| 摘要 |
Provided are a phosphate fertilizer that has a high ratio of citric acid-soluble phosphate and can contribute to phosphorus resource saving and energy saving in fertilizer production, and a production method for a phosphate fertilizer. The phosphate fertilizer is obtained by firing a mixed raw material containing: sewage sludge and/or a sewage sludge-derived material; and a calcium source. In addition, the phosphate fertilizer has a content of CaO of 35 to 60 mass%, a content of SiO 2 of 5 to 35 mass%, a content of P 2 O 5 of 5 to 35 mass%, and a content of components except for CaO, SiO 2 , and P 2 O 5 of 30 mass% or less. Further, the production method for a phosphate fertilizer includes: a mixing step of mixing sewage sludge and/or a sewage sludge-derived material with a calcium source and optionally with a silica source to obtain a mixed raw material; and a firing step of firing the mixed raw material by using a firing furnace at 1,150 to 1, 350°C to obtain the phosphate fertilizer as a fired product. |
