This invention provides a process a process for recovering terephthalic acid from pulverized products of spent polyethylene terephthalate. In particular, a one-sided CCM may be used where it may not be practicable to coat both sides of the ion-exchange membrane with catalyst layers such as when PTFE is added to the anode catalyst layer to render it reversal tolerant. Either an anode or a cathode is formed on the heat-resistant planarizing film. An elongated actuator is pivotally mounted on the housing for rotating movement between an open position allowing the flat circuit to be inserted into the opening and a closed position biasing the flat circuit against the terminals. Argon and nitrogen are filled into the vacuum chamber to respectively ionize the silver target and one of the zirconium target, titanium target, or chromium target. By using the rotary tool comprising an Ir alloy, the refractory metals can be welded to each other by means of friction stir welding.