MANUFACTURING METHOD OF PHOSPHORIC ACID FERTILIZER, AND PHOSPHORIC ACID FERTILIZER

• Main Authors: TAKAHASHI KATSUNORI, KOBAYASHI SAKI
• Format: Patent
• Language: English; Japanese
• Published: 10.10.2019
• Subjects: CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; FERTILISERS; MANUFACTURE THEREOF; METALLURGY; METALLURGY OF IRON; PHOSPHATIC FERTILISERS; PRETREATMENT OF RAW MATERIALS; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; PRODUCTION AND REFINING OF METALS; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

To provide a phosphorus acid fertilizer containing phosphoric acid high in citrate solubility and silicic acid high in solubility using steel slag as a raw material.SOLUTION: A phosphorus acid fertilizer is manufactured through: a first process for reduction treating a phosphorus-containing steel slag generated in a steel-making refining process by using a reductant containing at least one selected from carbon, aluminum, and silicon, and reducing iron oxide in the steel slag to recover the same as a phosphorous-containing molten iron; a second process for dephosphorylation treating the phosphorus-containing molten iron obtained in the first process to recover resulting high phosphorus slag; a third process for heating the high phosphorus slag obtained in the second process to a temperature of 1500°C or higher to separate it into two liquid phases, and recovering ultra high phosphorus slag in an upper layer; and a fourth process for melting and mixing the ultra high phosphorus slag obtained in the third process to obtain the phosphorus acid fertilizer.SELECTED DRAWING: None 【課題】製鋼スラグを原料として、ク溶性が高いリン酸及び可溶性の高い珪酸を含有するリン酸質肥料を提供する。【解決手段】製鋼精錬プロセスにおいて発生したリン含有製鋼スラグを、炭素、アルミニウムおよびシリコンのうちから選んだ少なくとも１つを含む還元剤を用いて還元処理し、該製鋼スラグ中の鉄酸化物を還元しリン含有溶融鉄として回収する第一の工程と、前記第一の工程で得られたリン含有溶融鉄を脱リン処理し、得られた高リンスラグを回収する第二の工程と、前記第二の工程で得られた高リンスラグを、１５００℃以上の温度に加熱して二液相分離し、上層の超高リンスラグを回収する第三の工程と、前記第三の工程で得られた超高リンスラグに珪酸源を溶融混合してリン酸質肥料を得る第四の工程とを経て、リン酸質肥料を製造する。【選択図】なし