الفهرس 
INTRODUCTION AND LITLUTURE REVIEWOnly 14 pages are availabe for public view
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Abstract
Egyptian monazite mineral is produced as a by-product during the separation of more abundant heavy economic minerals from Egyptian black sand beach deposits. Monazite mineral is consider as one of the major rare earth elements (REEs) natural resources in addition to thorium and uranium (consists mainly of REEs, Th & U phosphates). Radiation management is necessary in dealing with thorium containing ores. Monazite contains thorium and uranium in the ratio of about 0.1 and 0.01 parts per part of rare earths, respectively. Radiation protection is concerned largely with controlling 228Ra (‟mesothorium Iˮ, a radium isotope), 226Ra (radium), and their daughters 220Rn (‟thoronˮ, a radon isotope) and 222Rn (radon) their associated gamma and alpha radiations. The presence of thorium in rare earth materials is undesirable, and thorium and uranium radioactive daughter products in the ore are must be removed and suitably disposed off. Radiation measurements results are briefly studied in this work. A proposed safety program is finally skitched for radiation monitoring and / or elimination in a REEs production pilot plant. The monitoring work is oriented to asses the radioactivity in two main directions: 1-The processes which carried out during the monazite mineral chemical processing (Digestion, dissolution, separation of the mineral components and solid waste residue treatment). 2- The internal bodies which produced before, during and after the liquid & solid main processes products. The inspection of the monazite mineral chemical processing accompanied radioactivity and its effective and annual dose rates is fulfilled to establish a primary assessment scheme for the whole process throughout input & output materials. Digestion, dissolution of mineral and separation of the various mineral components in mass product, in addition to process solid residue are the main targeted process compartments for different radiation levels and radioactive nuclide detection. Man is continuously exposed to ionizing radiation from Naturally Occurring Radioactive Materials (NORM). The origin of these materials is the Earth’s crust, but they find their way into building materials, air, water, food and the human body itself. The worldwide average indoor effective dose due to gamma rays from building materials is estimated to be about 0.4 mSv per year (milli Sievert (Sv): Radiation measurement unit for the effective dose in the International System of Units (SI)). Generally, natural building materials reflect the geology of their site origin. The average activity concentrations of 226Ra, 232Th and 40K in the Earth’s crust are 35, 30 and 400 Bq/kg respectively (Becquerel (Bq): Is the (SI) derived unit of radioactivity; one becquerel is defined as the activity of a quantity of radioactive material in which one nucleus decays per second). On the other hand, there exist only a few studies relating to passive measurements of thoron. It is traditionally assumed that the inhalation dose to the general population resulting from thoron and its progeny is negligible although recent studies in many countries have revealed that this may not be entirely correct. Most importantly, in monazite rich high background radiation areas (HBRAs) such as those found in India, China and Brazil, a significant part of the inhalation dose might be attributed to thoron (Th) and its progeny. As these areas provide excellent settings for epidemiological surveys relating to the effects of low doses of radiation, large scale monitoring of thoron (Th) and its progeny becomes imperative in order to provide realistic estimates of inhalation exposures. The radioactivity assessment results may necessitate the reduction of its source to reduce the dose rate. The radioactive sources emit various types of hazardous nuclear radiation with different emissions, such as alpha and beta particles in addition to gamma radiation. Thoron and radon were detected and captured via barium salt addition. The total effective dose of hazardous nuclear radiation during the monazite mineral processing in the different working scales, first in the laboratory scale and the pilot scale with and without addition of barium salt were assessed and monitored, the recorded values were 0.12, 0.30 and 0.64 mSv/h respectively. The activity concentrations of 226Ra (U-series), 228Ra (Th-series) and potassium (40K) were determined and evaluated in monazite mineral were 784.22±24.08, 2808.74±5.96 and 243.58±4.72 Bq/kg for238U, 232Th and 40K, respectively. The activity concentrations of 226Ra (U-series), 228Ra (Th-series) and potassium (40K) were determined and evaluated in thorium precipitate were 935.63 ±64.70, 5229.62 ±21.47, 216.48 ± 14.74 Bq/kg for 238U, 232Th and 40K, respectively. Also the activity concentrations in rare earth precipitate contains uranium were determined giving the following 516.83 ± 10.15, 235.15 ±1.64, 64.64 ± 1.51 Bq/kg for 238U, 232Th and 40K respectively. At last, measured the activity concentrations of the un-reacted part of monazite after digestion (waste) which equals134.48 ± 11.14, 532.89 ± 2.41, 82.25 ± 2.24 Bq/kg for 238U, 232Th and 40K respectively. Radiation measurements were briefly studied in this work. A proposed safety program is finally flow-sheeted for radiation reduction or elimination in a REEs production pilot plant after calculations of annual dose rate for environmental mitigation and remediation purposes.