Characterisation of LD slag fines by X-ray Diffraction

Abstract

The reject of waste recycling plant (WRP) i.e. LD slag fines (0–6 mm) after metal recovery does not contain much of metallic iron, but this contains substantial quantity of calcium bearing mineral phases like mono, di and tri calcium silicates along with free lime content varying in the range of 11–15%. The WRP waste of − 6 mm is further subjected to sieving mainly in to three different size fractions viz. +10 mesh (− 6.0 mm +2.0 mm), +60 mesh (− 2.0 mm +0.25 mm), − 60 mesh (− 0.25 mm). These three size fractions of WRP waste shows the free lime content varying from 3.4% for +10 mesh and 9.7% for − 60 mesh. The X-ray diffraction analysis shows portlandite, merwinite, dicalcium silicate – alpha, calcium silicate – beta, and brownmillerite and di calcium diferrate as the major phases in the above said size fractions. The X-ray diffraction analysis was carried out in this paper to get the deeper insight in the mineralogical constitution and behaviour of such waste which represents a valuable raw material for many infrastructure industries including the road construction industry.