Radiological measurement of phosphate rock and phosphogypsum from fertilizer industries in India

Phosphate deposits are generally characterized by high levels of natural radionuclide concentrations. Natural radionuclides from the uranium and thorium series were measured, using high-resolution gamma-spectrometry in phosphate rock and phosphogypsum samples from the phosphate fertilizer industry in India. Equilibrium was found to be disrupted during the chemical processing of phosphate rock with 83 % of the 226 Ra and only 5 % of 238 U fractionating to phosphogypsum. Activity concentrations of 238 U and 226 Ra in phosphogypsum produced from various fertilizer industries of India showed levels < 1,000 Bq kg −1 and pose no restriction for use in building/construction material.