5
Figure 3 shows that the results for acid pretreating
and acid injection were essentially the same, with 98–99%
Ni, 92–93% Co, 94% Cu, 9–10% Fe, and 6–7% Mn
extraction. Test 7 offered better extractions at a lower acid
addition compared to Test 6 for reasons unknown, which
may be a result of an anomalous condition within Test 6
that impacted the leach performance, though it was not
physically noticeable/quantifiable
0
10
20
30
40
50
60
70
80
90
100
Ni Co Cu Fe Mg Al Mn
Test 3: 5% solids, 690 kPa overpressure, 800 kg/t acid, 150°C
Test 4: 20% solids, 0 kPa overpressure, 800 kg/t acid, 150°C
Test 5: 20% solids, 0 kPa overpressure, 800 kg/t acid, 225°C
Test 6: 30% solids, 0 kPa overpressure, 650 kg/t acid, 225°C
Figure 2. Metal Extractions from Test 3 through Test 6
0
10
20
30
40
50
60
70
80
90
100
Ni Co Cu Fe Mg Al Mn
Test 7: 30% solids, 500 kg/t acid, Pretreat Addition, 225°C
Test 8: 30% solids, 500 kg/t acid, Inject Addition, 225°C
Figure 3. Metal Extractions for Test 7 and Test 8
Calculated
Extraction
(%)
Calculated
Extracti
(%)
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