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J. Antrekowitsch and G. Hanke
of secondary resources and the optimization of existing processes are two major
concerns. The challenge of the years to come is, at the same time, to minimize newly
generated residues and to achieve maximum product quality within the recycling
process. In addition, the quality of the products influences the targeted market and
achievable revenues. Therefore, the state-of-the-art processes have to be continuously
adapted regarding energy consumption, mass-balancing, and further improvement
of the product quality.
A specific geochemical, mineralogical, and metallurgical characterization creates
the basis for improving such existing processes. Thus, it will be possible to obtain
higher product qualities and lower amounts of newly generated waste streams.
As demonstrated by several investigations carried out at Montanuniversität
Leoben, the residues are not at all homogenous. Hence, it is not possible to recycle
such residues as one combined single input stream. In order to increase the recoverable metal grade and to reduce the content of substances that hinder the metallurgical
process, some separation by physical/mechanical techniques is required. If such a
process shall be developed systematically rather than by trial-and-error, the residue
must be characterized properly in terms of its properties relevant to a separation
process. Fractional analysis is the standard tool in mineral processing for assessing
the amenability of primary mineral resources to be upgraded to saleable products of
defined and consistent quality. Taking into account the heterogeneity of the residues,
it is expected that some upgrading is possible which may pay off during recycling.
Fractional analysis yields the optimum results for separating a given feed material
by assuming perfect separation. Thus, it also serves as a benchmark for assessing the
performance of an existing process. The possible benefits of assessing and processing the residues in a similar way to primary mineral resources are obvious. As some
common properties of the residues (e.g. the generally fine particle size distribution of
dusts, just to name one) are problematic in fractional analysis, the methods require
further adaptations.
In order to find the suitable processing chain, test work needs to be carried out.
Once done for a residue, the obtained data will be collected and condensed in a
database, which acts in future assessments as a decision support tool. Although
similarities within the same type of material (e.g. slags and dust) can be found,
each residue is generated in slightly different processing routes with varying input
material. This leads to variable extraction yields, consumable consumption, energy
input, obtained product quality, etc. Based on the experimental results, the database
will grow, and the more materials are cataloged, the more accurate the data for the
assessment becomes.
One major disadvantage of past attempts in recycling by-products was that often
just one single metal was recovered while possible further valuable metals distributed
into newly generated wastes and were therefore lost for production. Pyrometallurgical
concepts allow the recovery of valuable metals by applying different basic operations:
forming a volatile phase, where, e.g., zinc or lead can be collected as oxides in the
J. Antrekowitsch and G. Hanke
of secondary resources and the optimization of existing processes are two major
concerns. The challenge of the years to come is, at the same time, to minimize newly
generated residues and to achieve maximum product quality within the recycling
process. In addition, the quality of the products influences the targeted market and
achievable revenues. Therefore, the state-of-the-art processes have to be continuously
adapted regarding energy consumption, mass-balancing, and further improvement
of the product quality.
A specific geochemical, mineralogical, and metallurgical characterization creates
the basis for improving such existing processes. Thus, it will be possible to obtain
higher product qualities and lower amounts of newly generated waste streams.
As demonstrated by several investigations carried out at Montanuniversität
Leoben, the residues are not at all homogenous. Hence, it is not possible to recycle
such residues as one combined single input stream. In order to increase the recoverable metal grade and to reduce the content of substances that hinder the metallurgical
process, some separation by physical/mechanical techniques is required. If such a
process shall be developed systematically rather than by trial-and-error, the residue
must be characterized properly in terms of its properties relevant to a separation
process. Fractional analysis is the standard tool in mineral processing for assessing
the amenability of primary mineral resources to be upgraded to saleable products of
defined and consistent quality. Taking into account the heterogeneity of the residues,
it is expected that some upgrading is possible which may pay off during recycling.
Fractional analysis yields the optimum results for separating a given feed material
by assuming perfect separation. Thus, it also serves as a benchmark for assessing the
performance of an existing process. The possible benefits of assessing and processing the residues in a similar way to primary mineral resources are obvious. As some
common properties of the residues (e.g. the generally fine particle size distribution of
dusts, just to name one) are problematic in fractional analysis, the methods require
further adaptations.
In order to find the suitable processing chain, test work needs to be carried out.
Once done for a residue, the obtained data will be collected and condensed in a
database, which acts in future assessments as a decision support tool. Although
similarities within the same type of material (e.g. slags and dust) can be found,
each residue is generated in slightly different processing routes with varying input
material. This leads to variable extraction yields, consumable consumption, energy
input, obtained product quality, etc. Based on the experimental results, the database
will grow, and the more materials are cataloged, the more accurate the data for the
assessment becomes.
One major disadvantage of past attempts in recycling by-products was that often
just one single metal was recovered while possible further valuable metals distributed
into newly generated wastes and were therefore lost for production. Pyrometallurgical
concepts allow the recovery of valuable metals by applying different basic operations:
forming a volatile phase, where, e.g., zinc or lead can be collected as oxides in the