This document is a student research paper investigating the effects of pre-leaching and particle size on copper slag bioleaching. The paper includes an introduction to copper and its production methods, as well as a literature review on factors that can influence bioleaching such as bacterial adaptation, pH, particle size, and pretreatment. The methodology describes shake flask and column experiments testing different pH levels, particle sizes, nitric acid concentrations, and flow rates. The results show that higher pH levels and smaller particle sizes increased copper extraction, and that a mixture of sulfuric and nitric acids was more effective than sulfuric acid alone. The paper concludes by recommending areas for further study.

1. In the name of Allah, the designer, the creator and
the initiator
1

2. Title:
Investigation of Pre-leaching and particle size’s effects on
copper slag bioleaching
Malek-Ashtar University of Technology 2019-Feb-11
Supervisor:
Dr. Khalilzadeh
Presented by:
Sajad Mohammadi
Advised by:
Dr. Shahrivar
2

3. 1) Introduction
2) Literature Review
3) Methodology
4) Results
5) Suggestion
Content
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching 3

4. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
Introduction
✓A chemical element with symbol Cu and atomic number 29.
✓ It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity.
Application
43%
19%
19%
12%
7%
Building conestruction Transportation
Electric & electronic Consumer & general
Industrial machinery & equipment
4

5. How to produce copper?
oCopper in nature
chalcopyrite Bornite enargite chalcocite Covellite
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
Introduction
5

6. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
Copper production’s methods
Pyrometallurgy Hydrometallurgy
1 Thermal treatment
2 produce products able to be sold
such as pure metals.(Cu, Zn,Mn,
Ch)
3 The energy is usually provided in
the form of combustion or from
electrical heat.
Introduction
6

7. Copper slag
•Copper slag is a by-product of copper extraction by smelting.
•Slag from ores that are mechanically concentrated before smelting contain mostly
iron oxides and silicon oxides.
•Copper slag is mainly used for surface blast-cleaning.
•Copper slag can be used in concrete production as a partial replacement for sand.
•It contains 2% - 6% copper.
Introduction
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching 7

8. Hydrometallurgy is typically divided into three general areas:
1)Leaching
2)Solution concentration and purification
3)Metal or metal compound recovery
Chemical leaching
Bioleaching
Solvent extraction
Ion exchange
electrowinning
precipitation
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching 8

9. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
•All kinds of Leaching Introduction
9

10. o Impressive factors
Impressive factors in bioleaching Variables
Physicochemical parameters of a bioleaching
environment
Temp, pH, redox potential, 𝑐𝑜2, mass transfer,
nutrition, pressure, surface tension, 𝐹𝑒2+
&
𝐹𝑒3+
Microbiological parameters Type of bacteria, population, distribution,
adaptation
Properties of the mineral Type & structure, chemical components,
particle size, prosity
processing Leaching mode, pulp density, flowrate, stirring
rate( tank leaching ), time
Literature review
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
10

11. ▪ Adaptation
The microorganism adaptation has been reported as being worthwhile, since it
increases the metabolic capacity and as a consequence the solubilisation of the
metals.
Influence of Bacterial
Adaptation on Copper
Bioleaching
Influence of Bacterial Adaptation on Copper Bioleaching from
Printed Circuit Boards. May 2018. University of São Paulo, Brazil
Literature review
11

12. Time
Provides more time for the acid and bacteria to react with the ore at the curing humidity, which
allowed for greater solid liquid interaction. This transformed the minerals in the ore, dissolving
mineralogical species and forming new more soluble ones.
Effect of Pretreatment on Leaching Primary Copper
Sulfide in Acid-Chloride Media. December 2017. Chile
Literature review
12

13. ❑ pH
• T. Ferrooxidans, T.Thiooxidans, L.Ferrooxidans are acidophilic which means that these bacteria can
grow and oxidise Iron in a pH range of 1 to 2.5. The strain used by silverman and lundgren in 1959,
Oxidised iron at a pH between 3.0 and 3.6.
• The optimal pH for oxidation and cell growth can vary between strains and is also dependent on
experimental conditions.
• A study on the effect of initial pH ranging from pH 1.0 to 1.7 on the bioleaching of chalcopyrite
concentrate by T. ferrooxidans showed that the dissolution rate of copper and iron increased when
using an initial pH of 1.0.
Nakazawa et al. (1998)
Literature review
13

14. ❖ Particle size
a) Ahonen and tuovinen (1995) stated that the leaching rates for metal sulphide ores increased
with a reduction in particle size and this effect was enhanced at lower pH values.
b) The reaction surface is a determinant factor in catalytic reactions.
c) Particle size, affects microbial performance by altering surface area available for bacterial
attachment.
d) The copper and nickel leaching rate approximately doubled when the particle diameter was
decreased from 5, 10 mm to 1.68, 5 mm.
Bioleaching of chalcopyrite. A thesis for the degree of DOCTOR OF
PHILOSOPHY. The university of Birmingham. 2003
Literature review
14

15. Well controlled column bioleaching of a low-grade
copper ore by a novel equipment. 2015
Literature review
15

16. ➢ What we have done?
Si
K
Ca
Ti
Cr
Mn
Element
13.39
1.08
9.28
0.17
0.21
0.12
%
Cu
Zn
Sb
S
Mg
Al
Element
3.06
4.26
0.19
1.12
1.53
3.02
%
-----
Na
O
Pb
Ba
Fe
Element
-----
0.43
35.46
2.42
0.26
24
%
13.39
Methodology
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching 16

17. •Using taguchi method for experimental design(L9)
level pH Particle
size(mm)
Flow rate(
𝒎𝒍
𝒎𝒊𝒏
) %Nitric acid
1 0.8 2-5 1 0
2 1.2 5-11 1.5 33
3 1.5 2-11 2 50
variable
Methodology
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching 17

18. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
•Shake flask tests
Methodology
ICP analysis
6 Erlenmeyers
Pulp density
20%
pH=0.8&1.5-
sulfuric & nitric acid and
their combination
Shaker incubator:
150rpm & 35 Celsius
Centrifuge
10 mins & 5000
rpm
1
2
3
4
5
6
18

19. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
NO pH Particle size (mm) Flow rate ( ml/min) % Nitric Acid
1 0.8 2-5 1 0
2 0.8 2-11 1.5 33
3 0.8 5-11 2 50
4 1.2 2-5 1.5 50
5 1.2 2-11 2 0
6 1.2 5-11 1 33
7 1.8 2-5 2 33
8 1.8 2-11 1 50
9 1.8 5-11 1.5 0
Methodology
✓ Column test
19

20. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
51.5
64
49.2
10.9
17.2 17.4
0
10
20
30
40
50
60
70
H2SO4 H2SO4/HNO3 1:1 H2SO4/HNO3 2:1
Acid
Consumption
(ml)
pH=0.8 pH=1.5
0%
20%
40%
60%
80%
100%
H2SO4
H2SO4/HNO3 1:1
H2SO4/HNO3 2:1
48%
84%
77%
74%
33%
53%
pH=0.8 pH=1.5
Results
20

21. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
Results
• Column pre-leaching
21

22. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
350
385
420
455
490
525
560
595
630
665
700
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
ORP(mV)
Time(day)
‫تیواکسیدانس‬ ‫تیوباسیلوس‬ ‫اسیدی‬ ‫فرواکسیدانس‬ ‫لپتوسپریلیوم‬ ‫فرواکسیدانس‬ ‫تیوباسیلوس‬ ‫اسیدی‬
• Growth curve Results
22

23. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
Results
• Bioleaching results
0%
10%
20%
30%
40%
50%
60%
C 1 C 2 C 3 C 4 C 5 C 6 C 7 C 8 C 9
Cu
extraction
Column NO
23

24. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
• Taguchi analysis
Results
24

25. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
Results
▪ Effects of pH, particle size
1 .8
1 .2
0.8
60.00%
50.00%
40.00%
30.00%
20.00%
pH
Cu
extraction
Boxplot of Result
25

26. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
▪ Effects of nitric acid & flow rate Results
26

27. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
Results
➢Optimal pH & particle size
27

28. Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
28

29. 1) Magnetic field has positive effects on bacterial growth by altering medium’s
surface tension.
2) It would have better efficiency, if thermophilic bacteria was used.
3) If there is no problem with operational cost, it is better to use tank bioleaching
to reach high copper recovery rate.
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching
Suggestions
29

30. 30

31. References
[1] h. R. Watling, “the bioleaching of sulphide minerals with emphasis on copper sulphides — A review,” vol. 84, pp.
81–108, 2006.
[2] d. Mishra, D. Kim, J. Ahn, and Y. Rhee, “bioleaching : A microbial process of metal recovery ; A review,” vol. 11, no.
3, pp. 249–256, 2005.
[3] r. Ngulube, M. Wanjiya, and K. Nyirenda, “AN OVERVIEW OF SUSTAINABLE COPPER RECOVERY
METHOD,” no. November, pp. 54–59, 2016.
[4] d. M. Urosevic, M. D. Dimitrijevic, and Z. D. Jankovic, “RECOVERY OF COPPER FROM COPPER SLAG AND
COPPER SLAG FLOTATION TAILINGS,” vol. 51, no. 1, 2015.
[5] a. Tahmasbi, S. B. S. A, a. R. Shahverdi, and M. Oliazadeh, “bio-assisted leaching of copper reverberatory furnace
slag,” pp. 4–6, 1994.
[6] h. Zilouei, S. A. Shojaosadati, and R. Khalilzadeh, “bioleaching of copper from low-grade ore using isolated bacteria
and defined mixed cultures,” vol. 1, no. 3, pp. 162–168, 2003.
[7] y. Wang, L. Zhang, C. Zhu, and M. Feng, “effect of particle size on the column bioleaching of tibet yulong copper
ore,” vol. 1130, pp. 375–378, 2015.
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching 31

32. [8] n. Jamett and Y. Ghorbani, “effect of pretreatment on leaching primary copper sulfide in acid-chloride media,” no.
1100685, 2017.
[9] w. Jun, H. U. Ming-hao, Z. Hong-bo, and T. A. O. Lang, “well-controlled column bioleaching of a low-grade copper ore
by a novel equipment,” pp. 3318–3325, 2015.
[10] s. M. Mousavi, S. Yaghmaei, M. Vossoughi, R. Roostaazad, and A. Jafari, “the effects of fe ( II ) and fe ( III )
concentration and initial ph on microbial leaching of low-grade sphalerite ore in a column reactor,” vol. 99, pp. 2840–2845, 2008.
[11] j. J. Plumb, R. Muddle, and P. D. Franzmann, “effect of ph on rates of iron and sulfur oxidation by bioleaching
organisms,” vol. 21, pp. 76–82, 2008.
[12] m. Dopson et al., “Silicate mineral dissolution during heap bioleaching,” vol. 99, no. 4, pp. 811–820, 2008.
[13] a. Halinen, N. Rahunen, A. H. Kaksonen, and J. A. Puhakka, “hydrometallurgy heap bioleaching of a complex sul fi de
ore part I : effect of ph on metal extraction and microbial composition in ph controlled columns,” vol. 98, pp. 92–100, 2009.
[14] e. M. Córdoba, J. A. Muñoz, M. L. Blázquez, F. González, and A. Ballester, “hydrometallurgy leaching of chalcopyrite
with ferric ion . part I : general aspects,” vol. 93, pp. 81–87, 2008.
Title: Investigation of Pre-leaching and particle size’s effects on copper slag bioleaching 32