D2 Arna Pálsdóttir

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


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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


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Research on lithium extraction Separation methods:

─ Precipitation methods─ Membrane transport─ Adsorption/ion exchange─ Supercritical fluid extraction


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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


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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


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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


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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:

Engineering

D2 Arna Pálsdóttir