Utilization of secondary lead slag as construction material

Secondary lead slag, a waste product from battery smelting using CaCO3 as flux, has been investigated for its use as an admixture and/or aggregate in the production of concrete blocks. The slag was added as partial replacements of cement and/or aggregate. The results revealed that the oxide components of the slag were similar to those of ordinary Portland cement (OPC). The CaO content in the slag is 6.2 times less than that in OPC, while its iron content, as FeO, is 15.1 times higher. Interestingly, it also possesses magnetic property. All samples exhibited higher compressive strengths than that of the sample without slag (STD) which increased with increasing the slag contents and ages. The highest compressive strength was of the sample containing 20% slag as cement substituent and 100% slag as aggregate replacement owing to 259% of that of the STD at 60 days. All samples showed higher water absorption than that of the STD. The higher the slag contents, the more the water absorption. The absorption was, as expected, decreased with ages. Magnetic property of the slag plays an important role in the properties of the concrete blocks. For environmental concern, leachability of lead (Pb) from all samples was also carried out.