Proceedings of the 12th European Conference on Knowledge ...

Simona-Clara Bârsan, Mihaela-Georgia and Dan Săvescu
3.2 Technology for obtaining high purity copper from solid waste with high content
<strong>of</strong> copper
The utilised raw material is represented by solid waste with high content <strong>of</strong> copper (metal residues,
bar ends, winding wires etc.), finally resulting, by applying <strong>the</strong> above mentioned technology,
electrolytic copper cathodes with purities <strong>of</strong> 99% or even higher (Linder et al, 1991). These cathodes
are commonly used in <strong>the</strong> electrical and electro technical industry, in electronics and
telecommunication, electrochemistry.
The carried out market studies have showed that <strong>the</strong> internal market necessary <strong>of</strong> electrolytic copper
is around tens <strong>of</strong> thousands annually. At <strong>the</strong> same time, in Romania <strong>the</strong>re is an important amount <strong>of</strong>
untapped copper waste. The lack <strong>of</strong> a domestic manufacturer determines <strong>the</strong> cover <strong>of</strong> <strong>the</strong> necessary
<strong>of</strong> electrolytic copper from external sources, while <strong>the</strong> emergence <strong>of</strong> a domestic manufacturer <strong>of</strong>
electrolytic copper cathodes would allow acquisitions at lower prices, under <strong>the</strong> conditions <strong>of</strong> <strong>the</strong>ir
manufacturing at <strong>the</strong> same quality with those <strong>of</strong> imported cathodes.
The technology for obtaining electrolytic copper from solid waste with high content <strong>of</strong> copper is based
on <strong>the</strong> electrolysis <strong>of</strong> some acid copper sulphate solutions with soluble anodes. One works in batches
(<strong>the</strong> medium time is approx. 12 days, out <strong>of</strong> which <strong>the</strong> first 2 days are for preparing <strong>the</strong> batch). The
quantity <strong>of</strong> electrolytic copper / batch may vary depending on <strong>the</strong> market and may be adjusted by
modifying <strong>the</strong> number <strong>of</strong> electrodes existing in each vat and, respectively, <strong>the</strong> number <strong>of</strong> vats in a
batch. The copper sulphate (bluestone) is <strong>the</strong> resulted by-product that can be used in various fields
(agriculture – viticulture, fruit trees, vegetable growing, chemical industry, electrochemical industry –
electroplating, textile and lea<strong>the</strong>r industry).
As regarding costs, this technology has two major advantages:
<strong>the</strong> raw material (solid waste with high content <strong>of</strong> copper) presents a copper content / costs ratio
superior to that corresponding to <strong>the</strong> raw material used in classical technologies (copper ore), that
leads to lower raw material costs;
by using titanium anodic baskets (which also represent <strong>the</strong> main original element <strong>of</strong> this
technology), one eliminates <strong>the</strong> stage <strong>of</strong> previous melting <strong>of</strong> <strong>the</strong> copper waste, which requires
high energy consumption.
3.3 Technology for recovering copper ions from diluted solutions
In <strong>the</strong> case <strong>of</strong> this technology, <strong>the</strong> raw material is represented by <strong>the</strong> diluted solutions that contain
copper ions (for example, <strong>the</strong> washing waters in <strong>the</strong> electroplating process). This industrial waste
cannot be discharged in environment before a preliminary processing, so as to remove those ions.
The dilution <strong>of</strong> <strong>the</strong> respective solutions (that contain less than 10 g/l copper ions) generates two sets
<strong>of</strong> problems: on <strong>the</strong> one hand, <strong>the</strong> ions extraction is difficult and expensive (very low productivity) and,
on <strong>the</strong> o<strong>the</strong>r hand, a very import amount <strong>of</strong> used solution is necessary to be transported, reported to
<strong>the</strong> metal ions content (Platona, 1997). The solution <strong>of</strong>fered to this problem by this technology is
represented by <strong>the</strong> purification installation, which is a mobile one, being thus able to be moved to <strong>the</strong>
client’s headquarters, thus avoiding <strong>the</strong> transport <strong>of</strong> some large amounts <strong>of</strong> used solutions, potentially
dangerous. The diluted solution containing copper ions is circulated in <strong>the</strong> installation and <strong>the</strong> resulted
purified solution is recycled in <strong>the</strong> client’s technological process. The processing time depends on <strong>the</strong>
concentration and composition <strong>of</strong> <strong>the</strong> respective solution.
The resulted copper powder can be utilised for sintering various parts (strip conductors, bearings).
By applying this technology, one ensures <strong>the</strong> management <strong>of</strong> <strong>the</strong> diluted liquid waste, containing
copper ions, due to <strong>the</strong> original and very ingenious method <strong>of</strong> advanced purifying diluted solutions.
3.4 Technology for recovering silver ions from diluted solutions
In this case, <strong>the</strong> utilised raw material is represented by diluted solutions containing silver ions, such as
<strong>the</strong> washing waters in photo labs (Florea, 2010). As already presented in <strong>the</strong> previous technology,
nei<strong>the</strong>r this waste can be discharged in environment, before a preliminary processing so as to remove
<strong>the</strong> silver ions. The dilution <strong>of</strong> <strong>the</strong> respective solutions (containing less than 10 g/l silver ions)
generates special problems, <strong>the</strong> ion extraction being difficult and expensive (productivity is very low
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