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Update An Inside Look: UK Collaborative Research Project Dissemination Conference

Dr. John Henderson, senior project Manager at C-Tech Innovation gave a progress report on the Stowurc multi-partner project, developing processes for the sustainable treatment of waste using recycled chitosans and intermediate derivatives prepared from crab shells to remove and capture metals such as copper and nickel from PCB manufacturing effluent. The project was nine months into a two-year programme.  Techniques for the demineralisation, deproteination, and deacetylation had been investigated and costed, and extensive studies had been made of absorption rates and exchange capacities. Chitosan had been shown to be capable of achieving close to the benchmark performance of proprietary ion-exchange resin but production costs were not currently competitive. However, it appeared that demineralised shell could provide a cost-effective alternative for dealing with short-term incidences of high copper concentration in effluent.

Dr. Andrew Ballantyne, University of Leicester  

The sustainable solder flux project, supported by IeMRC, was a further area of development in ionic liquid technology, presented by Dr. Andrew Ballantyne from University of Leicester. Deep eutectic solvents were finding many applications in metal finishing, plating, electropolishing, metal recovery and recycling. A particular attribute was their exceptional ability to dissolve metal oxides without the use of acids, and this offered the prospect of formulating environmentally-friendly soldering fluxes which would clean metal surfaces, prevent metal oxidation during soldering and hence maximise the wetting interaction between substrate and solder. Remarkable results had been observed in preliminary tests on copper, brass, stainless steel, and even cast iron--a material previously considered unsolderable using conventional fluxes. 

Focusing specifically on PCB finishes, solderability tests had been conducted on a range including bare copper, OSP, ENIG, immersion silver, immersion tin, tin-lead HASL, and lead-free HASL, on test-pieces representing plated through holes, surface mount pads, and ball grid arrays, using a standard test flux as reference. In all cases, the DES flux showed excellent wetting, even enabling solder levelling directly on electroless nickel and introducing the prospect of a novel PCB finish, HASLEN. Collaboration with a solder paste manufacturer has demonstrated that DES-based pastes were feasible, and initial stencil-printing trials had shown promising results.

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