Microbial induced carbonate precipitation (MICP) is gaining recognition for enhancing the mechanical properties of construction materials. This study aims to explore the potential of using phosphogypsum (PG), a solid waste mainly composed of CaSO42H(2)O, as both a sufficient calcium source for MICP based bio-cement and an aggregate for mine backfill applications. First, the interaction between MICP bacteria and the PG was assessed by monitoring pH, electrical conductivity, and Ca2 + and SO42- levels. Results indicated that bacteria maintained robust urease activity in the PG environment, leading to CO32- production. These ions, combined with the Ca2+ naturally present in PG to form CaCO3 precipitation, which acted as a binding agent for PG backfill. Further testing of the bio-cemented PG backfill showed excellent fluidity which is suitable for efficient pipeline transportation in underground mining. After a 7-day curing period, the backfill exhibited an unconfined compressive strength (UCS) of 947 kPa, meeting the standards for mining backfill applications. Additionally, the environmental impact of the bio-cemented PG backfill was notable. Unlike traditional cement-based backfills with high pH levels (>11), the leachate from the bio-cemented PG backfill maintained a neutral pH (7.16), highlighting its eco-friendly nature. This positions the bio-cemented PG backfill as a sustainable solution for the construction and mining industries.

来源平台：CONSTRUCTION AND BUILDING MATERIALS