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Waste to Value Creation: Metals and Metal Mining from Icelandic
Geothermal ProcessesArna Pálsdótt i r
I n co l l abo ra t i o n w i th : Sunna Ó la f sdó t t i r Wa l l ev i k and S ig rún N anna Ka r l sdó t t i r a t Geros ion and Jeffe rso n Tes te r , J ohn T hompso n and
Lau ra S inc l a i r a t Co rne l l U n ive r s i t yGEORG Geotherma l Wo rksho p 2016
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Dissolved materials in geothermal systems Amounts of dissolved materials highly
variable Generally detrimental to power
generation Fairly moderate amounts of dissolved
materials in Icelandic geothermal systems
─ Reykjanes system has highest TDS (about 30,000-40,000 mg/L)
Scaling in a pipe at Reykjanes, RN-9Photo: Vigdís Harðardóttir, 2011.
GEORG Geothermal Workshop November 2016
Valuable materials recovered from geothermal brines Fine table salt (NaCl) Silica
─ Fumed silica ─ Colloidal silica for health products─ Glassy products
Zinc─ Batteries─ Alloys
Manganese─ Steel─ Alloys
Lithium─ Batteries
3GEORG Geothermal Workshop November 2016
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History of metal extractions: Select examples Numerous attempts to recover metals from the Salton
Sea brines─ Early experiments to recover gold and silver─ Pilot scale zinc extraction from Salton Sea by CalEnergy in 2000s─ Demonstration scale lithium extraction from Salton Sea by Simbol
Materials in 2010s
A great deal of research on extractions in New Zealand and Japan
Gallup, 1992 and 1998; Simbol Materials, 2015 ; Salton Sea Funding Corporation 8-K, 2004
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Metal content and value in Icelandic systems Analysis of the value of metals in Icelandic geothermal
systems─ Paper by Kaasalainen et al, 2015, used for metal content
Metals with highest value identified
Base metals:─ Thallium
Precious metals:─ Germanium
Specialty metals:─ Cesium─ Rubidium─ Lithium
GEORG Geothermal Workshop November 2016
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Technical Challenges Typically low concentrations
─ Tl, Ge, Cs: 1-30 μg/L─ Li, Rb: 3-4 mg/L
High concentration of other dissolved species complicates separation processes
Chemical similarity to other dissolved elements can present challenges
─ E.g. germanium‘s similarity to silicon
Lithium and rubidium are the only feasible metals for extraction
Expensive extraction processes
GEORG Geothermal Workshop November 2016
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Research on lithium extraction Separation methods:
─ Precipitation methods─ Membrane transport─ Adsorption/ion exchange─ Supercritical fluid extraction
GEORG Geothermal Workshop November 2016
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Adsorption/Ion exchangeAdsorption /Ion exchange resins:
Requires silica removal and pH changes
Geothermal brines can decompose/dissolve adsorption media
Can be highly functional after silica removal
Harrison, 2014; Mroczek, 2015
GEORG Geothermal Workshop November 2016
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Supercritical fluid extractionFluid extraction:
Liquid-liquid extraction not feasible
Bi-phasic supercritical fluid extraction:─ No silica removal or pH changes─ Low residence times─ Pumping requirements
GEORG Geothermal Workshop November 2016
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Conclusions Lithium most attractive metal for extraction
─ From Reykjanes and Svartsengi brines
Most extraction methods researched require silica removal
Best options:─ Adsorption/ion exchange─ Supercritical fluid extraction
General comments:─ Volatility in metal market prices will affect options
─ e.g. the price of lithium has doubled in the last year─ Other metals, e.g. rubidium might become more attractive with new industrial
applications, e.g. catalysis
GEORG Geothermal Workshop November 2016
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AcknowledgementsGerosion: Sunna Ólafsdóttir Wallevik Sigrún Nanna Karlsdóttir Kolbrún Ragna RagnarsdóttirHS Orka: Kristín Vala Matthíasdóttir Albert AlbertssonInnovation Center Iceland: Þorsteinn I. Sigfússon
Cornell Univerisity: Jefferson W. Tester John F. H. Thompson Christopher A. Alabi
Funding for project:
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