Application Examples

Equilibrium and Kinetic Simulations of the Basic Oxygen Furnace Process

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Relevant Topics

  • Basic oxygen furnace (BOF)
  • Steelmaking
  • Reaction kinetics simulated using the Effective Equilibrium Reaction Zone model (EERZ)
  • Removing phosphorus (P) from steel
  • Predicting and optimizing costs of raw materials
  • Predicting and optimizing costs of recycling
  • Process Metallurgy Module

Two in-depth Examples Related to Steelmaking in a Basic Oxygen Furnace

This page includes two examples related to steelmaking in a Basic Oxygen Furnace (BOF). The first shows how you can use equilibrium calculations set up in the Process Metallurgy Module to gain a general understanding of your BOF process and help you determine optimal operation conditions and predict and optimize costs of raw materials and recycling.

The second example gives detailed instructions on how to simulate the kinetics of the BOF process using the kinetic process simulation released in Thermo-Calc 2020b.

Both examples include calculation files, which can be accessed directly from your software and run if you have a license for Thermo-Calc 2021b or newer and the relevant databases.

About a Basic Oxygen Furnace

A basic oxygen furnace (BOF) is a vessel used to convert hot metal into steel. The process is known as the basic oxygen furnace process, basic oxygen steelmaking, or the oxygen converter process. During the process, oxygen is blown into a BOF converter containing liquid hot metal containing high carbon content. The oxygen combines with the dissolved carbon to form CO, which then escapes as gas. Thus, the hot metal is transformed into liquid steel with a low carbon content.

About the Equilibrium Example

The BOF process can be used to remove other impurities in addition to carbon. Two elements that are very important in steelmaking and steel refining are sulfur (S) and phosphorus (P). Both elements are usually undesirable and must be removed from the liquid steel. This is generally done by transferring them to a CaO-rich slag phase. In this example, we show how the Process Metallurgy Module in Thermo-Calc can be used to investigate suitable conditions to remove P from liquid steel using a BOF. In a later example, the Module is used to investigate desulphurization in a ladle furnace.

Watch the Video

This example includes a video, which shows you how to set up the equilibrium basic oxygen furnace simulation in the Process Metallurgy Module.

metal_composition_slag_and_no_slag

Two plots from the example showing the change of the chemical composition of the liquid metal as a function of added oxygen. In the left plot, no slag formers are added. In the right plot, 3t of CaO rich slag formers are added, leading to a reduction in P content during the end of the blow, as shown by the green line.

Calculate the Total Cost of the Converter Process

The Process Metallurgy Module also allows you to calculate an optimum combination of amount of oxygen and amount of slag required to remove both C and P from the liquid steel for a given hot metal and slag composition. In the equilibrium example, about 5500 Nm3 of oxygen needs to be blown and about 2.7 t of high CaO slag former must be added.

Such a calculation not only predicts the amount of raw materials required, but also the amount of waste produced and the yield of the process. If the cost of the raw materials and the cost of recycling the produced slag is known, then this allows you to calculate and optimize the total cost of the converter process.

Carbon-and-phosporous-content-in-liquid-metal-and-total-amount-of-oxide-phases-and-oxygen-content

Carbon and Phosphorous content in liquid metal (left) and total amount of oxide phases and oxygen content in the liquid metal (right) as a function of oxygen and slag phase added to the system. The optimal combination is shown as a black dot.

How to Run the Equilibrium Calculation

To run this example, open Thermo-Calc and navigate to the Help Menu → Example Files… → Process Metallurgy. This example includes three calculation files:

  • PMET_01a_Basic_Oxygen_Furnace: works with the free Educational Package and the OXDEMO database.
  • PMET_01b_Basic_Oxygen_Furnace: can be run with the OXDEMO database but requires a full license for Thermo-Calc 2021b or newer.
  • PMET_01c_Basic_Oxygen_Furnace: requires a full license for Thermo-Calc 2021b or newer, the Metal Oxide Solutions Database TCOX11 or newer, and a license for the Process Metallurgy Module.

The example also includes a PDF with in-depth explanations of all the calculations and interpretation of the results.

Read the Equilibrium Example

About the Kinetic Example

This example simulates the kinetics of the BOF process. Metallurgical processes such as the BOF process rarely reach equilibrium. Therefore, a model description must include kinetics if meaningful results are to be obtained. In recent years, a simple but powerful model termed the Effective Equilibrium Reaction Zone (EERZ) model has been developed and widely applied to simulate various metallurgical processes. The model was introduced into Thermo-Calc’s Process Metallurgy Module beginning with the 2020b release.

This example shows you how to set up a kinetic simulation of the BOF process in the Process Metallurgy Module and includes a description of the EERZ model.

How to Run the Kinetic Simulation

To run this example, open Thermo-Calc and navigate to the Help Menu → Example Files… → Process Metallurgy. This example includes three calculation files:

  • PMET_04a_Basic_Oxygen_Furnace_Kinetics: works with the free Educational Package and the OXDEMO database.
  • PMET_04b_Basic_Oxygen_Furnace_Kinetics: can be run with the OXDEMO database but requires a full license for Thermo-Calc 2021b or newer.
  • PMET_04c_Basic_Oxygen_Furnace_Kinetics: requires a full license for Thermo-Calc 2021b or newer and a license for the Metal Oxide Solutions Database TCOX11 or newer.

The example also includes a PDF with in-depth explanations of all the calculations and interpretation of the results.

Read the Kinetic Example

Additional Examples Using the Process Metallurgy Module

The Process Metallurgy Module can be used to investigate the entire steelmaking process, from scrap to fully refined steel. The examples below investigate other steps in the steelmaking process:

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