Permanent Magnetsfor Energy Applications

Part 2Stan Trout

August 11, 2014

Permanent Magnets for Energy Applications Part 2• Rare Earths

– Basic facts– The crisis– Mines– Applications

• Magnet Recycling• Permanent Magnet Selection &

Specification• Case Studies• The Future

Rare Earths

Sc Y La

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Rare Earths 101

• Ores contain all rare earths except Pm• The rare earths are chemically very similar• There is no shortage of ore for light RE’s

– Bastnasite & Monazite are the most common• Most ores are rich in Ce, La, Nd and Pr

– Not all rare earths are rare in the Earth• Magnetic, optical, electronic and catalytic

properties vary widely• The lanthanide contraction• Producers try to balance supply and

demand– And are rarely successful!

Dilbert, February 28, 2011

Critical Materials Institute

• DOE Program– $120 million, 5

years– National Labs– Academe– Industry

• Reduce criticality• CMI opened

officially on Sept. 10, 2013

Source: DOE Announcement May 2012

Recent RE Metal Prices

Source: U.S. Geological Survey

Two Confusing Points

• Analysis and Recovery, are not the same thing

• Balance– What is it?– Why it is important to the RE industry

and to customers

Rare Earth Analysis

Source: Castor, Resource Geology vol. 58, No. 4, 337-347 (2008)

The Castor Analysis

• Original report 1986, almost 30 years old

• First Mass Spec-ICP• A single sample• Widely quoted, sometimes abridged to

omit heavy RE’s• Widely believed to predict recovery

accurately– At best only an upper limit

Analysis vs. Recovery

Analysis• Goal: understand

composition• Scale: 10 gram• Digestion: complete

as possible• Separation: no

Recovery• Goal: sell into

marketplace• Scale: 1010 gram• Digestion: appropriate

for scale and market• Separation:

appropriate for market conditions

Balance• The attempt by each rare earth

processor to balance the available ore with the needs of the marketplace.

Source: Kingsnorth

Bayan Obo mine ,near Baotou, ChinaPhoto from Google

Earth

1 km

Mountain Pass, CA, Source: Molycorp

~1 km

Rare Earth Sources

• Active mines– China

• Baotou• Ionic Ores

• Mines coming on stream– USA

• Mountain Pass, CA

– Australia• Mt. Weld

• Under Development– Australia

• Nolan’s Bore

– Canada• Hoidas Lake• Nechalacho

– India– Brazil– USA– Vietnam– Russia

Early Lighting Options

WelsbachCandoluminescence

EdisonIncandescence

Source: Wikipedia

Source: Auer Licht

Source: Gas Light Guys

Lighting Phosphors

Lighting Phosphors

• What we see depends on the phosphors

• Red: Y2O3: Eu

• Green: (La, Ce, Tb) PO4

• Blue: BaMgAl10O17:Eu

Source: GE Lighting

Compact Fluorescent Lights (CFL)

Fluorescent Lighting

• Advantages– Higher output

• 58 lu/W vs. 13.5 lu/W

– Lower operating cost

• 10 W vs. 40 W

– Longer life • 12,000 hrs vs. 1,000

hrs

• Disadvantages– Slightly higher

price– Difficulty dimming– Unappealing light?

• Cheap bulb = cheap phosphors

– Hg in bulb, special disposalData source: GE

Lighting

Automotive Catalysts

Source: BASF The metal oxide is cerium

Refining Catalysts

• Fluid Cracking Catalyst (FCC)– A traditional use of lanthanum– Ideal for heavy crude to make gasoline– Ion-exchanged zeolite (cat litter)– Variable demand

• Driving season and heating season• Available crude oil

Current Magnet Applications

• Hard drive– Voice Coil Motor (VCM)– Spindle motors– 5 x 108 per year

Source: Western Digital

Current Magnet Applications

Cruise Control

Mirror MotorsTailgate

MotorDoor Lock

MotorFour Wheel

Steering

Anti-skidSensor

and Motor

WindowLift

Motor

SuspensionSystem

FuelPumpMotor

Seat Belt

MotorSeat

AdjustMotors

Antenna

LiftMotor

TractionControl

Heater-A/C Blower Throttle

and Cranksha

ftPositionSensors

WindshieldWiperMotor

StarterMotor

CoolantFan

Motor

IgnitionSystems

HeadlightDoor

Motor

Economy and

PollutionControl

LiquidLevel

Indicators

Windshield

WasherPumpGauges

CDPlayer

HeadRest

MotorSunRoof

Motor

ElectricPower

Steering and Sensor

Lumbar Support

AutomaticTemperature

Control

DoorGasket

DefoggerMotor

Speakers

Source: Magnequench

New Rare Earth Magnet Applications

• Automotive– Hybrids– Electric vehicles

Source: Toyota

Emerging Magnet Applications

The basic components of a wind turbine.

Source: Department of Energy

Emerging Magnet Applications

• Wind Turbines– Reliability– The gearbox– About 500 kg of

magnet per MW– Small % use

magnets– 260 GW more in US

by 2030*

Source: Vestas AS

*Source: AWEA.org

Recycling

• Historically unimportant– Value– Difficulty

• Interest rises and falls with prices• Two areas of interest

– Eu, Tb and Y oxides from lighting phosphors

– Nd and Dy from magnets, mainly hard drives

Material Selection & Specification of Permanent Magnets

• Motivation• Basic Considerations• Advanced Considerations• Specification• Checklist

Motivation

• Gross oversimplification• Errors of omission• Lack of protocol

Basic Considerations

Advanced Considerations

• Physical• Mechanical• Corrosion• Magnetizing

• Assembly• Adhesives• Testing

Writing a Specification

• Two Approaches– What I happen to have

– What I actually need• Avoid Contradictions• IEC or IMA (MMPA) standards• Supplier Reference, or equivalent

Checklist

• Magnetic parameters• Flux variations• Dimensions/Tolerances• Testing• Magnetizing

• Coating• Adhesive• Assembly• Others

Case Study 1

• Direct substitution of bonded NdFeB for ferrite– Saturated return structure– Poor performance

• Increase the thickness of the return path, more poles

Case Study 2

• Bonded NdFeB ring for angle sensing application– Incorrect magnetization (axial) yields poor performance– Correct magnetization, with hairpin fixture, yields good

signal and contained flux

B = Br ln (do/di)

Case Study 3

Window Lift MotorToyota Prius and Toyota

Harrier

Source: Dr. B. GriebMagnequench

3D Model of Benchmark2 Pole PMDC (Brush Motor)Skewing on the armature teeth

Torque-Speed and Torque-Current Characteristics for the Benchmarked and

Redesigned Motors

Torque-Efficiency Characteristics for the Benchmarked and Redesigned Motors

Benchmarked Motor

Redesigned Motor

1 1 1 1 1 1

0.74 0.74

0.88

0.380.44

0.99

Diameter Length Width Weight Volume Cost

2-Pole Ferrite 4-Pole Bonded Neo

The Future• Niels Bohr, “Prediction is very difficult,

especially about the future.”• Supply and Demand are dynamic• Overreacting and underreacting are

normal– Supply– Demand– Government

• Finding equilibrium is difficult & takes time• Energy conservation is a major driver• We need to use these materials wisely

Permanent Magnets for Energy Applications Part 2• Rare Earths

– Basic facts– The crisis– Mines– Applications

• Magnet Recycling• Permanent Magnet Selection &

Specification• Case Studies• The Future