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    四川某地陶瓷砖产品的铅、镉迁移量和放射性核素限量水平的测定和评定

    Migrated Amounts of Lead and Cadmium and Determination and Judgement on the Level of Upper Limit of Natural Radionuclides of Ceramic Bricks Produced by Somewhere in Sichuan Province

    • 摘要: 将陶瓷砖样品清洗、烘干并粉碎至通过0.080 mm孔径的网筛制成分析用样品。取此样品10.000 g,加入50%(体积分数)硝酸溶液25 mL,在200℃电热板上加热2 h,取下,静置1 h,过滤并将滤液用水定容至50.0 mL。按电感耦合等离子体原子发射光谱法选择220.3 nm作为铅的分析谱线,228.8 nm作为镉的分析谱线测定溶液中铅、镉的迁移量。另取经洁净、烘干并粉碎至通过0.18 mm孔径的网筛的陶瓷砖样品500 g置于凹型样品盒中,密封7 d后按能谱仪工作条件测定样品中226Ra、232Th和40K的放射性活度比,并计算其内、外照射指数,从而判别其是否符合GB 6566-2010中关于放射性核素限量的规定。对30个批次样品,按上述方法进行测定。镉的迁移量远低于HJ/T 297-2006标准中所规定的要求(不大于5 mg·kg-1);铅的迁移量测定中有2个批次的样品结果超过上述标准的规定(不大于20 mg·kg-1),其余样品均合格,合格率为93.3%。关于放射性核素限量的评定,30批次样品全部符合国家标准中A类装饰和装饰材料的要求。

       

      Abstract: Sample of ceramic bricks were washed, dried and crashed to pass sieve with bore of 0.080 mm. A portion of 10.000 g of the minus sieve was heated in 25 mL of 50% (φ) HNO3 solution on a hot plate at low temperature (ca. 200℃) for 2 h and the mixture was then removed from the hot plate and stayed at normal temperature for 1 h. The mixture was then filtered and the filtrate was diluted to 50.0 mL with water. This is the testing solution for determination of migrated lead and cadmium by ICP-AES with analytical spectral lines of 220.3 nm for lead, and 228.8 nm for cadmium. Another portion of the brick sample was pretreated in the same way but crashed to pass sieve with bore of 0.18 mm. And 500 g of the minus sieve were placed into a concave sample case and sealed for 7 d, after which the specific radioactivities of 226Ra, 232Th and 40K were determined under the working conditions of the low-background multichannel γ-spectroscope and their indexes of internal and external exposure were calculated by the given formulas. As shown by the results of analysis of 30 samples taken from various batches, the amounts of cadmium migrated were found to be much lower than the limit value stipulated in the standard of HJ/T 297-2006 (i.e., not higher than 5 mg·kg-1); however the amount of lead migrated in 2 of the 30 samples were found to be higher than the stipulated value (i.e., not higher than 20 mg·kg-1), giving a qualification percentage of 93.3%. With reference to the national standard of GB 6566-2010, the results of levels of natural radionuclides found were all attained to the A class standard for decorating and fittingup materials.

       

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