Looking Down Under for a Circular Economy of Indium

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Looking Down Under for a circular economy of indium Tim T. Werner, Luca Ciacci, Gavin Mark Mudd, Barbara K. Reck, and Stephen Alan Northey Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.7b05022 • Publication Date (Web): 04 Jan 2018 Downloaded from http://pubs.acs.org on January 4, 2018

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Environmental Science & Technology

Looking Down Under for a circular economy of indium

1 2 3 4 5

Tim T. Werner1,4*, Luca Ciacci2, Gavin Mark Mudd1, Barbara K. Reck3, Stephen Alan Northey4

6 7

1 Environmental Engineering, School of Engineering, Building 10, Level 13, Room 5a, RMIT University, Melbourne, VIC, Australia

8

2

Dipartimento di Chimica Industriale "Toso Montanari", University of Bologna, Viale del Risorgimento 4, Bologna, Italy

9

3

Center for Industrial Ecology, School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511, USA

10

4

Faculty of Engineering, Monash University, Clayton, VIC, Australia

11

*

Corresponding author: [email protected]

12 13

Abstract

14 15

Indium is a specialty metal crucial for modern technology, yet potentially critical due to its by-

16

product status in mining. Measures to reduce its criticality typically focus on improving its

17

recycling efficiency at end-of-life. This study quantifies primary and secondary indium

18

resources (“stocks”) for Australia through a dynamic material flow analysis. It is based on

19

detailed assessments of indium mineral resources hosted in lead-zinc and copper deposits,

20

respective mining activities from 1844-2013, and the trade of indium-containing products

21

from 1988-2015. The results show that Australia’s indium stocks are substantial, estimated

22

at 46.2 kt in mineral resources and an additional 14.7 kt in mine wastes. Australian mineral

23

resources alone could meet global demand (~0.8 kt/year) for more than five decades.

24

Discards from post-consumer products, instead, are negligible (43 t). This suggests that the

25

resilience of Australia’s indium supply can best be increased through efficiency gains in

26

mining (such as introducing domestic indium refining capacity), rather than at end of product

27

life. These findings likely also apply to other specialty metals such as gallium or germanium,

28

and other resource-dominated countries. Finally, the results illustrate that national circular

29

economy strategies can differ substantially.

30 31 32 33

ACS Paragon Plus Environment


Highlights

34 35 36

1.

A product-level dynamic material flow analysis of indium in Australia is presented.

2.

Australia hosts large quantities of indium in mineral deposits, tailings and slags.

3.

Australia’s in-use stocks of indium are minor in comparison to mineral resources, tailings and slags. On a per-capita basis, our results show that recycling will not provide adequate quantities of indium even in other developed countries with higher populations than Australia’s. Policies to improve primary refining capacity should instead be favoured.

37 38 39 40 41 42 43 44 45


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1.

46

Introduction

47

Critical metals are those that are important to society, but which are problematic to supply.

48

This can be due to their supply chains being at risk of some constraint (e.g. geopolitical in

49

nature or due to concentrated supply chains), and/or their production being environmentally

50

harmful1, 2. A number of studies have quantified these factors to establish ratings of metal

51

criticality, generally agreeing that the specialty metals used in modern technologies like

52

indium, germanium, gallium, antimony and the rare-earth elements are typically the most

53

critical3-9. Despite this classification, these metals often remain less economic to extract for

54

mining and/or metal refining companies than major metals such as zinc, copper, gold or

55

silver. The lesser economic value of the critical metals means that of the many mines and

56

processing facilities that could produce these metals, only a select few actually do so. Global

57

mining activities therefore result in the continuous extraction of rock containing critical metals,

58

but with large portions of these metals being lost during various stages of mineral processing

59

and separation8.

60

Indium is one such metal that is often considered critical (e.g. European Commission

61

is poorly studied and remains inefficiently produced and recycled. Given its primary uses in

62

LCD/LED displays and solar panels, it is projected that indium demand (currently ~800 t/year)

63

will continue to increase for the foreseeable future11. Recent estimates of the global mineral

64

resources of indium show that mineral resources are not a limiting factor for demand this

65

century12. However, while large resources exist even outside of the current suite of

66

producing countries, the production of refined indium remains concentrated in China and a

67

small number of other producers, placing risks and limitations on the actual supply of refined

68

indium to the global market in the short to medium term. This was highlighted in a recent

69

study by Frenzel, et al.13, who found that indium is at risk of reaching its full production

70

potential sooner than other critical metals such as germanium and gallium. The pertinent

71

question around future indium supply is therefore not whether we as a society will run out of

72

indium, but which pathway for supply is the most resilient and sustainable in the medium to

73

long term. It is here that material flow analyses can shed new light, namely by highlighting

74

how this metal is currently used, and where it accumulates as a waste or potential resource

75

(e.g. Chen & Graedel14). This study examines the stocks and flows of indium in Australia, a

76

resource-rich economy which exports large quantities of indium’s hosts zinc and copper, but

77

produces no critical metal by-products of these metals. We employ a detailed product-level

78

dynamic material flow analysis to analyse quantities of indium within mineral resources,

79

through to end of life wastes and draw conclusions on Australia’s potential to become a

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major supplier of refined indium in future.


10

) yet


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2.

82

Methods

83

A national scale material flow analysis involves the characterisation of a number of stocks

84

and flows along the life cycle of a metal. In Fig. 1, a generalised life cycle for indium in

85

Australia is shown. The stocks (shown in blue and green) represent locations of interest for

86

their future resource value. The flows (grey arrows) are of interest because they determine

87

the rates of stock accumulation. The nodes shown in orange are processing stages where

88

materials are transformed, which ultimately affect the direction and magnitude of the flows.

89

This study aims to characterise, quantify and analyse each of these components for the

90

years 1988-2015, although early stages in the indium cycle are characterised as far back as

91

1844 due to the availability of detailed mining production data.

92

The starting point of any metal cycle is its extraction (or mining) from stocks in mineral

93

deposits. Indium mineral resources in Australia were determined using an approach of

94

estimating contents of indium in individual deposits. For those deposits where contained

95

indium was not explicitly reported by mining companies or in the literature reviewed, indium

96

grades were inferred using a proxy method developed in previous work, which the reader is

97

referred to for discussion of uncertainty 12.

98

The trade of ore and concentrates over time was determined from various past and present

99

Australian government agencies (e.g. Bureau of Mineral Resources (BMR), Australian

100

Bureau of Agricultural and Resource Economic (ABARE), and the Office of the Chief

101

Economist (OCE))15,

102

deported to concentrates that would ultimately become domestic slag, or be exported to

103

overseas refineries (of which only a portion is actually extracted17). These trade data allowed

104

the present day resource estimate of indium to be backtracked to the beginning of mining

105

activity in Australia. The relative proportions of mined indium appearing in various product

106

and waste streams was determined from a review of individual deposits where indium

107

deportment data were available. These indicated a range of deportment values, of which the

108

average was taken (see Table S2), allowing for the accumulation of indium in mine tailings to

109

be estimated. The wastage of indium in Australian refinery slags was not necessary to

110

examine in detail, as a lack of domestic refining capacity for indium implies that all indium in

111

domestically shipped concentrates is destined to appear in slag.

112

In assessing the flows of indium beyond the mining and mineral processing sectors, the

16

or direct company reporting, indicating the proportion of indium

113

method broadly followed the retrospective dynamic MFA approach described by Müller, et al.

114

18

, with the addition of a product-level analysis as described by Harper


19

. A review was

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115

conducted to identify all of indium’s past and present applications in society, particularly in

116

Australia. A set of trade tariff codes that encompass these applications was determined20-22,

117

resulting in 8 semi-finished goods and 23 end use goods identified as relevant to Australia.

118

Subsequently, Australia’s trade of indium-containing products was calculated by obtaining

119

historical import/export data of these codes (notably from the United Nations Comtrade

120

database, supplementary tables S3-4). An additional table of codes pertaining to indium

121

which might be relevant for indium MFA of other countries is provided in Table S5. As

122

multiple products can be traded under a singular tariff code, it was necessary to determine

123

the market share of those products which do or do not contain indium. This information was

124

obtained through a combination of literature review and direct industry contact. Estimates of

125

the content of indium within the indium-containing products were also necessary, including

126

considerations of how indium contents in a particular product might change over time (e.g.

127

changing average screen sizes in a TV or computer monitor); these were obtained from a

128

broad literature review and all assumptions and references are provided in the

129

supplementary material (Tables S6-9). Contents were estimated using arithmetic averages,

130

with upper and lower bounds representing three standard deviations of uncertainty. These

131

uncertainty bounds were extended to estimates of in-use stocks. A detailed breakdown on

132

the methods and assumptions used for the analysis of indium in solar photovoltaic cells is

133

provided by Werner 23.

134

In addition to the volumes of traded indium, domestic manufacturing potential was also

135

considered. An approach of reviewing Australia’s manufacturing capacity in a number of

136

indium-relevant sectors was employed, highlighting a number of key companies potentially

137

producing indium-based products or requiring indium intermediates. This was cross checked

138

with a general approach of reviewing literature which lists major producers of indium-

139

containing products or intermediates. These sources often excluded Australia as a producer

140

in many cases, allowing certain sectors or products to be ruled out for further analysis (e.g.

141

24, 25

142

producers of a particular indium-containing product/intermediate were not known, domestic

143

production was assumed to exist at a level proportional to global production for that year

144

(using total GDP or GDP per capita). Given Australia’s small population and estimated

145

imports of semi-finished goods, this assumption had little effect, but is noted as a source of

146

uncertainty. The apportionment of semi-finished goods for domestic manufacturing of

147

indium-related products is shown in Fig. 2, alongside estimated production losses. The

148

construction of this figure was based on global averages, except where more information

149

about the Australian context was available (e.g. lack of indium tin oxide (ITO) manufacturing

150

from unwrought indium). Losses in production may arise from the manufacture of LCD/LED

). Where actual production data were not available from individual companies, or the



151

products architectural glass, and solar panels, but were assumed to be negligible for alloys

152

and thermal interface materials for printed circuit boards. Further detail on the losses of

153

indium during manufacturing processes is available from

154

effect of these losses is minimal in the context of the overall Australian indium cycle. Given

155

the prevalence of ITO recycling in recent years, it was assumed that ITO imports were also

156

recycled. While this could not be independently verified, this assumption had minimal effect

157

on the overall throughput of indium to end of life goods, and was maintained as a

158

conservative overestimation of Australia’s potential indium use.

159

Finally, the stages of product use and end of life were analysed using probabilistic lifetime

160

functions which estimate the time a product spends in use before either being recycled or

161

landfilled. Lifetime distribution variables and sources are listed in Table S10. Some

162

estimates of in-use stocks were cross referenced with external data or bottom up studies to

163

verify the validity of our assumptions around product stocks and lifetimes. Losses due to in-

164

use dissipation were assumed to remain negligible as per Ciacci et al. 30.

26-29

165 166


, although as noted later, the

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167

3.

Results and Discussion

168

3.1 Resources, mining and mineral processing

169

Mineral resources of indium in Australia are estimated at ~46,213 t In among 247 mineral

170

deposits, mapped in Fig S1. Such quantities, if extracted and refined, would be sufficient on

171

their own to meet global demand for many decades, although at present the infrastructure

172

and economic drive within the Australian mining industry does not exist to support such

173

activities. The apportionment of indium in various Pb-Zn and Cu mineral processing wastes

174

over time (namely, mine tailings and smelter/refinery slags) was also assessed (Fig S2).

175

Information on indium deportment was necessary to determine the proportion of indium in

176

these flows, however indium deportment is poorly understood at a global level. Only studies

177

listing these values on a case study basis were identified (Table S2). These suggested that

178

some 65% of milled indium typically appears in Pb and Zn concentrates, with ~19%

179

deporting to tailings and the remaining ~%16 to other various concentrates. Given

180

Australia’s lack of domestic refining capacity for indium, the indium content of locally

181

processed concentrates reported annually was assumed to remain in slag. This leads to the

182

first finding that at least ~14,750 (±3,062) t In has accumulated in Australian slags and

183

tailings, a very large figure in relation to Australian or even global demand. Notably, as there

184

are significantly fewer refineries than mines, the quantities present in slag are concentrated

185

in a handful of locations (e.g. Risdon and Townsville). It is possible that the economic value

186

of indium and other unprocessed critical metals present in these wastes provides some

187

incentive for recovery or rehabilitation in future. However, the reprocessing of tailings and

188

slags presents new technical challenges (e.g. the remaining minerals are often more

189

refractory31) meaning the indium contained is largely uneconomic to extract. It is perhaps

190

more likely that if Australia did produce indium in future, it would be as a by-product during

191

the initial processing of Zn and Cu. However, this will be dependent on whether increasing

192

indium criticality or prices arise to foster a better strategic or economic case for recovery.

193

Past economic conditions have led to at least 18,600 t In in mined ore and concentrates

194

being exported since 1844, without the apparent need for consideration of these quantities

195

by Australian mining companies.

196

For the majority of the trade history assessed, large portions of indium-laden concentrates

197

would not have reached smelters capable of extracting indium (even only ~30% in recent

198

years). For the remaining portion, a typical recovery rate of 50% is assumed, suggesting that

199

~35% of indium in concentrates will end up being refined17. However, as shown in Table 1 of

200

Werner, Mudd and Jowitt 11, other studies estimate a much lower proportion only a few years

201

prior. Using these fluctuating published values of processing efficiency, it is possible to



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202

estimate what percentage of indium exported in Australian concentrates was refined at

203

overseas facilities over time. Using global production data available from the USGS32 we

204

estimate that some 20% of global indium production in recent years has been initially

205

sourced from Australia (Fig. 3). The calculated peak in the 1980’s is attributable to a decline

206

in global indium production coinciding with a period of substantial reported Australian zinc

207

concentrate exports. This peak is possibly a result of limited location-specific data for

208

concentrate exports. Considering the annual price of refined indium and accounting for

209

inflation to 2015 dollars, it is estimated that at least US$1.19 billion

210

production has originated from Australian exports since 1972. Nearly all of this value can be

211

attributed to the companies operating the refineries in which indium separation took place,

212

as the price of specialty metal by-products are rarely (if ever) accounted for in the sale of

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concentrates8.

of refined indium

214 215

3.2

Net imports of semi-finished and finished products

216

The analysis of trade volumes, market shares, domestic manufacturing capacity, and indium

217

contents in products over time enabled an estimation of Australia’s net imports of semi-

218

finished and finished goods. Large uncertainties arise from market share and indium content

219

estimates. This is mainly due to limited data and issues with aggregated reporting of HS

220

codes which contain multiple products, only some of which contain indium. Additional

221

uncertainties of applying the dynamic MFA methodology to a metal with as little data

222

available as for indium are discussed in Ciacci et al. 33. Our results for net imports have been

223

checked against other studies (e.g. Ciacci et al.

224

remain reasonable by these standards. While we perform product level analyses of trade

225

flows (see Fig S3), it is possible to aggregate these to end-use sectors to enable a

226

comparison with prior studies of indium usage at this scale. Such a comparison is given in

227

supplementary figure S4.

228

It is estimated that Australia now imports 1328-6566 (avg. 3606) kg In/yr in semi-finished

229

forms and ~2293-5226 (avg. 3707) kg In/yr in finished products, representing a significant

230

increase in recent years. LCD/LED screens for TVs, laptops, tablets and desktop computers

231

account for the majority of imported indium to Australia (at least since 1995). This is rather

232

unsurprising, given the rapid increase in the use of these products in recent years. The

233

indium contained in solar panels has become a major factor since 2009/10, which is

234

consistent with industry statistics showing an exponential increase in solar photovoltaic (PV)

235

installations on Australian households from this time35. The imports of solders, alloys and

33

, Zhu, et al.


34

, see also section 3.3) and

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236

miscellaneous chemicals contribute only marginally to Australian indium use.

237 238 239

3.3 Stocks in use and assessment of uncertainty

240

In addition to the direct imports of semi-finished and finished goods, domestic manufacturing

241

was considered and apportioned as per Fig. 2. It was found to be particularly difficult to find

242

production statistics for goods containing indium in Australia. Hence, for the most part, it was

243

necessary to review literature to verify whether Australia was listed as a source for any

244

indium products, and whether manufacturing capacity existed in Australia for products

245

containing indium (see supplementary Table S11). Quantities imported for domestic

246

manufacturing were assumed to be processed at global average processing efficiencies as

247

per Fig. 2, and then added to direct imports of finished goods. For the production of products

248

containing refined indium, rates of dissipation may be assumed to range from 5% for ITO-

249

containing goods (as per Ciacci, et al.

30

) and 10% in all other cases (as per Zimmermann

36

250

and Gößling-Reisemann

251

losses occurring during use, and so these were assumed to remain negligible. Following the

252

top-down approach for in-use stock estimation (described in Gerst and Graedel

253

and Graedel

254

should be noted that the majority of these functions have been assigned based on studies

255

conducted outside of Australia, and hence may not reflect Australian consumer behaviour

256

with respect to indium-containing goods. The exception is Golev, et al.

257

mobile phone lifetimes based on Australian consumer survey data. The resulting annual

258

estimation of in-use stocks of indium in Australia is provided in Fig. 4. It shows that Australia

259

might be approaching saturation of in-use stocks from around 2012, had it not been for the

260

boom in solar PV installations occurring around this time, which contributed to the estimate

261

of approx. 25 t In in use by 2015. The apparent saturation of indium stocks in LCD displays

262

is consistent with the phase out of cathode ray tube (CRT) screens, and the introduction of

263

newer generation TVs now largely replacing LCD screens. The introduction of tablet

264

technologies in recent years can be seen to have had a noticeable influence on in-use

265

stocks, however the dominant reservoir of indium is in flat panel TV’s, due to their larger

266

screen size. Thus, if policies were implemented to explore recycling as an avenue for indium

267

supply, TV’s would present the most obvious target for collection. This may change in

268

coming decades as solar panels have a longer assumed lifetime (~28 years40).

269

It should be noted that there are considerable uncertainties associated with the in-use stock

270

estimates shown in Fig. 4. While the error bars indicating the uncertainty due to prior market

38

), however there is little information pertaining to dissipative 37

and Chen

), lifetime probability functions were used for each product (see Table S10). It


39

, which estimates


271

share and product content estimates appear reasonable, they do not encapsulate the

272

uncertainty associated with other possible estimates for product lifetimes. In many cases, it

273

was only possible to find one reference for relevant product lifetime parameters, and hence

274

the exploration of the effect of varying these parameters was limited and could not be

275

quantified to the extent that they could be incorporated into these error bars. It appears that

276

these results are more sensitive to product lifetime estimates than to product content

277

estimates. To at least partially address this source of uncertainty, these results have been

278

compared with Zhu et al.

279

survey data of Australian households, and Ciacci et al.

280

indium in Europe using a similar approach to this study. Table 1 shows the comparison of

281

our results in four product categories to that of Zhu et al.

282

uncertainties, and considerably different approaches taken, it is encouraging that our results

283

are in the same order of magnitude, and reflect the same relative scale between product

34

, who assess in-use stocks of indium in Australia using based on 33

, who assess in-use stocks of 34

. Given the large number of

284

categories. That our estimates are higher on average is perhaps explained in that Zhu et al.

285

34

286

We can compare to Ciacci et al. 33 in terms of per-capita stocks as the population and hence

287

total in-use indium stocks in Europe are considerably higher. We found that in-use stocks of

288

indium appears to have grown to around 1.1 g In per capita in recent years, which is highly

289

consistent with an assessment of ~1 g In per capita in Europe. While stocks in LCD displays

290

have quadrupled in recent years, Fig. 4 shows that this has somewhat plateaued. However,

291

solar PV installations remain as a growing category. Certainly the cost of installing solar PV

292

has decreased41, suggesting that installations will continue to push growth in in-use stocks of

293

indium in this category. Australia’s solar PV capacity has been projected to increase tenfold

294

from 2017 to 204042, suggesting that in use indium stocks in this category could increase

295

accordingly. If it is assumed that all other product categories are in fact saturated, and

296

indium in solar panels increased to this level, a new high of ~2.3 g In/cap is calculated (Fig

297

S5). As Australia ranks second on the human development index43 (HDI), this value might

298

feasibly represent a higher end estimate for what other countries might achieve as they

299

develop further (pending no major changes to indium’s applications in society). If China were

300

to sit at this upper estimate, its current population (~1.382 Billion) would result in an

301

estimated 3,179 t In in use. Similarly, the global population of ~7.5 Billion at this high end

302

figure equates to ~17,250 t In in use. These resources are of course dispersed among

303

millions of products, making this indium resource difficult to collect and process as a whole.

304

Furthermore, only ~20% of this is currently recyclable30, suggesting global in-use stocks

305

might provide 3,450 t In if collected and processed. This value is less than 1% of estimated

do not consider stocks in use for commercial applications.


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306

global indium mineral resources of over ~356,000 t In44, and unlikely to foster significant

307

changes in the supply security of this critical metal if recovered.

308 309 310

3.4 Australian indium cycle and future research

311

The combined results of our analyses are presented in Fig. 5. It can be seen that the

312

quantities in both stocks and flows occupying earlier stages of the Australian indium cycle

313

are significantly greater than that of end of life, largely due to low recovery rates in mining

314

and mineral processing. This is not particularly surprising for a relatively resource rich and

315

low population country like Australia. However, as a developed nation, the magnitude of

316

stocks in use on a per-capita basis is notably low. Alongside similar per-capita results

317

estimated for Europe33, this highlights that other developed countries are likely to also

318

possess low in use stocks of indium. Globally, the end-of-life recycling rate for indium is

319

estimated to be less than 1%45, which has led some to suggest that recycling rates of indium

320

must be improved45-50. Some studies go on to highlight that a focus on product design and

321

waste management strategies are virtually essential to managing the future supply of

322

indium49-51. Our study presents an alternative view that efforts to secure future indium

323

supplies would be better focussed on the construction of new indium circuits in existing zinc

324

processing facilities. Following this, any efforts to improve the technical or economic

325

feasibility of extracting critical metals from mine wastes appear worthwhile, given the large

326

quantities that could potentially become unlocked. .

327

Potentially thousands of tonnes of indium are estimated for the slags of the zinc processing

328

facilities in Port Pirie, Hobart and Townsville alone, which represent far more concentrated

329

and higher tonnage sources of indium than end of life goods. Indium is rarely reported as a

330

potential resource in slag, with Zeehan, Tasmania noted as a particular exception for

331

Australia (Table S1). That this particular location is reported using the joint ore reserves

332

committee (JORC) codes in Australia (see Mudd et al.8), suggests that the indium contained

333

in this slag was in fact considered potentially economically extractable by the reporting

334

company Intec, however there remain many technical and economic barriers to mine and

335

processing waste recovery which still need to be addressed if these quantities are to

336

become available to the broader indium market (see also Werner et al.

337

assaying of mining and processing wastes for critical metals, and a more detailed

338

assessment of the ways in which processing facilities can be adapted to facilitate critical

339

metal by-products would be beneficial to understand the true supply potential of the


44

). Increased


340

quantities estimated in this study. A starting point for Australia may be to further study the

341

zinc refinery at Risdon, which the owner Nyrstar has indicated may be adapted to include

342

indium capacity in the near future53, pending the right market conditions.

343

While our results suggest that recycling for indium is not a priority for Australia (at least in

344

terms of contributing meaningfully to global supplies), we must be clear that we do not

345

propose an end to recycling of electronics altogether. Indeed, the recycling of e-waste will be

346

an important process in reducing landfill-related hazards, and may be economically viable for

347

the recovery of other resources like gold, silver and copper 54. Nonetheless, some change in

348

rhetoric around the circular economy, and how a circular economy for other by-

349

product/critical metals might be achieved, is warranted. That Australia’s best contributions to

350

a circular economy can be made through efficiency gains in mining highlights that circular

351

economy strategies can be quite country-specific.

352

Given that other critical metals like gallium and germanium are also produced as by-products

353

of zinc, are not currently produced in Australia and have low-concentration applications in

354

electronic devices, it is possible that they exhibit similar cycles. The similarity of Australia

355

and Europe’s per-capita estimates of indium in use suggests that other industrialised

356

resource-rich nations would also exhibit a similar overall structure to their cycles of gallium,

357

germanium and other critical metals. This raises questions about the viability of recycling

358

critical metals more broadly. Additional MFA studies of by-product/critical metals at a

359

national level for other industrialised nations would help to verify this, and hopefully better

360

guide decision makers interested in securing significant sources of critical metal supply in

361

future. In the meantime, it is clear that Australia has some potential to reduce the risks of

362

indium supply disruptions in future.

363

Acknowledgements

364 365 366

A portion of this work was conducted as a component of the ‘Wealth from Waste’ research

367

cluster, a collaborative program between the Australian Commonwealth Scientific Industrial

368

Research Organisation (CSIRO); the University of Queensland, the University of Technology,

369

Sydney; Monash University, Swinburne University of Technology and Yale University. The

370

authors would like to thank Ermelinda Harper for sharing her experience in MFA

371

methodology, and Brian O’Neill of AIM Minor Metals for his valuable discussions and data on

372

the indium market.


Page 12 of 24

Page 13 of 24


373

Supporting Information Available

374

Additional information on the methodology employed and detailed data used in the

375

estimation of indium stocks and flows are available as supporting information. This

376

information is available free of charge via the Internet at http://pubs.acs.org.

377 378 379

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Looking Down Under for a circular economy of indium

Figures and Tables Tim T. Werner1,4+, Luca Ciacci2, Gavin Mark Mudd1, Barbara K. Reck3, Stephen Alan Northey4 1

Environmental Engineering, School of Engineering, RMIT, Melbourne, VIC, Australia

2

Dipartimento di Chimica Industriale "Toso Montanari", University of Bologna, Viale del Risorgimento 4, Bologna, Italy 3

Center for Industrial Ecology, School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511, USA 4

Faculty of Engineering, Monash University, Clayton, VIC, Australia

+

Corresponding author: [email protected]


Page 18 of 24

Page 19 of 24


Other regions Slag

Met. proc.

Concentrates

Refined In

Met. proc.

(no In capacity)

International mines

Concentrates

Slag

Slag

Manufacturing

Australia Slag

Direct ore export

Semifinished forms

Slag Concentrates

Ore

Bulk rock

Met. proc.

Milling

Mining

Low grade ore + waste rock

Mineral deposits

No domestic refining

Tailings

Finished goods

In-use Finished goods

End of life goods

Process waste

Manufacturing

Waste mgmt.

No domestic recycling Not recovered

Mine waste

Landfill

Figure 1: Domestic and international stocks, flows and processes considered in this study (Met. proc. = metal processing).



Page 20 of 24

Stockpiles No stockpiling in Aust.

1224

167 (100%)

167 (14%)

355 (29%)

695 (57%)

Unwrought indium No primary ITO manuf. in Aust.

85 (7%)

PCBs

1042 (86%) Other alloys

Thermal interface materials

85 (7%) Dental alloys

857

Alloys 2658 (19%)

1774 (6%)

15509

26616 (90%)

LCD products

Solar panels

27 (0.2%)

126 (0.3%)

Architectural glass

29426 (70%)

3428 (8.9%)

336 (0.8%)

ITO

1232 (4%)

Production losses

Elec. compounds & semiconductors

Recycling

9757 (69%)

13465

1717 (12%)

Direct Imports

Added to direct finished good imports

8407 (20%)

LED products

Added to direct finished good imports

10000

1000-5000 >15000

Figure 2: Apportionment of semi-finished imports to finished goods, taking into account production efficiencies. Apportionment estimates are derived as an average of Chang, et al. 26, Licht, et al. 27, Nakajima, et al. 28 and Yoshimura, et al. 29 modified to represent the Australian context. All units are in kg, with cumulative flows from 1988-2015 depicted.


Page 21 of 24


900 800

80% Global Production Australian sourced Australian sourced (%)

700

60%

600

t In

70%

50%

500 40% 400 30%

300

20%

200

10%

100

0 0% 1972 1977 1982 1987 1992 1997 2002 2007 2012 Figure 3: Proportion of global indium production estimated to originate from Australian zinc concentrates 1972-2012, in absolute and percentage terms.



40,000

Solar Panels Flat Panel TV's

35,000

Laptops + Tablets LCD/LED Screens - PC

30,000

Mobile Phones Research samples, standards and glass Batteries

25,000

Locally manufactured LCD Products

kg In

PCBs / Thermal interfaces

20,000

LED Semiconductors Motor Vehicles Cameras for Film >16 mm

15,000

Cameras for Film

Looking Down Under for a Circular Economy of Indium

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