Dear colleague Holland,

As per my knowledge we can use furnace slag as construction material (fine or coarse aggregate depending upon the fineness modulus) in cement-concrete system . Several researchers have worked on the utilization of blast furnace slag, steel and iron slag, copper slag etc. as constructional material in concrete production (for structures, pavements, roads etc.). These days utilization of industrial wastes in construction industry gaining much popularity due to minimization in the use of non renewable raw materials, less production of CO2 and green house gases (during cement production) and reduced mining of sand beds (less use of natural sand).

I don't know about the fate of lead in the slag on utilization, but it has been reported that use of industrial wastes in cement-concrete reduces the mobilization of heavy metals (also termed as Solidification/stabilization).

The slag heat is most certainly not renewable, as conventional fuels / electricity is used to produce it in the first place.

There may be ways to extract waste heat from it, driving some low temperature steam or hot water process e.g. by dumping the slag into water. With lead however, there are environmental and health risks, which has to be mitigated.

Thank you Kunal and David for your answers. We cannot put water anywhere near the slag as it ignites. For this type of slag, maybe you are right David, the levels of lead (seen as much as 120,000 ppm in test results) means that it's high toxicity and lack of being able to be reused can only end in its fate to prescribed waste landfills.