Application of ICP-MS technique for analysis of heavy metals in LD slag fines

Inductively coupled plasma-mass spectrometry (ICP-MS) is a powerful tool for analysing trace metals in environmental samples, industrial wastes and samples of biogenic nature. In the present study, this technique has been used to analyse the content of heavy metals in trace levels which specifically include elements like lead, cadmium, selenium and arsenic in LD slag fines. LD slag is the waste generated during the Linz-Donawitz steel making process or the basic oxygen furnace process. LD slag fines in the size range 0-6 mm are obtained after the recovery of metallic iron by means of physical separation in waste recycling plants, and are mostly recycled in sinter-making process. The non-metallic portion of LD slag fines is generally used as an aggregate in road construction, in acid mine drainage treatment and as an acidic soil conditioner. All these applications require a thorough analysis of trace and heavy metals as they can leach and penetrate into the soil and potentially contaminate it. The present study addresses this issue by analysing heavy metals in traces levels using ICP-MS. The analysis reveals that most of the heavy and hazardous elements are present in very low concentrations in the slag itself when compared with the EPA maximum allowed concentration in the leachate samples. However, the concentration of mercury in LD slag is more than the limit set by EPA in the leachate, and leachability of mercury needs to be studied further. The study also reveals that there are traces of platinum and palladium in the slag, indicating the requirement of future studies to understand their economic recovery.