Two laboratory experiments were conducted to evaluate the amount of P utilization from two different types of sparingly soluble phosphate rock by aquatic biotic communities. The first type was Mussoorie Phosphate Rock or MPR (sedimentary in origin) and other was Purulia Phosphate Rock or PPR (igneous in origin). The two trials were with eight different treatment combinations. Among various trea...

Phosphate-rock or more precisely the phosphorites form the repository of phosphate supply for the fertilizer industry for manufacture of elemental phosphorus, phosphoric acid and innumerable alkali phosphates. It has now been universally agreed that phosphorites have some kind of sedimentary marine origin, the source of phosphorous being of organic and/or inorganic origin (1). The principal pho...

Three quarters of the world’s phosphate deposits are of sedimentary origin and 75%–80% of those include carbonate gangue. In this study, carbonate sedimentary phosphate deposits of the Lar Mountains of southwest Iran are studied. These deposits consist mainly of calcite, fluorapatite, quartz, kaolinite and illite, with an average P2O5 grade of 9%–10% (low-grade). Various pre-processing and proc...

There is a great need for more precise absolute ages for sedimentary rocks. We have been actively involved in developing techniques to directly date sedimentary rocks, rather than using associated igneous rocks, or using relative dating techniques. Sedimentary phosphate nodules (i.e. coprolites) are ideal candidates for absolute dating of sedimentary rocks. Phosphates occur commonly within the ...

Dolomite [CaMg(CO3)2] is an intolerable impurity in phosphate ores due to its MgO content. As high grade phosphate reserves become depleted, the need to develop a cost effective method for the removal of dolomite from high-MgO phosphate ores becomes increasingly important. The jigging process has been investigated as a method for the beneficiation of high-MgO sedimentary phosphate ores. A labor...

Removal of carbonate impurities in sedimentary phosphate is one of the most important issues in the industry. Poor selective flotation of those ores is due to the similarity of Physico-chemical surface properties, solubility and electrokinetic characteristics of sparingly soluble phosphate and carbonate minerals. In this study, the effect of ultrasonic irradiation as a pretreatment method o...

The oxidation and reduction that occur during early diagenesis of sediments has been studied in the interstitial waters of a rapidly accumulating sedimentary sequence from the Mediterranean margin of Spain. A series of reactions that are mediated by progressively lower free energy derived from oxidation of organic matter is evident in the sedimentary sequence. Iron and manganese are rapidly red...

The bulk of the world's phosphate reserves is located in sedimentary horizons that contain appreciable amounts of carbonate. During beneficiation of phosphate rocks, huge amounts of oversize phosphate rocks are rejected from crushers. This reject also mostly contains low tricalcium phosphate and high carbonate content. In this study, experiments have been carried out to reduce/eliminate car...

The distribution of major phosphate deposits in the Precambrian sedimentary rock record is restricted to periods that witnessed global biogeochemical changes, but the cause of this distribution is unclear. The oldest known phosphogenic event occurred around 2.0 Ga and was followed, after more than 1.3 billion years, by an even larger phosphogenic event in the Neoproterozoic. Phosphorites (phosp...