Uranium Extraction Technology (Technical Reports (International Atomic Energy Agency))

TECHNICAL REPORTS SERIES No.

359

Uranium Extraction Technology

%ffij

INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1993

The cover picture shows the in situ uranium central processing facility, Hobson Uranium Project, Everest Mineral Corporation, Karnes County, Texas, United States of America. By courtesy of Lanmon Aerial Photography Inc., Corpus Christi, Texas.

URANIUM EXTRACTION TECHNOLOGY

The following States are Members of the International Atomic Energy Agency: AFGHANISTAN ALBANIA ALGERIA ARGENTINA ARMENIA AUSTRALIA AUSTRIA BANGLADESH BELARUS BELGIUM BOLIVIA BRAZIL BULGARIA CAMBODIA CAMEROON CANADA CHILE CHINA COLOMBIA COSTA RICA COTE D'lVOIRE CROATIA CUBA CYPRUS CZECH REPUBLIC DEMOCRATIC PEOPLE'S REPUBLIC OF KOREA DENMARK DOMINICAN REPUBLIC ECUADOR EGYPT EL SALVADOR ESTONIA ETHIOPIA FINLAND FRANCE GABON GERMANY GHANA GREECE

GUATEMALA HAITI HOLY SEE HUNGARY ICELAND INDIA INDONESIA IRAN, ISLAMIC REPUBLIC OF IRAQ IRELAND ISRAEL ITALY JAMAICA JAPAN JORDAN KENYA KOREA, REPUBLIC OF KUWAIT LEBANON LIBERIA LIBYAN ARAB JAMAHIRIYA LIECHTENSTEIN LUXEMBOURG MADAGASCAR MALAYSIA MALI MAURITIUS MEXICO MONACO MONGOLIA MOROCCO MYANMAR NAMIBIA NETHERLANDS NEW ZEALAND NICARAGUA NIGER NIGERIA NORWAY PAKISTAN

PANAMA PARAGUAY PERU PHILIPPINES POLAND PORTUGAL QATAR ROMANIA RUSSIAN FEDERATION SAUDI ARABIA SENEGAL SIERRA LEONE SINGAPORE SLOVAK REPUBLIC SLOVENIA SOUTH AFRICA SPAIN SRI LANKA SUDAN SWEDEN SWITZERLAND SYRIAN ARAB REPUBLIC THAILAND TUNISIA TURKEY UGANDA UKRAINE UNITED ARAB EMIRATES UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND UNITED REPUBLIC OF TANZANIA UNITED STATES OF AMERICA URUGUAY VENEZUELA VIET NAM YUGOSLAVIA ZAIRE ZAMBIA ZIMBABWE

The Agency's Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The Headquarters of the Agency are situated in Vienna. Its principal objective is "to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world". ©

IAEA, 1993

Permission to reproduce or translate the information contained in this publication may be obtained by writing to the International Atomic Energy Agency, Wagramerstrasse 5, P.O. Box 100, A-1400 Vienna, Austria. Printed by the IAEA in Austria December 1993 STI/DOC/10/359

TECHNICAL REPORTS SERIES No. 359

URANIUM EXTRACTION TECHNOLOGY

INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 1993

VIC Library Cataloguing in Publication Data Uranium extraction technology. — Vienna : International Atomic Energy Agency, 1993. p. ; 24 cm. — (Technical reports series, ISSN 0074-1914 ; 359) STI/DOC/10/359 ISBN 92-0-103593-4 Includes bibliographical references. 1. In situ processing (Mining). 2. Leaching. 3. Solution mining. 4. Uranium mines and mining. I. International Atomic Energy Agency. II. Series: Technical reports series (International Atomic Energy Agency) ; 359. VICL

92-00074

FOREWORD In 1983 the Nuclear Energy Agency of the Organisation for Economic Cooperation and Development (OECD/NEA) and the IAEA jointly published a book on Uranium Extraction Technology. A primary objective of this report was to document the significant technological developments that took place during the 1970s. The purpose of this present publication is to update and expand the original book. It includes background information about the principles of the unit operations used in uranium ore processing and summarizes the current state of the art. The publication also seeks to preserve the technology and the operating 'know-how' developed over the past ten years. Relatively little of this experience has been documented in recent years because technical personnel have moved to other industries as mines and mills have closed down throughout the world. Extensive references provide sources for specific technological details. This publication is one of a series of Technical Reports on uranium ore processing that have been prepared by the Division of Nuclear Fuel Cycle and Waste Management at the IAEA. A complete list of these reports is included as an addendum. The IAEA wishes to thank the consultants and their associates who took part in the preparation of this publication. It is primarily the work of a consultants group consisting of the following members: G.M. Ritcey (Gordon M. Ritcey and Associates, Canada), R.J. Ring (Australian Nuclear Science and Technology Organisation, Australia), M. Roche (Compagnie gen6rale des matieres nucl6aires, France) and S. Ajuria (Instituto Nacional de Investigaciones Nucleares, Mexico). Components of several chapters were provided by other contributors. The IAEA is also grateful to the Member States and individual organizations for their generous support in providing experts to assist in this work. The IAEA officer responsible for this work was D.C. Seidel of the Division of Nuclear Fuel Cycle and Waste Management. Mr. Seidel also participated as a technical expert and contributing author.

EDITORIAL NOTE The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries. The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA.

CONTENTS

INTRODUCTION

1

PART I. URANIUM RESOURCES AND MINING TECHNOLOGY ....

5

CHAPTER 1. URANIUM RESOURCES

7

1.1. 1.2. 1.3. 1.4.

Introduction Geological types of uranium deposits Uranium resource classification system Uranium resources in WOCA

7 7 13 15

References

18

CHAPTER 2. MINING TECHNOLOGY

19

2.1.

19 19 19 22 22 23 24

2.2.

2.3.

2.4.

Types of mining and mining practice 2.1.1. Uranium ore bodies 2.1.2. Mining recovery Radiological and environmental aspects 2.2.1. Identification of radiological risks 2.2.2. Regulatory aspects 2.2.3. Dosimetric survey of workers 2.2.4. Radiological impact of ore mining and ore treatment on the environment Grade control 2.3.1. General theory 2.3.2. Grade control during exploration 2.3.3. Grade control during mining 2.3.4. Grade control during ore haulage delivery to die mill Co-ordination with mill 2.4.1. Metallurgical balance

24 26 26 27 28 28 29 30

References

30

PART II. PROCESSING TECHNOLOGY

33

CHAPTER 3. PROCESSING CONCEPTS

35

References

37

CHAPTER 4. ORE PREPARATION

39

4.1. 4.2.

39 39 39 40 41 42 44 44 44 45 60 60 61 64 65 66 66 67 67 69

4.3.

4.4.

Introduction Crushing and grinding 4.2.1. Introduction 4.2.2. Comminution theory 4.2.3. Grindability 4.2.4. Circuits and equipment Beneficiation 4.3.1. Introduction 4.3.2. Preconcentration processes 4.3.3. Radiometric sorting 4.3.4. Photometric and conductimetric sorting 4.3.5. Separation on the basis of size and shape 4.3.6. Separation on the basis of gravity 4.3.7. Separation on the basis of magnetic susceptibility 4.3.8. Flotation Roasting 4.4.1. Introduction 4.4.2. Roasting chemistry 4.4.3. Roasting processes 4.4.4. Roasting equipment

References

69

CHAPTER 5. LEACHING

75

5.1. 5.2. 5.3.

5.4.

5.5.

5.6. 5.7.

Introduction Leaching chemistry Leaching conditions and mineralogy 5.3.1. Uranium 5.3.2. Gangue minerals Sulphuric acid leaching systems 5.4.1. Atmospheric agitation 5.4.2. Pressure leaching Carbonate leaching systems 5.5.1. Atmospheric leaching 5.5.2. Pressure leaching Strong acid pugging and curing 5.6.1. Somair and Cominak mills Alternative leaching systems 5.7.1. Removal of radium and thorium

75 78 80 81 85 89 89 97 100 100 101 104 104 109 109

5.8.

5.9.

In situ and in place leaching 5.8.1. Introduction 5.8.2. In situ leaching 5.8.3. In place leaching Heap and vat leaching 5.9.1. Introduction 5.9.2. Heap leaching 5.9.3. Vat leaching

Ill Ill 113 119 121 121 121 127

References

127

CHAPTER 6. SOLID-LIQUID SEPARATION

137

6.1. 6.2.

137 137 138 141 143 145 145 149

6.3.

Introduction Concepts 6.2.1. Thickening 6.2.2. Filtration 6.2.3. Flocculation , Applications in uranium milling 6.3.1. General circuit descriptions 6.3.2. Solid-liquid separation equipment

References

154

CHAPTER 7. SOLUTION PURIFICATION

157

7.1. 7.2.

157 158 158 158 161 183 183 186 191 192 195 195 196 206 210 210 214

7.3.

Introduction Resin ion exchange 7.2.1. Introduction 7.2.2. Ion exchange chemistry and resin characteristics 7.2.3. Ion exchange systems Purification by solvent extraction 7.3.1. Introduction 7.3.2. Extractants 7.3.3. Modifiers 7.3.4. Diluents 7.3.5. Stripping 7.3.6. Dispersion and coalescence 7.3.7. Contacting equipment 7.3.8. Solvent-in-pulp extraction 7.3.9. Solvent losses 7.3.10. Process development 7.3.11. Materials of construction

7.4.

7.3.12. Economics 7.3.13. Environmental aspects Recovery of uranium from phosphoric acid 7.4.1. Introduction 7.4.2. Processes for uranium recovery from phosphoric acid

215 215 216 216 216

References

226

CHAPTER 8. PRODUCT RECOVERY

235

8.1. 8.2. 8.3. 8.4.

235 235 236 237 237 238 239 239 242 243 244 246 246 246 247 248 248 248 248

8.5. 8.6. 8.7.

Introduction Product specifications Solution characterization Precipitation 8.4.1. Precipitation testing and evaluation 8.4.2. Direct precipitation from acidic solutions 8.4.3. Direct precipitation from alkaline solutions 8.4.4. Precipitation from acid stripping solutions 8.4.5. Precipitation from alkaline stripping solutions 8.4.6. Ammonium uranyl tricarbonate system Solid-liquid separation Drying or calcination Operating practice for product recovery 8.7.1. Rabbit Lake 8.7.2. Rio Algom Panel 8.7.3. Key Lake 8.7.4. Ciudad Rodrigo 8.7.5. Cluff Lake 8.7.6. Lodeve

References

249

CHAPTER 9. BY-PRODUCTS

251

9.1. 9.2. 9.3. 9.4. 9.5. 9.6. 9.7.

251 251 252 254 255 255 256

Introduction Vanadium Molybdenum Copper Nickel, cobalt and arsenic Gold (and silver) Rare earths

9.8.

Chemical salts 9.8.1. Sodium sulphate 9.8.2. Ammonium sulphate

257 258 258

References

258

PART HI. WASTE MANAGEMENT AND THE ENVIRONMENT

261

CHAPTER 10. TAILINGS MANAGEMENT TECHNOLOGY

263

10.1. 10.2. 10.3. 10.4. 10.5.

263 263 264 264 265 265 266 267 268 269 269 269 270 271 271 272 273 273 274

10.6. 10.7.

10.8. 10.9. 10.10. 10.11. 10.12. 10.13.

Introduction Tailings and waste rock characteristics Toxicity of effluents Wastewater regulations Design of overall treatment system 10.5.1. Influence of die process 10.5.2. Site selection options Disposal Water management 10.7.1. Tailings ponds 10.7.2. Dewatering of tailings 10.7.3. Water recycling and reuse Weathering and migration 10.8.1. Dissolution, precipitation and exchange processes Effluent treatment Decommissioning, reclamation and covers Monitoring of tailings impoundment sites Corporate responsibility and ongoing research The model

Selected bibliography

275

PART IV. FLOW SHEET EXAMPLES

287

CHAPTER 11. OLYMPIC DAM

289

11.1. 11.2. 11.3. 11.4.

289 289 290 290

Introduction Geology and resources Mineralogy Production capacity

11.5.

Mining 11.5.1. 11.5.2. 11.5.3. 11.5.4. 11.5.5.

and milling Mining Copper concentrator Hydrometallurgical plant Copper smelter Copper refinery and precious metals plant

290 291 291 292 296 297

References

297

CHAPTER 12. KEY LAKE

299

12.1. 12.2. 12.3. 12.4. 12.5.

299 299 299 300 300 300 302 302 303 303 303

Introduction Geology and resources Mineralogy Production capacity Milling 12.5.1. Size reduction 12.5.2. Leaching and solid-liquid separation 12.5.3. Solvent extraction 12.5.4. Yellow cake precipitation and calcination 12.5.5. Ammonium sulphate crystallization plant 12.5.6. Neutralization of tailings pulp and liquids

References

304

CHAPTER 13. RABBIT LAKE

305

13.1. 13.2. 13.3.

305 305 308 308 308 308 308 309 309 311 311

13.4.

Introduction Mill circuit and feed types Flow sheet of the process 13.3.1. Ore preparation 13.3.2. Leaching 13.3.3. CCD 13.3.4. Solvent extraction 13.3.5. Impurity removal from the stripping liquor 13.3.6. Two stage precipitation 13.3.7. Calcining Tailings management

References

313

CHAPTER 14. LODEVE

315

14.1. 14.2. 14.3. 14.4.

315 315 315 316 318 318 318 319 319 319 320 320

Introduction Geology and resources Mineralogy Milling 14.4.1. Size reduction 14.4.2. Ore sorting 14.4.3. Leaching and solid-liquid separation 14.4.4. Uranium precipitation 14.4.5. Molybdenum recovery 14.4.6. Organic matter elimination 14.4.7. Sodium sulphate recovery 14.4.8. Tailings management

References

320

CHAPTER 15. ROSSING

321

15.1. 15.2. 15.3. 15.4.

321 321 322 322 322 324 324 324 325 325

Introduction Geology and mineralogy Mining Milling operations 15.4.1. Crushing and grinding 15.4.2. Leaching 15.4.3. Solid-liquid separation 15.4.4. Concentration and purification 15.4.5. Product recovery 15.4.6. Tailings disposal

References

325

CHAPTER 16. COMINAK

327

16.1. 16.2. 16.3. 16.4.

327 327 327 327 329 329 329 329 330

Introduction Geology Mineralogy Mining and milling 16.4.1. Mining 16.4.2. Size reduction 16.4.3. Leaching 16.4.4. Solid-liquid separation 16.4.5. Solvent extraction

16.4.6. Uranium recovery 16.4.7. Molybdenum recovery 16.4.8. Tailings management

330 330 331

References

331

CHAPTER 17. WHITE MESA

333

17.1. Introduction 17.2. Mineralogy and geology 17.3. Mill construction and operation 17.3.1. Grinding and leaching circuits 17.3.2. CCD washing circuit 17.3.3. Uranium solvent extraction and precipitation 17.3.4. Vanadium processing 17.3.5. Mill circuit features 17.4. Tailings management

333 333 336 336 337 337 338 338 339

Reference

340

CHAPTER 18. ROSITA (IN SITU LEACHING)

341

18.1. 18.2. 18.3. 18.4. 18.5. 18.6.

341 341 345 345 351 353

Introduction Geology Hydrology Well field developments and restoration Well field and process plant operations Operational waste management

References

355

CONTRIBUTORS TO DRAFTING AND REVIEW

357

INTRODUCTION During the past 40 years the uranium industry has grown dramatically. This growth, however, has not been steady or predictable. Production expanded from a few hundred tonnes of uranium a year prior to 1942 to a peak WOCA (world outside centrally planned economies area) production rate of about 44 0001 U/a in the early 1980s. Since that time production has decreased significantly owing to changing demand and market conditions; in 1990 the production rate was approximately 30 000 t U/a. Uranium ore processing technology developed rapidly, particularly during the 1950s. Significant innovations in leaching and in solid-liquid separation equipment were made. The industry pioneered hydrometallurgical applications of ion exchange and solvent extraction technologies. New techniques such as in situ leaching were also developed. Changing demands and market conditions have played a major role in the growth and development of the uranium industry. Prior to about 1960 essentially all of the uranium produced worldwide was purchased by government agencies for military uses. During the period from 1942 to 1945 the total annual uranium production reached a maximum of about 10 000 t U/a. Most of this was sold under contract to the United States Manhattan Project. The ores processed during this period were treated by earlier techniques developed for recovering radium from pitchblende ores or for vanadium recovery from carnotite ores. Uranium separations were achieved by the use of roasting technology or by multiple stage precipitations from leach solutions. The milling operations reflected little change from the methods that had been used 40 years earlier. After the passage of the US Atomic Energy Act in 1946, the US Atomic Energy Commission emphasized the importance of the worldwide discovery and development of new uranium sources. In the United States of America a wide range of incentives were established: these included a guaranteed fixed price for ore, bonuses, haulage allowances, buying stations, access roads, etc. Many organizations initiated major research efforts to improve the processing technology then in use. These efforts produced improvements that led to a greater utilization of lower grade ores than had previously been considered possible. The operations included processing the uranium bearing gold ores in South Africa and developing the large low grade deposits in the Beaverlodge, Elliot Lake and Bancroft regions of Canada. Similar developments also took place in France, the former USSR and other countries. In the late 1950s a boom in uranium demand, based on projected civil requirements, led to a remarkable amount of exploration and the construction of many new uranium mills. Some 26 facilities were operating in the USA in the period from 1960 to 1962, 19 in Canada in 1959, and many more in other countries, notably South Africa. By 1970 many of these plants were closed or on stand-by because the market 1

INTRODUCTION

$40

40 S . «*

0.02 (1-5)

- 6 5 +25

West Rand Consolidated

F.A. Saaiplaas

0.005-0.020 (1-5)

Haartebeestfontein

0.005-0.020 (10-15)

Western Holding

0.005-0.020 (5-10)

Mine 'A'

0.159

-250 +50

75

0.096

-250 +50

55

China Mine 'B'

57

CHAPTER 4. ORE PREPARATION

Accept + unsorted ore Mass

(%)

75.5

Reject

Grade (%) (g/t)

Recovery

0.470

98.98

Mass

Grade (%) (g/t)

Recovery

(%)

25.0

0.015

1.02

Status

(%) Two MKVIA type sorters One M17 sorter

66.3

0.130

95.4

33.7

45-75

0.11-0.18

-

25-55

94.5-93.8

27.5-30.25

72.5-69.75 85

0.13

-

98

15

0.012