Prof. Peng, Syd S.
West Virginia Uni., USA



Prof. Kitamura S.
Tohoku Uni., Japan 

Extract of P and Mn from Steelmaking Slag

Steelmaking slag contains considerable amount of Mn and P, and in Japan, for resource security, the recycling them is an important issue. Since Mn is an alloy added to enhance the steel quality, while P is a harmful impurity in the steel product, they need to be separated for recycling. For this purpose, two principles are considerable. One is to use the different property of each mineralogical phase in slag, and the other is to use the different thermodynamic property of each element in slag.

In steelmaking slag, P is enriched in the dicalcium silicate phase (C2S) and form the solid solution with tricalcium phosphate (C3P). As the solubility of this phase to the aqueous solution is widely different from that of other phases in slag, we have proposed the leaching treatment to separate C2S-C3P phase from slag. The dissolution ratio of P from the synthesized slag has reached about 91%. After the separation of residue, pH of the leachate increased to precipitate phosphate. 80% or more of the P in the leachate was precipitated and the phosphate content of the precipitate was about 25% after calcination.  

The reduction of steelmaking slag was conducted by many researchers to recover Fe and P. However, by the simple reduction, Mn was also reduced and the product of C saturated iron with high content of Mn and P is hard to reuse. In thermodynamics, MnO is basic oxide but P2O5 is acid oxide, and the temperature dependences of the equilibrium constants of their reduction reactions are widely different. We have already found the possibility of separating Mn and P from steelmaking slag by selectively reducing P2O5 and FeO while suppressing the reduction of MnO. By the fundamental study, it was found that a decrease in slag basicity suppressed the reduction rate of Mn while enhancing that of P. To analyze this result, the activity coefficients of both Mn and P in the Fe-P-Mn-C(sat.) alloy (2.5–15.2 mass% of P and 2.9–12.8 mass% of Mn), which is obtained by the reduction of steelmaking slag were investigated. A comparison with the results obtained by reduction experiment indicated that the activity coefficients of P and Mn obtained in the study were applicable.

yeh Prof. Yeh, Jien-Wei
Tsing Hua Uni., Taiwan 

tasi Dr. Hwan-Tang Tsai 
Principal Scientist
Global R&D Center

ArcelorMittal USA


Sustainable Development of Automotive Steels

Production of motor vehicle in China has grown from 5% of the world production in 2001 to 30% in 2016.  ArcelorMittal produced over 17 million tons of steel for the automotive industry worldwide.  ArcelorMittal Global R&D with 1,500 full time researchers focused on the innovation of automotive steel development and its applications.  Since June 2014, ArcelorMittal has successfully launched a joint venture (Valin ArcelorMittal Automotive Co.) in Hunan, China with a capacity of 1.5 million tons per annual.  A clean steel platform has been established which helps to stabilize the production of high-quality automotive steel.  The origin of sliver was identified as alumina, spinel and calcium aluminates from the deoxidation and re-oxidation products, mold powder entrainment, argon bubbles and other mechanically induced defects.  Systematic analyses of the sliver defects and countermeasures taken at steelmaking and continuous casting have greatly improved the steel surface quality downstream.  Sustainable growth of steel industry in the future is built on low carbon, clean air and a circular economy.  For the sustainable development of automotive steels, ArcelorMittal has initiated the S-in motion which provided solutions to reduce car weight by using hot stamped parts and laser welded blanks at the same cost with better safety.  The lightest BiW, hang-on parts and chassis have resulted in a weight reduction of 16% in the C-class vehicle.  Saving of 73 kg for the whole vehicle induces a reduction of 6.23-gram CO2/km during its life cycle.

Tsuji Pic 003

Prof. Takeshi Tsuji
Department of Earth
Resources Engineering
Kyushu University,Japan
Prof. Takeshi Tsuji is the director of the Department of Earth Resources Engineering at the Kyushu University.  He is an expert on exploration geophysics and has worked on a wide spectrum of different geophysical topics, including seismic wave propagation, CO2 geological storage, rock physics, hydrothermal fluid flow, 3D seismic, ambient noise surface wave tomography, and gas hydrate, to name a few. His broad backgrounds and interests give him an integrated view on many important research topics on exploration geophysics.  We look forward to hearing his presentation during this meeting.