Feasibility Study of Uranium Mill Tailings as Construction Material by Making Bricks and Assessment of Its Radiological Significance

Abstract

The feasibility study of the uranium mill tailings generated from the Turamdih process plant as a construction material was evaluated by making bricks using the tailings as one of the components of the bricks. Two major techniques, such as moulding and pressing, were used to produce bricks from the tailings. Mill tailings in the bricks varied from 15 to 62% with other materials such as sand, cement, gypsum, lime, bed materials, LD slag, fly ash, and aggregates. The major qualifying criteria, such as compressive strength, water absorption, leaching test, and ²²²Rn exhalation rate, were estimated using the standard methods to assess the suitability of the bricks for use as construction material. Three types of qualified bricks with different tailings compositions (30%, 40% and 50%), along with the other materials in bulk quantities, were produced and used in the model house to evaluate the associated in situ radiological hazards. The in situ mean ²²²Rn exhalation rates from walls were 0.0007 Bq/m²/s, 0.0012 Bq/m²/s, and 0.0021 Bq/m²/s made of tailings bricks with respective tailings compositions of 30, 40, and 50%. The maximum indoor radon concentration likely to be contributed by the 50% tailings bricks was estimated to be less than 20 Bq/m³ for minimum air changes of 0.5 per h. The estimated radium equivalent activity (Ra_eq) indicated that the bricks can be suitably used in industrial buildings, foundations of non-residential buildings, and the construction of roads and bridges without any significant radiological hazards to members of the public.