead they
may vary within the scope of the claims.
Claims (11)
1. A method for controlling the flotation process of sulphide ores including separation of sulphide minerals from pyrite in an alkaline environment created by lime, characterized by measuring the molybdenum electrode potential of an aqueous slurry of the ore and adjusting the addition of lime based. on the measured molybdenum electrode potential to in the molybdenum electrode potential of the slurry in a preselected range.
2. A method according to claim 1, characterized by measuring the molybdenum electrode potential while the slurry is in flow.
3. A. method. according to claim. 1 or 2, characterized by using a low—resistance molybdenum electrode.
4. A method according to claim 3, wherein the electrode has a resistance below 1.0 ohm.
5. A method according to any one of claims 1 to 4, characterized by experimentally ng the optimum range for the molybdenum electrode potential to be used as the preselected range.
6. An apparatus for controlling the ion process of sulphide ores including separation of sulphide minerals from pyrite in an alkaline environment created by lime, wherein the apparatus comprises means for measuring the enum electrode potential of an s slurry of the ore and means for lling the addition of lime based on the measured molybdenum electrode potential to in the molybdenum electrode ial of the slurry in a preselected range.
7. An apparatus according to claim 6, wherein the means for measuring the molybdenum electrode potential of the slurry comprise a enum electrode and a reference electrode placed at a point in the process where the slurry is in flow.
8. An apparatus according to claim 6 or 7, wherein the molybdenum electrode is a low—resistance ode.
9. An tus according to claim 8, wherein the electrode has a resistance below 1.0 ohm.
10. An apparatus according to Claim 6, wherein the means for controlling the addition of lime comprise means for comparing the measured molybdenum electrode potential with the ected range and means for changing the feed rate of lime to the slurry if the measured enum electrode potential deviates from the preselected range.
11. A method according to claim 1, substantially as herein. bed with. reference to any one of the Examples and/or
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/RU2012/000398 WO2013169140A1 (en) | 2012-05-10 | 2012-05-10 | Method and apparatus for controlling the flotation process of pyrite - containing sulphide ores |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ631479A NZ631479A (en) | 2015-02-27 |
NZ631479B2 true NZ631479B2 (en) | 2015-05-28 |
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