Sulphur removal in ironmaking and oxygen steelmaking

Abstract

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) treatment. For sulphur removal a low oxygen activity and a basic slag are required. In the BF typically 90% of the sulphur is removed; still, the HM contains about 0.03% of sulphur. Different HM desulphurisation processes are used worldwide. With co-injection or the Kanbara reactor, sulphur concentrations below 0.001% are reached. Basic slag helps desulphurisation in the converter. However, sulphur increase is not uncommon in the converter due to high oxygen activity and sulphur input via scrap and additions. For low sulphur concentrations SM desulphurisation, with a decreased oxygen activity and a basic slag, is always required.

A Review of Modeling Hot Metal Desulfurization

“…In lance injection, the desulfurization reagent is delivered pneumatically through a submerged lance . A distinction can be made between mono‐ and co‐injection of reagents . Although it is more common to use an inert carrier gas (e.g.…”

“…nitrogen or argon), hydrocarbons such as natural gas or propane have also been used on an industrial scale. Initially, lance injection practice used to take place in torpedo cars, but nowadays it is more common to use ladles, which enable longer reagent residence times and easier removal of the slag . The lance injection practice is common in Europe, America, and India .…”

“…The Rheinstahl stirrer features a paddle‐type stirrer, which is submerged only partially in the metal bath to provide turbulent mixing of desulfurization fluxes in the upper part of the metal bath . The Kanbara reactor (KR) process was developed by Nippon Steel in 1965 and represents a hot metal desulfurization practice, which makes use of a rotating submerged lance equipped with four rotor blades . The reagent is usually added on top of the metal bath, but the reagent can also be injected through the rotating lance with a carrier gas .…”

“…The KR process excels at achieving low sulfur contents consistently, but is characterized by greater metal losses and higher refractory wear . The KR process is widely used nowadays in Asia, especially in Japan …”

Thermal Isolation of a Clean Alloy from Waste Slag and Polymeric Residue of Electronic Waste

“…It seemed that the P impurity was distributed throughout the iron matrix, mainly in the white dots. The removal of this P is well-established in the steelmaking industry using post-treatment [37,38]. Neither the WDS map nor the point analyses confirmed traces of Br and S in the recycled metal, indicating that all Br and S were expelled in the gaseous form, which was in accordance with the GC/MS and FTIR analyses.…”