Exhalation rates determined in construction material produced from niobium waste

• Autor(a) principal: SILVA, PAULO S.C. da
• Data de Publicação: 2019
• Outros Autores: EL HAJJ, THAMMIRIS M., DANTAS, G.A.S.A., TORQUATO, HENRIQUE, INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE
• Tipo de documento: Artigo de conferência
• Título da fonte: Repositório Institucional do IPEN
• Texto Completo: http://repositorio.ipen.br/handle/123456789/30398
• topic: breath; building materials; cements; construction; dose rates; exhalation; gamma spectroscopy; neutron activation analysis; niobium; public health; radon; statistical data; thorium

Mining operations annually generate large volumes of mining waste that can have several environmental impacts requiring appropriate management strategies in the short and long term. Recently, in Brazil, we have witnessed the catastrophic consequences of poor management of these tailings. One way to better manage mining waste may be to reduce its quantity by reusing it. In the case of niobium industry one possibility for the huge amount of solid tailing generated is its application as construction material. Nevertheless, these tailing also carries some radioactive elements. Exposure to radiation originated from construction material is mainly due to the presence of radionuclides from uranium and thorium series. The external exposure comes from the gamma emitters present in the material while internal exposure can come from radon and thoron gas. This study had evaluated the radiological impact of using niobium waste tailing in concrete plates and proof bodies, for use in construction material. It was determined the activity concentration of 238U, 226Ra, 210Pb, 232Th, 228Th, 228Ra and 40K in cement made with niobium waste to compare with commercial cement. Exhalation rates for 222Rn and 220Rn were determined for cement plates and proof bodies made with 0, 50 and 100% of niobium waste. Results showed that the exhalation rates varied from 0.032 ?? 0.004 to 0.20 ?? 0.01 Bq/m2.s for 222Rn and from 0.044 ?? 0.005 to 0.8 ?? 0.1 Bq/m2.s for 220Rn in the different cements. The exhalation rate of the plates varied from 0.035 ?? 0.002 to 0.35 ?? 0.02 Bq/m2.s for 222Rn and from 0.048 ?? 0.006 to 1.2 ?? 0.1 Bq/m2.s for 220Rn and the variation for the proof bodies was 0.0042 ?? 0.0006 to 0.2 ?? 0.1 Bq/m2.s and from 0.008 ?? 0.001 to 0.054 ?? 0.006 Bq/m2.s for 222Rn and 220Rn, respectively.