Etchant Recovery SystemEPA Contract Number: EPD05019
Title: Etchant Recovery System
Investigators: Sallo, Jerome S.
Small Business: Republic Anodes Fabricators, Inc.
EPA Contact: Manager, SBIR Program
Project Period: March 1, 2005 through August 31, 2005
Project Amount: $68,200
RFA: Small Business Innovation Research (SBIR) - Phase I (2005) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , Hazardous Waste/Remediation , SBIR - Waste
Cupric chloride and ammoniacal etchants are used to remove unwanted copper from printed circuit boards. They are used in a continuous “bleed and feed” mode, which leads to the formation of a hazardous copper-containing waste. This waste material must be hauled from the site for disposal. In addition, cupric chloride etchant requires the use of hazardous oxidants, such as chlorine gas or sodium chlorate, for its regeneration. Republic Anodes Fabricators, Inc., will replace this method with an electrolytic device that will recover and automatically remove nonhazardous copper metal at the cathode and regenerate the spent etchant at the anode. It is essential to immediately remove the metallic copper from the system so that it cannot re-dissolve in the etchant. The system will eliminate the handling of hazardous oxidants and the creation of a hazardous waste; it will create a closed loop system using existing etching equipment. The system also will be considerably less costly per ounce of copper etched and will not require membranes because it does not require the separation of anolyte and catholyte.
Republic Anodes Fabricators already has developed an electrolytic device for the regeneration of ferric chloride etchant, which is widely used in the photochemical machining industry. Use of the existing device with the etchants used in the printed circuit industry results in the evolution of chlorine gas. The present device will automatically recover copper metal from the spent cupric chloride etchant and remove it from the system. In Phase I, a new design for the existing device will be developed that will redirect the chlorine gas formed at the anode into the spent etchant, thus preventing its evolution. This represents the in situ generation of the oxidant already in use to re-oxidize the spent cupric chloride etchant. It is planned to accomplish this new design by building a laboratory-sized version of the existing device that can be easily modified and was designed for experimentation. Several concepts are suggested for this new design; however, there is no certainty that this can be done to capture and react all of the chlorine gas formed at the anode. Chemical studies are planned to facilitate the redesign. This effort should be equally applicable to ammoniacal etchant if successful. In Phase II, a commercially usable larger machine, based on the redesign developed in Phase I would be constructed and tested.