Optimizing of phophorus and potassium contents in cattle manure ash during combustion
摘要
This article indicates the best combustion condition of cattle manure to produce ash as fertilizer with high phosphorus and potassium content. The iso-curve response from combustion temperature (X1) and residence time (X2) reveals high phosphorus content within the following optimal area: cattle manure mass of 22.5 g, combustion temperature ranged between 550 and 685 °C and residence time of 120 min with phosphorus content of 4000 mg/Kg. While the iso-curve response from residence time (X2) and cattle manure mass (X3) gave the highest potassium content. The corresponding optimal area is defined by the coordinates: cattle manure mass varying from 28 to 30 g, residence time ranged between 150 and 230 min and combustion temperature of 600 °C with 8400 mg/Kg of potassium content. The optimal condition from overlap iso-curve response indicated the best combustion condition both for phophorus and potassium at combution temperature ranged from 600 to 700 °C, cattle manure mass varied between 18 and 26 g and residence time of 120 min for 2259 mg/Kg and 8072 mg/Kg respectively for phosphorus content and potassium content. The chemical composition of cattle manure ash produced at the coordinates 600 °C combustion temperature during 120 min for 22.5 g burning mass (chosen within the optimal area) revealed the values of phosphorous and potassium near to theoretical values. The toxic metals associated were less than the limit set, thus, this ash could be used as raw material for fertilizer production and then, contribute to the environment sustainability.