Grantee Research Project Results

Final Report: In-Process Recycling of a Spent Electroless Nickel Plating Bath

EPA Contract Number: 68D98136
Title: In-Process Recycling of a Spent Electroless Nickel Plating Bath
Investigators: Renz, Robert P.
Small Business: Faraday Technology, Inc.
EPA Contact:
Phase: I
Project Period: September 1, 1998 through March 1, 1999
Project Amount: $69,857
RFA: Small Business Innovation Research (SBIR) - Phase I (1998) RFA Text |  Recipients Lists
Research Category: SBIR - Pollution Prevention , Pollution Prevention/Sustainable Development , Small Business Innovation Research (SBIR)

Summary/Accomplishments (Outputs/Outcomes):

Purpose

The overall objective of the program is to develop and commercialize a novel electrochemical/electrodialysis system for in-process recycling of a spent electroless nickel (EN) plating bath. Currently, there is no technology available to treat the spent EN bath for in-process recycling. Additionally, current waste treatment processes generate a large volume of toxic sludge and, therefore, waste disposal costs are high. The proposed system will reduce the concentration of orthophosphite, H2PO3-, which has adverse effect on EN deposits, without altering the other bath constituents. Consequently, the treated bath can be in-process recycled to the EN plating operation.

Research Work Carried Out

The phase I work successfully demonstrated technical and economic feasibility for separation of orthophosphite from an EN bath. Additionally, our test results showed that we can successfully separate orthophosphite from EN bath without changing Ni2+ concentration and with little changing of hypophosphite concentration after Cell #1 treatment. In this manner, we can in-process recycle the EN bath after Cell #1 treatment. Consequently, Phase I experimental results demonstrate not only the feasibility for in-process recycle of EN bath, but also reduction of treatment steps compared to our original proposed process. Therefore, our system allows in-process recycling of the electroless nickel bath and eliminates waste treatment and sludge disposal. The proposed system will 1) reduce the bath cost due to extended bath life and 2) considerably reduce the waste disposal cost. The in-process recycling system is schematically shown in Figures 1 and 2, respectively.

Figure 1: Electrochemical Cell #1 for Separation of Cations and Anions.

 

Figure 2: Electrochemical Cell #2 for Conversion of Orthophosphite to Hypophosphite.

 

The key technical challenge associated with this system is to reduce the concentration of orthophosphite, which has adverse effects on nickel deposits without affecting the other constituents of the bath, particularly the nickel concentration. It may also be advantageous to convert the orthophosphite to hypophosphite.

Results

Nine experiments were run including a DC baseline test. The following operating parameters were used: flow rate - 0.8 L/min: frequency - 10 and 100 Hz: average current - 4 and 25 A: duty cycle - 20 and 80 %. A Taguchi experimental matrix was generated and is presented in Table 2. Each experiment was run for four hours with samples taken from Cell #1 in the anolyte loop and samples taken from Cell #2 in the catholyte loop at 20, 40, 60, 120, and 240 minutes. Cell #1 was run on one day and the contents of the anolyte tank were used as the catholyte for the Cell #2 part of the experiment, which was run on the following day. Samples were analyzed for orthophosphite and hypophosphite. In all of the tests the solution in each tank was 16 L.

Potential Commercialization

Commercialization will occur in conjunction with a shop floor validation at a job shop plating facility. One such shop participated in the Phase I effort by supplying contaminated electroless nickel plating chemistry for our experiments. Commercialization of an emerging technology requires the developer to focus, not on increasing sales volume from, say 50 to 100 units (the market share mentality), but to generate sufficient data and experience from actual Beta testing to affect an initial sale. The vendor community, who will ultimately distribute our in-process recycling system, is risk averse. In other words, they are not necessarily interested in risking the addition of another product line (e.g. our in-process recycling system) until it has been fully validated (Beta tested) and installed on several full production plating lines. For this purpose, Faraday Technology, Inc. and our Phase I partner have executed a mutual non-disclosure agreement and are planning to work closely in the Phase II program.

Beta Testing and Technical Marketing - As referenced above, it is anticipated that during a Phase II program we will complete a field demonstration in conjunction with a job shop plater, or another company of interest to our USEPA program officer. Additionally, we have most recently presented and published the results of our Phase I effort at the AESF Week 99 conference and exhibition. This presentation has resulted in an interest from more than 30 plating shops, vendors, and regulators. Finally, Faraday Technology, Inc. has agreed to collaborate a rectifier manufacturer via a joint tradeshow booth display registered for the upcoming IPC 99 (electronics industry) tradeshow to be held in Long Beach, Ca. during March, 1999. This collaboration is a key component of utilization of our technology, because, although the rectifier manufacturer fully understands the electronic and circuitry requirements for implementing modulated and modulated reverse electric fields, they need an electrochemical engineering expertise (Faraday Technology, Inc.) to assist their customers in optimizing the appropriate waveform for the required output.

Supplemental Keywords:

Sustainable Industry/Business, Scientific Discipline, Waste, Hazardous, Technology for Sustainable Environment, Engineering, Chemistry, cleaner production/pollution prevention, New/Innovative technologies, electrochemical, nickel plating, recycled waste products, in-process recycling, innovative technologies, electrochemical treatment, industrial wastewater, electrochemical techniques, electroplating, electroless plating, industrial innovations, innovative technology