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Dr David Johnson S

DON'T. PANIC. Outline of Presentation. Cementitious stabilisation of metals Potential problems relating to grouts Grout componentsStandards relating to composition of componentsRadioactive elements in the components. Cementitious Grouts. Cementitious grouts are used to encapsulate certain radioa

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Dr David Johnson S

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    1. Dr David Johnson S/S Remediation Consultancy Radioactive Elements Present in Cementitious Grouts

    2. DONT PANIC

    3. Outline of Presentation Cementitious stabilisation of metals Potential problems relating to grouts Grout components Standards relating to composition of components Radioactive elements in the components

    4. Cementitious Grouts Cementitious grouts are used to encapsulate certain radioactive waste streams Metals are immobilised by both physical and chemical means

    5. Chemical Treatment of Contaminants Heavy metal salts are converted to low solubility forms

    6. Decreased Solubility of Metals

    7. Some Technical Concerns Cementitious materials contain heavy metals and radioactive elements These can add to those already present in the waste Composition varies with source Raw materials used in manufacturing may be obtained from outside UK There may be scale-up inconsistencies

    8. Heavy Metals Present in Cement PCA (US) data from 97 kilns Metals held in glassy matrix of clinker and do not leach out

    9. Effect of Cement Source Obtained samples of cement (BS EN 197-1 CEM I Class 42.5N) from 8 works across England, Scotland and N.Ireland Used samples of the local soil to represent made ground Soil (at constant water content) mixed with 10% cement Compacted and cured for 28 days => strength Cured for 28 days => leaching

    10. Effect of Cement Source on 28-Day Strength

    11. Effect of Cement Source on Leaching of Cr and Cu

    12. Grout Components Cement Portland cement (OPC) Calcium sulfoaluminate cement (CSA) Ground granulated blastfurnace slag (GGBS or BFS) Pulverised-fuel ash (PFA) Water

    13. Standardisation of Grout Components

    14. Raw Materials Used in Manufacturing

    15. Composition of Cement

    16. Wastes Used in OPC Phosphogypsum is employed as set time adjuster By-product of fertiliser industry Relatively high levels of 238U, 234U, 210Pb and 210Po 222Rd emission also observed Content varies with origin of phosphate rock Red Mud is used as source of iron oxide or alumina By-product of bauxite processing Contains significant levels of 238U and 232Th

    17. Hungary (1984)

    18. Albanian Clays (2000)

    19. Other Countries

    20. CSA Manufacture

    21. Radioactivity Associated with BFS

    22. Radioactivity of PFA

    23. Radioactivity of Coal (Australia)

    24. Radioactivity of Coal (The Netherlands)

    25. Radioactivity of Coal (Hungary & Spain)

    26. Conclusions

    27. Dr David Johnson S/S Remediation Consultancy Radioactive Elements Present in Cementitious Grouts

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