LAUSR

Abstract Microbial Induced Calcium Carbonate Precipitation (MICP) has some disadvantages, such as low crystallization conversion rate of calcium carbonate and insufficient strength properties of tailings. In this paper, a modified method combining soft template calcium carbonate mineralization technology with microbial grouting reinforcement technology was proposed. The tailings solidification was studied with the control of nine different concentrations of egg white (0%, 5%, 10%, 15%, 20%, 30%, 40%, 60% and 80%). After 14 days of grouting reinforcement experiment, the results are as follows. ① The shear strength of tailings was improved remarkably, and the best reinforcement effect was at 5% egg white. Compared with the control group, the effective cohesion of tailings increased by 437.61%. ② The fitting curve between the content of calcium carbonate in tailings and its cohesion shows that there is an exponential relationship between them. ③ The results of microscopic examination showed that the proportion of columbite-type calcium carbonate increased with the increase of egg white concentration. The corresponding egg white concentration of calcite-type calcium carbonate was 5%. At this time, the maximum particle size could reach 100 µm. ④ The infrared absorption characteristic curves of the interporous cements of tailings indicate that the changes of crystal form, crystal morphology and particle size of calcium carbonate may be due to the strong interaction between polar groups such as N H, C H and C O in the composition of egg white and calcium carbonate crystal. ⑤ The bonding, connecting and packaging of fibers in egg white will cause fundamental changes in the bonding mode of tailings. The test results showed that the combination of mineralization regulation of egg white and MICP technology can achieve complementary advantages, which is of great engineering significance for improving the stability and safety of tailings dam.