Resource Efficiency Evaluation of Pyrometallurgical Solutions …
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Fig. 7 Normalized value of resource consumption, measured by exergy destruction, respect the
minimum resource consumption value. The closer to 100%, the lower resource consumption. Red
represents the base case, green the pyrometallurgical treatment of the jarosite, and yellow the DZS
with high zinc fuming rates
in the zinc smelters increases. Therefore, this supposes a trade-off that the environment must accept if the production of jarosite wants to be eliminated. For this
reason, a quantitative evaluation of factors affecting the environmental sustainability
of the system can be also done in the same way that the land use indicator used to
start discussing the social impacts. In this case, the resource consumption increases
in every evaluated alternative. Therefore, by normalizing the resource consumption
with respect to the base scenario, i.e. dividing the exergy destruction of the base
case by the exergy destruction of every case, an indicator of how close the alternative is to the minimum exergy destruction, on a scale from 0 to 100%, can be
obtained as represented in Fig. 7. As the results show, the 100% DZS with high zinc
fuming rates alternative (represented in yellow) accounts for the lowest resource
consumption within the alternatives to the RLE. The largest resource consumption,
as discussed before, happens when the DZS is operated without oxygen enrichment,
while the pyrometallurgical treatment of jarosite accounts for the second lowest
resource consumption within the alternatives.
Another indicator of the effects of the system on the environment is the CO 2
emissions. As done with the exergy indicator, the CO 2 emissions of the system can
be normalized with respect of the 100% RLE scenario, which accounts for the lowest
CO 2 emissions of all the cases, as explained before. The results of Fig. 8 show that the
alternative that is closer to the minimum of CO 2 emissions is the pyrometallurgical
treatment of the jarosite with a deviation of 9% on its relative value with respect
to the minimum CO 2 emission (best case represented as 100%) as depicted by the
green bar.
Effects on Economics
The pyrometallurgical flowsheets evaluated as alternatives in this paper would require
considerable investment for the RLE plants, even if the smelting and reduction stages
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Fig. 7 Normalized value of resource consumption, measured by exergy destruction, respect the
minimum resource consumption value. The closer to 100%, the lower resource consumption. Red
represents the base case, green the pyrometallurgical treatment of the jarosite, and yellow the DZS
with high zinc fuming rates
in the zinc smelters increases. Therefore, this supposes a trade-off that the environment must accept if the production of jarosite wants to be eliminated. For this
reason, a quantitative evaluation of factors affecting the environmental sustainability
of the system can be also done in the same way that the land use indicator used to
start discussing the social impacts. In this case, the resource consumption increases
in every evaluated alternative. Therefore, by normalizing the resource consumption
with respect to the base scenario, i.e. dividing the exergy destruction of the base
case by the exergy destruction of every case, an indicator of how close the alternative is to the minimum exergy destruction, on a scale from 0 to 100%, can be
obtained as represented in Fig. 7. As the results show, the 100% DZS with high zinc
fuming rates alternative (represented in yellow) accounts for the lowest resource
consumption within the alternatives to the RLE. The largest resource consumption,
as discussed before, happens when the DZS is operated without oxygen enrichment,
while the pyrometallurgical treatment of jarosite accounts for the second lowest
resource consumption within the alternatives.
Another indicator of the effects of the system on the environment is the CO 2
emissions. As done with the exergy indicator, the CO 2 emissions of the system can
be normalized with respect of the 100% RLE scenario, which accounts for the lowest
CO 2 emissions of all the cases, as explained before. The results of Fig. 8 show that the
alternative that is closer to the minimum of CO 2 emissions is the pyrometallurgical
treatment of the jarosite with a deviation of 9% on its relative value with respect
to the minimum CO 2 emission (best case represented as 100%) as depicted by the
green bar.
Effects on Economics
The pyrometallurgical flowsheets evaluated as alternatives in this paper would require
considerable investment for the RLE plants, even if the smelting and reduction stages