Red mud and bismuth oxide based X-ray shielding tiles for upcoming hospitals: A comprehensive study on phase quantification and physical properties

Abstract

Red mud (RM) is a solid alumina industry waste generated in millions of tonnes and is stockpiled across the globe. From the environmental perspective, research and innovation strategies are utmost necessary for the minimization and utilization of red mud. In an attempt to develop an environmentally friendly technology, RM was utilized with Bi2O3 for the development of radiation shielding tiles. RM is a source of many metal oxides, which react with Bi2O3 during sintering and form various high-dense phases. The Rietveld refinement of the tiles sintered from 600 to 1100°C confirms the formations and transformations of several high-dense phases like Bi24Ti2O40, BiFeO3, and Na0.5Bi0.5TiO3. The RM-Bi2O3 mixture sintered at 1100°C (RMBi1100) exhibited high density (3.64 ×103 kg m−3), less porosity (10 %), and flexural strength of 24 MPa. The results showed that the developed sample has a half-value layer (HVL) of 1.15 mm at 140 kV. The 15.5 mm, 13.5 mm, and 7 mm thick RMBi1100 tiles can effectively replace 2.3 mm, 2 mm, and 1 mm thick lead sheets respectively, that are used to establish radiation shielding structures in computed tomography, radiography & fluoroscopy, and dental infra oral radiography installations, respectively. It can promote the utilization of red mud and thereby reduce the environmental pollution associated with lead and red mud.