Lead Leachate from Rubies Undergone Heat Treatment Process

Low quality rubies are usually undergone heat treatment to improve their color and clarity. Some chemical additives may have been added during the treatment. Consequently, some toxic elements, particular lead, have been concerned as well as durability of the treated stones. Lead leachates from treated ruby have therefore been investigated; besides, changes of color and clarity have also been observed throughout the experiment. Three-Stage Sequential Extraction Procedure (BCR) was applied for leaching experiment. This process consists of 3 steps including BCR1 (exchangeable step), BCR2 (reduction step) and BCR3 (oxidation step). This procedure has been suggested to represent natural processes that may altered materials including hazardous one. Apart from regular procedure, we also rearrange the step orders. This aims to find out the most effective condition of lead leaching. The results indicate that the most effective step seems to be BCR 3 which is an aggressive reaction compared to the other steps. However, BCR 2 also yields the highest lead concentration after activating initially by BCR I in series I. On the other hand, BCR1 is unable to extract lead from the treated ruby. Moreover, the appearances of rubies in each series have been altered towards the experimental steps and well corresponded to the concentrations of lead in leachate.