Experimental study on physical and mechanical properties of MICP- reinforced uranium tailings combined with modified jute fibers

Abstract

Microbially induced calcium carbonate precipitation (MICP) is a promising methods for filling and cementing of tailings, offering the advantage of efficient and cost-effective performance. This research employs modified jute fibers combined with MICP to enhance the physical and mechanical properties of uranium tailings as filling materials, and to address the shortcomings of uneven reinforcement and brittle failure of MICP technology. The effect of hydrothermal treatment duration, fiber length, fiber content, and cementing solution concentration on the unconfined compressive strength of MICP-reinforced uranium tailings with different grades was investigated by orthogonal experiments, and the optimal bio-cement parameters were determined. The crystal types of calcium carbonate formed by modified jute fibers combined with MICP were characterized, and the effect mechanisms of modified jute fibers on the mechanical properties of MICP-reinforced uranium tailings were investigated. The results demonstrate that the surface roughness of jute fiber increases after hydrothermal treatment duration, thereby creating increased areas for microbial attachment and reproduction. This results in an increase in the production and uniformity of calcium carbonate in uranium tailings, as well as an improvement in the unconfined compressive strength of the uranium tailings. This is achieved by promoting the growth, reproduction, migration and fixation of microorganisms. The physical and mechanical properties of uranium tailings reinforced with modified jute fiber combined with MICP are optimal when applying uranium tailings with gradation number A3, a cementing solution concentration of 1.5 mol/L, a jute fiber content of 3%, a jute fiber length of 20 mm, and a hydrothermal treatment duration of 2h.