Hideki Ono

Electrochemical Formation of Tb Alloys in Molten LiCl–KCl Eutectic Melts and Separation of Tb

The electrochemical formation of Tb-Ni alloys was investigated in a molten LiCl–KCl–TbCl3 (0.50 mol% added) at 723 K. Open-circuit potentiometry was conducted using a Ni electrode after electrodepositing Tb metal at 0.20 V (vs. Li+/Li) for 300 s. There were four potential plateaus at (a) 0.66 V, (b) 0.80 V, (c) 0.95 V and (d) 1.56 V, respectively. Alloy samples were prepared by potentiostatic electrolysis at 0.60 and 0.70 V at 723 K. The alloy phase was identified as only TbNi2. Anodic dissolution of Tb from the formed TbNi2 was conducted at 0.90, 1.20 and 1.60 V, respectively. In the sample obtained at 0.90 V for 3 h, the existence of TbNi3 was identified by the XRD. Phase of the sample obtained at 1.20 V for 3 h was TbNi5. The sample obtained at 1.60 V for 3 h was Ni. Alloy samples were prepared by potentiostatic electrolysis at 0.50–0.80 V for 1 h using Ni plate cathodes in a molten LiCl–KCl containing TbCl3 (0.50 mol%) and NdCl3 (0.50 mol%). The highest mass ratio of Tb/Nd in the alloy sample was 56 at 0.70 V.

Evaluation of Carbonisation Gas from Coal and Woody Biomass and Reduction Rate of Carbon Composite Pellets

Carbon composite iron oxide pellets using semichar or semicharcoal were proposed from the measured results of the carbonisation gas release behaviour. The carbonisation was done under a rising temperature condition until arriving at a maximum carbonisation temperature Tc,max to release some volatile matter (VM). The starting point of reduction of carbon composite pellets using semicharcoal produced at Tc,maxu2009=u2009823u2009K under the rising temperature condition was observed at the reduction temperature TRu2009=u2009833u2009K, only a little higher than Tc,max, which was the aimed phenomenon for semicharcoal composite pellets. As Tc,max increases, the emitted carbonisation gas volume increases, the residual VM decreases, and, as a whole, the total heat value of the carbonisation gas tends to increase monotonically. The effect of the particle size of the semicharcoal on the reduction rate was studied. When TR is higher than Tc,max, the reduction rate increases, as the particle size decreases. When TR is equal to Tc,max, there is no effect. With decreasing Tc,max, the activation energy Ea of semicharcoal decreases. The maximum carbonisation temperature Tc,max may be optimised for reactivity (1/Ea) of semicharcoal and the total carbonisation gas volume or the heat value.

Electrochemical separation of Dy from Nd magnet scraps in molten LiCl–KCl

We proposed a new separation and recovery process for RE metals from Nd magnet scraps using molten salt electrolysis. The present study focused on the electrochemical formation of RE–Ni (REu2009=u2009Dy, Nd, Pr) alloys in a molten LiCl–KCl system at 723u2005K. Cyclic voltammetry was conducted using a Ni electrode in molten LiCl–KCl–RECl3 systems at 723u2005K. In the negative scan for the DyCl3 added system, a large cathodic current was observed from 0.70u2005V (vs. Li+/Li) as a result of the formation of Dy–Ni alloys. In contrast, large cathodic currents as results of the formation of Nd–Ni and Pr–Ni alloys were observed from 0.60u2005V. On the basis of these results, an alloy sample was prepared by potentiostatic electrolysis at 0.65u2005V for 1u2005h using a Ni plate cathode in a molten LiCl–KCl–DyCl3–NdCl3–PrCl3 system. The mass ratio of Dy/Nd+Pr in the alloy sample was found to be 50 by ICP-AES. Finally, a Dy permeation experiment was conducted with a new electrolytic cell.

Examples of Steelmaking Thermochemistry

In this chapter, we shall show several examples of the application of thermochemistry to steelmaking. This includes fundamentals on removal of impurities from molten steel, silicon deoxidation, calcium treatment, and reaction equilibrium with solid oxides. Through these, we can learn the practical use of thermodynamic data to the refining of plain and highly alloyed steels. Moreover, the method to control the chemical potential with gas mixture is described, that is useful to study the reaction kinetics or equilibria between gaseous and condensed phases.

Electrochemical Formation of Tb Alloys in LiCl-KCl Eutectic Melts

The electrochemical formation of Tb-Ni alloys was investigated in a molten LiCl-KCl-TbCl3(0.50 mol% added) at 723 K. Open-circuit potentiometry was conducted using a Ni electrode after electrodepositing Tb metal at 0.20 V (vs. Li+ / Li) for 300 s. There were four potential plateaus at (a) 0.66 V, (b) 0.80 V, (c) 0.95 V and (d) 1.56 V, respectively. Alloy samples were prepared by potentiostatic electrolysis at 0.60 V and 0.70 V at 723 K. The alloy phase was identified as only TbNi2. Anodic dissolution of Tb from the formed TbNi2 was conducted at 0.90 V, 1.20 V and 1.60 V, respectively. In the sample obtained at 0.90 V for 3 h, the existence of TbNi3 was identified by the XRD. Phase of the sample obtained at 1.20 V for 3 h was TbNi5. The sample obtained at 1.60 V for 3 h was Ni.