Development and utilisation of Jinchuan copper slag and desulfurisation ash

Abstract

Copper slag (CS) from the copper smelting plant and desulfurisation ash (DAH) from the thermal power plant in Jinchuan mine are the two most common industrial wastes and have caused serious secondary environmental pollution. In order to make full use of the industrial wastes and reduce the environment impact, experimental investigations were conducted to study the feasibility of using CS and DAH as cementitious materials, and using rod milling sands (RMS) as aggregate in backfill. The activity of Jinchuan CS and DAH and their respective influences on compressive strength were studied. The results reveal that Jinchuan CS is an inert material without potential activity. DAH had an outstanding effect on the later compressive strength at 28 days. The best mixtures’ proportions of the new cementitious materials by weight are obtained through the regression and optimised analysis; sodium sulfate 5%, sodium hydroxide 1%, DAH 18%, lime 5%, and iron slag 71%. Another experimental investigation was conducted which used Jinchuan CS as aggregate to replace RMS and cement as cementitious materials. Five CS ratios were studied; 10, 20, 30, 40 and 50%. The reaction products and compressive strengths of the specimens were evaluated by contrastive analysis of scanning electron microscope (SEM). The results indicate that Jinchuan CS could be used as a replacement for 20% rod milling sands and DAH could be used as cementitious materials when the compressive strength meet the need of backfilling. This study provides a theoretical basis for the effective utilisation of Jinchuan CS and DAH.