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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

The future of subsurface monitoring: AEC’s breakthroughs in CCS technology

Carbon capture and storage (CCS) has emerged as a key solution in the fight against climate change. However, for CCS to succeed, it is crucial to ensure that the sequestered CO2 stays safely trapped underground. The U.S. Department of Energy (DOE) has emphasized the need for advancements in subsurface monitoring, measurement, reporting, and verification. Aside from caprock integrity failure, the other primary failure points usually involve defective cement in the casing annulus of wellbores or plugged and abandoned wells. In addition, many energy producers (e.g., oil and gas, geothermal) and storage and disposal operators (e.g., H2 and water) must deal with the same issue. Poorly placed or degraded cement can create pathways for gas or fluid to escape from casing annuli and in plugged and abandoned or orphan wells, posing environmental risks. Yet, a reliable and cost-effective way to monitor cement and well integrity over multiple decades is still unavailable. Traditional geophysical methods like 4D seismic imaging and surface-based electromagnetic monitoring lack the resolution and accuracy for detecting these types of failures (Vasco et al., 2022; Fawad and Mondol, 2021). Wireline logging is expensive to run continuously and is obtrusive to the operation. While fiber optics can potentially be a solution, its bulkiness can significantly compromise the cement's integrity. To address these challenges, the Advanced Energy Consortium (AEC) at The University of Texas at Austin’s Bureau of Economic Geology (the Bureau) has been pioneering research in subsurface monitoring using its portfolio of distributed autonomous microfabricated sensors for harsh subsurface environments since 2008. A class of these microsensors [System on a Chip (SoC)] can be mixed in cement and permanently placed without compromising the cement column; the sensors would then communicate with each other or a data acquisition (DAQ) master node. Another class of the AEC microsensors can be fully autonomous, with rechargeable micro-batteries capable of exceeding 100°C, flash memory, and, currently, a pressure and temperature sensor. They are designed to circulate in mud, geothermal fluids, U-loops, or pipelines. They can log data into memory and are unobtrusive to operations. Our team has been working on a multi-year DOE-funded project (DE-FE0031856)—supported by $2.95M in federal funding and $0.75M in cost-matching from the AEC—to demonstrate SoC sensor utility for CO2 leakage monitoring in CCS applications. This multi-institutional collaboration developed a novel sensing architecture utilizing radiofrequency (RF) microsensors embedded within the cement sheath. These sensors detect CO2 migration and are interrogated via a Smart Casing Collar (SCC).

58 GEOSCIENCES↗
DOE OSTI2021

Plastic deformation mechanism of calcium-silicate hydrates determined by deviatoric-stress Raman spectroscopy

Highlights: • C-(A-)S-H samples under stress were characterized at the bond and grain level. • Small angle scattering showed that 720 MPa reduced grain thickness by 30%. • In-situ Raman showed that cross-linked C-A-S-H slips along its intralayer. • However, in-situ Raman showed that C-S-H slips along the interlayer. • In-situ Raman also showed a growth in CaCO{sub 3}, indicating fracture in both samples. Creep of the cement matrix affects the structural stability of concrete. In Portland cements, the creep is largely controlled by the binding phase calcium-(aluminum-)silicate-hydrate, or C-(A-)S-H. This phase has a lamellar structure and under deviatoric stress aligns its c-axis with the principal stress. However, the limiting resistance to this reorientation is unknown at the nanocrystalline level. Small-angle X-ray scattering shows that the lamellae thickness decreases under 100's MPa deviatoric stress. Deviatoric stress Raman spectroscopy shows that there are two ways that this break-up can occur. If the material's silicate chains are cross-linked, then strain in SiO bonds does not increase above certain stresses, indicating a relaxation adjacent to the SiO bond. If the chains are not cross-linked, then the silicate chains are broken up by rastering against each other, introducing defects. These results show that the plastic deformation of C-(A-)S-H is relevant for Portland cement creep.

36 MATERIALS SCIENCE↗
DOE OSTI2021

The chemical and physical origin of incineration ash reactivity in cementitious systems

Incorporating industrial byproducts and waste in concrete is the key to reducing landfill usage as well as lowering the environmental footprint of cement industry. An emerging industrial byproduct which can partly replace cement is the Municipal Solid Waste Incinerator Ash (MSWI ash: residue that is left after incineration of municipal solid waste in a Waste-to-Energy facility). These ashes are predominantly calcium-rich; however, they also contain additional elements whose speciation is not known. These elements can significantly alter the hydration characteristics of a cementitious system. Here, our results suggest these ashes can accelerate as well as retard cement hydration. Specifically, Pb, Br, S, Ca, and Cl appear to accelerate cement hydration, whereas Cu, Fe, Al, Ti, Si, K, Zn, and Sr appear to retard cement hydration. Changes in hydration characteristics can have a strong bearing on the physical characteristics of cementitious systems incorporating incineration ashes. Thus, to selectively screen ashes that synergistically enhance the physical characteristics, we introduce a novel “Incineration Ash Coefficient (IAC),” which shows a strong correlation with the compressive strength (R 2 =0.79) of cement-ash binary mixtures.

42 ENGINEERING↗
DOE OSTI2020

Characterization of paste microstructure for durability properties of concrete

In this study, paste samples from different cementitious systems were characterized by using X-Ray Micro Computed Tomography (µ-CT) and Fluorescence Microscopy techniques. Quantitative and qualitative aspects of defects from paste samples were investigated to develop indicators of durability related properties of corresponding concrete samples. In the first phase of this study, hour glass shaped 3D printed molds were used to investigate five cementitious combinations consisting of three cement types (Coarse Ground portland cement, Type IL Portland Limestone Cement and Type I/II ordinary portland cement) and fly ash as a supplementary cementitious material. In the second phase, metal molds were used to compare the results of Coarse Ground portland cement with Type I ordinary portland cement, 5% of which was replaced with colloidal nanosilica. Potential correlations between paste and concrete have been presented. This work was supported by US Department of Energy and North Dakota Department of Commerce.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Integrated Multiphysics Modeling of Environmentally Assisted Brittle Fracture

Brittle materials, such as cement, compose major portions of built infrastructure and are vulnerable to degradation and fracture from chemo-mechanical effects. Currently, methods of modeling infrastructure do not account for the presence of a reactive environment, such as water, on the acceleration of failure. Here, we have developed methodologies and models of concrete and cement fracture that account for varying material properties, such as strength, shrinkage, and fracture toughness due to degradation or hydration. The models have been incorporated into peridynamics, non-local continuum mechanics methodology, that can model intersecting and branching brittle fracture that occurs in multicomponent brittle materials, such as concrete. Through development of new peridynamic capabilities, decalcification of cement and differential shrinkage in clay-cement composites have been evaluated, along with exemplar problems in nuclear waste cannisters and wellbores. We have developed methods to simulate multiphase phenomena in cement and cement-composite materials for energy and infrastructure applications.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Casing Annulus Monitoring of CO 2 Injection Using Wireless Autonomous Distributed Sensor Networks

Effective and secure carbon subsurface storage, involving the deep underground injection of CO 2 into geological formations where it is permanently trapped, is paramount to mitigating CO 2 emissions (Figure I). Ensuring the integrity of these storage sites and detecting potential leakage through the casing annulus necessitates robust monitoring. This work provides the first integrated demonstration of a wireless casing-annulus monitoring architecture that can operate in highly attenuating cement-brine environments relevant to CO 2 storage. This project focused on developing and validating a novel sensor system for integration with autonomous monitoring near the cement reservoir interface. The goal was a fully integrated Technology Readiness Level (TRL) 4/5 field validation of a distributed wireless intelligent sensor system providing real-time, direct subsurface formation measurements to enhance fluid movement monitoring in the cemented casing annulus. Achieving this objective required the development and integration of 1) wireless autonomous microsensor technology by California Institute of Technology (Caltech); 2) sensor packaging and emplacement technology by Research Triangle Institute (RTI); and 3) smart well completions using wireless active casing collars and NOV pipe by the Sandia National Lab (SNL). The collaboration with the Caltech team in this project aimed to develop millimeter-scale radio frequency identification (RFID) sensors capable of detecting CO 2 , pH, and/or methane levels. These sensors are engineered to be impervious to fluids, allowing them to be mixed with cement and installed within the casing annulus. They operate using RFID protocols at frequencies of 902–928 MHz for both power and communication. A Sandia National Laboratories’ team engaged their expertise in the development of a Smart Collar system designed for the wireless data collection from these RFID sensors embedded in the cement annulus and transmission of this information to the ground surface via IntelliPipe/IntelliServ NOV drill pipe. This is accomplished through inductive coupling at the collar, which facilitates data transfer through each segment of the pipe. Because the system cannot transmit a direct current signal to power the Smart Collar, both power and communication were implemented using alternating current and electromagnetic signals at varying frequencies. Furthermore, the developed microsensor technology had to be demonstrated and validated in comparison with reference transducer measurements in a field test site at The University of Texas at Austin (UT-Austin). Although the full sensor suite did not reach field-deployment readiness, the system-level integration achieved in this project establishes a validated pathway for future incorporation of advanced microsensors.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

Development Of Thermodynamic and Kinetic Simulation Tools and Testing Procedures for Enhanced Durability of Concrete Containing Industrial By-Products

This project developed screening tools that enable evaluation of alternative cementitious binders that create concretes to significantly reduce energy and emissions while remaining cost competitive on both initial and long-term costs. The team began with the viewpoint that acceptance of new cementitious binder products has a substantially greater chance of successful implementation when capital investment is not excessive and the end product has customers that have experience and resources to use this. As such, a binder system that is based on portland cement with blended using industrial by-products (alternative cementitious materials) has the potential for dramatic and meaningful impact. The team has focused on developing implementable solutions in specifications and current practice. This however requires three main factors: 1) ability to screen byproducts and alternative materials for success, 2) ability to ‘treat’ materials chemically to enhance kinetics, and 3) ability to provide predictions of performance of both binders and concrete from first principles. The project developed/refined a state of the art and scientifically based screening test for SCM called the pozzolanic reactivity test. The team developed kinetic models to simulate these materials as well as experimental approaches to alter selected reactions. Simulation tools were developed that enable the performance of concrete to be predicted based on the chemistry and reactivity of the cement and alternative SCM. Specifically, this project: • enhanced the kinetic reactivity models for use in multi-scale computational programs that use thermodynamics to predict reaction products. 2 • developed scaling models to extend thermodynamic modeling to link these models with pore structure. This enables strength, transport property, and coupled transport prediction. • developed tools to predict performance of cementitious materials using the pozzolanic reactivity test and chemical composition. The predicted properties are consistent with AASHTO R101 and the CEB-FIP model code and can be measured using associated test procedures. • demonstrated mechanical and fracture based modeling tools that thermodynamic predictions and inputs to predict concrete service life. These results have been used to demonstrate the value of enabling specifications to include ASTM C 595 cement as well ASTM C150 cement. In addition, these products are being used to expedite the evaluation of alternative SCM to aide in determining which materials have potential value and what ‘compositions’ of blended cements merit further investment.

42 ENGINEERING↗
DOE OSTI2023

Atomic-scale identification of defects in alite

Crystallographic defects play a crucial role in cement hydration, with initial dissolution being dominated by the formation of etch pits that rely on the intersection of defects on surfaces. However, the defects present in cement particles have remained a mystery due to the lack of detailed direct observation at the atomic scale. In this study, we used scanning transmission electron microscopy to unravel the defects in alite particles at the single-atom level. Our observations identified different types of defects, including vacancies, doping, dislocations, rough surfaces, and grain boundaries. Atomic ordering in the alite crystal was further examined based on our single-atom recognition method. Our findings indicate that defects in cement particles may serve as reactive sites during the early hydration stage, facilitating the initial dissolution and providing nucleation sites for hydration products. Finally, this work provides insights into cement defect formation at the single-atom level and offers new opportunities in tuning the hydration process through defect engineering of cement particles.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Recent Cryogenic Carbon Capture™ Field Test Results

Sustainable Energy Solutions (SES) has been developing Cryogenic Carbon Capture™ (CCC) since 2008. In that time, two processes have been developed, the External Cooling Loop and Compressed Flue Gas CCC processes (CCC-ECL and CCC-CFG, respectively). The CCC-ECL process cools the flue gas with an external refrigerant loop. This process currently captures up to 1 tonne of CO2 per day (TPD). SES has tested CCC-ECL on real flue gas slip streams from subbituminous coal, bituminous coal, biomass, natural gas, shredded tires, and municipal waste fuels at field sites that include utility power stations, heating plants, cement kilns, and pilot-scale research reactors. The CO2 concentrations from these tests ranged from 5 to 22% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at a modest rate. The CCC-CFG process has been scaled up to a 0.25 ton per day system. This system has been tested on real flue gas streams including subbituminous coal, bituminous coal, and natural gas at field sites that include utility power stations, heating plants, and pilot-scale research reactors. CO2 concentrations for these tests ranged from 5 to 15% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2, and PMxx at 95+%. NO was also captured at 90+%. Hg capture was also verified and the resulting effluent from CCC-CFG was below a 1ppt concentration. This paper will focus on discussion of the capabilities of CCC generally, the results of CCC-ECL field testing, and future steps surrounding the development of this technology. Test results that will be presented have been collected during 9 months of testing at a commercial power plant under funding from the US Department of Energy (DOE) and the host utility. Testing of one of the systems at a commercial cement plant in the United States will also be discussed. During this testing, the system captured CO2 from the cement plant and stored the CO2 in pressurized tanks. These tanks were provided to a partner company that later used the CO2 in a CO2 utilization demonstration. The CO2 was utilized to cure concrete manufactured using cement from the same plant where the CO2 was captured. This integrated capture and utilization demonstration was the first time that the cement industry has shown in the field that it can sequester its CO2 emissions in its main product stream. This represents a potential game changing solution for industrial CO2 emissions. Operational data and host-site feedback indicate that the CCC process is ideally suited for deployment into a variety of commercial environments. A few areas of de-risking remain to make sure the technology can meet very strict industrial reliability standards. These areas of de-risking are identified and discussed. The product CO2 is shown to meet specification for many uses including industrial and merchant applications. The technology is nearing readiness for deployment at commercial scale and several initial target markets have been identified.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2020

Using Radioiodine Speciation to Address Environmental Remediation and Waste Stream Sequestration Problems at the Fukushima Daiichi Nuclear Power Plant and a DOE Site

Iodine-129 ( 129 I), with a half-life of half-life of 16 million years, is commonly considered the single greatest risk driver in high-level and low-level nuclear repositories. This risk stems from several basic properties of 129 I, and under many geochemical conditions, it can move as an anion at nearly the rate of water through the subsurface environment. 129 I is also extremely radiologically toxic because over 90% of body burden accumulates in the thyroid, which weighs only about 14g in an adult. There is also a large worldwide inventory of radioiodine as a result of its high fission yield and this inventory is rapidly increasing as a result of nuclear energy production. Radioiodine is produced at a rate of 40 GBq (1 Ci) per gigawatt of electricity produced by nuclear power. To illustrate how the properties of 129 I magnify its risk, 129 I accounts for only 0.00002% of the radiation released from the Savannah River Site in Aiken, South Carolina, but contributes 13% of the population dose, a six orders of magnitude magnification of risk with respect to its radioactivity. The currently favored solid phase for LLW immobilization is cement, while HLW immobilization is the incorporation of waste into glass (vitrification). However, so far, the incorporation into cement and subsequent leaching of only iodide has been seriously investigated. The major problem with this approach is that it ignores the complex speciation of iodine, i.e., it ignores iodate and organo-iodine which have different chemistries. Most of the past research was devoted to the mechanism of iodide uptake in cement hydrate phases that is sorption and/or incorporation. Very few data exist on iodate and organo-iodine incorporation in cement, even though large quantities of liquid waste containing also radioiodine have already been solidified in cement Iodine-129 from low-level waste is commonly disposed of in cementitious materials. Grout, a dense cementitious fluid, mixed with a reducing slag, is often used to immobilize radionuclides. However, the reducing environment might not be conducive to immobilize iodine. For example, the silver based immobilization technologies (e.g., AgCl, Ag-impregnated granular activated carbon, Ag-mordenite) remove iodine from the aqueous phase by promoting the formation of Ag-iodide precipitates. The solubility of AgI is eight orders of magnitude lower than it is for AgIO 3 . Similarly, coprecipitation of iodine into calcium carbonate phases occurs only with IO 3 - and not with I - and org-I. If one would want to immobilize iodine more effectively, different engineering approaches would need to be used to promote binding of I - , IO 3 - , or organo-I. Using laboratory experiments with grout, slag, and silver-based adsorbents, and GC-MS and I K-edge XANES and EXAFS and C K-edge XANES spectroscopy for identifying iodine speciation, the major problems with these methods have been identified as focused too much on just one of the iodine species for immobilization, while others, especially organo-I, remained mobile. Finally, we established that most of the adsorbents that are used contain sufficient amounts of organic matter to create organo-I . It is anticipated that increased attention directed at understanding and quantifying the speciation of radioiodine, as opposed to simply total radioiodine, will lead to improved remediation results to be used for long-term radioiodine disposal in cementitious waste forms.

129-Iodine↗
DOE OSTI2022

Model Package Report: Composite Analysis Solid Waste Release Model (CASWR Model)

This document describes the implementation of a solid waste form release model in GoldSim for the Hanford Site Composite Analysis (CA) Update. This Composite Analysis Solid Waste Release model (CASWR model) was designed to generate deterministic radionuclide release rates for Hanford’s Central Plateau solid waste disposal sites using single realizations of release model coefficients. Five generalized waste form types are used for the conceptual model of waste release: surplus reactor block, cement, soil-debris, grouted residual waste, and ancillary equipment. The surplus reactor block waste form consists of radionuclide leaching from surplus production graphite reactor core blocks via unspecified processes (White et al., 1984 as cited in PNNL-15965). The cement waste form represents solidified wastes whose permeability is much lower than that of the surrounding soil. The soil-debris waste form type is defined as unconsolidated waste mixed with soil material. Tanks and canyon complexes comprise the grouted residual waste form such that their solid waste will be grouted and capped with a surface barrier at the completion of their cleanup. Finally, the ancillary equipment waste form constitutes contaminant releases from ancillary and auxiliary waste form residues associated with tank farms at closure. Individual sub-models are implemented to numerically represent a respective waste form within the CASWR Model: Surplus Reactor Block Sub-model, Cement Sub-model, SoilDebris Sub-model, Grouted Residual Waste Sub-model, and Ancillary Equipment Submodel. Advection is assumed to be the primary transport process governing the release of radionuclides in the Ancillary Equipment and Soil-Debris Sub-models. Diffusion is assumed to be the primary release process in the Grouted Residual Waste and Cement Sub-models. An unspecified zero-order release process is considered in the Surplus Reactor Block Sub-model due to the lack of information regarding actual processes involved in irradiated graphite leaching. The Surplus Reactor Block, Cement, and SoilDebris Sub-models were compared against analytical solutions (PNNL-11800, Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site). The agreement between results of these analytical solutions and the corresponding waste form models verified their correct implementation in GoldSim. A 1-D modeling abstraction approach for the Grouted Residual Waste and Ancillary Equipment Sub-models was adopted from existing Performance Assessment (PA) models. Despite the simplifications made in these sub-models, they were found to be appropriate representations of the waste forms, similar to what was used in the Waste Management Area C PA model (RPP-ENV-58782, Performance Assessment of Waste Management Area C, Hanford Site, Washington, Rev. 0). A sensitivity analysis was conducted to identify the most influential parameters in each waste form sub-model. Suggestions for considering pH-dependent and redox-dependent release mechanisms are formulated through the development of a conditional constant approach in GoldSim.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Application of Interparticle Spacing Model to Maximize Filler Content in Cementitious Pastes

One of the most impactful ways to reduce embodied carbon of concrete in the near term is by partially replacing Portland cement with supplementary cementitious materials and/or fillers. This article describes an approach to reduce cement content in concrete through the development of high filler, low water (HFLW) cementitious pastes. Pastes with cement content as low as 50% (% weight of fines) were designed by applying models that maximize the packing density of the granular system and that consider the characteristics of the materials to calculate interparticle spacing (IPS), thereby allowing to obtain pastes with higher solids concentration and lower water demand. Strong correlations were found between IPS, the consistency index of the Herschel-Bulkley rheological model, and cement hydration kinetic parameters of binary and ternary pastes containing a Portland limestone cement and up to two different types of ground limestone. The approach showed to be feasible for the design of HFLW concrete paste fraction.

Antunes da Silva, Denise↗
DOE OSTI2021

Effects of organic additives on calcium hydroxide crystallisation during lime slaking

Highlights: • Sucrose and lignosulfonate reduce the crystallite size of Ca(OH){sub 2}. • Lime slaking in sucrose solutions leads to Ca(OH)2 with irregular shape. • Lime slaking in presence of lignosulfonate leads to plate-like Ca(OH){sub 2} crystals. • Effects of additives are enhanced when introduced before slaking. • Additives stabilise the unstable edge faces of Ca(OH){sub 2} during ageing. Organic compounds, often used in cement systems as admixtures, may affect the crystallisation and carbonation kinetics of Ca(OH){sub 2}, an important phase of hydrated cement. Here, we investigated changes in Ca(OH){sub 2} morphology in the presence of 3 organic compounds, commonly encountered in cement and lime-based materials: sucrose, pectin and calcium lignosulfonate. The additives were introduced either before or after lime slaking to determine the influence of temperature. Ca(OH){sub 2} crystals and supernatant solutions were characterised at time of slaking and after 6 months of ageing using scanning electron microscopy, X-ray diffraction and optical emission spectroscopy. Our results indicate that the morphology of Ca(OH){sub 2} crystals is modified by the characteristics of the organic molecules which promote formation of Ca(OH){sub 2} with habits that can result in faster carbonation, an effect that is detrimental to cement used in reinforced concrete. These effects are enhanced when the additives are introduced before slaking, likely as a result of thermal degradation.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Estimating viscoelastic compliance of desiccating cementitious materials using drying prism tests

Highlights: • Determining relative humidity and degree of reaction of desiccating cementitious materials via an integrated method • Extracting moisture diffusion coefficient of cement mortar using the mass loss data of the prism specimens • Estimating uniaxial viscoelastic compliance of cement mortar using the shrinkage strain data of the prism specimens An integrated modeling approach to determining internal relative humidity and degree of reaction of desiccating cementitious materials has been developed. By simultaneously accounting for both self-desiccation and external drying, the model is capable of predicting the evolution of material properties of desiccating cementitious materials. Using the mass loss data of the prism specimens, the moisture diffusion coefficient of a nonlinear model for cement mortar was determined. Additionally, a previous poroviscoelastic shrinkage model was modified and extended. Through comparison of predicted and measured axial strain of the prism specimens, the viscoelastic compliance of cement mortar was extracted. The present work revealed that it is possible to use a simple drying prism test to fit the moisture diffusion coefficient and creep compliance of cementitious materials, though the comparison of the extracted viscoelastic compliance with measured compliance was only reasonable if the outer layer of the drying mortar was presumed to have microcracking.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Factors affecting the reactivity of slag at early and late ages

This study investigates the difference between the reactivity of slag in NaOH solution (w/s = 100) and in cement paste (w/b = 0.4). The reactivity of slag is much higher in NaOH solution than in cement paste. When the NaOH solution is saturated with portlandite, the rate of reaction of slag decreases to approach that in cement paste. This suggests that the slower reaction of slag in cement paste might be due to the presence of calcium ions released by the clinker phases. At 28 days, relative humidity measurements indicate that water is only present in pores less than 6 nm. Above 6 nm, hydration cannot take place due to the lack of water. From a thermodynamic point of view, the small size of water filled pores may slow down the slag reaction due to the high concentration of species in solution required for hydrate growth to balance the increase of the surface energy.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Development of Magnesium Oxysulfate Formulation for SRPPF Aqueous Recovery Liquid Solidification

The liquid effluent from the Savannah River Plutonium Processing Facility (SRPPF) Aqueous Recovery Processes will be solidified into a stable form that is acceptable by Waste Isolation Pilot Plant (WIPP) for disposal. The current Aqueous Recovery flow sheet proposes to solidify the liquid effluent using a grout formula that was developed and tested for the former Waste Solidification Building process. This Portland cement based mixture results in a high pH (~13) leachate from the solidified waste form which is not acceptable to WIPP in the large quantities expected from production at SRPPF. Various cementitious materials were previously evaluated as alternative grout formulations to Portland cement and a MgO-based mix was identified as a promising alternative. A magnesium oxysulfate (MOS) cement formulation comprised of reactive magnesium oxide (MgO), anhydrous magnesium sulfate (MgSO 4 ), and sand, as a non-reactive heat sink provided good mixability, similar density to the original Portland-cement based mix, and a leachate pH of 9.4, within the assumed WIPP brine pH range. However, the MOS formulation exhibited an appreciable amount of heat generation, which resulted in premature setting of a large-scale test.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Municipal Solid Waste Incineration Ash-Incorporated Concrete: One Step towards Environmental Justice

Municipal solid waste and cement manufacture are two sources of environmental justice issues in urban and suburban areas. Waste utilization is an attractive alternative to disposal for eliminating environmental injustice, reducing potential hazards, and improving urban sustainability. The re-use and recycling of municipal solid waste incineration (MSWI) ash in the construction industry has drawn significant attention. Incorporating MSWI ash in cement and concrete production is a potential path that mitigates the environmental justice issues in waste management and the construction industry. This paper presents a critical overview of the pretreatment methods that optimize MSWI ash utilization in cement/concrete and the influences of MSWI ash on the performance of cement/concrete. This review aims to elucidate the potential advantages and limitations associated with the use of MSWI ash for producing cement clinker, alternative binder (e.g., alkali-activated material), cement substitutes, and aggregates. A brief overview of the generation and characteristics of MSWI ash is reported, accompanied by identifying opportunities for the use of MSWI ash-incorporated products in industrial-scale applications and recognizing associated environmental justice implications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗