736
A. Cybulski
Unfortunately, drying of metallic Al–Cu foam with milled limestone did not give
a positive result in a form of the production of loose Al–Cu drosses. During drying
with slaked lime, the incandescence was observed on the produced powdery Al–Cu
drosses and small flames of burning hydrogen from the decomposition of Ca(OH) 2
could be observed.
The most favorable results in terms of the possibility to dry the metallic Al–Cu
foam and provide safety during drying were obtained for the process performed with
the application of sodium carbonate and quicklime.
The analysis of the lead decoppering process with the application of aluminum
shows that the main factors that may cause the ignition of Al–Cu drosses are:
• too long drying of the metallic Al–Cu foam causing high level of oxygen saturation
of the produced Al–Cu drosses,
• application of aluminum scrap with high content of flammable compounds,
• application of flammable battery spacers for the process of drying of metallic
Al–Cu foam,
• large surplus of aluminum added to the lead decoppering process,
• high sulfur content in the produced Al–Cu drosses.
Conclusions
In order to eliminate the problem of Al–Cu dross ignition, it is necessary to strictly
and rigorously follow the instructions for the process of lead decoppering with application of aluminum in technical and technological terms, with a particular regard to
occupational health and safety regulations. The instructions include all the factors
that may lead to the spontaneous combustion as well as their storage.
Another alternative that may eliminate this undesirable phenomenon is the application of the second lead decoppering method with the application of aluminum,
where Al–Cu alloy is produced. This alloy is collected from the lead surface in the
metallic form after the decoppering process. The second lead decoppering method
with application of aluminum does not produce the metallic Al–Cu foam which
requires drying. Even when it is formed, the amounts are very small. The produced
Al–Cu alloys are more valuable by-product that contains approx. 32 wt% Cu and
small amount of Pb. This alloy, after the initial refining, can be used as a ready byproduct, i.e. for the production of copper-aluminum radiators. In a process conducted
in this way, the amount of by-products is below 1% of the mass of refined lead, which
significantly increases the refining efficiency and lead yield. The application of lead
decoppering process with application of aluminum that produces Al–Cu alloy results
in a significant financial profit when compared to the sulfur technology or the first
lead decoppering method that generates Al–Cu drosses.
A. Cybulski
Unfortunately, drying of metallic Al–Cu foam with milled limestone did not give
a positive result in a form of the production of loose Al–Cu drosses. During drying
with slaked lime, the incandescence was observed on the produced powdery Al–Cu
drosses and small flames of burning hydrogen from the decomposition of Ca(OH) 2
could be observed.
The most favorable results in terms of the possibility to dry the metallic Al–Cu
foam and provide safety during drying were obtained for the process performed with
the application of sodium carbonate and quicklime.
The analysis of the lead decoppering process with the application of aluminum
shows that the main factors that may cause the ignition of Al–Cu drosses are:
• too long drying of the metallic Al–Cu foam causing high level of oxygen saturation
of the produced Al–Cu drosses,
• application of aluminum scrap with high content of flammable compounds,
• application of flammable battery spacers for the process of drying of metallic
Al–Cu foam,
• large surplus of aluminum added to the lead decoppering process,
• high sulfur content in the produced Al–Cu drosses.
Conclusions
In order to eliminate the problem of Al–Cu dross ignition, it is necessary to strictly
and rigorously follow the instructions for the process of lead decoppering with application of aluminum in technical and technological terms, with a particular regard to
occupational health and safety regulations. The instructions include all the factors
that may lead to the spontaneous combustion as well as their storage.
Another alternative that may eliminate this undesirable phenomenon is the application of the second lead decoppering method with the application of aluminum,
where Al–Cu alloy is produced. This alloy is collected from the lead surface in the
metallic form after the decoppering process. The second lead decoppering method
with application of aluminum does not produce the metallic Al–Cu foam which
requires drying. Even when it is formed, the amounts are very small. The produced
Al–Cu alloys are more valuable by-product that contains approx. 32 wt% Cu and
small amount of Pb. This alloy, after the initial refining, can be used as a ready byproduct, i.e. for the production of copper-aluminum radiators. In a process conducted
in this way, the amount of by-products is below 1% of the mass of refined lead, which
significantly increases the refining efficiency and lead yield. The application of lead
decoppering process with application of aluminum that produces Al–Cu alloy results
in a significant financial profit when compared to the sulfur technology or the first
lead decoppering method that generates Al–Cu drosses.