Utilization of Spent Pot Liner (SPL) as a Raw Mix Component in Cement Manufacturing

摘要

Spent Pot Liner (SPL) is a waste generated by Aluminium Industry during the manufacture of aluminium metal in electrolytic cell. SPL is considered hazardous waste in many countries because it contains significant quantities of absorbed fluorides along with traces of cyanide. Disposal of SPL has been primarily in land filling because of the difficulties in the development of a successful techno-economical SPL treatment process. Increasing generation of SPL and taking into environmental consideration many countries have banned land filling form of disposal and it has become a greatest environmental problem of the aluminium industry. Spent pot liner sample was collected from an aluminium plant located in Orissa, India. The sample was crushed & ground in laboratory jaw crusher & ball mill. The chemical analysis of SPL was carried out by conventional gravimetric & volumetric analytical techniques. Chemically Spent Pot Liner contains silica, alumina & iron oxides impregnated with fluoride & sodium salts and carbonaceous compounds. The calorific value of sample was determined using Leco bomb calorimeter AC-350. The SPL is composed of carbon material comes from the cathode block and lining refractory materials. The calorific value of composite SPL sample was measured 1700Kcal/kg. The CV depends on the carbonaceous content in sample, which may vary with the percentage of refractory materials. The utilization of SPL as raw mix component for cement manufacturing has been studied. The burnability of cement raw mix in presence of SPL showed reduction in free lime due to mineralizing effect of fluoride present in SPL. The carbonaceous content of SPL is well burnt at higher temperature and provides additional heat to the system. The study reveals that up to 1% SPL can be very well used as raw mix component in cement manufacturing