Elect Row Inning Copper and Silver From Nitric Acid

8/2/2019 Elect Row Inning Copper and Silver From Nitric Acid

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Electrometals Technologies Limited

A C N 000 751 09328 Commercial Drive Ashmore Queensland Australia 4214Telephone: 61 7 5526 4663 Facsimile: 61 7 5527 0299

Email Address: [email protected]

Electrowinning of Silver and Copperfrom a Nitric Acid based Electrolyte

August 2003

CONFIDENTIAL


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Silver, copper, lead EW Programme October 2003

The following report details the results of a series of EMEW electrowinning test runs carried to assess theability of the EMEW cell to recovery metals in nitric acid based electrolyte containing silver, lead and

copper. This testing was carried out during August/September 2003. The target solution was fabricated inElectrometals laboratory in Australia, based on the expected composition of a silver refinery bleed stream.Relevant metal concentrations in the nitric acid feed solution were as follows:

Silver : 163 g/LLead : 30 g/LCopper : 45 g/L

The primary thrust of the programme has been to establish a direct method for removal of copper from an

electrorefinery bleed stream, and thereby allow:

1. Recycle of solution, rather than dumping when copper levels become too high in the refinery, and2. Refineries to source and refine high copper silver scrap without high disposal cost penalties.

A total of 15 tests were performed, targeting the three metals of interest (silver, lead and copper) in thefollowing stages:

Stage 1 : Electrowinning of silver and lead from copper bearing nitric solution

Stage 2 : Electrowinning of copper from nitric solutionStage 3 : Electrowinning of copper from nitric solution containing leadStage 4 : Electrowinning of low levels of silver from copper bearing nitric solution

The results of the programme have been positive, with relevant conclusions and observations beingsummarised as follows.

In initial electrowinning, with the three metals in solution, silver and lead are recoveredcontemporaneously with the silver forming a metal powder on the cathode and the lead forming anoxide on the surface of the anode.

High current efficiency was achieved with silver recovery between 163 g/L and 82 g/L at a currentefficiency in excess of 90%. In the first series of tests silver was depleted to approximately 25 g/Lwith, as would be expected, some deterioration in current efficiency at low concentration. Lead wasdepleted from 30.1 to 9.7 g/L in this series.

Some attempt was made to obtain a clean separation between the two products in the initialelectrowinning, using a sock covering the anode to collect lead oxide. Operating parameters werenot optimised, or a variety of diaphragm materials tested but this work indicates that, with the right

materials, a clean separation can be achieved.

The programme has therefore demonstrated the viability of stripping of both lead and silvercontemporaneously from a nitric solution as two separable products, at high current efficiency.

As copper was the major target of the programme, a number of tests were performed on copper nitricsolution. These tests, under appropriate operating conditions, have demonstrated virtually straight line


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The copper electrowinning tests were carried out at varying concentrations of free nitric acid andcopper. Operating at a current density of 500 A.m-2 and free acid concentration of 300 g/L, little or nocopper recovery was achieved. However, highly efficient stripping was accomplished at 250 g/L acid,at the same current density. A potential limit to efficient stripping of copper is therefore indicated but it is possible that further optimisation of operating parameters (higher current density) may lift thatlimit.

A series of low copper feed tests (8 g/L Cu) have demonstrated the capability of the EMEW cell tostrip the contaminant metal down to around 20 ppm.

Testing of solution containing low levels of silver (12-13 g/L), with high copper (30g/L), demonstrated

the progressive stripping of the two metals. In the relevant tests, silver was first stripped to very lowlevel (8-10 ppm) prior to the onset of copper recovery.

The programme has therefore effectively demonstrated that the EMEW technology can be viably used to:

1. Recover silver from a high concentration nitric solution down to negligible levels (


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TABLE OF CONTENTS

Page

SUMMARY 2

TEST METHODOLOGY 5

TEST RESULTS 6

Stage 1 7Stage 2 9

Stage 3 10Stage 4 11

CONCLUSION 12

APPENDIX Test Data Sheets


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1.0 TEST METHODOLOGY

Standard EMEW tests are performed using a laboratory scale cell through which the target solution is pumped on a continuous basis. An inventory of between 5 and 20 litres of solution is established andrecycled through the cell for a period of time, whilst electrowinning is being performed. A variety of testsare performed under differing electrowinning conditions (current density and flow). Periodic samples aretaken of the inventory to determine progressive depletion of the target metals. This methodology allows:

1. Current efficiency to be determined at specific metal concentrations,2. Production rate in electrowinning over specific metal concentration ranges

3. Determination of product nature and quality

The laboratory scale EW tests were conducted on a 50mm EMEW cell with a DSA3 (oxygen evolvinganode) and a stainless steel cathode shim. The extensive data base collected on performance of the EMEWcell over the past ten years allows confident scaling up of performance data to the commercial size units.

Periodic samples were taken throughout each run and analysed to monitor the depletion of target metals.All samples were analysed by AAS in the Electrometals laboratory. Electrolyte pH and conductivity wereperiodically measured throughout the runs. Cell voltage was periodically recorded.

The continuous flow through the EMEW cell avoids mass transfer limitations of other electrowinningtechnologies allowing efficient recoveries at low grade by continuously replenishing the electrolyte near thecathode, minimising localised depletion. The sealed nature of the circuit allows gases produced to behandled at the most convenient point in the circuit, where scrubbers and/or ventilation may be positioned.This prevents mist generation and the release of toxic or flammable gases within the cell operatingenvironment.


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2.0 TEST RESULTS

Individual tests data sheets are provided in the Appendix to this report for all of the test runs completed.Each of these data sheets provides:

The conditions under which the run was performed

Cell current, voltage and flow

Periodic assays for silver, lead and copper

Product description

Metal depletion graph

The test data sheets also provide the equivalent silver and copper production rates that would be achievedin a six or eight inch diameter EMEW cell:

1. On a periodic basis between sample intervals (i.e. from the concentration reported in the precedingsample time), and

2. On a cumulative basis from the initial feed concentration down to the silver value recorded ateach sample interval.

The following table summarises the conditions under which each run was performed, in each stage of theprogramme.

Run CD

(A.m-2)

Flow

(L.hr-1)

Metals in

solution

HNO3 Acid

(g/L)

Product

Stage 1

R-01 480 600 Ag, Pb, Cu 5 Ag powder & lead oxide

R-02 480 600 Ag, Pb, Cu 20 Ag powder & lead oxideR-03 240 600 Ag, Pb, Cu 20 Ag powder & lead oxide

Stage 2

RCu-1 500 500 Cu 20 Cu plate



RCu-4 500 500 Cu 100 Brittle Cu plate

R-04 500 500 Cu 60 Cu plate

R-05 500 500 Cu 300

R-06 500 500 Cu 300R-07 500 500 Cu 250 Cu plate

Stage 3

R-08 500 500 Cu, Pb 60 Cu plate & lead oxide

Stage 4

R-09 500 250 Ag, Cu 40 Ag powder & Cu plate

R-10 500 250 Ag, Cu 60 Ag powder


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2.1 STAGE 1

Stage 1 of the programme was aimed at obtaining initial data on operating performance and potentialselectivity for the three target metals. The solution was fabricated in Electrometals laboratory inaccordance with a detailed composition provided by a silver refinery, as detailed in the following table.

Supplied

assay Prepared solution

Element Average Reagent Amount

(mg/L) used used (g/L)

Cd 24

Be


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Metals Depletion Profile

0

20

40

60

80

100

120

140

160

180

0.00 1.00 2.00 3.00 4.00 5.00 6.00

Elapsed time (hr)

Ag

(g/L)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

Pb,

Cu(g/L)

Ag

Pb

Cu

Silver was recovered in the form of a coarse powder which liberates readily from the cathode suitingautomated harvesting in the EMEW powder cell. The lead was deposited on the DSA anode in the cell, asan oxide. Electrometals anode supplier has indicated that the anode will not be damaged by this lead oxide

coating, but they do recommend that temperature in the electrolyte be maintained at less than 50oC.

Some of the silver powder produced in the test work was pressed into pellets to determine the achievabledensity of a compacted product. The maximum density achieved at 1000MPa was 10.36 g.cm-3. This isequivalent to 98.7% of the SG of silver metal.

Indicated metal production rates (for the 8 inch powder cell) are as follows:

Silver 35-40 kg/day

Lead 12-15 kg/day

The second test run in this series utilised the same batch of solution as the first run with a filter cloth placed over the anode to achieve some separation of the silver and lead products. Current density wasmaintained at around 500 A.m-2, but flow rate was lower than the first run. Due to the progressive depletionof the metals and the lower flow rate, current efficiency in this run was lower than the first (silver recoverybetween 82 and 25 g/L at a cumulative current efficiency of 25%).

A reasonable physical separation of the lead oxide from the silver powder was obtained, indicating that this

should be readily achievable in a full sized cell. Some development work will be required to identify asuitable material for a diaphragm and a suitable mechanism for its mounting in the cell. A methodology forharvesting of the two products will also have to be established. However, it is also probable that the twoproducts could be readily separated from a mixed powder, given that the lead is oxidised.

The third run in the series again achieved stripping of silver and lead to levels of 89 and 9.7 g/Lrespectively at a lower current density than the first two runs (240 A.m -2). Current efficiency was

ll l th th t hi d t 500 A -2 d il l d i ifi tl t d th d f


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2.2 STAGE 2

Electrowinning of copper was carried out over a range of acid concentrations, to determine the impact ofacid concentration on electrowinning performance - and to obtain data on operating performance in theselected copper concentration range.

The lowest acidity was a pH of 0.5 (approx 20 g/L HNO3) and the highest contained approximately 300g/Lnitric acid. The eight tests carried out in this series were operated at constant electrowinning conditions 500 A.m-2 and 500 L/hr flow rate. They were carried out in two groups one commencing at 50g/L Cu(Tests R4-7); and the other at approximately 8 g/L (RCu1-4) targeted at establishing performance data

over the entire possible concentration range.

Little or no copper recovery was achieved at a free acid concentration of 300 g/L. However, as illustratedin the following plot, excellent recovery to low concentrations was obtained at acid concentrations of 60and 250 g/L. Both of the tests achieved a cumulative current efficiency of around 80% in stripping copperfrom 50 g/L down to 1 g/L. These results suggest that there may be a limitation to the electrowinning atvery high acid concentration. However it is considered possible that with further optimisation of theelectrowinning conditions (for example higher current density) that the indicated limit can be lifted.

Copper depletion

Tests 4 and 7

0

10

20

30

40

50

60

0 5 10 15 20 25 30

Test duration (hrs)

Cu

(g/l) HNO3 - 60 g/l

HNO3 - 250 g/l

Product from the electrowinning in these two tests was a good coherent cathode. Equivalent productionrate for a commercial production cell would be of the order of 5.7 kg/cell/day of copper for the standard 6inch EMEW cell (in excess of 11 kg/day if an 8 inch diameter unit were to be used). Final production rate

ill d d h i hi h h l i i i f d


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Copper profiles

Low Cu, varying acid

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00Elapsed time (hrs)

Cu

(g/l) 20 g/l

60 g/l

100 g/l

250 g/l

Efficient copper recovery was achieved at all acid concentrations. However at 100 g/L efficiency is clearlylower. Insufficient work has been carried out to determine the reason for the lower efficiency at this acidlevel but it is potentially an effect of the differing rates that copper will dissolve in nitric. It is expectedthat efficiency at this level can be increased through further optimisation of the electrowinning conditions.

2.3 STAGE 3

A single test run was performed to determine the effect, on copper recovery, of high levels of lead insolution. A 5L sample of synthetic electrolyte was taken. A solution of NaCl was added to precipitate thecontained silver as AgCl. The precipitate was removed by filtration. The silver content of the resultingsolution was 0.56 mg/L. There was no attempt made to optimise the silver precipitation stage. An excessof chloride was added which resulted in some chlorine evolution during electrowinning.

The resulting solution contained approximately 42 g/L Cu and 25 g/L Pb. As illustrated in the metal profile

for this test, the presence of high lead concentration did not prevent the recovery of copper but the leadwas contemporaneously stripped as an oxide on the anode, in a similar manner to the initial tests wheresilver and lead were stripped together. Current efficiency remained high for the copper to produce acoherent cathode.


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Cu and Lead

0.0

5.0

10.015.0

20.0

25.0

30.0

35.0

40.0

45.0

0.00 5.00 10.00 15.00Elapsed time (hr)

Cu(g/L)

2.4 STAGE 4

The final two tests in this programme were targeted at assessing the level of contamination of the productwhen progressively stripping silver from a copper contaminated solution. Silver was stripped from the firsttest run too quickly for useful data to be contained. The silver powder product from the second run washarvested periodically and kept separate for later analysis; the results of this analysis are shown below.Since electrolyte was being depleted as the silver powder was produced the range product represents arerange of silver concentrations.

Silver grade range

(g/L)

Copper contamination within range

(%)

13.0 - 10.5 0.00810.5 5.4 0.009

5.4 2.9 0.037

2.9 0.2 0.055

0.2 - 0.07 0.27

0.07 0.10 23.5

Copper contamination becomes significant when the silver in the electrolyte is in the range 70-100 mg/L.It is possible to extend the range where high purity silver powder is produced by changing operating

parameters for example, operating at a lower current density at lower silver concentration.

These results are in line with data collected from previous programmes in confirming that a high gradesilver product can be electrowon from a contaminated solution down to low silver concentration. In thisapplication, in excess of the silver can be recovered from the refinery bleed stream (prior to copperrecovery) as a product that does not require further refining.


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CONCLUSION

The programme reported here has successfully examined a number of separate targets in treatment of asilver refinery waste stream, using EMEW direct electrowinning. It has not necessarily optimisedelectrowinning conditions for all possible solution compositions but it has clearly demonstrated thefollowing:

1. The work has confirmed the results from previous testing with production of high quality silver froma nitric solution contaminated with relatively high levels of copper. In all cases, silver has beenrecovered as a powder on the cell cathode, which suits automated harvesting using the EMEW powder

cell. Production rate in a commercial facility will vary depending on the concentration widow targetedand the electrowinning conditions used. Under selected conditions, production rate from a singleEMEW powder cell can reach 35+ kg per day of silver.

2. The programme has established that the EMEW cell is capable of successfully stripping copper fromnitric solution under a widely varying set of conditions. It is probable that electrowinning conditionscan be optimised further, but appropriate settings have been generated for stripping of copper from 45g/L down to approximately 20 ppm.

3. It has been established that the EMEW cell is capable of contemporaneous recovery of silver and lead,or copper and lead, from a complex nitric solution. In both cases, lead is recovered as an oxide on theanode while either a silver powder or competent copper plate is formed on the cathode. It is possiblethat the two products can be separately harvested from the cell, or they can be chemical separated afterharvesting.

4. The work illustrates also that the EMEW cell is capable of stripping lead from nitric waste solutions

The precise flow sheet setting and performance requirements for a commercial plant will depend on clientrequirements. However, for indicative purposes, the result of the test programme indicate the following

plant sizing, for a production rate of 25 tonnes per month of silver and/or 10 tonnes per month of copper:

Silver powder production: 30 EMEW powder cells;

Copper cathode production: 60 EMEW plating cells.

The final size of the plant will be determined by actual composition of the electrolyte and the acidity of theelectrolyte in copper electrowinning. It is possible that the plant size could be further reduced throughhigher current density in one or other of the applications. There are a number of decisions that will have tobe made prior to obtaining a pricing on these facilities (such as the configuration of the circuits and the

degree to which they would be automated).


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CONFIDENTIAL 13 4.08.2005

CLIENT: R

Test No.: R-01 Rationale: Synthetic electrolyte Cell used: 50mm

Date: 5-Aug-03

Cathode: S/S Batch Volume: 5.00 L Current: 20 A Target Metal: Ag

Anode: DSA3 Flowrate: 600 L/hr Cathode: 480 Am-2

Faraday's constant: 4.022 g/Ahr

Gap: 12.5 mm Velocity: 0.11 m/s Anode: 961 Am-2

Operator: YC

8in cell

Sample Elapsed Flowrate Current Voltage Ag Pb Cu pH Conductivity Ag Per Ag Cum Ag Per Prod Ag Cum Prodtime (hr) L/hr A V g/L g/L g/L CE% CE% kg/day kg/day

0 0.00 600 20.0 1.95 163 30.1 45.8 2.04 92.70

1 1.00 600 20.0 1.50 151 26.1 47.1 104.60 75.8% 75.8% 35.2 35.2

2 1.17 600 20.0 1.26 153 25.9 48.4 56.1% 26.0

3 1.67 600 20.0 1.74 138 22.8 48.3 118.30 173.2% 91.2% 80.3 42.3

4 1.67 600 20.0 1.61 143 23.6 50.1 74.0% 34.3

5 2.17 600 20.0 1.49 133 22.2 49.9 205.80 122.6% 85.2% 56.8 39.5

6 2.67 600 20.0 1.25 126 20.0 50.2 81.4% 84.5% 37.7 39.2

7 2.67 600 20.0 1.77 128 21.4 51.8 78.7% 36.5

8 3.17 600 20.0 1.86 119 19.2 52.4 102.8% 82.5% 47.7 38.3

9 4.17 600 20.0 1.54 99 17.2 51.9 169.20 112.5% 89.7% 52.2 41.610 5.17 600 20.0 1.38 82 16.7 53.9 191.10 95.5% 90.8% 44.3 42.1

Product Description

Nature: Powder

Colour:

Coverage: Even and complete

Morphology:

Adherence: Requires mechanical removal at high [Ag]

Appearance: Bright

Other: Bleck dendritic deposit on anodeProduct Reconciliation

Shim weight: 7.9 g

Metal from solution: 377.44 g


0

20

40

60

80

100

120

140

160

180

0.00 1.00 2.00 3.00 4.00 5.00 6.00

Elapsed time (hr)

Ag

(g/L)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

Pb,C

u(g/L)

Ag

Pb

Cu

APPENDIX: Test Data Sheets:


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CLIENT: RTest No.: R-02 Rationale: Synthetic electrolyte - with 'sock' on anode Cell used: 50mm

Date: 15-Aug-03





Operator: YC

8in cell

Sample Elapsed Flowrate Current Voltage Ag Cu Pb pH Ag Per Ag Cum Ag Per Prod Ag Cum Prod

time (hr) L/hr A V g/L g/L g/L CE% CE% kg/day kg/day

0 0.00 150 20.0 1.93 82 53.9 16.9

1 1.00 150 20.0 1.83 63 54.4 16.0 84.6% 84.6% 39.2 39.2

2 2.00 150 20.0 1.55 54 54.8 15.7 37.1% 60.9% 17.2 28.2

3 3.00 150 20.0 1.83 49 55.7 15.3 24.9% 48.9% 11.5 22.7

4 4.00 150 20.0 1.78 46 55.2 14.6 10.9% 39.4% 5.1 18.3

5 4.50 150 20.0 1.89 46 55.3 14.7 4.1% 35.5% 1.9 16.4

6 4.50 150 20.0 2.05 44 54.5 16.7 0.48 37.1% 17.2

7 5.50 150 20.0 1.73 31 55.6 15.9 49.6% 39.4% 23.0 18.3

8 7.67 150 20.0 1.93 29 56.3 14.3 3.4% 29.2% 1.6 13.5

9 8.67 150 20.0 1.99 26 55.9 13.7 14.5% 27.5% 6.7 12.8

10 9.67 150 20.0 1.99 25 55.4 13.0 3.7% 25.0% 1.7 11.6

Product Description

Nature: Powder

Colour: silver

Coverage: even (patchy at low [Ag])

Morphology:

Adherence: Easily washed off

Appearance:

Other: Black deposit on anode.

Product ReconciliationShim weight: 7.9 g



0

10

20

30

40

50

60

70

80

90

0.00 2.00 4.00 6.00 8.00 10.00

Elapsed time (hr)

Ag(g/L)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

P

b,

Cu(g/L)

Ag

Cu

Pb


15/26




Client: RTest No.: R-03 Rationale: Synthetic electrolyte - with 'sock' on anode Cell used: 50mm

Date: 15-Aug-03





Operator: YC

8in cell

Sample Elapsed F lowrate Current Voltage Ag Cu Pb pH Conductivity Ag Per Ag Cum Ag Per Prod Ag Cum Prod

time (hr) L/hr A V g/L g/L g/L CE% CE% kg/day kg/day

0 0.00 500 10.0 1.74 161 49.4 29.6 2.39

1 1.00 500 10.0 1.63 151 49.3 28.1 85.5% 85.5% 19.8 19.8

2 2.00 500 10.0 1.59 154 49.7 25.6 0.81 29.2% 6.8

3 3.00 500 10.0 1.47 137 49.2 21.8 150.1% 69.5% 34.8 16.1

4 4.00 500 10.0 1.51 129 50.2 17.9 0.47 62.3% 67.7% 14.4 15.7

5 4.00 500 10.0 1.57 129 49.9 17.9 67.9% 15.7

6 5.00 500 10.0 1.66 117 48.6 16.9 0.26 102.8% 74.9% 23.8 17.4

7 6.00 500 10.0 1.53 108 49.8 16.2 68.2% 73.8% 15.8 17.1

8 7.00 500 10.0 1.56 100 49.7 14.8 63.7% 72.3% 14.8 16.8

9 8.00 500 10.0 1.43 92 50.2 14.0 60.1% 70.8% 13.9 16.4

10 9.00 500 10.0 1.60 88 49.6 12.9 26.1% 65.8% 6.0 15.3

11 9.25 500 10.0 1.61 85 48.7 12.5 93.2% 66.6% 21.6 15.412 10.25 500 10.0 1.63 87 49.5 11.7 59.0% 13.7

13 12.25 500 10.0 1.70 96 51.6 11.3 43.9% 10.2

14 13.92 500 10.0 1.43 89 50.3 9.7 29.0% 42.1% 6.7 9.8

Product Description

Nature: Powder (some dendrites)

Colour: Silver on cathode. Black on anode.

Coverage: Even and complete.

Morphology:

Adherence: Easily removed

Appearance:Other: Lead oxide deposit on anode.

Product Reconciliation



0

20

40

60

80100

120

140

160

180

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00

Elapsed time (hr)

Ag(g/L)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

Pb,

Cu(g/L)

Ag

Cu

Pb


16/26




CLIENT: R

Test No.: R-04 Rationale: Synthetic electrolyte (pH 0 or approx. 60g/L Nitric acid) Cell used: 28mm full cell

Date: 5-Sep-03

Cathode: S/S Batch Volume: 5.00 L Current: 10 A Target Metal: Cu




Operator: YC

6 in cell

Sample Elapsed Flowrate Current Voltage Cu pH Conductivity Per Cum Per prod Cum prod

time (hr) L/hr A V g/L CE% CE% kg/day kg/day

0 0.00 500 10.0 2.41 51.4 0.00

1 0.75 500 10.0 2.35 49.4 112.5% 112.5% 8.0 8.0

2 1.75 500 10.0 2.72 46.0 141.6% 129.1% 10.0 9.2

3 2.75 500 10.0 2.71 43.9 86.3% 113.6% 6.1 8.1

4 4.75 500 10.0 2.46 41.1 56.8% 89.6% 4.0 6.4

8 9.75 500 10.0 2.14 35.5 0.15 66.6%

9 10.75 500 10.0 2.35 33.4 0.08 82.8% 68.2% 5.9 4.8

10 11.75 500 10.0 2.35 30.6 0.00 108.9% 71.6% 7.7 5.1

11 12.75 500 10.0 2.18 25.8 0.05 107.9% 74.5% 7.7 5.3

12 13.75 500 10.0 2.15 23.7 0.00 85.6% 75.3% 6.1 5.3

13 14.75 500 10.0 2.56 20.0 0.03 115.0% 78.0% 8.2 5.5

14 15.75 500 10.0 2.63 17.7 -0.02 95.1% 79.1% 6.7 5.6

15 16.75 500 10.0 2.37 14.7 .0.03 97.6% 80.2% 6.9 5.7

16 16.75 500 10.0 2.53 14.9 0.25 78.9% 5.6

17 17.75 500 10.0 2.47 12.4 0.21 95.1% 79.8% 6.7 5.7

18 18.75 500 10.0 2.55 10.1 0.23 89.3% 80.3% 6.3 5.719 19.75 500 10.0 2.66 7.30 0.02 113.8% 82.0% 8.1 5.8

20 20.75 500 10.0 2.60 4.96 0.23 96.7% 82.7% 6.9 5.9

21 21.75 500 10.0 2.59 2.82 0.21 90.5% 83.1% 6.4 5.9

22 22.75 500 10.0 2.89 0.783 0.34 88.4% 83.3% 6.3 5.9

23 23.75 500 10.0 2.81 0.245 0.34 23.5% 80.8% 1.7 5.7

Product Description

Nature: Copper plate

Colour:


Morphology: Some dendrites at high [Cu]

Adherence: No stree or pealling

Appearance:

Other: Plate became brittle at high acidity.




0.0

10.0

20.0

30.0

40.0

50.0

60.0

0.00 5.00 10.00 15.00 20.00 25.00

Elapsed time (hr)

Cu(g/L)


17/26




CLIENT: RTest No.: R-05 Rationale: Cu EW (approx. 300 g/L HNO3) Cell used: 28mm full cell

Date: 5-Sep-03





Operator: YC

6 in cell

Sample Elapsed Flowrate Current Voltage Cu pH Conductivity Per prod Cum prod

time (hr) L/hr A V g/L kg/day kg/day

0 0.00 500 10.0 2.01 51.9

1 2.00 500 10.0 2.11 51.9

2 3.00 500 10.0 2.14 51.9

3 5.00 500 10.0 2.02 51.9

4 6.00 500 10.0 2.13 51.9

Product DescriptionNature:

Colour:

Coverage:


18/26


19/26



CONFIDENTIAL19 4.08.2005

CLIENT: R

Test No.: R-07 Rationale: Cu EW from 250 g/L HNO3 (neutralised JBR-06 electrolyte.) Cell used: 28mm full cell

Date: 15-Sep-03





Operator: YC

6 in cell

Sample Elapsed Flowrate Current Voltage Cu HNO3 Conductivity Cu Per Cu Per C u Per Prod Cu Cum Prod

time (hr) L/hr A V g/L g/L CE% CE% kg/day kg/day

0 0.00 500 10.0 1.82 49.8

1 2.00 500 10.0 2.07 49.6 314 4.4% 4.4% 0.3 0.32 2.00 500 10.0 1.74 46.8 244 2.2% 0.2

3 4.00 500 10.0 1.99 42.5 97.4% 49.8% 6.9 3.5

4 5.50 500 10.0 2.05 38.8 110.4% 66.3% 7.8 4.7

5 7.50 500 10.0 2.04 34.4 97.2% 74.6% 6.9 5.3

6 9.50 500 10.0 2.07 29.9 98.2% 79.5% 7.0 5.6

7 11.50 500 10.0 2.08 25.0 105.6% 84.1% 7.5 6.0

8 12.50 500 10.0 2.08 23.3 251 72.3% 83.1% 5.1 5.9

9 14.50 500 10.0 2.17 18.6 98.7% 85.3% 7.0 6.0

10 16.50 500 10.0 2.16 13.5 105.7% 87.8% 7.5 6.2

11 18.50 500 10.0 2.51 8.9 94.9% 88.5% 6.7 6.3

12 20.50 500 10.0 2.56 5.2 73.2% 87.0% 5.2 6.2

13 22.50 500 10.0 2.36 1.8 259 68.3% 85.4% 4.8 6.114 24.50 500 10.0 2.25 1.5 5.9% 78.9% 0.4 5.6

15 25.50 500 10.0 2.31 1.0 17.8% 76.5% 1.3 5.4

Product Description

Nature: Plate

Colour:


Morphology:

Adherence:

Appearance:Other:




0.0

10.0

20.0

30.0

40.0

50.0

60.0

0.00 5.00 10.00 15.00 20.00 25.00 30.00

Elapsed time (hr)

Cu(g/L)


20/26




CLIENT: RTest No.: R-08 Rationale: Cu EW from an electrolyte containing Pb Cell used: 28mm full cell

Date: 17-Sep-03


Anode: DSA3 Flowrate: 500.0 L/hr Cathode: 997 Am-2



Operator: YC

6 in cell

Sample Elapsed Flowrate Current Voltage Cu Pb pH Conductivity Cu Per Cu Cum Cu Per Prod Cu Cum Prod


0 0.00 500 20.0 3.52 42.1 25.8 0.661 1.00 500 20.0 3.52 35.4 24.5 0.00 113.1% 113.1% 16.0 16.0

2 2.00 500 20.0 2.96 32.6 22.0 -0.09 46.5% 79.8% 6.6 11.3

3 3.00 500 20.0 2.52 27.9 19.1 0.00 76.7% 78.8% 10.9 11.2

4 4.00 500 20.0 2.56 21.4 13.3 0.00 104.4% 85.2% 14.8 12.1

5 6.00 500 20.0 1.90 14.8 9.2 0.00 52.1% 74.1% 7.4 10.5

6 8.00 500 20.0 2.60 2.16 4.6 0.00 98.0% 80.1% 13.9 11.4

7 10.00 500 20.0 2.60 0.018 6.7 0.00 16.3% 67.3% 2.3 9.5

8 12.00 500 20.0 2.78 4.7 0.00 0.1% 56.1% 0.0 8.0

Product Description

Nature: Cathode plate (Pb deposit on anode)

Colour:


Morphology:

Adherence:

Appearance:

Other: PbO coating on anode that washed off.Product Reconciliation



0.0

5.0

10.0

15.020.0

25.0

30.0

35.0

40.0

45.0

0.00 2.00 4.00 6.00 8.00 10.00 12.00

Elapsed time (hr)

Cu

(g/L)

Cu

Pb


21/26




CLIENT: R

Test No.: R-09 Rationale: Low grade Ag (approx. 40g/L HNO3) Cell used: 50mm

Date: 24-Sep-03





Operator: YC

8in cell

Sample Elapsed Flowrate Current Voltage Ag Cu pH Conductivity Ag Per Ag Cum Ag Per Prod Ag Cum Prod

time (hr) L/hr A V mg/L g/L g/L CE% CE% kg/day kg/day

0 0.00 500 20.0 1.64 12300 33.9 0.25 166.00

1 1.00 500 20.0 1.63 15 34.9 183.00 76.4% 76.4% 35.4 35.4

2 2.00 500 20.0 1.89 8 32.6 0.23 185.00 0.0% 38.2% 0.0 17.7

3 3.00 500 20.0 1.87 31.7 182.00 0.0% 25.5% 0.0 11.8

Product Description

Nature: Fine Ag powder with Cu plate

Colour: Grey Ag powder

Coverage: Ag powder washed off cell inlet

Morphology:

Adherence:

Appearance:

Other: Cu production occurred after Ag was removed




0

2000

4000

6000

8000

10000

12000

14000

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50

Elapsed time (hr)

Ag

(mg/L)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

C

u(g/L)

Ag

Cu


22/26




CLIENT:R

Test No.: R-10 Rationale: Low grade Ag-EW (approx. 60g/L HNO3) Cell used: 28mm 1/2 cell

Date: 24-Sep-03





Operator: YC

8 in cell

Sample Elapsed Flowrate Current Voltage Ag Cu pH Conductivity Ag Per Ag Cum Ag Per Prod Ag Cum Prod


0 0.00 250 5.0 1.29 13.0 28.8 128.001 0.50 250 5.0 1.18 10.5 28.8 128.70 124.3% 124.3% 57.2 57.2

2 1.00 250 5.0 1.23 8.0 28.4 131.90 123.2% 123.8% 56.7 57.0

3 1.50 250 5.0 1.23 5.4 28.8 134.90 125.4% 124.3% 57.8 57.2

4 2.00 250 5.0 1.45 2.9 28.6 138.00 118.0% 122.7% 54.4 56.5

5 3.00 250 5.0 1.40 0.2 28.3 140.60 64.4% 103.3% 29.7 47.6

6 4.00 250 5.0 1.72 0.07 27.8 223.90 3.1% 78.2% 1.4 36.0

7 5.00 250 5.0 1.93 0.011 27.6 142.80 1.3% 62.8% 0.6 28.9

8 6.00 250 5.0 1.89 27.5 155.20 0.1 24.1

9 7.00 250 5.0 1.92 27.3 143.90 0.0 20.7

10 8.00 250 5.0 2.07 27.3 141.60 0.0 18.111 9.00 250 5.0 2.13 26.6 141.40 0.0 16.1

12 9.78 250 5.0 2.12 26.2 0.0 14.8

Product Description

Nature: Powder

Colour:


Morphology:

Adherence: Easily washed off

Appearance:

Other:Product Reconciliation



0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

0.00 2.00 4.00 6.00 8.00 10.00 12.00

Elapsed time (hr)

Ag(g/L)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

Cu(g/L)

Ag

Cu


23/26




CLIENT: R

Test No.: RCu-01 Rationale: Synthetic electrolyte (approx. 20 g/L HNO3) Cell used: 28mm full cell

Date: 19-Aug-03





Operator: YC

6 in cell

Sample Elapsed Flowrate Current Voltage Cu pH Conductivity Cu Per Cu Cum Cu Per Prod Cu Cum Prod


0 0.00 500 10.0 2.75 8.84 0.531 0.50 500 10.0 2.58 7.50 113.1% 113.1% 8.0 8.0

2 1.00 500 10.0 2.47 6.38 69.90 93.3% 103.2% 6.6 7.3

3 1.50 500 10.0 2.38 5.05 0.51 78.70 109.3% 105.2% 7.8 7.5

4 2.00 500 10.0 2.35 3.82 0.46 84.10 99.7% 103.9% 7.1 7.4

5 2.50 500 10.0 2.39 2.53 0.44 100.80 103.2% 103.7% 7.3 7.4

6 3.00 500 10.0 2.32 1.32 0.43 121.70 95.5% 102.4% 6.8 7.3

7 3.50 500 10.0 2.33 0.365 0.41 107.50 74.3% 98.3% 5.3 7.0

8 4.00 500 10.0 2.35 0.081 0.41 107.30 21.8% 88.8% 1.5 6.3

9 4.50 500 10.0 2.49 0.060 0.41 104.50 1.6% 79.1% 0.1 5.6

10 5.00 500 10.0 2.48 0.048 0.42 103.10 0.9% 71.3% 0.1 5.1

11 6.00 500 10.0 2.57 0.026 0.50 154.50 0.8% 59.5% 0.1 4.2

Product Description

Nature: Plate

Colour: Red/brown

Coverage: Even & complete

Morphology: No dendrites or nodules - smooth plate

Adherence:

Appearance:

Other: A strong dense plate was producedProduct Reconciliation

Shim weight: 7.9 g



0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00

Elapsed time (hr)

Cu

(g/L)

Cu


24/26




CLIENT: R

Test No.: RCu-02 Rationale: Synthetic electrolyte (pH 0 or approx 60g/L HNO3 ) Cell used: 28mm full cell

Date: 20-Aug-03





Operator: YC

6 in cell



0 0.00 500 10.0 2.27 7.57 0.03 237.101 0.50 500 10.0 2.32 6.67 0.08 250.10 75.9% 75.9% 5.4 5.4

2 1.00 500 10.0 2.32 5.97 253.50 58.3% 67.1% 4.1 4.8

3 1.50 500 10.0 2.12 4.81 OVER 95.3% 76.5% 6.8 5.4

4 2.00 500 10.0 2.13 3.54 103.0% 83.1% 7.3 5.9

5 3.00 500 10.0 2.39 1.67 74.8% 80.4% 5.3 5.7

6 4.00 500 10.0 2.44 0.03 64.5% 76.4% 4.6 5.4

7 5.00 500 10.0 2.46 0.034 0.0% 61.1% 0.0 4.3

8 6.00 500 10.0 2.59 0.051 -0.7% 50.8% 0.0 3.6

Product Description

Nature: Strong Cu plate

Colour:

Coverage: Even & complete

Morphology: Smooth surface

Adherence:

Appearance:

Other: Nodules/powder at cell outlet


25/26




CLIENT: R

Test No.: RCu-03 Rationale: Synthetic electrolyte (approx. 250g/L Nitric acid) Cell used: 28mm full cell

Date: 20-Aug-03





Operator: YC

6 in cell



0 0.00 500 10.0 2.05 8.55

1 0.50 500 10.0 2.06 7.31 104.6% 104.6% 7.4 7.42 1.00 500 10.0 2.10 6.25 88.3% 96.5% 6.3 6.8

3 1.50 500 10.0 2.20 5.51 60.8% 84.6% 4.3 6.0

4 2.00 500 10.0 2.23 4.65 69.7% 80.9% 4.9 5.7

5 3.00 500 10.0 2.21 3.19 58.4% 73.4% 4.1 5.2

6 4.00 500 10.0 2.25 2.21 38.7% 64.7% 2.7 4.6

7 5.00 500 10.0 2.32 1.140 41.6% 60.1% 3.0 4.3

8 6.00 500 10.0 2.34 0.893 9.5% 51.7% 0.7 3.7

9 6.00 500 10.0 2.24 1.147 50.1% 3.5

10 7.00 500 10.0 2.39 0.738 15.2% 45.1% 1.1 3.2

11 8.00 500 10.0 2.24 0.496 8.9% 40.6% 0.6 2.9

12 9.00 500 10.0 2.27 0.315 6.5% 36.8% 0.5 2.6

13 10.00 500 10.0 2.36 0.096 7.8% 33.9% 0.6 2.4

Product Description

Nature: Strong Cu plate

Colour:

Coverage: Even & complete (thinner at outlet)

Morphology: Some nodules at outlet end of cell.

Adherence:

Appearance:




0.00

1.00

2.00

3.004.00

5.00

6.00

7.00

8.00

9.00

0.00 2.00 4.00 6.00 8.00 10.00 12.00

Elapsed time (hr)

Cu(g/L)

Cu


26/26




CLIENT: R

Test No.: RCu-04 Rationale: Synthetic electrolyte (approx. 100g/L Nitric acid) Cell used: 28mm full cell

Date: 25-Aug-03





Operator: YC

6 in cell



0 0.00 500 10.0 2.23 8.37

1 0.50 500 10.0 2.27 7.77 50.6% 50.6% 3.6 3.62 1.00 500 10.0 2.25 7.23 45.0% 47.8% 3.2 3.4

3 1.50 500 10.0 2.18 7.08 12.3% 36.0% 0.9 2.6

4 2.00 500 10.0 2.17 6.68 32.4% 35.1% 2.3 2.5

5 2.50 500 10.0 2.16 6.24 35.2% 35.1% 2.5 2.5

6 3.00 500 10.0 2.17 6.01 18.1% 32.3% 1.3 2.3

7 4.00 500 10.0 2.36 5.580 16.7% 28.4% 1.2 2.0

8 5.00 500 10.0 2.39 5.100 18.4% 26.4% 1.3 1.9

9 5.50 500 10.0 2.38 4.800 22.7% 26.1% 1.6 1.8

10 6.50 500 10.0 2.13 4.280 19.4% 25.0% 1.4 1.8

Product Description

Nature: incoherent plate

Colour:

Coverage:

Morphology: Flow lines visible on surface

Adherence: Peels away easily

Appearance:




0.00

1.00

2.00

3.004.00

5.00

6.00

7.00

8.00

9.00

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00

Elapsed time (hr)

Cu(g/L)

Cu

Documents

Elect Row Inning Copper and Silver From Nitric Acid