Investigation of iron-containing minerals in the biox™ process

1.

NAVOI STATE UNIVERSITY OF MINING AND TECHNOLOGIES
Faculty of Metallurgy and Chemical Engineering
Group:
Specialty:
Student:
15 M -21
Chemical Technology
Nodira Saidova
Master’s thesis defense:
INVESTIGATION OF IRON-CONTAINING
MINERALS IN THE BIOX™ PROCESS
26/06/2023

2.

CONTENT
Introduction
Experiments
Results
Conclusion

3.

INTRODUCTION
The aim of the work:
Studying chemical and physical properties of minerals which are produced in the BIOX
process, especially iron-bearing minerals.
Research object:
Kokpatas and Daugiztau deposits at the 3rd hydrometallurgical plant of the Navoi
Mining and Metallurgical Combine
Research subject:
Investigation of physico-chemical properties of sulfide ores from different stages of
bacterial leaching: ore preparation, enrichment, up to thickening, neutralization,
sorption cyanidation and analysis of cyanidation tailings

4.

INTRODUCTION
Kokpatas mine
Daugyztau mine
LOCATION: Uchkuduk district of Navoi region
YEAR OF LAUNCH: 1991
ANNUAL ORE MINING CAPACITY: 3,5 million tonnes
of ore
TYPE OF MINED ORE: sulphide ore
LOCATION: Kanimex district of Navoi region
YEAR OF LAUNCH: 2001
ANNUAL ORE MINING CAPACITY: 2,7 million
tonnes of ore
TYPE OF MINED ORE: sulphide ore

5.

INTRODUCTION
Pyrite (FeS2):
Brittle
Mohs scale hardness 6-6.5
Specific gravity
4.95-5.10
Density
4.8-5 g/cm3
Insoluble in water
https://www.ngmk.uz/en
Arsenopyrite (FeAsS):
Brittle
Mohs scale hardness 5.5-6
Specific gravity
5.9 - 6.2
Density
6.0-6.2 g/cm3
Soluble in nitric acid

6.

INTRODUCTION
The oxidation reactions are:
2FeS2 + 7O2 + 2H2O → 2FeSO4 + 2H2SO4
4FeSO4 + 2H2SO4 + O2 → 2Fe2(SO4)3 + 2H2O
4FeS2 + 15O2 + 2H2O → 2Fe2(SO4)3 + 2H2SO4
4FeAsS + 11O2 + 2H2O → 4HAsO2 + 4FeSO4
HAsO2 + 2FeSO4 + H2SO4 + O2 → Fe2(SO4)3 + H3AsO4
4FeAsS + 13O2 + 2H2SO4 + 2H2O → 2 Fe2(SO4)3 + 2H3AsO4 + 2HAsO2
The main end-product of the oxidation reaction is ferric sulfate. The
hydrolysis reactions include:
Jarosite:
Brittle
Hardness
2.5-3.5
Specific gravity 3.15-3.26
Fe2(SO4)3 + 3H2O → Fe2O3 + 3H2SO4
The overall reaction is given by the combination of reactions:
4FeS2 + 15O2 + 8H2O → 2Fe2O3 + 8H2SO4
Further reactions lead to the formation of jarosites.
Fe2(SO4)3 + 2H2O →Fe(OH)SO4 + H2SO4
3Fe2(SO4)3 + 14H2O →2H3OFe3(SO4)2(OH)6
3Fe2(SO4)3 + M2SO4 + 12H2O → 2MFe3(SO4)2(OH)6 + 6H2SO4
(M = Ag+, NH4+, K+, 1/2Pb2+)
https://doi.org/10.1016/j.scitotenv.2022.159078

7.

MATERIALS AND METHODS
The research material:
samples of sulfide ores from different
stages of bacterial leaching, from ore
preparation, enrichment, up to
thickening, neutralization, sorption
cyanidation and analysis of
cyanidation tailings
Filtration and separation of the liquid phase
Solid residue
Treating with concentrated nitric acid at a
temperature of 600℃ and drying in an oven for 4
hours
Solid residue
Firing in a muffle furnace at a temperature of 450℃.
• Liquid phase of the samples
• Liquid chromatography
• Solid phase
• X-ray diffraction spectral analysis

8.

MATERIALS AND METHODS
In relation to the action of NH4OH, group III cations
are divided into three subgroups:
1) Fe2+, Mn2+;
2) Co2+, Ni2+, Zn2+;
3) Fe3+, Al3+, Cr3+, Ti4+, Zr4+.
Mn2+ + 2NH4OH Mn(OH)2 + 2NH4+
Ni(OH)2 + 6NH3 [Ni(NH3)6]2+ + 2OHFeCl3 + 3NH4SCN Fe(SCN)3 + 3NH4Cl
4Fe3++3[Fe(CN)6]4-=Fe4[Fe(CN)6]3↓
3Fe2+ + 2[Fe(CN)6]3- = Fe3[Fe(CN)6]2-↓

9.

RESULTS
Mineral composition of sulfide ores
Characteristics of samples by density, ratio solid phase and medium pH
Rock-forming
minerals
Conten Accessory
t,%
minerals
Content,%
Ore
minerals
Conten
t,%
Quartz and
feldspars
22-57
Rutile
Ilmenite
0,2-0,7
0,02
Pyrite
3,0-9,0
Arsenopyrite 0,1-1,5
Hydromicas,
kaolinite,
dickite, biotite
25-60
Magnetite
-«-
Antimonite
Ankerite,
oligonite,
siderite, calcite
2-17
Carbonaceous
matter
Barite
3
Zircon
Tourmaline
-«-«-
Sphalerite
Fahlore
0,01
-«-
0,020,2
moissonite
-«-
Pyrrhotite
-«-
0,050,2
grenades
-«-
Boulangerite -«-
Apatite
-«-
Chalcopyrite -«-
Gold
-«-
№
Sample name
Density,
Solids ratio
medium
g/cm3
pH
g
%
1
Top drain classifier
1,146
135
11,78
8,07
2
Flotoconc.
1,239
252
20,33
8,45
3
Reactor 1
1,210
216
17,85
2,05
4
Reactor 2
1,195
226
18,91
2,15
5
Reactor 3
1,185
114
9,62
2,10
6
Reactor 4
1,180
125
10,59
2,08
7
Reactor 5
1,175
148
12,59
2,10
8
Reactor 6
1,173
139
11,84
2,10
9
CCD-1
1,068
10
CCD-3
1,145
328
28,64
6,15
11
Nutrition CHEMIX
1,308
486
37,15
9,82
12
Cyanidation tailings
1,180
253
21,44
11,95
4,26

10.

RESULTS
Name of
nutrients
Consumption
of nutrients
kg/t conc.
N
1,7
P
0,3
K
0,9
Overall:
2,9
Reagents
containing
nutrients
(NH4)2S
O4
(NH4)2H
PO4
K2SO4
Quantity,
kg/t conc.
Quantyty
,
t/day.
Substance
Physical Enthalpy, Entropy,
state
Kj/mole J/mole*K
6,93
7,408
FeS2
Crystal
1,33
1,422
FeSO4
Crystal
2,10
2,245
10,365
11,075
Preparation and dosing of the nutrient mixture for production
environments
-177,40
(-163,2)
-927,59
(-3016)
52,99
Free
energy
(Gibbs),
KJ/mol
-266,05
107,53
-819,77
Thermodynamic characteristics of some substances
involved in bacterial oxidation processes

11.

RESULTS
a. Concentration of Na
Sample
No
1
44Ca
%
0,0016
0,16
2
0,00163
0,163
3
0,0022
0,22
4
0,00288
0,288
5
0,00309
0,309
6
0,00276
0,276
7
0,00261
0,261
8
0,00287
0,287
9
0,00278
0,278
10
0,00267
0,267
11
0,0023
0,23
12
0,00273
0,273
13
0,00309
0,309
b. Concentration of K
Behavior of (a) Sodium and (b) Potassium ions during leaching
The behavior of calcium ions at different stages of leaching.

12.

RESULTS
1
1
4,5
4
3,5
3
2,5
2
1,5
1
0,5
0
13
12
11
13
2
12
3
4
10
5
9
6
8
7
Behavior of iron ions during leaching
1
4,5
4
3,5
3
2,5
2
1,5
1
0,5
0
11
8000000
2
13
6000000
5000000
12
3
3
4000000
3000000
2000000
4
11
4
1000000
0
10
5
9
6
8
2
7000000
7
Behavior of phosphorus ions in leaching processes
10
5
9
6
8
7
Behavior of arsenic in oxidation processes

13.

RESULTS
Name of options
1
Top drain classifier
160
13
2
140
Flotation concentrate
120
Reactor 2-1
100
12
3
80
Reactor 2-2
60
Reactor 2-3
40
11
4
20
Reactor 2-4
0
Reactor 2-5
10
5
Reactor 2-6
Countercurrent decanting unit Dec-1
9
6
Countercurrent decanting unit Dec -3
Nutrition CHEMIX
8
7
Behavior of gold ions at different stages of leaching
Cyanidation tailings
Cyanidation tailings cinder
Samples
Sample 1 acid
Sample 1 alkali
Sample 2 acid
Sample 2 alkali
Sample 3 acid
Sample 3 alkali
Sample 4 acid
Sample 4 alkali
Sample 5 acid
Sample 5 alkali
Sample 6 acid
Sample 6 alkali
Sample 7 acid
Sample 7 alkali
Sample 8 acid
Sample 8 alkali
Sample 9 acid
Sample 9 alkali
Sample 10 acid
Sample 10 alkali
Sample 11 acid
Sample 11 alkali
Sample 12 acid
Sample 12 alkali
Sample 13 acid
Sample 13 alkali
Au (ppb)
797,76716
389,15825
291,86604
0
1478,9281
0
379,42662
0
3327,3969
428,06867
3989,1352
0
5477,7156
0
5964,2433
933,98302
8387,176
1439,8998
14313,834
0
8250,9392
0
7287,5946
1235,7839
39880,71
3784,6911
Results of analyzes of gold content in solid samples after acid and alkali
treatment

14.

RESULTS
№
Sample name
1
2
3
4
5
6
7
8
9
Upper drain classifier
Flotation conc.
Reactor 2-1
Reactor 2-2
Reactor 2-3
Reactor 2-4
Reactor 2-5
Reactor 2-6
Dec-1
Ionic composition of liquid
sample phases
SO42-,
Cl-, mg/l
NO3mg/l
mg/l
1493
283
15,6
2872
320
12,4
2548
155
29,4
2453
164
35,7
2215
124
47,5
1955
145
35,6
1877
159
29,1
1785
164
19,8
2065
305
15,6
Quantitative characterization of the detected anions in BIOX samples
Correlation between the rate of sulfide sulfur
biooxidation and the rate of gold recovery

15.

RESULTS
The degree of solubility of chemical elements in the liquid phase of
sulfide samples (µg/l).
Content
Na, %
Dissolved elements in the composition of sulfide minerals
Si, % Р, % К, % Са,% Fe,%
Li
Mg
Neutral,
рН – 7,8
0,095
0,37
0,019 0,061
0,16
0,02
1397,3
73143,8
13973,2
Concentrate
0,092
0,374
0,02
0,22
0,02
1395,2
76411,2
14607,4
Sulfuric
рН - 1,5,
96 hours
0,0009
0,406 0,026 0,052 0,309
4,157
2114,7
1603438,5
667836
Decantation,
рН – 4,5
0,0005
0,322 0,019 0,046 0,267
0,137
1636,7
852911,23
20165,2
alkalized.,
рН - 11,5
0,0091
0,388 0,019 0,053 0,273
0,043
1392,3
22897,0
16939,7
Tails cyanide.,
рН – 9,5
0,0021
0,383 0,043 0,104 0,309
0,025
1457,6
41118,1
24699,5
0,057
Al
The nature of the manifestation of minerals
in the ore in X-ray diffraction analysis.

16.

RESULTS
SEM image of the
biooxidized
product after 10
days of oxidation;
a light coating is
observed on most
particles
X-ray diffraction patterns of different samples:
(a) flotation concentrate predominantly containing pyrite and quartz;
(b) biooxidized product after 10 days of oxidation, predominantly containing
jarosite, pyrite, and quartz;
(c) biooxidized product after the removal of jarosite, predominantly containing
pyrite and quartz.
SEM image of the
jarosite removal
product after 10 days
of biooxidation

17.

RESULTS
№
Name of samples
Name of minerals
1.
neutral,
pH - 7.8
Quartz, albite, calcite, muscovite, ankerite, pyrite,
chalcopyrite (arsenopyrite)
2.
Concentrate
The same as in ore.
3.
Sulfate
pH - 1.5,
96 hours
Albite Na[AlSi3O8], anorthite Ca[Al2Si2O8],
pyrite, phengite, yansite (CaMnMn), todorokite,
vashigite, quartz, orthoclase K[AlSi3O8].
4.
decantation,
pH - 4.5
The same as in the sulfuric acid environment.
5.
alkalization,
pH - 11.5
The same as in the sulfuric acid environment.
6.
cyanide tailings,
pH - 9.5
The same as in the sulfuric acid environment.
7.
cinder of cyanide
tailings
Quartz, hematite Fe2O3, berlinite, calcite, analbite,
silicon aluminum phosphate, muscovite.
X-ray diffraction analysis of samples of sulfide ores in the process of
bacterial leaching
Group
Gold recovery, %
Concentrate
Gold concentration
(g/t)
12.08
Biooxidation product
15.02
59.52
After removal of jarosite
10.25
70.03
10.01
The influence of secondary products on the gold extraction rate
obtained without activated carbon during cyanidation

18.

RECOMMENDATION
The oxidation efficiencies of concentrate with different approaches
The surface morphologies of pyrite coupons with different
processes.
A: Untreated; B: Chemical oxidation; C: Biological oxidation;
D: Two-stage approach
https://doi.org/10.1016/j.hydromet.2020.105421
The schematic diagram of two-stage oxidation process for refractory gold concentrate with
high arsenic and sulfur.
https://doi.org/10.1016/j.mineng.2022.107976

19.

CONCLUSION
• Investigated:
• Mineral composition of sulfide ores
• Characteristics of samples by density, ratio solid phase and medium Ph
• Behavior of sodium, potassium, calcium, iron, phosphorus, arsenic, gold ions during leaching
• Gold content in solid samples after acid and alkali treatment
• Quantitative characterization of the detected anions in BIOX samples
• Correlation between the rate of sulfide sulfur biooxidation and the rate of gold recovery
• The degree of solubility of chemical elements in the liquid phase of sulfide samples (µg/l)
• The nature of the manifestation of minerals in the ore in X-ray diffraction analysis
• X-ray diffraction patterns of different samples

20.

Q&A
THANK YOU FOR YOUR
ATTENTION!

21.

BACK-UP
forsterite Mg[SiO4],
fayalite Fe2[SiO4],
anorthite Ca[Al2Si2O8],
albite Na[AlSi2O8],
quartz SiO2 or
feldspar K[AlSi3O8]
serpentine - Mg3[Si2O5]·(OH)4)
Chalcopyrite – CuFeS
goethite, FeOOH

22.

BACK-UP
DOI: 10.1080/10643389.2014.966423

23.

BACK-UP
ORE
Crushing and
grinding
Residue for
calnination
Flotation
Recovery
smelting
Biooxidation
Wash
water
Pure iron
Countercurrent
decantation
Acid runoff
Hard part
for
cyanidation
NH4OH
Iron
precipitation
Sludge
filtration
Filtrate for
further
processing