Spectrophotometric determination of uranium in waste water of phosphoric acid and fertilizer manufacturing process

In this study, waste water drains and produced phosphate fertilizers of con ventional wet-process (hemihydrate) phosphoric acid and phosphate fertilize r plants were investigated to determine the average uranium contents in the active manufacturing period. The method chosen for the determination of ur anium was an extension of an existing spectroanalytical method and was adop ted for waste water analysis as described. The results show that average ur anium contents (mg m(-3)) in a three-month period are appreciable in the wa ste water channel of the H3PO4 unit, produce acid containing 28% P2O5 (20.7 5), H3PO4 unit, produce acid containing 54% P2O5 (35.69), NPK (Nitrogen, Ph osphorus, Potassium fertilizer) process (23.94), DAP (diamonium phosphate f ertilizer) process (58.26) and dilution with the factory's other waste wate r streams which contain no uranium do not help to reduce the content to the EPA's (Environmental Protection Agency) stated permittable U level (for un derground waters 20 mg m(-3)) in the sea discharge joint waste channel (34. 01). The phosphate fertilizers such as composite NPK with 15% P2O5 were als o found to contain appreciable amounts of uranium, 25.28 and 51.76 respecti vely (mg kg(-1)).