Optimization of chicken manure combustion parameters in the aspect of phosphorus recovery

PurposeThe increasing demand for phosphorous for the production of mineral fertilizers forces the continuous development of research and new technologies in the field of obtaining it from sources other than phosphate rocks. This paper presents an analysis of optimizing the combustion parameters of chicken manure in the aspect of phosphorous recovery. Methods The combustion process was carried out in different time (۳-۸ hours) and temperatures (۷۰۰-۹۰۰oC) in laboratory of electric furnace. The content of macro and micronutrients was determined by XRF and ICP-OES analysis. To identify the mineral composition of ashes, the XRD analysis was applied. The content of total phosphorus in ash extracts was determined by photometric method. Results Concentration of p ۲O۵ in ash samples detected by ICP-OES and XRF was comparable, ۳۰.۳۷ wt.% and ۳۱.۷۷ wt.% at ۹۰۰oC, ۲۶.۲۷ wt.% and ۲۶.۷۱wt.% at ۷۰۰oC and ۲۵.۳۱wt.% and ۲۵.۰۰ wt.% at ۵۰۰oC, respectively. The mineral composition of ashes showed two phases: crystalline and amorphous. The estimated values of p ۲O۵ content in crystalline phase was ۱۴.۸۳wt.% at ۵۰۰oC, ۲۰.۹۶wt.% at ۷۰۰oC and ۲۳.۸۰wt.% at ۹۰۰oC. The estimated p ۲O۵ content in amorphous phase was ۱۰.۴۸wt.% at ۵۰۰oC and decreased at higher temperature to ۵.۳۱wt.% at ۷۰۰oC and ۶.۵۷wt.% at ۹۰۰oC. Conclusion The chemical composition of ashes from chicken manure depends on the combustion temperature. The highest concentration of phosphorous in their bioavailable forms was determined for samples burned in ۵۰۰oC. The results indicate that a valuable source of phosphorous is the amorphous phase.    

Keywords:

Phosphorous availability , organic wastes , ash , Amorphous phase