Radiological assessment of different monazite grades after mechanical separation from black sand

Area of Science:

• Geochemistry and Mineralogy
• Radiological Sciences
• Environmental Health

Background:

• Monazite, found in Egyptian black sands, is a valuable mineral containing thorium, uranium, and rare earth elements.
• Evaluating gamma-ray exposure from primordial radionuclides is crucial due to mining activities.
• This study addresses the radiological impact of monazite extraction and processing.

Purpose of the Study:

• To conduct a radiological assessment of monazite raw material across different grades.
• To quantify the activity concentrations of key radionuclides (232Th, 238U, 40K, 138La).
• To calculate associated hazard indices and assess potential risks to workers.

Main Methods:

• Utilized a hyper pure Germanium detector (HPGe) for precise activity measurements.
• Analyzed monazite samples of varying grades (90%, 75%, 50%).
• Calculated absorbed and effective doses, alongside hazard parameters.

Main Results:

• Activity concentrations of 232Th, 238U, and 40K were determined for each monazite grade.
• Specific activities for 90% monazite: 348,008±1406 Bq/kg (232Th), 69,299±2086 Bq/kg (238U), 27,510±245 Bq/kg (40K).
• Calculated effective and absorbed dosages surpassed the worker's exempt limit (20 mSv/y), and hazard parameters exceeded recommended limits.

Conclusions:

• Monazite raw material in Egyptian black sands exhibits significant levels of primordial radionuclides.
• Radiological risks associated with monazite handling and processing are substantial.
• Implementation of stringent radiation safety protocols is essential to protect workers from ionizing radiation hazards.