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increases to 3,348 tpa to 2,710 tpa with a midpoint of 2,976 tpa. This corresponds with an overall
recovery rate of 64%–73%.
Table 29. Short-Term Indium Supply Scenarios
Short-Term Indium Recovery Scenarios
Recovery at Each Stage
(tonnes)
Corresponding Recovery
Efficiency (%)
A,C
Low
Mid
High
Low
Mid
High
Indium contained in mined zinc ores
100
100.0
100
Indium reporting to concentrate
50.0
60.0
70.0
50%
60%
70%
Indium sent to indium-capable smelter
35.0
42.0
49.0
70%
70%
70%
Indium recovered by smelter
17.5
21.0
24.5
50%
50%
50%
Indium recovered by special metal
refinery
14.0
16.8
19.6
80%
80%
80%
Estimates of indium metal recovered
731
731
731
Overall indium recovery rate
14%
17%
20%
Equivalent amount of indium 'mined'
5,221
4,351
3,730
Scenario 1: If All Indium Concentrates Make Their Way to Indium-Capable Smelters
Indium contained in mined zinc ores
5,221
4,351
3,730
Indium reporting to concentrate
2,611
2,611
2,611
50%
60%
70%
Indium sent to indium-capable smelter
2,611
2,611
2,611
100%
100%
100%
Indium recovered by smelter
1,305
1,305
1,305
50%
50%
50%
Indium recovered by special metal
refinery
1,044
1,044
1,044
80%
80%
80%
Estimates of indium metal recovered
1,044
1,044
1,044
Overall indium recovery rate
20%
24%
28%
Scenario 2: Scenario 1 + Improved Recovery Efficiencies
b
Indium contained in mined zinc ores
5,221
4,351
3,730
Indium reporting to concentrate
3,916
3,481
3,170
75%
80%
85%
Indium sent to indium-capable smelter
3,916
3,481
3,170
100%
100%
100%
Indium recovered by smelter
3,524
3,133
2,853
90%
90%
90%
Indium recovered by special metal
refinery
3,348
2,976
2,710
95%
95%
95%
Estimates of indium metal recovered
3,348
2,976
2,710
Overall indium recovery rate
64%
68%
73%
a
The quantity of mined indium is the value with the highest uncertainty in our analysis. As a result, we back
calculate mined indium from refined indium and a range of overall recovery efficiencies. From these starting points
for mined indium, we then proceed to vary recovery rates to calculate the potential amount of metal recovered.
b
Highlighted cells in light green show values that have changed from the base case.
c
Target recovery efficiencies are based on current technologies and have been taken from feasibility studies.
Using the midpoint data from Scenarios 1 and 2 in Table 29, we can now see how short-term
initiatives might affect the availability of primary indium and the cost at which that supply might
be available. The supply curves depicted in Figure 30 include the status quo scenario from Figure
29 as well as Scenarios 1 and 2. The cost allocations in the simulation remain unaltered per
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individual simulation realizations;
44
only the quantity produced is scaled to match the increased
average recovery coinciding with Scenarios 1 and 2, respectively.
Figure 29. Short-term primary indium supply, including pipeline efficiency improvements
The Medium Term
We use a similar approach to generate the medium-term supply curves but have made certain
adjustments:
•
Capital costs are included. Because operators have the option to invest in new capacity
or shut down in the medium term, we adjust costs to reflect returns to capital and
eliminate all realizations in the simulation that would not generate positive returns for
investors.
•
Variations in the long-term main-product average prices are used to assess
feasibility. Readers should examine the long-term historical prices of tin and zinc in
Appendix C.
Primary indium is, to our knowledge, currently produced only as a byproduct from zinc, and to a
lesser degree tin and copper ores; thus, we may reasonably assume that the growth of indium
production will follow anticipated changes to main product supply. For this analysis, we concern
ourselves only with the growth of zinc production and assume that the ratio of total indium
production to total zinc production is constant over time. Taking two medium-term snapshots,
one in 2016 and the other at 2031, and assuming a possible range of main product growth of 2%–
3%, total indium production in 2016 and 2031 is forecasted to be 827 tonnes and 1,365 tonnes,
respectively (see Table 31).
44
By increasing the recovery efficiency one would anticipate that indium increases in significance to a particular simulation
realization. If the model were rerun, assuming that recoveries of other main product metals remained
unchanged, indium could
move from byproduct to coproduct and then costs would be reallocated on the appropriate basis. This level of detail has not been
considered for the short run and the curves above should be considered a first pass at how quantities of indium and costs might
react to changing recovery efficiencies.