Desulfurization of High-Sulfur HIsarna Hot Metal

The HIsarna process is one of the emerging low-CO₂ ironmaking processes that could help the steel industry in achieving their carbon footprint goals. HIsarna hot metal contains 3–4 times more sulfur than hot metal from blast furnaces (BFs). Therefore, a literature study, a thermodynamic analysis, and plant data analysis from Tata...

Optimal hot metal desulphurisation slag considering iron loss and sulphur removal capacity part I: fundamentals

In hot metal desulphurisation (HMD) the slag will hold the removed sulphur. However, the iron that is lost when the slag is skimmed off, accounts for the highest costs of the HMD process. These iron losses are lower when the slag has a lower viscosity, which can be achieved by changing the slag composition. A lower slag basicity decreases the...

Optimal hot metal desulphurisation slag considering iron loss and sulphur removal capacity part II: evaluation

The optimal hot metal desulphurisation (HMD) slag is defined as a slag with a sufficient sulphur removal capacity and a low apparent viscosity (η_slag) which leads to low iron losses. In part I of this study, the fundamentals behind the optimal slag were discussed. In this part these fundamentals are explored by a Monte Carlo...

Lowering iron losses during slag removal in hot metal desulphurisation without using fluoride

To lower the iron losses of the hot metal desulphurisation (HMD) process, slag modifiers can be added to the slag. Slag modifiers decrease the apparent viscosity of the HMD slag. Most common slag modifiers in industry contain fluoride as a fluidiser. However, fluoride leads to a higher magnesium consumption and has health, safety and...

Effect of graphite on hot metal desulphurisation

During the magnesium-lime co-injection process for hot metal desulphurisation, graphite can precipitate as a result of carbon oversaturation. The formed graphite is known to form a layer between the slag and the hot metal. This potentially blocks the sulphides, that are formed during the desulphurisation process, to reach the slag phase thus...

The hampering effect of precipitated carbon on hot metal desulfurization with magnesium

Carbon may precipitate during the hot metal desulfurization (HMD) process as a result of carbon oversaturation because of temperature decrease. The precipitated carbon flakes form a layer between hot metal and slag. It is postulated that this carbon layer hampers desulfurization with magnesium by preventing MgS particles from reaching the...

Effect of KAlF4 on the efficiency of hot metal desulphurisation with magnesium

At the hot metal desulphurisation (HMD) stations of Tata Steel’s BOS plant in Port Talbot (UK), KAlF4 is injected together with magnesium in order to increase the fluidity of the slag and thus to decrease the iron loss. Although KAlF4 is successfully contributing to a lower iron loss during HMD, it also has a negative effect on the...

Desulphurisation of Hisarna hot metal: a comparisson study based on plant data

HIsarna is a smelting reduction ironmaking process that is currently in the pilot plant development phase. HIsarna produces hot metal with higher sulphur, lower phosphorus and manganese, almost no silicon and titanium and a lower temperature compared to the blast furnace. Because of that, desulphurisation of the HIsarna hot metal is one of the...

Sulphur removal in ironmaking and oxygen steelmaking

Sulphur removal in the ironmaking and oxygen steelmaking process is reviewed. A sulphur balance is made for the steelmaking process of Tata Steel IJmuiden, the Netherlands. There are four stages where sulphur can be removed: in the blast furnace (BF), during hot metal (HM) pretreatment, in the converter and during the secondary metallurgy (SM...