The natural radioactivity in zirconium samples used in the ceramics industry has
been measured. One of the most important use of zircon is as opacifier for ceramic
tiles. The measurements were made by gamma spectrometry with a high purity
germanium detector (HPGe). The gamma index, I, the external hazard index, Hex
and the internal hazard index, Hin, were calculated. The investigated samples can
be used as one component in the recipe for the production of ceramics only if 3%
of the samples used

Janković, Marija M.

Todorović, Dragana

Repository of the Vinča Nuclear Institute (VinaR)

       PHYSICAL CHEMISTRY 2010  10th International Conference on Fundamental and Applied Aspects of Physical Chemistry  Proceedings      The Conference is dedicated to the 100th Anniversary of the academician Pavle Savić birthday and 20th Anniversary of the Society of Physical Chemists of Serbia         21-24 September 2010 B E L G R A D E                            ISBN 978-86-82475-17-0 Title: Physical Chemistry 2010. (Proceedings) Editors: S. Anić and Ž. Čupić Published by: Society of Physical Chemists of Serbia, Studentski trg 12-16 P.O.Box 47, 11158 Beograd, 218, Srbija Publisher: Society of Physical Chemists of Serbia For Publisher: S. Anić, President of Society of Physical Chemists of Serbia Printed by: “Jovan” Printing and Publishing Company; 200 Copies; Number of pages 16 + 388, Format: B5; Printing finished in September 2010.  Text and Layout: “Jovan”  200 - Copy printing    II   The Society of Physical Chemists of Serbia  in co-operation with   Institute of Catalysis, Bulgarian Academy of Sciences  Boreskov Institute of Catalysis, Siberian Branch of  the Russian Academy of Sciences  Faculty of Physical Chemistry, University of Belgrade, Serbia  Institute of Chemistry Technology and Metallurgy, University of Belgrade, Serbia  Vinča Institute, University of Belgrade, Serbia   Institute of General and Physical Chemistry, Serbia                         IV  International Organizing Committee  Chairman:             S. Anić (Serbia) Vice-chairman:     N. Stepanov (Russia)                                B. Adnađević (Serbia)  Members: M. Gabrovska (Bulgaria), N. Cvijetićanin (Serbia), T. Grozdić (Serbia),  D. Jovanović (Serbia), M. Lalić (BiH), D. Marković (Serbia), B. Milosavljević (USA), N. Miljević (Serbia), M. Mojović (Serbia), N. Ostrovski (Serbia), C. Pona (Italy), B. Simonović (Serbia), D. Stanisavljev (Serbia), A. G. Stepanov (Russia), V. Vasić (Serbia), N. Vukelić (Serbia), V. Vukojević (Sweden)   International Scientific Committee  Chairman:              Ž. Čupić (Serbia) Vice-chairmans:     V. N. Parmon (Russia)                                 M. Franko (Slovenia)  V. Vasić (Serbia)  Members: A. Antić-Jovanović (Serbia), G. Bačic (Serbia), R. Cervellati (Italy), R. Compton (United Kingdom), V. Gaspar (Hungary),  M. Jeremić (Serbia), A. L. Kawczyñski (Poland), Lj. Kolar-Anić (Serbia), S. Kuchanov (Russia), R. Leblanc (USA),  S. Mentus (Serbia), S. Milonjić (Serbia), Lj. Morozova-Roche (Sweden),  D. Moscone (Italy), J. Nedeljković (Serbia), Z. Noszticzius (Hungary), M. Perić (Serbia), V. Petruševski (Macedonia), M. Plavšić (Serbia), G. Smulevich (Italy),  G. Schmitz (Belgium), I. Schreiber (Czech), P. Ševčik (Slovakia), N. Stepanov (Russia), M. Trtica (Serbia), D. Veselinović (Serbia)  Local Executive Committee  Chairman:              B. Adnadjević Vice-chairmans:    S. Blagojević                                 A. Ivanović  Members: A. Abu Rabi-Stanković, P. Banković, N. Begović, S. N. Blagojević,  N. Cvjetičanin, M. Daković, A. Đerić, A. Ignjatović, Lj. Ignjatović, A. Jović,  J. Krstić, S. Kuprešak, D. Lončarević, J. Maksimović, V. Marković, M. Milenković, M. Milojević, Z. Mojović, B. Nedić, I. Pašti, N. Pejić, A. Popović-Bjelić, M. Petković, N. Potkonjak, D. Ranković, R. Ranković, M. Stević,  I. Stojković, B. Šljukić, M. Vujković    VRADIOACTIVITY IN RAW MATERIALS USED IN CERAMICS INDUSTRY  M. Janković and D. Todorović  Institute Vinča, Radiation and Environmental Protection Department, P.O. Box 522, 11001 Belgrade, Serbia  Abstract The natural radioactivity in zirconium samples used in the ceramics industry has been measured. One of the most important use of zircon is as opacifier for ceramic tiles. The measurements were made by gamma spectrometry with a high purity germanium detector (HPGe). The gamma index, I, the external hazard index, Hex and the internal hazard index, Hin, were calculated. The investigated samples can be used as one component in the recipe for the production of ceramics only if 3% of the samples used.  Introduction The investigation of zirconium ores as sources of TENORM (technologically enhanced natural radioactivity) began in the late 1970s and early 1980s [1,2]. These works highlighted the relatively high concentrations of natural radionuclides in zirconium ores. At present Australia, South Africa, Ukraine, India, China, Brazil and Sri Lanka are the largest exporters of zirconium minerals [2]. The aim of this study was to measure the radioactivity in zirconium used as raw material in ceramics industry for production of ceramic colors, glazes, tiles and sanitary and to estimate the radiological hazards. These materials are tested continuously in Laboratory for Radiation and Environmental Protection Department, Vinča Institute, Belgrade, as part of regular inspection of imported goods from the customs.  Experimental The investigated material was zirconium glaze. Before measurements, the samples were crushed, sieved and placed in the plastic 500 cm3 Marinelli beakers. All samples were measured immediately after preparation because of the rapid assessment of whether the activity in a given sample is in accordance with applicable regulations or not. The spectra of samples were acquired using a high purity germanium detector (HPGe) with relative efficiency of 23 % and energy resolution of 1.8 keV for the 1332 keV 60Co peak. The activity of 226Ra and 232Th was determined by measuring activity of their decay products: 214Bi (609 keV, 1120 keV and also 1764 keV), 214Pb (295 keV and 352 keV) and 228Ac (338 keV and 911 keV), respectively. The activities of 40K and 137Cs were determined from 1460 keV and 661 keV γ-lines, respectively. 235U was determined via its lines on 143 keV and 163 keV. 238U was determined by measuring activity of their decay products: 234Th (63 keV) or by 234Pa (1000 keV). 594Results and discussion The measured specific activities of 226Ra, 232Th, 235U and 238U are presented in Table 1. The 238U concentration ranging from 672-6524 Bq kg-1 was higher than concentration of 232Th (187-885 Bq kg-1), 235U (42-279), 40K (<MDC (16 Bq kg-1) and 137Cs (<2 Bq kg-1) in all samples. On the other hand activity ratio 238U/226Ra was approximatelly 1, and can be assumed that these two radionuclides are in the radioactive equilibrium. In order to estimate the radiological hazards the gamma index, the external hazard index and the internal hazard index must be calculated. Due to the high activity of 226Ra and 232Th in the samples, it must be determined what percentage of the sample can be used in the recipe for the production of ceramics. Gamma index can be calculated using the following relation [3]: 3000300200KThRa CCCI ++=       (1) where ,  and  are the activity concentrations of 226Ra, 232Th and 40K in Bq kg-1 in the building material, respectively. Gamma index must be less than 1 that the material could be used in high construction for interior, exterior and low construction. This applies to any building material. Gamma index for the investigated samples will be less than 1 only if 3% of the sample used. The obtained values for gamma index are presented in Table 1. For all investigated samples I < 1 (in the account, 3% of the activity of 226Ra, 232Th and 40K was used). RaC ThC KC Table 1. Activity concentrations of radionuclides in zirconium and appropriate gamma index Activity concentrations of radionuclides / Bq kg-1 № imported 226Ra 232Th 235U 238U I 1 2312 ± 347 367 ± 73 194 ± 58 2236 ± 894 0.38 2 2969 ± 297 816 ± 106 78 ± 33 3540 ± 1133 0.53 3 4147 ± 415 665 ± 80 266 ± 27 4522 ± 588 0.69 4 3967 ± 397 509 ± 61 230 ± 44 3855 ± 694 0.65 5 4350 ± 434 885 ± 88 178 ± 53 3853 ± 462 0.75 6 3201 ± 320 643 ± 64 191 ± 34 3948 ± 592 0.54 7 2732 ± 137 526 ± 68 164 ± 16 2425 ± 1336 0.46 8 3031 ± 303 630 ± 94 198 ± 20 3055 ± 611 0.52 9 3993 ± 399 555 ± 72 203 ± 32 3517 ± 914 0.66 10 3661 ± 366 658 ± 79 279 ± 28 3410 ± 682 0.62 11 Italy 2961 ± 296 570 ± 74 214 ± 21 2630 ± 736 0.50 12 2021 ± 202 396 ± 59 55 ± 26 1867 ± 672 0.35 13 3511 ± 351 454 ± 54 162 ± 41 2958 ± 740 0.57 14 Great Britain 3778 ± 378 584 ± 64 215 ± 54 4037 ± 1009 0.63 15 2603 ± 234 460 ± 60 42 ± 24 2266 ± 748 0.44 16 2106 ± 210 428 ± 51 54 ± 19 2687 ± 564 0.36 17 Slovenia 814 ± 163 187 ± 47 71 ± 14 672 ± 138 0.14 18 Sweden 2941 ± 294 565 ± 85 225 ± 56 2859 ± 715 0.50 19 Spain 3008 ± 301 596 ± 89 206 ± 21 3808 ± 762 0.51 20 Slovakia 4090 ± 1227 550 ± 165 193 ± 58 6524 ± 1174 0.67 21 Germany 4092 ± 409 624 ± 69 258 ± 52 3570 ± 714 0.68  The external hazard index, Hex, is defined as [1]: 4810/259/370/ KThRaex CCCH ++=     (2) where ,  and  have the same meaning as in equation (1). The value of this index must be less than unity in order to keep the radiation hazard RaC ThC KC595insignificant. The obtained values of  for the zirconium ranged from 0.09 to 0.46 as shown in Fig. 1, values which are indeed less than unity (results obtained with 3% of the activity of 226Ra, 232Th and 40K). In addition to the external hazard, radon and its short-lived products are also hazardous to the respiratory organs. The internal exposure to radon and its decay products is quantified by the internal hazard index, Hin, which is given by the equation [4]: exH4810/259/185/ KThRain CCCH ++=     (3) For the safe use of a material in the ceramics industry, Hin should be less than unity. The calculated values of Hin ranged from 0.15 to 0.81 as shown in Fig. 1. 0 3 5 8 10 13 15 18 200.00.20.40.60.81.0  Internal ExternalHazard indexMaterials  Fig.1. The measured values of both the external and the internal hazard indices.  Conclusion Based on the results of measurement it can be concluded that the investigated materials are not radioactive in the context of the law [5]. Keeping in mind that the investigated samples used as one component in the recipe for the production of ceramics it can be concluded that there are no legal restrictions in terms of radioactivity in circulation and use of the investigated materials only if 3% of the samples used.  References [1]  J. Beretka, P. J. Mathew, Natural radioactivity of Australian building materials, industrial wastes and by-products, Health Phys., 1985, 48, 87-95. [2]  G. F. Bothe, D. Stewart Smith, D. Wagstaff, M. Dibblee, The radiological aspects of zircon sand use, Health Phys., 1980, 38, 393-398. [3]  Official Journal of the Federal Republic of Yugoslavia, Regulations for the maximum limits of radioactive contamination of the human environment and decontamination procedures. Serbia, 1999, 9, 4. [4]  L. Xinwei, Radioactivity level in Chinese building ceramic tile, Radiat. Prot. Dosim., 2004, 112, 323-327. [5]  Official Journal of the Federal Republic of Yugoslavia, Regulation on conditions for trade and use of radioactive materials, x-ray apparatus and other devices that produce radioactive radiation, 1998, 32.  596

Radioactivity in raw materials used in ceramics industry

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Radioactivity in raw materials used in ceramics industry

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