Precipitation of impurities in 9-32-0 grade fluid fertilizers
For several years TVA has been studying production of 9-32-0 ammonium polyphosphate suspension produced from ammoniated merchant-grade wet-process orthophosphoric acid. Suspensions containing polyphosphate have an advantage over those that contain only orthophosphate in that they can be stored satisfactorily at much lower temperature. However, the introduction of polyphosphate (pyrophosphate anion) complicates the precipitation of impurities and has yielded inconsistent storage characteristics in 9-32-0 fluid fertilizers. Fluorine also has been shown to affect suspension fertilizer properties. The viscosity of 13-38-0 orthophosphate suspension fertilizers is affected by the atomic ratios F:(Al + Fe + Mg). Addition of fluorine prevents sludges and precipitates in ammonium polyphosphate fertilizer solutions - the proper amount of fluorine is related to the amount of each of the metallic impurities present and also to the fraction of the phosphate present as pyrophosphate. Incorporation of polyphosphate or fluorine or both has been shown to have positive effects on ammoniated wet-process phosphoric acid (WPPA), but they do not report the solubility relationships of the cation impurities (Fe, Al, Mg, and Ca) with respect to the anion constituents (PO/sub 4/, P/sub 2/O/sub 7/, and F). Therefore, a factorial study was developed to determine the solubility relationships of the precipitated metal impurities encountered in 9-32-0 fluid fertilizers. 10 refs., 1 fig., 20 tabs.
- Research Organization:
- Tennessee Valley Authority, Muscle Shoals, AL (USA). Office of Agricultural and Chemical Development
- OSTI ID:
- 6071026
- Report Number(s):
- TVA/OACD-86/6; ON: DE86901143
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
AMMONIUM COMPOUNDS
AMMONIUM PHOSPHATES
CHEMICAL COMPOSITION
CHEMICAL PREPARATION
DATA
ELEMENTS
EXPERIMENTAL DATA
FERTILIZERS
FLUORINE
HALOGENS
IMPURITIES
INFORMATION
NONMETALS
NUMERICAL DATA
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PRECIPITATION
SEPARATION PROCESSES
SYNTHESIS
VISCOSITY