Browsing by Author "Mhuza, Gregory Casmir"

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    Investigation into suitable methods for utilization of local phosphate deposites in preparation of fertilizers.
    (University of Dar es Salaam, 1977) Mhuza, Gregory Casmir
    This investigation sets out to explore possibilities for suitable methods for utilization of local phosphate deposits in preparation of fertilizers phosphorus occurs in nature as impure forms of calcium phosphate Ca3 (PO4)2 Commonly known as phosphate rock. The chief ore is the appetite which may be the chloro or fluoralpatite Caq(PO4)6 . XCaCO3 Ca (F.CL)2 and the phosphlorite Caq (PO4)6. Ca (OH)2. Since phosphate rock could serve as a cheap and important phosphate fertilizer but the mineralo is characterized by poor solubility which limits prospects for direct application in the field. Plants absorb phosphorus as the orthophosphate ions H2PO4- and HPO42- and to achieve quicker action as a fertilizer, phosphate rock has to be converted into a form that rock has to be converted into a form that will provide these ions in solution. The performance of this task is the basic purpose of all phosphate fertilizer manufacturing processes. In industry, for example, superphosphate fertilizer is made by the action of sulphuric or phosphoric acid on phosphate rock and the basic reaction is Ca3(PO4)2 +4H+CA(H2PO4)2 +2CA++. The rock was then mixed with a solution of carbondioxide in water under pressure and left on a shaking machine for some days to find the solubilizing effect of carbondioxide solution on the rock. The soluble phosphorus was then analysed. The procedure was repeated with the phosphate rock mixed with ammonium nitrate. The last attempt was heat treating a mixture of phosphate rock with sodium hydrogen sulphate and polassium hydrogen sulphate. This reaction gave some promising data. The rest of the work was concentrated in finding out the oplinium temperatures for this to occur. The method was by differential thermal analysis (DTA).