Analysis of Slag Composition and Utilisation Potential from Delta Steel Company Operations in Delta State

This study analyses the chemical and mineralogical composition of blast furnace and electric arc furnace slag generated at Delta Steel Company, Ovwian-Aladja, Delta State, South South Nigeria, and evaluates its potential utilisation as a supplementary cementitious material and road base aggregate. Large volumes of slag are generated annually at Delta Steel Company, and their characterisation is a prerequisite for the development of value-added applications that reduce landfill disposal and environmental impact. Slag samples are collected from active tipping areas and subjected to chemical analysis by XRF, mineralogical phase analysis by X-ray diffraction, and physical characterisation including bulk density, specific gravity, and Los Angeles abrasion value. Hydraulic activity index is determined by the strength activity index test following ASTM C989. Leachate toxicity is evaluated by the TCLP method. Results confirm that blast furnace slag exhibits latent hydraulic properties with a glass content above 65 percent, qualifying it as a Grade 100 slag cement by ASTM C989. EAF slag is predominantly crystalline and demonstrates satisfactory Los Angeles abrasion values, supporting its use as road base aggregate. Leachate testing indicates chromium and vanadium concentrations below regulatory thresholds. The study recommends the commercialisation of Delta Steel slag through a formal slag granulation and cement blending programme. Keywords: blast furnace slag, slag cement, Delta Steel Company, supplementary cementitious material, Delta State.