Reacquiring Rare Earth Metal Electrodes from Biosense and Webster Cardiac Catheters

Abstract

background: To decrease health care’s emissions, the reacquiring of rare earth metals from a complex single use medical device was researched. For a complex single use device (SUD), a cardiac catheter was used, which has electrodes in its tip made of platinum, iridium and palladium. methods: A patent study was done to gain insight into the design and assembly of the catheters, which resulted in the identification of the plastics present. Depending on the electrode type, polyether etherketone (PEEK) or polyamide 12 (PA12) were dominant plastics surrounding the electrode. 5 concepts were developed, all involving a chemical or thermal treatment, which were assessed on their ability to structurally remove these plastics. The treatments used were: nitric acid treatment, sulphuric acid treatment, pyrolysis treatment, toluene treatment and phenol treatment. Treatment removal ability and the purity of the acquired electrodes, were assessed through the use of mass fractions and SEM analyses. Practical aspects, which will be relevant for scale up, such as risk indications, waste created and costs were briefly assessed as well. results: The only treatment that was able to structurally remove all plastics without compromising electrode’s purity, was the sulphuric acid treatment. It is in line with literature that sulphuric acid is the only agent able to structurally remove PEEK at room temperature. Pyrolysis could remove the plastics, but the electrodes were charred. Nitric acid and phenol could only dissolve PA12 but left PEEK structurally present, whereas toluene left all plastics structurally present. conclusion: Reacquiring the electrodes chemically is possible through the use of sulphuric acid. If the spent sulphuric acid can be regenerated, this would be a great benefit since no constant replenishment of acid is required. Pyrolysis could also be investigated further, but a separate cleaning step would be required.