Phosphorus-Containing Raw Material Nitriding for Low-Energy Dephosphorization

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Solution Overview

Problem

Conventional methods for removing phosphorus from phosphorus-containing substances used in metal smelting and refining are energy-intensive, costly, and inefficient, often requiring high temperatures and causing equipment wear, and do not effectively address the issue of phosphorus absorption into valuable metals like iron and manganese.

Innovation Solution

A method involving heating phosphorus-containing substances to an unmolten state and reacting them with a nitrogen-containing gas to remove phosphorus as a nitride gas, utilizing a reducing agent to reduce metal oxides and control oxygen partial pressure, thereby facilitating efficient phosphorus removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional dephosphorization treatment is performed by oxidizing phosphorus with oxygen source to form P2O5 and transfer into slag, then phosphorus can be removed from molten pig iron, but iron is also oxidized and consumed, increasing production cost and reducing efficiency

Engineering Contradiction:
Improvephosphorus removal efficiencyVSAvoidiron oxidation loss
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The invention extracts phosphorus from the molten metal by forming a separate phosphorus-containing slag phase that is removed from the metal. By using CaO as a flux to form Ca3(PO4)2 in the slag, phosphorus is effectively separated from the iron melt, achieving selective removal without requiring oxidation of the iron itself.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces CaO as an intermediary substance that facilitates phosphorus removal. CaO reacts with phosphorus to form Ca3(PO4)2, which has low solubility in the metal and preferentially enters the slag phase. This intermediary mechanism allows phosphorus removal without direct oxidation of iron.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If high temperature treatment is used to remove phosphorus from phosphorus-containing substances, then phosphorus can be effectively removed, but energy consumption increases and equipment wear accelerates

Engineering Contradiction:
Improvephosphorus content reductionVSAvoidenergy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The invention changes the chemical parameters of the system by introducing CaO flux and controlling the oxidation state. By adjusting the chemical environment rather than relying solely on high temperature, the process achieves effective phosphorus removal at lower temperatures, reducing energy consumption and equipment wear while maintaining high phosphorus content reduction efficiency.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If phosphorus-containing substances are used as raw materials for metal smelting, then production cost decreases, but phosphorus content in the metal increases, requiring additional dephosphorization treatment

Engineering Contradiction:
Improveraw material costVSAvoidphosphorus concentration in metal
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The invention performs preliminary dephosphorization treatment on phosphorus-containing raw materials before they enter the main smelting process. By pre-treating the raw materials to reduce phosphorus content, the subsequent smelting process requires less additional dephosphorization effort, making the use of low-cost phosphorus-containing raw materials economically viable while maintaining metal quality.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method allows for the effective reduction of phosphorus content in metal smelting and refining processes, enabling the reuse of by-products, reducing auxiliary raw material usage, and promoting the recycling of phosphorus-containing substances.

Implementation Method 1

reacting with a nitrogen-containing gas so that phosphorus in the phosphorus-containing substance is removed through nitriding

Methodology Applied
Scientific EffectNitriding: Nitriding

Implementation Method 2

a reduction treatment is performed in which the phosphorus-containing substance is heated to an unmolten state temperature range so as to react with a reducing agent, thereby reducing at least a part of metal oxide in the phosphorus-containing substance

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 3

the phosphorus-containing substance is heated to an unmolten state temperature range

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3992145B1Method for removing phosphorus from phosphorus-containing substance, method for producing starting material for metal smelting or starting material for metal refining, and method for producing metal
Publication Date: 2025.07.02 JFE STEEL CORP
  • EP3992145B1 patent drawingFigure 1~2
  • EP3992145B1 patent drawingFigure 3~4
  • EP3992145B1 patent drawingFigure 5~6

AI summary

Proposed is a method for removing phosphorus from a phosphorus-containing substance, which is applicable on an industrial scale, so as to effectively decrease phosphorus contained in the phosphorus-containing substance, which is a solid oxide that is used as a main raw material or an auxiliary raw material for metal smelting or metal refining, and also proposed are a method for manufacturing a raw material for metal smelting or refining, and a method for manufacturing metal. In the method for removing phosphorus from a phosphorus-containing substance, the phosphorus-containing substance that is used as a raw material for metal smelting or refining is reacted with a nitrogen-containing gas so that phosphorus in the phosphorus-containing substance is removed through nitriding. Prior to a treatment of a nitriding removal of phosphorus from the phosphorus-containing substance, a treatment is performed in which the phosphorus-containing substance is heated to an unmolten state temperature range so as to react with a reducing agent, thereby reducing at least a part of metal oxide in the phosphorus-containing substance. Also provided are the raw material for metal smelting or refining and the method for manufacturing metal using the same.