metallurgy integrated with biotechnology for gold recovery
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Keiko SASAKI Department Earth Resources Engineering
Kyushu University
12:15-12:40 Nov 24th 2021Brown Bag Seminar, QAOS
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Metallurgy integrated with biotechnology for gold recovery
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biohydrometallurgy
bio hydro metallurgy
バイオ ハイドロ メタラジー
バイオハイドロメタラジー
Environmental microbiologyBiogeochemistry
Chemical engineeringMetallurgy
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bio·hydro·metallurgy
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⽣物 湿式 冶⾦学
Micron scale miners
Microorganisms acquire energy through decomposition of minerals.
OresExtraction of
valuable metals
Cu
U
Zn
Ni
CoAu
Bioleaching(生物的浸出)
l Successful biotechnology business (annually 10 billion USD)
l 10% of Cu production is from bioleaching
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Biooxidation(生物的酸化)
Why Biohydrometallurgy ?
● Low grade ore can be explored 従来廃石とされていた低品位鉱石の開発が可能
● Advantages in environment, energy, safety and cost 環境面・エネルギー面・安全面・コスト面での優位性
● Depletion of high grade ore 高品位鉱石の枯渇
Indispensable technology for SDGs
● Necessity to recover rare metals from urban mines 都市鉱山からのレアメタル回収技術開発の必要
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CuNiZn
CuNiPbZn
Major producing countries of “base metals”(Cu, Ni, Pb, Zn)
PbMetal resources are localized in the specific areas, in particular developing countries.
Total share of the top 3 countries
オーストラリア
Copper price fluctuations are a barometer of the economy 7
Copper (Cu) is highly conductive and versatile material used everywhere.
Around 100 kg Cu is spent per one family!
10 yen coinCu 95%Zn 3-4%Sn 1-2%
電解銅Electrolyte copper
Cu 99.99%
銅鉱石Copper oreCu 0.1-1%
Natural copper
銅精鉱Cu concentrate
Cu 20-40%
MiningOre body blast
DiggingOpen cut
Mineral processing
GrindingMineral processing(Flotation)
RefiningFlash smelter
ConverterPurified furnace
Electrolytic furnace
Process from Cu ores to Cu products 8
採鉱
鉱物処理(選鉱)
製錬
biohydrometallurgy
2 x 3 km wide, 810 m depth
www.min.tu-clausthal.de
World largest scale of open pit Cu mines
Chuquicamata copper mines, Chile9
Chuquicamata
Clark et al., Hydrometallurgy, 2006
10Copper Extraction Technologies
EU largest scale of bioheap leaching Tarvivaara mines, Finland
2.4 km wide, 800 m deep, 15 m tall. Grain side: P80 = 8 mmAir up-flow, lixivium down-flow
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Tarvivaara
Bioleaching (生物的浸出)
Success in bioleaching reduced the number of employees from 2000 to 500.
Ni ore (with grade 0.22%) 1550 Mt
12Reaction inside the heap
~70ºC 15 m
eter
http://www.talvivaara.com/
Black shale from Talvivaara mines
Chalcopyrite CuFeS2 à CuPentlandite (Fe,Ni)9S8 à NiPyrrhotite Fe1-xSà NiPyrite FeS2 à CoSphalerite ZnS à ZnMicas (biotite/phlogopite) Graphite
Selective recovery depending on the solubility product (Ksp).
Sasaki and Tokoro, J. MMIJ, 127 (2011) 724-728.
M2++ S2- = MSKsp = [M2+][S2-] at
25˚C
CuS 8.0 x 10-36
ZnS 3.0 x 10-22
NiS 2.0 x 10-21
CoS 8.0 x 10-23
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tons
15Gold price chart
Au
16World largest open pit Au mines
Kalgoorlie gold mines, Australia
3.5 km long, 1.5 km wide and over 600 m deep1.5 g/ton, around 15 million ton of rock per year
Biooxidation (⽣物的酸化) 17
Bioreacter typeBirthplace of biooxidation
South AfricaBarberton mine
BIOX® Plant (1986~)
(340 m3 62 tpd)
Biooxidation of sulfides prior to cyanidation of gold
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Osseo-Asare et al, 1984, Prec. Met.: Min. Extrac. Proc.
Adsorption of Au(CN)2- on carbonaceous matter
CYANIDATION
Ag
Ag
Au
Au
Gold recovery from DRGO is <50%.
https://www.uky.edu/KGS/coal/coal-diagram-download.php
How to recover Au(0)?
Au(CN)2-
What is double refractory gold ore (DRGO)? 18
sulfides
silicates
gold
carbonaceous matter
Challenging history in recovery of gold from DRGO
Conventional method causes recovery loss by adsorption of Au(CN)2-on residual carbon.
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1000ºC
500ºC
calcinationSOx, As2O3 + Fe oxides
BIOX
sulfur-oxidizing bacteria
Lignin-degrading enzymes
CN-
Au(CN)2-
Au(CN)2-
Au(CN)2-
air pollution
“Gold-robbing”30~70%
Conventional
Novel
activated carbon adsorption
White-rot fungus
O2
CN-
CN-
O2
CN-
O2
carbonaceous matter
Sulfides(Fe, As, S)
gold(Au(0))
Past
Arriagada and Osseo-Asare, 1984
Konadu and Sasaki, 2017
Elemental compositions of DRGO (example) 20
Elements (wt%)
Fe S As C Si Al Na Mg Others
10.19*1 8.56*1 1.60*1 5.86*2 19.32*3 7.59*3 0.38*3 0.078*3 -
11.09*4 8.42*4 1.14*4 0.51*4 8.55*4 1.8*4 0.17*4 0.13*4 16.86
ØFlotation concentrate from an anonymous mine
ØEthanol washing to remove flotation reagent P80 of 75 µm
ØAu content 40.39 g/t
*1 acid digestion, *2 CHN analysis, *3 XRF analysis
Background 351800 2.9202952802…Fe Sulphides 3081956 25.583347244…Arsenopyrite 389568 3.2338078218…Gold 31 0.0002573313…Other Sulphides
12302 0.1021190236…Jarosite17 0.0001411171…Dolomite
8613 0.0714965982…Calcite3372 0.0279910053…Siderite
33 0.0002739333…Amphibole11530 0.0957106440…Illite/Kaolinite
741470 6.1549498050…Carbonaceous Illite1941246 16.114302249…C-Si-Al
1941724 16.118270132…Muscovite
161196 1.3380895906…K-feldspar
575411 4.7764924032…Quartz
2385398 19.801212395…Fe-oxyhydroxide
606264 5.0326034615…Carbonaceous Fe Oxide
43307 0.3594918354…Rutile
127587 1.0591009491…
Apatite
13487 0.1119557204…
Other
2215 0.0183867369…
Mineral Name Area (Mine… Area %
Liberated pyriteAssociated with quartz
Associated with carbonaceous illite Others
-100
0/+5
3 µm
-53/
+10 µm
-10 µm
QEMSCAN* map for DRGO 21
Mineral wt%Fe sulphides 15.04Arsenopyrite 2.45
Dolomite 0.09Calcite 0.03
Amphibole 0.07Illite/Kaolinite 3.44
Carbonaceous illite 7.62C-Si-Al 1.61
Muscovite 0.54K-feldspar 2.74
Quartz 9.62Fe-oxyhydroxide 3.56
Carbonaceous Fe Oxide 0.48Rutile 1.08
Apatite 0.14Others 0.02
Total (-1000 µm/+10 µm) 48.6710 µm
50 µm
200 µm
*Quantitative Evaluation of Minerals by SCANning electron microscopy
Au
C
Decomposition of powder activated carbon (PAC) in spent medium for Phanerochaete chrysosporium
Konadu, et al., Hydrometallurgy 168 (2017) 76–83.
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Abu
ndan
ce/ a
rb. u
nit
200 150 100 50 0Chemical shift/ ppm
biotreated PAC
PAC
arom
atic
C-H
alip
hatic
C-H
arom
atic
C=C
PAC1480 m2/g48 mmol-Au/g-AC
10 um
13C-NMR
biotreated PAC911 m2/g16 mmol-Au/g-AC
10 um
Phanerochaetechrysosporium
White rot fungusto release oxidizing enzymes
(LiP, MnP etc) and H2O2
Sequential biotreatment should be performed to decompose in the order of sulfides and then graphitic carbon. Konadu, et al., Mineral. Engng., 138 (2019) 86-94.
iron-oxidizing archaeon
LiP, MnP
Gold recovery after sequential biotreatments of DRGO 23
pH 1.5@70ºC
pH 4.0@37ºC
Phanerochaetechrysosporium
Comminution
Cyanidation for gold recovery
pH adjustment & enzyme treatment
Fungal culturepH 4.0 and 37°CEnzyme
treatmentpH 4.0 and 37°C
Mill
DRGO
Cell Free Spent
Medium (CFSM)
P. chrysosporium
medium
Alkaline washing0.1~1 M NaOH, RT
NaOH and Ca(OH)2
CyanidationpH 11
KCN
Alkaline washing
Biooxidation of sulfides
BiooxidationpH 1.5 and 70°C
A. brierleyi
Proposed process to treat double refractory gold ore 24
Konadu, et al., Hydrometallurgy, 196 (2020) 105434.
References and acknowledgements 25
JSPS KAKENHI 18HP0703JSPS KAKENHI JP19KK0135
JSPS International Exchange Program JPJSBP120196505 JSPS International Exchange Program JPJSCCB20200003 JSPS International Exchange Program JPJSBP120219929
公益財団法⼈ 新井科学技術振興財団 ARAI SCIENCE AND TECHNOLOGY FOUNDATION
Interdisciplinary fusion with agriculture Academic-industrial collaboration
Collaborators:Hirofumi Ichinose
Kojo T. Konadu (Ghana)Diego M. Mendoza (Peru)
Ryotaro SakaiCindy (Indonesia)
Ikumi Suyama
External collaborators:Yuji Aoki (SMM)
Nana Murase (SMM)Jacques Eksteen (AUS)
Richmond Asamoah (AUS)Susan Harrison (SA)
Didi Manuka (SA)Takashi Kaneta (Okayama)
Grace Ofori-Sapong (Ghana)Clement Owusu (Ghana)
International collaboration with Ghana and US
International collaboration with South Africa
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JSPS KAKENHI 18HP0703
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40% ladies!
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JPJSCCB20200003FY2020-2022
超難処理⾦鉱⽯のバイオハイドロメタラジー研究拠点の形成
Advanced Research Network for Biohydrometallurgy of Double Refractory Gold Ore
Coordinator: Keiko Sasaki(Kyushu University)40% ladies!
International MOU through international collaboration 29
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