RAW MATERIAL FOR SILICATE PHOSPHATE FERTILIZER AND METHOD FOR PRODUCTION THEREOF

A raw material for a silicate phosphate fertilizer comprising a slag recovered in a pre−treatment process for a blast furnace hot−metal which contains silicates as oxides of silicon in the hot−metal and phosphates as oxides of phosphorus and contains acid−soluble silicic acid in an amount of 10 mass % or more; and a method for producing the raw material which comprises adding a CaO source and an oxygen source to the hot−metal in the pre−treatment process for a blast furnace hot−metal to effect the oxidation of silicon and the dephosphorization of the hot−metal, and recovering a slag containing silicates and phosphates formed by the above reactions, followed by solidification, to thereby produce a slag containing acid−soluble silicic acid in an amount of 10 mass % or more and also phosphates. The raw material has excellent properties as a fertilizer, since it exhibits excellent characteristics of dissolution of silicates and improved absorption of silicates by a plant, due to the effect of co−existing phosphates, and also acts as a phosphate fertilizer, and it can be produced at a markedly reduced cost since the slag recovered in a pre−treatment process for a hot−metal can be used as it is. A raw material for a silicate phosphate fertilizer comprising a slag recovered in a pre-treatment process for a blast furnace hot-metal which contains silicates as oxides of silicon in the hot-metal and phosphates as oxides of phosphorus and contains acid-soluble silicic acid in an amount of 10 mass % or more and a method for producing the raw material which comprises adding a CaO source and an oxygen source to the hot-metal in the pre-treatment process for a blast furnace hot-metal to effect the oxidation of silicon and the dephosphorization of the hot-metal, and recovering a slag containing silicates and phosphates formed by the above reactions, followed by solidification, to thereby produce a slag containing acid-soluble silicic acid in an amount of 10 mass % or more and also phosphates. The raw material has excellent properties as a fertilizer, since it exhibits excellent characteristics of dissolution of silicates and improved absorption of silicates by a plant, due to the effect of co-existing phosphates, and also acts as a phosphate fertilizer, and it can be produced at a markedly reduced cost since the slag recovered in a pre-treatment process for a hot-metal can be used as it is. La présente invention concerne un fertilisant de phosphate de silicate comprenant u