Resource Efficiency Evaluation of Pyrometallurgical Solutions …
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would be the most suitable option to avoid the generation of a wet hydrometallurgical residue. An existing RLE plant and the infrastructure required for the DZS
could create this integrated system, with the difference of, instead of splitting the
concentrate and feeding it to the DZS, only the produced jarosite residue would be
fed to the pyrometallurgical flowsheet; thus, the concentrate would be entirely fed
to the RLE flowsheet (scenario “100 RLE + jarosite treatment”).
In terms of material recovery, elements co-precipitated with the jarosite residue,
e.g. indium, germanium, or antimony, could be recovered through the fumes generated during the pyrometallurgical treatment of the jarosite, if these were not recovered
during the typical RLE operations. Additionally, the copper, cobalt, nickel, cadmium,
and lead-silver residues would be still produced; thus, the recovery of these elements
through further treatment would be possible. Therefore, the material recovery would
improve with respect to the base scenario, while in addition, the jarosite residue is
converted into a clean slag with the potential of being commercialized as construction
material.
Obviously, the resource consumption of the integrated system would increase in
comparison to the base case and the high-fuming DZS. The reason is simple, the 2LT
dictates that every extra process performed will require extra resources to be used or
destroyed. However, the extra resources required to conduct this pyrometallurgical
treatment are not much larger than the options shown in Fig. 4. Furthermore, the same
occurs with the GWP of the integrated system. An increase in the CO 2 emissions is
expected when the system is integrated because of the fuel and reductant required
for the thermal treatment, however, the CO 2 emissions of this scenario are the lowest
of all the considered alternatives.
The considered alternatives for a lower generation of residues within the zinc
production must guarantee a sustainable development. It can only be achieved if the
social, environmental, and economic sustainability are fulfilled, as they are the three
pillars of sustainability [17]. A first quantification of the factors affecting these three
pillars can be done by normalizing the indicators provided by the simulation. For
instance, the CO 2 emissions, which affect to the environmental sustainability, can be
normalized with respect to the lowest emissions value of all the evaluated alternatives
(best-case scenario), or even to the emission limit, to evaluate the deviation of the
emission values for every scenario. The same can be done for resource consumption,
land use, or CAPEX/OPEX. If the normalized values are calculated in a scale from
0 to 100%, where 0 is the scenario with the most negative impact and 100 is the
best-case scenario (positive one), a good view of all the evaluated factors affecting
society, environment, and economics can be obtained, thus a first conclusion about
the effect of the different solutions in the resource efficiency of each solution can be
obtained. The effects of the CE solutions for the reduction of iron-rich precipitate
during hydrometallurgical zinc production on these three pillars are discussed, with
a few examples on how the impact of some factors affecting them can be quantified.
359
would be the most suitable option to avoid the generation of a wet hydrometallurgical residue. An existing RLE plant and the infrastructure required for the DZS
could create this integrated system, with the difference of, instead of splitting the
concentrate and feeding it to the DZS, only the produced jarosite residue would be
fed to the pyrometallurgical flowsheet; thus, the concentrate would be entirely fed
to the RLE flowsheet (scenario “100 RLE + jarosite treatment”).
In terms of material recovery, elements co-precipitated with the jarosite residue,
e.g. indium, germanium, or antimony, could be recovered through the fumes generated during the pyrometallurgical treatment of the jarosite, if these were not recovered
during the typical RLE operations. Additionally, the copper, cobalt, nickel, cadmium,
and lead-silver residues would be still produced; thus, the recovery of these elements
through further treatment would be possible. Therefore, the material recovery would
improve with respect to the base scenario, while in addition, the jarosite residue is
converted into a clean slag with the potential of being commercialized as construction
material.
Obviously, the resource consumption of the integrated system would increase in
comparison to the base case and the high-fuming DZS. The reason is simple, the 2LT
dictates that every extra process performed will require extra resources to be used or
destroyed. However, the extra resources required to conduct this pyrometallurgical
treatment are not much larger than the options shown in Fig. 4. Furthermore, the same
occurs with the GWP of the integrated system. An increase in the CO 2 emissions is
expected when the system is integrated because of the fuel and reductant required
for the thermal treatment, however, the CO 2 emissions of this scenario are the lowest
of all the considered alternatives.
The considered alternatives for a lower generation of residues within the zinc
production must guarantee a sustainable development. It can only be achieved if the
social, environmental, and economic sustainability are fulfilled, as they are the three
pillars of sustainability [17]. A first quantification of the factors affecting these three
pillars can be done by normalizing the indicators provided by the simulation. For
instance, the CO 2 emissions, which affect to the environmental sustainability, can be
normalized with respect to the lowest emissions value of all the evaluated alternatives
(best-case scenario), or even to the emission limit, to evaluate the deviation of the
emission values for every scenario. The same can be done for resource consumption,
land use, or CAPEX/OPEX. If the normalized values are calculated in a scale from
0 to 100%, where 0 is the scenario with the most negative impact and 100 is the
best-case scenario (positive one), a good view of all the evaluated factors affecting
society, environment, and economics can be obtained, thus a first conclusion about
the effect of the different solutions in the resource efficiency of each solution can be
obtained. The effects of the CE solutions for the reduction of iron-rich precipitate
during hydrometallurgical zinc production on these three pillars are discussed, with
a few examples on how the impact of some factors affecting them can be quantified.