Mechanical and microstructure properties of phosphorus slag based geopolymer activated by carbide slag

Abstract

Yellow phosphorus slag (YPS) and carbide slag (CS), solid wastes generated in the manufacturing process of yellow phosphorus and acetylene, are encouraged to be used as precursor and activator respectively in geopolymer to solve the environmental issues, while the performance of YPS based geopolymer activated by CS is still unknown. This study investigates the performance of YPS based geopolymer activated by non-conventional activators, such as CS and lime. The effects of activator (CS and lime), YPS content (25/45/65/85%) and curing time (7, 28, 60 and 180 days) on the mechanical behavior, microstructure and environmental impact of YPS based geopolymer were studied by unconfined compression test, X-ray diffraction (XRD) analysis, Scanning electron microscope (SEM) observation and phosphorus (P)/fluorine (F) leaching test. Results show that the performance of YPS based geopolymer activated by CS is similar with that activated by lime. YPS content only influences the early-age performance of YPS based geopolymer, whose strength decreases with the increasing YPS content. However, after long-term curing, the effect of YPS content on the performance of YPS based geopolymer is negligible. Leaching test results show that the environmental effect of YPS based geopolymer is acceptable.