Natural Radioactivity in the Production of Titanium Dioxide Pigment: A Study of the Laporte Plant and Environment Behaviour of Radionuclides at Bunbury, Western Australia

摘要

A study of radioactivity levels in samples collected at a titanium dioxide plant at Bunbury in Western Australia is described. The radioactivities of the principal radionuclides present in the ilmenite feed ( exp 226 Ra, exp 228 Ra, and exp 228 Th) are followed throughout the pigment production process. It is found that approximately 67 MBq/day of activity due to each of exp 228 Ra and exp 228 Th enters the plant (equivalent to 17.8 kg of thorium), and approximately 14 MBq/day of activity due to exp 226 Ra. Essentially all of this radioactivity leaves the plant in the form of acidic effluent, which is pumped to disposal lagoons and allowed to neutralise and drain away. A preliminary study of possible environmental effects of radioactivity in the effluent is presented. It was established that in the presence of high sulphate ion concentrations in both the plant feed liquor and the effluent, thorium remains in solution whereas radium, which forms an insoluble sulphate compound, tends to coprecipitate and is found in solid residues throughout the process. (Atomindex citation 13:644987)