부산대학교 도서관

Phosphorus is an essential element in the buildup of the human body and all other livings skeletons. The main source of phosphorus is the natural phosphate. About 95 percent of the produced phosphates are consumed in the agricultural sector as fertilizers and animal feed stocks. Most of the balance is converted into phosphoric acid and elemental phosphorus which are the raw materials for manufacturing various phosphate compounds. The world annual phosphate production in 2012 is around 217 million tons, and the global reserves amount to 67 billion tons. With the population increase, researchers estimate that the existing phosphate reserves cover the world needs of phosphates for more than 100 years to come. Egypt has about 4 percent of the world phosphate reserves (2.78 billion tons), and produces about 3 percent of the world phosphate production (about 6 million t/y). The present article covers different aspects of the Egyptian phosphate rocks. The phosphate deposits in Egypt lie between latitudes 23˚ 10-30˚ 50' N, whereas the payable zone lies between latitudes 24˚ 30'-26˚ 50- N. They extend longitudinally from the Red Sea Coast to El Dakhla Oases. Geologically, the economic phosphate beds belong to the central facial zone of the Upper Senonian age (Upper Cretaceous and Lower Eocene) deposits. They cover the Red Sea Coast, Nile Valley, and Western Desert. The P_2 O_5 content ranges between 20 and 32 %. The gangue constituents are mainly carbonates, silica, and silicates (clays), depending on the region and locality. The phosphate ore is mined by open cast and/or underground mining. The underground mining is either long‐wall or room‐and‐pillar mining methods. Upgrading the phosphate rock is done through: crushing, screening, attrition scrubbing, desliming, and drying naturally or artificially. Flotation is a promising technique for the removal of all sorts of gangue minerals. This has been tested in laboratory and semi‐pilot scales.