3/22/20171

Recovery of Rare Earth Elements (REEs) from Coal Ash with a Closed Loop Leaching Process2017 Rare Earth Elements Portfolio Review

DE-FE-0027012

Period of Performance March 1, 2016 – August 31, 2017Principal Investigator: Rick Peterson, P.E.

Mike HeinrichsJustin Glier, Ph.D.Rachid Taha, Ph.D.Slawek Winecki, Ph.D.Kathryn JohnsonJackie Gerst

Battelle Memorial Institute505 King AvenueColumbus, OH 43201

petersonr@battelle.org

March 22, 2017

Project Goals and Objectives

• Validate economic viability of recovering Rare Earth Elements (REE) from coal byproducts using Battelle’s closed loop Acid Digestion Process Analyze and assess potential sources of coal byproducts as process feedstocks

Perform a techno-economic assessment based upon preliminary laboratory testing and process modeling

• Design a bench scale closed loop process for REE recovery from coal byproducts

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Presentation Outline

Project Overview

Sampling and Characterization Results

Preliminary Laboratory Testing Results

Feasibility Study Results

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Project Overview• Battelle proposed demonstration of a bench-scale

technology to economically separate, extract, and concentrate mixed REEs from coal and coal byproducts (AOI 1) Uses a closed loop acid leaching process incorporating the

Acid Digestion Process for acid recovery

Targets coal sources with >300 ppm REE by weight

Target concentration of >2% by weight for recovered REEs

• Award No. DE-FE0027012 $900,014 ($710,000 Federal;

$190,014 OCDO)

PoP = March 1, 2016 to August 31,2017

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Project Partners

• Battelle has identified project partners with the ability to support identification and procurement of high REE content coal samples The Ohio Coal Development Office includes key strategic partners such as AEP and can provide

access to coal ash samples and critical information for the economic feasibility assessment

Pennsylvania Bureau of Topographic and Geologic Survey will provide coal samples from their inventory for characterization

West Virginia Geological and Economic Survey will similarly provide coal samples from their inventory for characterization

5

Source: Rare Earth Elements in Coal Deposits – a Prospectivity Analysis

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Technical Approach• Proposed technology: concentration of rare earth oxides

and recovery of leach acid • Patented Acid Digestion Process previously demonstrated

for metal leaching and acid recovery at 70 lb/hr• Synergistic with current DOE/OCDO Project for direct coal

liquefaction

6

Rare earth oxides

Commercial separation and

purification processes

ConcentrationOhio coal ash- Fly Ash- Low Temperature Ash- Liquefaction Ash

Leach

Acid recovery

Makeup acid

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Sampling and Characterization Results

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Three Coal Ash Sources were Investigated

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High Temperature

Ash

ICP-MSMineralogy

ICP-MSMineralogy

Low Temperature

AshLiquefaction

Residual

ICP-MS

Densities:High, Medium,

Low

ICP-MSMineralogy

Particle Sizes: High, Medium,

Low

ICP-MSMineralogy

Coal

Sample Sources:• Pulverized Coal

Combustor (PCC) – 4 operating plants

• Fluidized Bed Combustor (FBC) – 1 plant

• Direct Coal to Liquids (CTL) – 1 pilot run

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PCC Fly Ash Tended to Have Higher REE+Y+Sc Concentrations than Bottom Ash

9

0

100

200

300

400

500

600

REE (ppm) REE+Y+Sc (ppm) HREE+Y (ppm) LREE+Sc (ppm)

ppm

PCC Fly Ash

Plant A Fly Ash Plant B Fly Ash Plant C Fly Ash Plant D Fly Ash

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0

100

200

300

400

500

600

REE (ppm) REE+Y+Sc (ppm) HREE+Y (ppm) LREE+Sc (ppm)

ppm

PCC Bottom Ash

Plant A Bottom Ash Plant B Bottom Ash Plant C Bottom Ash Plant D Bottom Ash

Fluidized Bed Combustor Ash was Diluted in Calcium

Calcium Total REE

Total REE+Y+Sc

HREE+Y

LREE+Sc

HREE/LREE

Weight Percent (%) ppm ppm ppm ppm RatioFluidized Bed Combustor Fly Ash 18.1% 147.5 188.1 38.6 149.5 0.26Fluidized Bed Combustor Bottom Ash 13.7% 121.4 153.2 30.5 122.7 0.25

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The low REE concentration in FBC is diluted in Limestone used to precipitate SO2, Reduce NOx and improve the heat transfer

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Higher Temperatures Lead to Formation of Refractory Phases

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Sample Percent Crystallinity

Middle Kittanning Coal

5%

Liquefaction Residual

7%

800°C Ash 35%1200°C Ash 42%

Battelle’s Direct Coal To Liquids (CTL) Separates Organic and Mineral Material

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Coal Liquefaction Increased TREE Concentration Over the Feed Coal on an Ash Basis

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0

100

200

300

400

500

600

700

800

Lu Sc Ce Dy Er Eu Gd Ho La Nd Pr Sm Tb Tm Y Yb HREE+Y LREE+Sc

CO

NC

ENTR

ATIO

N, P

PM

Feed Coal Low Density High Density >850 micron 600-850 micron 355-600 micron <350 micron

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Scandium Represents the Bulk of Material Value in the Fly Ash

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Preliminary laboratory testing

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Leaching Efficiencies Appear to Decrease at High Nitric Acid Concentrations

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ElementStarting Nitric Acid Concentration in PCC Fly Ash Leaches

17% 17% 17% 34% 51% 68% 34% (milled)

Sc 19.2% 20.8% 21.5% 21.5% N/A N/A 55.3%Y 24.6% 26.7% 28.0% 28.0% 14.9% 13.0% 46.9%La 19.0% 19.3% 20.0% 19.0% 9.9% 8.2% 35.4%Ce 21.0% 21.5% 21.7% 27.0% 11.9% 9.9% 34.0%Pr 20.3% 21.7% 22.4% 22.9% 11.6% 10.0% 36.3%Nd 20.8% 22.6% 23.4% 23.9% 12.3% 10.5% 39.5%Sm 22.5% 24.0% 25.0% 25.4% 13.7% 11.8% 40.5%Eu 22.7% 24.5% 25.4% 26.4% 14.8% 12.7% 42.4%Gd 25.0% 27.2% 28.5% 28.8% 15.7% 13.7% 45.2%Tb 23.3% 25.5% 26.9% 28.1% 15.4% 13.4% 44.3%Dy 24.1% 26.2% 27.6% 28.6% 15.5% 13.0% 41.9%Ho 24.6% 26.8% 28.0% 28.6% 15.2% 13.3% 41.8%Er 23.8% 26.2% 27.5% 27.8% 14.8% 12.6% 43.8%Tm 23.0% 25.2% 26.4% 26.9% 14.4% 12.0% 42.2%Yb 21.2% 23.1% 24.7% 24.8% 12.9% 10.6% 36.3%Lu 21.2% 22.6% 23.9% 24.3% 13.0% 10.2% 34.6%

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Serial Acid Contacts with Ash Decrease Leaching Rates

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0.00%

0.50%

1.00%

1.50%

2.00%

2.50%

3.00%

3.50%

4.00%

4.50%

5.00%

0 5 10 15 20 25 30 35

Perc

ent R

emov

al fr

om A

sh

Leach Time, minutes

Lutetium

1st Contact2nd Contact3rd Contact4th Contact

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Conceptualization of REE purification train.

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Compressive Strength Testing of Concrete Suggests Leached Ash Pozzolan Does not Adversely Affect Concrete Strength.

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Sample Description Cement (wt%)

Ash (wt%)

Sand (wt%)

Water/Cement weight ratio

Failure Pressure

AConcrete with post leached fly

ash 77 19 4 0.5 3,420 psiB Concrete with fly ash 77 19 4 0.5 3,420 psi

CConcrete without addition of fly

ash 77 0 23 0.5 3,250 psi

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Feasibility study

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Summary of Viable Coal Sources

Scenario

Revenue Requirement ($/tonne Coal

Ash Processed)

Percentage of Viable Coal Sources, Historical High

Prices

First-of-a-kind 103 25Nth-of-a-kind 62 47

CHEMCAD Simulation Has Been Developed to Model Proposed Plant

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• Model simulates a 30 tonne/day process. Sized to reflect full capacity of a typical coal plant.

• Laboratory testing results incorporated into process model: Species leaching efficiency

Acid loading capability

NOx generation rates

Acid roasting recovery estimates

• Model results used to inform equipment sizing parameters within TEA.

Approach to TEA follows EPRI’s TAG® method

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Installed equipment costs

E.H.O., Gen. Facilities, Contingencies

Fixed Charge Factor = Financial assumptions

Labor, utilities and feedstocks

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TEA results for FOAK and NOAK REE Recovery Plant

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Cost Component $Million per year (2015)

$/tonne Coal Ash

Processed

Annual Fixed Cost $5.4 $29Annual Variable Cost

$5.2 $28

Annualized Capital Cost

10.0 $56

By-Product Credits $(2.1) ($11)Total Annual Revenue Requirement

$19.1 $103

Cost Component $Million per year (2015)

$/tonne Coal Ash

Processed

Annual Fixed Cost $3.6 $20Annual Variable Cost

$5.2 $28

Annualized Capital Cost

4.7 $26

By-Product Credits $(2.0) ($11)Total Annual Revenue Requirement

$11.6 $62

First-of-a-Kind Plant Nth-of-a-Kind Plant

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Revenue requirement for FOAK and NOAK plants compared favorably to value present in coal ash.

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Summary of Viable Coal Sources

Scenario

Revenue Requirement ($/tonne Coal

Ash Processed)

Percentage of Viable Coal Sources, Current Prices

First-of-a-kind 103 5Nth-of-a-kind 62 20

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Next Steps

• Integrated Process Design Generation of Laboratory Test Plan

Laboratory testing to inform process design

Generation of design package for 100 lb/day system

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800.201.2011 | solutions@battelle.org | www.battelle.org

Selection of Analytical Method for Sample Characterization

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Comparison of Sodium Peroxide vs. Lithium Borate digestion using NIST sampleSodium Peroxide digestion method gives a closer result to the NIST reference material than Lithium Borate digestion

-70%

-60%

-50%

-40%

-30%

-20%

-10%

0%

10%

20%

As Ba Be Ce Co Cr Cs Cu Dy Eu Ga La Lu Nd Ni Pb Rb Sb Sc Sm Sr Ta Tb Th U V Yb Zn

Mea

n D

ista

nce

from

NIS

T Va

lue,

%

Element

Mean Distance from NIST Value as Percentage

Sodium Peroxide Lithium Borate

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