Extractive Metallurgy of Copper 4th ed. W. Davenport et. al. (2002) Episode 1 docx

CONTENTS Preface Preface to the Third Edition Preface to the Second Edition Preface to the First Edition Extracting Copper from Copper-Iron-Sulfide Ores Melting and Casting Cathode Coppe

- 4

0

cd

12

Mg

Ca

24.305 Magnesium

20

40.08 Calcium

56

137.33 BariWll

88

226.0254 Radium

3(IIIA) 4(IVA) 5 ( V A ) 6(VIA) 7(VIIA) 8 9(VIIIA)

Cr

1

Y I4'Zr 4Nb Mo 88.9059 91.22 92.9064 95.94 Yttrium Zirconium Niobium Molybdenutr

57

138.9055 178.4, 180.947, 183.85 Lanthanum Hafnium Tantalum Wolfram

39

La 72Hf 73Ta 74W

Ac

Lanthanide Metals 227.0278

18 (WIE

2

4.00260 Helium

He

9

F C1

Br

I

At

18.998403 Fluorine

17

35.453 Chlorine

35

79.904 Bromine

53

126.9045 Iodine

35

(210) Astame

18

39.94, Argon

83.80 Krypton

54

131.30 Xenon

(247) (251) Berkelium Californium

13 (IIIB) 14 ( N B )

10.81 12.011

A1 26.98154 28.085, Boron Silicon

67

Ho

164.9304 Holmium

15(VB) 16(VIB) 17(VIIB)

69

Tm 168.9342 Thulium

7 3 7 6 i343206 hosphorous Sulphur

65

Tb 158.9254 Terbium

70

Yb

No

173.0, Ytterbium

02

1259) Nobelium

71

Lu

Lr

174.96, Lutetium

I03

(260)

Lawrencium

Extractive Metallurgy

of Copper

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Phelps Dodge Mining Company

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A.K BISWASt

FOURTH EDITION

PERGAMON

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First edition 1916

Second edition 1980

Third edition 1994

Fourth edition 2002

British Library Cataloguing in Publication Data

Davenport, W G (William George)

Extractive metallurgy o f copper ~ 4th ed

Library of Congress Cataloging in Publication Data

A catalog record froin the Library of Congress has been applied for

ISBN: 0-08-044029-0

8 The paper used in this publication meets the requirements of ANSL’NISO 239.48-1992 (Permanence of Paper)

CONTENTS

Preface

Preface to the Third Edition

Preface to the Second Edition

Preface to the First Edition

Extracting Copper from Copper-Iron-Sulfide Ores

Melting and Casting Cathode Copper

Recycle of Copper and Copper-Alloy Scrap

Suggested Reading

References

2 Production and Use

2.1 Locations of Copper Deposits

2.2 Location of Extraction Plants

3.2 Crushing and Grinding (Comminution)

3.3 Flotation Feed Particle S i i -

3.4 Froth Flotation

3.5

3.6 Flotation Cells

3.7 Sensors Operation and Control

Specific Flotation Procedures far Cu Ores

xiii

xv xvii xix

vi Contents

3.8 The Flotation Product

3.9 Other Flotation Separations

4.2 Matte and Slag

4.3 Reactions During Matte Smelting

4.4

4.5

The Smelting Process: General Considerations

Smelting Products: Matte, Slag and Offgas

Suggested Reading

References

5 Flash Smelting - Outokumpu Process

5.1 Outokumpu Flash Furnace

Cu-in-Slag and Molten Converter Slag Recycle

Inco vs Outokumpu Flash Smelting

Operation and Control

Production Rate Enhancement

9.5 Recent Developments in Converting- Shrouded Blast Injection 148

viii Contents

10 Continuous Converting

10 I Common Features of Continuous Converting

10.2 Downward Lance Mitsubishi Continuous Converting

10.3 Solid Matte Outokumpu Flash Converting

10.4 Submerged-Tuyere Noranda Continuous Converting

Decreasing Copper in Slag I: Minimizing Slag Generation

Decreasing Copper in Slag 11: Minimizing Cu Concentration in

The Ideal Direct-to-Copper Process

Industrial Single Furnace Direct-to-Copper Smelting

13.1 The Mitsubishi Process

13.2 Smelting Furnace Details

20 1

20 1

Electric Slag Cleaning Furnace Details

Converting Furnace Details

Recent Mitsubishi Process Developments

Reaction Mechanisms in Mitsubishi Smelting

Optimum Matte Grade

Impurity Behavior in Mitsubishi SmeltingiConverting

Process Control in Mitsubishi Smelting/Converting

Offgases from Smelting and Converting Processes

Sulfuric Acid Manufacture

Smelter Offgas Treatment

Gas Drying

Acid Plant Chemical Reactions

Industrial Sulfuric Acid Manufacture

Recent and Future Developments in Sulfuric Acid Manufacture

Alternative Sulfur Products

Future Improvements in Sulfur Capture

Industrial Methods of Fire Refining

Chemistry of Fire Refining

Choice of Hydrocarbon for Deoxidation

Casting Anodes

Continuous Anode Casting

New Anodes from Rejects and Anode Scrap

Removal of Impurities During Fire Refining

Cells and Electrical Connections

Typical Refining Cycle

Refining Objectives

Maximizing Cathode Copper Purity

Optimum Physical Arrangements

Optimum Chemical Arrangements

Optimum Electrical Arrangements

Minimizing Energy Consumption

Recent Developments in Electrorefining

Summary

Suggested Reading

References

17 Hydrometallurgical Copper Extraction:

Introduction and Leaching

17.1 Heap Leaching

17.2 Industrial Heap Leaching

17.3 Steady-State Leaching

17.4 Leaching of Chalcopyrite Concentrates

17.5 Other Leaching Processcs

17.6 Future Developments

Suggested Reading

References

18 Solvent Extraction Transfer of Cu

from Leach Solution to Electrolyte

Industrial Solvent Extraction Plants

Quantitative Design of Series Circuit

Contents xi

19 Electrowinning

19 I Electrowinning Reactions

19.2 Electrowinning Tankhouse Practice

19.3 Maximizing Copper Purity

19.4 Maximizing Current Efficiency

19.5 Future Developments

Suggested Reading

References

20 Collection and Processing of Recycled Copper

20.1 The Materials Cycle

The Secondary Copper Smelter

Scrap Processing in Primary Copper Smelters

Overall Investment Costs: Mine through Refinery

Overall Direct Operating Costs: Mine through Refinery

Total Production Costs, Selling Prices, Profitability

Stoichiometric Data for Copper Extraction

Copper Recovery from Anode Slimes

Sketch of Series-Parallel Solvent Extraction Circuit

Extended List of Chinese Copper Refineries and their

xx Preface

directed to Metallurgical Thermochemistry by 0 Kubaschewski, E L Evans and

C B Alcock, an earlier volume in this series

The text of the book is followed by four appendixes which contain units and conversion factors: stoichiometric data; enthalpy and free energy data; and a summary of the properties of electrolytic tough pitch copper

Copper is one of man's most beautiful and useful materials It has given us great satisfaction to describe and discuss the methods by which it is obtained Both of

our universities have had a long association with the copper industries of our countries, and it is hoped that, through this book, this association will continue

A K Biswas

University of Queensland

W G Davenport

McGill Universify

2 Extractive Metallurgy of Copper

Fig 1.1 Principal processes for extracting copper from sulfide ores Parallel lines

indicate alternative processes *Principally Isasmelt/Ausmelt, reverberatory, shaft, electric, and Vanyukov smelting - Two furnaces, worldwide

Fabrication and use

Fig 1.2 Hydrometallurgical heap leach copper extraction flowsheet for 'oxide' and chalcocite ores

4 Extractive Metallurgy of Copper

(a) isolating an ore's Cu-Fe-S (and Cu-S) mineral particles into a concentrate

by froth flotation

(b) smelting this concentrate to molten high-Cu matte

(c) converting the molten matte to impure molten copper

(d) fire- and electrorefining this impure copper to ultra-pure copper

1.2 I Concentration by froth flotation (Chapter 3)

The copper ores being mined in 2002 are too lean in copper (0.5 - 2% Cu) to be smelted directly Heating and melting their huge quantity of waste rock (e.g granite) would require prohibitive amounts of hydrocarbon fuel Fortunately, the Cu-Fe-S and Cu-S minerals in an ore can be isolated by physical means into high-Cu 'concentrate' which can be smelted economically

The most effective method of isolating the Cu minerals is froth flotation This process causes the Cu minerals to become selectively attached to air bubbles rising through a water-finely ground ore mixture, Fig 1.3

Selectivity of flotation is created by using reagents which make Cu minerals water repellent while leaving waste minerals 'wetted' These reagents cause Cu

Air bubble dispersion system

Fig 1.3 Schematic view of flotation cell Reagents cause Cu-Fe sulfide and Cu sulfide minerals in the ore to attach to rising air bubbles, which are then collected in a short-lived

through several cells before being discarded as a final tailing Many types and sizes (up

to 100 m3) of ccll are used, Chapter 3

This froth is de-watered to become concentrate

Overview 5

minerals to 'float' on rising bubbles while the other minerals remain unfloated The 'floated' Cu-mineral particles overflow the flotation cell in a froth to become concentrate -30% Cu

Flotation is preceded by crushing and grinding copper ore into fines Its use has led to adoption of smelting processes which are effective at treating finely ground material

1.2.2 Matte smelting (Chapter 4)

Matte smelting oxidizes and melts flotation concentrate in a large, hot (1250°C) furnace, Fig 1.1 The objective of the smelting is to oxidize S and Fe from the Cu-Fe-S concentrate to produce a Cu-enriched molten sulfide phase (matte) The oxidant is almost always oxygen-enriched air

Example reactions are:

(1.1)

13 1 3 5

2CuFeS2 + T O 2 -+ Cu2S.-FeS + -FeO + -SO2

in oxygen molten matte

AH;,,, = - 20 M J k g mole FeO

The products of smelting are (i) molten sulfide matte (45-75% Cu) containing most of the Cu-in-concentrate and (ii) molten oxide slag as free of Cu as possible The molten matte is subsequently converted (oxidized) in a converting furnace to form impure molten copper The slag is treated for Cu recovery then sold or discarded, Chapter 1 1

S02-bearing offgas (10 to 60% SOz) is also generated SO2 is harmful to the environment so it must be removed before the offgas is released to the atmosphere This is almost always done by capturing the SO2 as sulfuric acid, Chapter 14

An important objective of matte smelting is to produce a slag which contains as little Cu as possible This is done by:

6 Extractive Metallurgy of Copper

*,

Slag

Fig 1.4 Outokumpu oxygen-enriched air flash furnace Flash furnaces are typically 20

m long and 7m wide They smelt 1000 to 3000 tonnes of concentrate per day

Fig 1.5 Noranda submerged tuyere smelting furnace Noranda furnaces are typically 20

to 25 m long and 5 m diameter They smelt 1500 to 3000 tonnes of concentrate per day Teniente smelting furnaces are similar

Overview 7

(a) including SiOz flux in the furnace charge to promote matte-slag immiscibility

(b) keeping the furnace hot so that the slag is molten and fluid

Matte smelting is most often done in flash and submerged tuyere furnaces (Figs

I .4 and 1.5) It is carried out to a lesser extent in top lance furnaces (Mitsubishi, Isasmelt, Ausnielt), shaft furnaces, reverberatory furnaces, and electric furnaces

In two cases, concentrate is flash smelted directly to molten copper, Chapter 12

1.2.3 Converting (Chapters 9 and IO)

Copper converting is oxygen enriched-air or air oxidation of the molten matte from smelting It removes Fe and S from the matte to produce crude (99% Cu) molten copper This copper is then sent to fire- and electrorefining Converting

is mostly carried out in the cylindrical Peirce-Smith converter, Fig 1.6

Liquid matte (1200°C) is transferred from the smelting furnace in large ladles and poured into the converter through a large central mouth, Fig 1.6b The oxidizing 'blast' is then started and the converter is rotated - forcing oxygen enriched-air or air into the matte through a line of tuyeres along the length of the vessel The heat generated in the converter by Fe and S oxidation is sufficient to make the process autothermal

The converting takes place i n two sequential stages:

(a) the FeS elimination or slag forming stage:

2FeS + 3 0 , + S O 2 + 2FeO.SiO2 + 2 S 0 , + heat

in molten in flux molten slag in

(b) the blister copper forming stage:

C u 2 S + O 2 + 2Cu" + 2 S 0 2 + heat

matte 'blast' copper offgas

Coppemaking (b) doesn't occur until the matte contains less than about 1% Fe

so that most of the Fe can be removed from the converter (as slag) before copper production begins Likewise, significant oxidation of copper does not occur until the sulfur content of the copper falls below -0.02% Blowing is terminated near this sulfur end point The resulting molten 'blister' copper (1200°C) is sent

to refining