KINETICS AND MECHANISM OF Er(Ⅲ) EXTRACTION FROM HYDROCHLORIC ACID SOLUTIONS WITH H(DEHP)

The kinetics of extraction of Er(Ⅲ) from hydrochloric acid solutions with H(DEHP) in n-heptane is investigated using the growing drop technique. The rate is found to be first order with respect to Er(Ⅲ) and a half order with respect to H2A2(0). The rate controlling step is found to be the chemical reaction of Er(Ⅲ) with HA at the aqueous, organic interface. The activation energy for the extraction is calculated.