Sonochemical Recovery of Metals from Recording Media

Abstract

Recording media (MD) was subjected to peeling with the disk having well-arranged pins, followed by acid leaching with HCl and HNO₃ solutions, respectively, under irradiation of ultrasound to investigate Tb, Co and Fe from the MD sample. The result was compared with those in the leaching conducted at room temperature and 60°C without ultrasound irradiation. The acid leaching of metals is accelerated by irradiating ultrasound, and is accomplished by 100% within 1 hour, irrespective of whether HCl or HNO₃ solution (1 N) is used. High yield extraction is not attained at all in the leaching without ultrasound irradiation over the same extraction time. The yield increases with an increase in the acid concentration, but it levels off beyond 1 N. Temperature for the leaching is also an important factor; however, ultrasound irradiation is the most effective means for extracting metals from the sample.