Method for producing ferric phosphate by dephosphorized converter slag

Abstract

The invention discloses a method for producing ferric phosphate by dephosphorized converter slag and belongs to the field of metallic materials, particularly relates to a process of producing ferric phosphate by multiple steps of extracting iron and phosphorus by reduction reaction, dephosphorizing to produce slag, dissolving phosphorus-rich slag and purifying and finally precipitating, washing and drying. The method includes subjecting dephosphorized converter slag to basicity regulation and carbon-burdened reduction to obtain high-phosphorus molten iron (%P=1-5%), jetting Na2Co3 into the high-phosphorus molten iron to dephosphorize and produce slag to obtain qualified molten iron (%P<0.15%) and phosphorus-rich slag (%P2O5>20%), returning the qualified molten iron to an iron producing process, while dissolving the phosphorus-rich slag to obtain solution containing rich Na<+>, Fe<3+> and PO4<3->, purifying the solution and then regulating the pH value to obtain ferric phosphate, precipitating, washing and drying the ferric phosphate to obtain the ferric phosphate crystal product. The method has the advantages of low energy consumption, high utilization rate of resources, high additional value of products, low production cost, remarkable economic benefit and the like, and solves the problems about utilization of the dephosphorized converter slag and periodic enrichment of phosphorus for iron and steel enterprises.

Description

technical field [0001] The invention belongs to the field of comprehensive recovery and utilization of dephosphorization slag in iron and steel metallurgy, and specifically relates to a method for obtaining qualified molten iron and phosphorus-rich slag to produce ferric phosphate through recycling and processing of dephosphorization slag. technical background [0002] The dual-connection method of the converter has the advantages of less slag, fast pace, and good quality of molten steel. It can adapt to the current situation of higher and higher requirements for steel quality and has broad prospects. However, the recycling of dephosphorization slag has always troubled iron and steel enterprises. Because it contains a large amount of CaO, a large part of the steel slag is returned to sintering as a sintering material, but the long-term return of dephosphorization slag to sintering will make the enrichment of phosphorus more and more difficult. The higher the dephosphorizatio...

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Problems solved by technology

Phosphorus in dephosphorization slag is mainly in the form of 2CaO·P 2 o 5 and 3CaO·P 2 o 5 The form exists in the calcium silicate phase, and it is difficult to dissolve in the acid-base environment, so it is impossible to directly use the dephosphorization slag to produce iron phosphate

Patent Nos. CN101844756 B and CN 101898757 B introduced the method of reducing steel slag and obtaining Fe-P alloy through magnetic separation, and Fe-P alloy was roasted in air to obtain P and Fe oxides to prepare LiFePO4 precursor. The magnetic separation of slag and metal is costly and incomplete, and the impurity content of the obtained alloy and P and Fe oxides are not disclosed, and the index detection and analysis of the prepared LiFePO4 material is not carried out

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