The galvanic gold plating process of printed circuit boards is associated with high water consumption and the use of valuable resources. Rinsing facilities within the process prevent cross contamination between the individual sub-steps, but valuable resources are lost in the rinsing facilities and subsequent wastewater treatment due to carryover. By integrating a membrane distillation unit, a circuit is created between the coating process and the rinsing water unit which reduces the carryover of valuable resources. The rinsing of the printed circuit boards takes place directly above the gold bath which gets contaminated by the rinsing process. The rinsing water is separated by the membrane technology and reused. New DCMD modules are integrated into an existing pilot plant, the plant and software are adapted for the operation of the new modules. During the test phase, the modules was tested with fully desalinated water (DI-water) and a permeate flow rate of 11.52 l/h is achieved. It was found that the feed inlet temperature and the flow rate are the biggest drivers to increase the permeate flow rate. Using gold solution and one membrane, a separation rate of 6.3 l/h was obtained. The stable process suitability and the resulting deposition efficiencies were used for further trials and full automation of the system. Complete wetting of the printed circuit boards during the rinsing process was not achieved and the system could only be used to a limited extent due to an unsuitable pump for the system concept.
|Translated title of the contribution||Commissioning and optimization of a direct membrane distillation plant in the galvanic gold plating process of printed circuit boards|
|Award date||30 Jun 2023|
|Publication status||Published - 2023|
Bibliographical noteembargoed until 08-05-2026
- Permeat flow rate
- Permeat flux
- Membrane distillation