Properties and Mechanism of Solidification of Simulated Radioactive Incineration Ash with Low Alkalinity Cement-Based Materials

Abstract

Abstract: The existence of metallic aluminum in the radioactive incineration ash results in the expansion and deterioration of cement waste forms, due to the reaction of metallic aluminum with high alkali pore solution to produce hydrogen gas in hardened Portland cement or alkali-activated cementitious materials. In this study, low alkalinity cement-based materials were prepared by Portland cement, silica fume and fly ash as the main raw materials, aiming to overcome this problem. Zeolite, polycarboxylate superplasticizer, diutan gum and polyaluminum sulfate were used as well to modify the properties. According to the results, 28 d compressive strength of over 16.6 MPa is achieved by low alkalinity cement-based materials waste forms with 30% (in mass) simulated radioactive incineration ash. The freeze-thaw resistance, immersion resistance and impact resistance meet the requirements of GB 14569.1—2011 specifications. The leaching rate of Ce³⁺ on the 42 d is 4.41×10^-9 cm/d, and the cumulative leaching fraction is 3.4×10^-7 cm. The relatively lower pH value of pore solution in the early age and high Ca concentration in pore solution hinders the reaction between the metallic Al and pore solution. At later age, no reaction between metallic Al and pore solution because the pH value of pore solution is below 11.75.

Key words: solid waste disposal, cement-based material, low alkalinity, radioactive incineration ash, elemental metal, solidification, leaching rate, cumulative leaching fraction

CLC Number:

TL941

WEI Qi, GENG Haining, MA Haosen, LIU Yan, CHEN Wei, WANG Dongwen, PAN Sheqi, LI Qiu. Properties and Mechanism of Solidification of Simulated Radioactive Incineration Ash with Low Alkalinity Cement-Based Materials[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2022, 41(1): 182-191.

References

[1] 李长成,姚燕,崔琪,等.改性碱激发水泥固化处置模拟放射性焚烧灰[J].硅酸盐学报,2010,38(7):1215-1219.
LI C C, YAO Y, CUI Q, et al. Solidification and disposal of simulated radioactive incineration ash by modified alkali-activated cement[J]. Journal of the Chinese Ceramic Society, 2010, 38(7): 1215-1219 (in Chinese).
[2] 华正韬,刘自强,侯辉娟.放射性焚烧灰处理工艺研究[J].产业与科技论坛,2020,19(21):45-47.
HUA Z T, LIU Z Q, HOU H J. Study on treatment technology of radioactive incineration ash[J]. Industrial & Science Tribune, 2020, 19(21): 45-47 (in Chinese).
[3] 逯迎春.放射性焚烧灰处理方法的研究[J].广东化工,2013,40(7):70-71+78.
LU Y C. Research on the treatment of incineration ash[J]. Guangdong Chemical Industry, 2013, 40(7): 70-71+78 (in Chinese).
[4] 陈乔,陈寒斌,许春霞.建筑胶凝材料固化生活垃圾焚烧飞灰研究进展[J].重庆建筑,2014,13(10):47-49.
CHEN Q, CHEN H B, XU C X. Study progress on fly ash by household garbage burning of building gelation materials solidification[J]. Chongqing Architecture, 2014, 13(10): 47-49 (in Chinese).
[5] XUAN D X, POON C S. Removal of metallic Al and Al/Zn alloys in MSWI bottom ash by alkaline treatment[J]. Journal of Hazardous Materials, 2018, 344: 73-80.
[6] 陈娟.硫铝酸盐水泥的性能调整与应用研究[D].武汉:武汉大学,2005.
CHEN J. Research of properties modification and applications of sulphoaluminate cement[D]. Wuhan: Wuhan University, 2005 (in Chinese).
[7] XUAN D X, TANG P, POON C S. Effect of casting methods and SCMs on properties of mortars prepared with fine MSW incineration bottom ash[J]. Construction and Building Materials, 2018, 167: 890-898.
[8] 沈晓冬,严生,吴学权,等.放射性废物水泥固化的理论基础、研究现状及对水泥化学研究的思考[J].硅酸盐学报,1994,22(2):181-187
SHEN X D, YAN S, WU X Q, et al. The theoretical basis and state-of-art of study on the immobilization of radioactive waste by means of cement and some considerations for the research of cement chemistry[J]. Journal of the Chinese Ceramic Society, 1994, 22(2): 181-187 (in Chinese)
[9] JACKSON M D, MOON J, GOTTI E, et al. Material and elastic properties of Al-tobermorite in ancient Roman seawater concrete[J]. Journal of the American Ceramic Society, 2013, 96(8): 2598-2606.
[10] 蒲心诚,王勇威.高效活性矿物掺料与混凝土的高性能化[J].混凝土,2002(2):3-6.
PU X C, WANG Y W. High efficiency active mineral admixture and high performance of concrete[J]. Concrete, 2002(2): 3-6 (in Chinese).
[11] 李顺,文梓芸.聚羧酸系减水剂的分散作用及引气性能[J].硅酸盐学报,2009,37(4):616-621.
LI S, WEN Z Y. Dispersibility and air entraining performance of polycarboxylate-type water reducers[J]. Journal of the Chinese Ceramic Society, 2009, 37(4): 616-621 (in Chinese).
[12] 张振国,张铭栋,顾平,等.沸石材料吸附水中放射性锶和铯的研究进展[J].化工进展,2019,38(4):1984-1995.
ZHANG Z G, ZHANG M D, GU P, et al. Progress in adsorption of radioactive strontium and cesium from aqueous solution on zeolite materials[J]. Chemical Industry and Engineering Progress, 2019, 38(4): 1984-1995 (in Chinese).
[13] 张郁,权娟娟,刘小华.高掺量矿渣水泥与普硅水泥的水化进程对比研究[J].硅酸盐通报,2014,33(11):3041-3045.
ZHANG Y, QUAN J J, LIU X H. Comparative study of slurry hydration process on high volume content slag cement and ordinary Portland cement[J]. Bulletin of the Chinese Ceramic Society, 2014, 33(11): 3041-3045 (in Chinese).
[14] 胡博,王建朝,刘影,等.铝合金在碱性环境中的耐腐蚀研究进展[J].电镀与环保,2014,34(3):4-6.
HU B, WANG J C, LIU Y, et al. Research progress in corrosion resistance of aluminum alloy in alkaline environment[J]. Electroplating & Pollution Control, 2014, 34(3): 4-6 (in Chinese).
[15] 邵海波,王晓艳,王建明,等.碱土金属离子与EDTA对纯铝在碱性溶液中的协同缓蚀作用[J].物理化学学报,2006,22(3):312-315.
SHAO H B, WANG X Y, WANG J M, et al. The cooperative inhibition effects of alkaline earth metal ions and EDTA on the corrosion of pure aluminum in an alkaline solution[J]. Acta Physico-Chimica Sinica, 2006, 22(3): 312-315 (in Chinese).