Phosphorus Gasification from Sewage Sludge during Carbothermic Reduction

摘要

The gasification process of phosphorus from municipal sewage sludge during carbothermic reduction process was investigated using a quadrupole mass spectrometer gas analysis and thermo-gravimetric analysis. Two types of sludge, with high and low Fe_2O_3 content, were used to evaluate the possible effect of Fe_2O_3 on the gasification behavior of phosphorus from sewage sludge during incineration processes. The gas species vaporized during the carbothermic reaction were measured by the quadrupole mass spectrometer with comparison to the ion currents for the respective molecular gas species. From the gas analysis, it was observed that PO and PO_2 gas species were dominantly vaporized around 1 073 K. Metallic phase phosphorus gas of P_2 vaporized in the 1 273-1 700 K temperature range. The evolution of another metallic phase phosphorus gas of P_4 was found to be negligibly small. Fe_2O_3 in the sludge has an important role in the phosphorus emission from the sludge during carbothermic reduction reaction, since metallic phosphorous gases react with the reduced iron and form Fe-P alloy.