Experimental Study on the Fine-Grained Uranium Tailings Reinforced by MICP

Gui, Rong; Pan, Yu-xiang; Ding, Dexin; Liu, Yong; Zhang, Zhijun

doi:10.1155/2018/2928985

Cited by 14 publications

(8 citation statements)

References 12 publications

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“…The samples were monitored using S-wave and P-wave velocity to better understand the changes in their mechanical behavior, and the findings are shown in Figure 7 . Since the P-waves and S-waves can only be transmitted through solids, the deposited calcium carbonate at the grain contact point had the greatest impact on the P-wave velocity ( Figure 7 a) and S-wave velocity ( Figure 7 b) (not through soil pores) [ 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

Durability Improvement of Biocemented Sand by Fiber-Reinforced MICP for Coastal Erosion Protection

et al. 2022

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Soil improvement via MICP (microbially induced carbonate precipitation) technologies has recently received widespread attention in the geoenvironmental and geotechnical fields. The durability of MICP-treated samples remains a critical concern in this novel method. In this work, fiber (jute)-reinforced MICP-treated samples were investigated to evaluate their durability under exposure to distilled water (DW) and artificial seawater (ASW), so as to advance the understanding of long-term performance mimicking real field conditions, along with improvement of the MICP-treated samples for use in coastal erosion protection. Primarily, the results showed that the addition of fiber (jute) improved the durability of the MICP-treated samples by more than 50%. Results also showed that the wet–dry (WD) cyclic process resulted in adverse effects on the mechanical and physical characteristics of fiber-reinforced MICP-treated samples in both DW and ASW. The breakdown of calcium carbonates and bonding effects in between the sand particles was discovered to be involved in the deterioration of MICP samples caused by WD cycles, and this occurs in two stages. The findings of this study would be extremely beneficial to extend the insight and understanding of improvement and durability responses for significant and effective MICP treatments and/or re-treatments.

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Section: Resultsmentioning

confidence: 99%

Durability Improvement of Biocemented Sand by Fiber-Reinforced MICP for Coastal Erosion Protection

et al. 2022

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“…As the pH of porewater increases, the conversion of NH 4 + (pKa = 9.25) to NH 3 is more favourable, which increases volatilization potential (Gui et al, 2018). This can also be attributed to a decrease in the availability of urea for ureolysis, as this would ultimately decrease NH 3 formation (Bhaduri et al, 2016;…”

Section: Effects Of Micp On Water Quality Parametersmentioning

confidence: 99%

“…In the presence of calcium ions, carbonates precipitate calcite (CaCO 3 ) crystals using bacterial cell walls as nucleation sites (Equation 2) (Ng, Lee, & Hii, 2012). The precipitation of CaCO 3 crystals on the surface of sediment facilitates binding at the contact points between tailings particles and reduces the size of the pore spaces, which can improve the mechanical strength of the soil matrix and reduce permeability (Gui, et al, 2018;Harkes et al, 2010). This treatment could be advantageous for tailings attenuation, as the formation of a cemented "biocrust" in the upper layer of tailings would reduce water and oxygen ingress, thus limiting the exposure of stored tailings to the weathering processes that control ARD.…”

Section: Introductionmentioning

confidence: 99%

Pilot-Scale Feasibility Study for the Stabilization of Coal Tailings via Microbially-Induced Calcite Precipitation

Rodin

Champagne

Mann

2022

Preprint

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Sustainable long-term solutions to managing tailings storage facilities (TSFs) are integral for mines to operate in a safe and environmentally responsible manner. The long-term storage of subaqueous tailings can pose significant safety, environmental, and economic risks, therefore alternative containment strategies for maintaining geochemical stability of reactive materials must be explored. In this study, the physical and geochemical stabilization of coal tailings using microbial induced calcite precipitation (MICP) was evaluated at a laboratory pilot scale. Three application techniques simulated commonly used agricultural approaches and equipment that could be deployed for field-scale treatment: spraying on treatment solutions with irrigation sprinklers, mixing tailings and treatment solutions with a rototiller, and distributing treatment solutions via shallow trenches using an excavator ripper. Test cells containing 1.0 x 1.0 x 0.5m of tailings were treated with ureolytic bacteria (Sporosarcina pasteurii) and cementation solutions composed of urea and calcium chloride for 28 days. Penetrometer tests were performed following incubation to evaluate the extent of cementation. The spray-on application method showed the greatest strength improvement, with in an increase in surface strength of more than 50% for the 28-day testing period. The distribution of treatment solution using trenches was found to be less effective and resulted in greater variability in particle size distribution of treated tailings and would not be recommended for use in the field. The use of rototilling equipment provided a homogenous distribution of treatment solution, however, the disruption to the tailings material was less effective for facilitating effective cementation. Bacterial plate counts of soil samples indicated that S. pasteurii cultures remained viable in a tailings environment for 28 days at 18˚C and near-neutral pH. The treatment was also found to stabilize the pH of tailings porewater sampled over the 28-day incubation period, suggesting the potential for the treatment to provide short-term geochemical stability under unsaturated conditions.

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“…of applications such as concrete remediation, wind erosion prevention, and landform stabilization (Arpajirakul et al 2021;Bayat et al 2021;Pungrasmi et al 2019). The precipitation of CaCO 3 crystals on the surface of sediment facilitates binding at the contact points between tailings particles and reduces the size of the pore spaces, which can improve the mechanical strength of the soil matrix and reduce permeability (Gui, et al 2018;Harkes et al 2010;Punnoi et al 2021). This treatment could be advantageous for tailings attenuation, as the formation of a cemented "biocrust" in the upper layer of tailings would reduce water and oxygen ingress, thus limiting the exposure of stored tailings to the weathering processes that control ARD.…”

Section: Introductionmentioning

confidence: 99%

Pilot-scale feasibility study for the stabilization of coal tailings via microbially induced calcite precipitation

Rodin

Champagne

Mann

2022

Environ Sci Pollut Res

View full text Add to dashboard Cite

Sustainable long-term solutions to managing tailings storage facilities (TSFs) are integral for mines to operate in a safe and environmentally responsible manner. The long-term storage of subaqueous tailings can pose significant safety, environmental, and economic risks; therefore, alternative containment strategies for maintaining geochemical stability of reactive materials must be explored. In this study, the physical and geochemical stabilization of coal tailings using microbially induced calcite precipitation (MICP) was evaluated at a laboratory pilot scale. Three application techniques simulated commonly used agricultural approaches and equipment that could be deployed for field-scale treatment: spraying on treatment solutions with irrigation sprinklers, mixing tailings and treatment solutions with a rototiller, and distributing treatment solutions via shallow trenches using an excavator ripper. Test cells containing 1.0 × 1.0 × 0.5 m of tailings were treated with ureolytic bacteria (Sporosarcina pasteurii) and cementation solutions composed of urea and calcium chloride for 28 days. Penetrometer tests were performed following incubation to evaluate the extent of cementation. The spray-on application method showed the greatest strength improvement, with in an increase in surface strength of more than 50% for the 28-day testing period. The distribution of treatment solution using trenches was found to be less effective and resulted in greater variability in particle size distribution of treated tailings and would not be recommended for use in the field. The use of rototilling equipment provided a homogenous distribution of treatment solution; however, the disruption to the tailings material was less effective for facilitating effective cementation. Bacterial plate counts of soil samples indicated that S. pasteurii cultures remained viable in a tailings environment for 28 days at 18 °C and near-neutral pH. The treatment was also found to stabilize the pH of tailings porewater sampled over the 28-day incubation period, suggesting the potential for the treatment to provide short-term geochemical stability under unsaturated conditions.

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Experimental Study on the Fine-Grained Uranium Tailings Reinforced by MICP

Cited by 14 publications

References 12 publications

Durability Improvement of Biocemented Sand by Fiber-Reinforced MICP for Coastal Erosion Protection

Durability Improvement of Biocemented Sand by Fiber-Reinforced MICP for Coastal Erosion Protection

Pilot-Scale Feasibility Study for the Stabilization of Coal Tailings via Microbially-Induced Calcite Precipitation

Pilot-scale feasibility study for the stabilization of coal tailings via microbially induced calcite precipitation

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