Untersuchung des Verhaltens von Phosphor, Schwefel und Kupfer während des Wasserstoffplasma-Schmelzreduktionsprozesses

Translated title of the contribution: Investigation of the behavior of phosphorus, sulfur and copper during the hydrogen plasma smelting reduction process

Bernhard Adami

Research output: ThesisMaster's Thesis

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Abstract

The global steel production is responsible for approximately 7% of the total CO2 emissions. In order to counteract climate change, a reduction of CO2 emissions must also be achieved in this industry sector. An alternative to conventional steel production methods is the hydrogen plasma smelting reduction process. Instead of fossil fuels, hydrogen in plasma form is used as a reducing agent, which can be produced environmentally friendly. Argon acts as a stabilizer for the plasma. This process has been in development at the Chair of Ferrous Metallurgy at the University of Leoben since 1992. To understand the behavior of phosphorus, sulfur and copper during this process, reduction experiments were conducted with different parameters on a laboratory reactor. Thereby, the slag basicities ranged from B4 = 0.23 to 2.0, the crucibles were made of steel and graphite and the hydrogen content in the plasma gas was either 20 vol.% or 40 vol.%. An Egyptian iron ore enriched with ferrophosphorus and copper sulfate was used as input material. After the reduction process, the chemical compositions of the obtained metal, the slag and two dust fractions were determined. The statistical analysis shows that with increasing calcium oxide content in the slag, the phosphorus concentration in the metal decreases due to the rising formation of tricalcium phosphate. Stronger reducing conditions lead to more phosphorus evaporation, as the thermal stability of tricalcium phosphate otherwise counteracts this phenomenon. Higher hydrogen content in the plasma gas and increasing slag basicities lead to better metal desulfurization. This element leaves the melt during the reduction phase both as hydrogen sulfide and in the form of evaporated metal sulfides. It is important to mention the formation of copper sulfide, which only occurs due to the strong thermodynamic imbalance in the melt. This can also explain the behavior of copper. As the slag basicity increases, its concentration in the metal decreases. Stronger reducing conditions have the opposite effect.
Translated title of the contributionInvestigation of the behavior of phosphorus, sulfur and copper during the hydrogen plasma smelting reduction process
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Schenk, Johannes, Supervisor (internal)
  • Ernst, Daniel, Co-Supervisor (internal)
Award date30 Jun 2023
DOIs
Publication statusPublished - 2023

Bibliographical note

no embargo

Keywords

  • hydrogen
  • plasma
  • iron making
  • phosphorus
  • sulfur
  • copper

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