2002 Progress Report: Electrolysis and Ion Exchange for the In Process Recycling of Copper from Semi-Conductor Processing SolutionsEPA Grant Number: R829627
Title: Electrolysis and Ion Exchange for the In Process Recycling of Copper from Semi-Conductor Processing Solutions
Investigators: Doyle, Fiona M. , Evans, James W.
Institution: University of California - Berkeley
EPA Project Officer: Carleton, James N
Project Period: January 1, 2002 through December 31, 2004 (Extended to April 30, 2007)
Project Period Covered by this Report: January 1, 2002 through December 31, 2003
Project Amount: $325,000
RFA: Technology for a Sustainable Environment (2001) RFA Text | Recipients Lists
Research Category: Sustainability , Pollution Prevention/Sustainable Development
The main objective of this research project is to develop an understanding of the electrodeposition of copper onto extended-area electrodes, and of the adsorption/desorption of copper onto ion exchange resins with a high affinity for copper. The principles elucidated in this research project will pave the way for subsequent development of commercial-scale electrolysis/ion exchange processes for recovering copper throughout semiconductor fabrication plants.
We performed the following activities during Year 1 of the project:
· Characterized the effect of glycine, citrate, ammonia, and pH on the electrodeposition of copper using a rotating disc electrode.
· Observed that the behavior is strongly sensitive to de-aeration prior to electrolysis.
· Probed the mechanism for the interaction of copper with different bis(pyridylmethyl) amines, the functional group on Dowex M4195.
· Determined kinetics and sorption isotherms for copper on Dowex M4195 in the absence of organic additives. Chloride appears to promote copper uptake.
· Determined the effect of various organic additives on the uptake of copper on Dowex M4195. In general, these additives had a negligible, or mildly deleterious effect, on copper sorption.
· Identified significant shortcomings with the amenability of Dowex M4195 to undergo repeated loading with copper and elution. These appear to be most pronounced when eluting at high pH with ammonia.
· Started the development of a model using the MatLab-based Simulink program to simulate integrated processes incorporating both the electrodeposition and ion exchange operations in different configurations.
During the next year, we plan to:
· Complete laboratory-scale electrochemical investigations using a rotating copper electrode, while expanding the scope to include an Electrochemical Quartz Crystal Microbalance.
· Start work on applying extended surface area electrodes to solutions representative of semiconductor industry wastes.
· Conclude work on elution of Dowex M4195, and its performance under repeated cycles of loading and elution.
· Obtain sorption and desorption isotherms for strong cation exchange resins such as sulfonates.
· Possibly obtain sorption and desorption isotherms for weak cation exchange resins, or anion exchange resins, to provide for flexibility in treating solutions with different speciation.
· Analyze sorption and desorption isotherms to provide a basis for models for uptake and selectivity of metals onto resins.