| dc.description.abstract | PCB (printed circuit board) is an integrated industry of optics, electricity,chemistry, machinery, and management. In year 2007, the total industry revenuealready reached 44.2 billion USD. The wet processes for plating of PCB
industry use large amount of metal salts. Therefore, their waste liquids usually contain high valuable metals, such as copper, lead, nickel, gold and palladium.In 2006, the reported amount of waste with heavy metals in Taiwan PCB
industry was around 322,907 ton. If these wastes are not well treated, their impact to environment and ecologic system will be serious and also will costenterprises and society more.
This thesis takes a PCB plant in northern Taiwan as an example to discuss theefficiency and operating cost, for recovering gold from waste liquid usingelectrolysis and ion exchange. This study shows the following results:
1. The efficiency of ion exchange is better than that of
electrolysis in gold recycle.
2. The efficiency of combination of ion resins is better
than that of the combination of ion resin and
electrolysis in gold recycle. This finding is different
from literatures. Therefore, it is suggested that the
recycling facility should be optimized to reduce the
loss of gold.
3. It was found that gold recycling efficiency was 96%.
Resin of ion resin for a PCB plant located in northern
Taiwan reached the capacity limit in the third day of
test. If the resin is not replaced, then breakthrough
will occur. Therefore, this study suggests the PCB
plants using ion resin for gold recycling must
understand the breakthrough point for flow and time
to avoid loss of gold.
4. The analysis indicates that semi-finished product is of
the highest percentage of the gold input. An efficient
recycling system is needed to properly deal with the
subsequent waste problem and avoid resource waste and
environmental pollution.
Key words ： printed circuit board, gold, ion exchange,
electrolysis, recycling efficiency. | en_US |