Microbial Growth and Calcium Carbonate Nucleation Properties in Mineral Admixtures

In this study, steel slag powder and fly ash were used as reinforcement and modification materials, and their effects on the growth, survival, and nucleation of mineral admixtures on bacteria were analyzed. Electrical conductivity, urease activity, and zeta potential tests were conducted, and the results showed that: (1) different mineral environments had different effects on the urease activity of Sporosarcina pasteurii. The steel slag powder solution inhibited urease activity, while the fly ash solution promoted urease activity. (2) S. pasteurii showed different growth characteristics in different mineral environments, especially in the fly ash solution, which showed higher hydrolysis efficiency, urease activity, and calcium carbonate yield. (3) The zeta potential test results showed that the nucleation of mineral admixtures on bacteria started to occur when the calcium ion concentration in the mineral filtrate was higher than 15 mmol/L. Different calcium ion concentrations showed greater impacts on the nucleation rate of mineral admixtures. The results of this study indicated the adaptability of microorganisms in the steel slag powder and fly ash solutions and the nucleation characteristics of calcium carbonate on the microbial surface, providing a theoretical and experimental basis for the subsequent development of new sand-fixing materials.