scholarly journals Evolution of Inclusions in Steelmaking Process of Rare Earth Steels Containing Arsenic with Alumina Crucibles

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 275 ◽  
Author(s):  
Hongpo Wang ◽  
Peng Yu ◽  
Silu Jiang ◽  
Bin Bai ◽  
Lifeng Sun ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Molten Steel ◽  
Arsenic Removal ◽  
Holding Time ◽  
Arsenic Content ◽  
Severe Reaction ◽  
Steelmaking Process ◽  
Alumina Crucible

In order to determine strategies for removing arsenic from rare earth arsenic-containing steels, the evolution of inclusions in the whole steelmaking process with alumina crucibles was investigated. It has been proven that adding lanthanum has a significant effect on both the existing state and content of arsenic in steel. The content of arsenic steeply decreased after adding 0.148% lanthanum by generating La–S–As inclusions. The addition of 0.054% lanthanum did not dramatically affect the content of arsenic. Both 0.148% and 0.054% additions of lanthanum modified the existing Si–Mn–Al–O inclusions, making them first change to La-containing inclusions, and then change back to Si–Mn–Al–O inclusions. During this process, the compositions of inclusions changed from (SiO2–MnO)-rich to Al2O3-rich ones, owing to the reactions between lanthanum and alumina crucibles. The addition of 0.148% lanthanum resulted in a relatively severe reaction with the alumina crucible. This led to the decomposition of a part of the existing La–S–As inclusions and a slight increase in the arsenic content. Therefore, it is noted that choosing an appropriate holding time after adding rare earth elements to molten steel has a significant effect on the arsenic removal and saving the consumption of rare earth elements.

scholarly journals Effect of Heterogeneous Nucleation on Removal of Arsenic from Molten Steel by Rare Earth Addition

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 664
Author(s):  
Hongpo Wang ◽  
Peng Yu ◽  
Silu Jiang ◽  
Yu Wang
Keyword(s):  
Rare Earth ◽  
Molten Steel ◽  
Heterogeneous Nucleation ◽  
Laboratory Experiments ◽  
Arsenic Removal ◽  
Rare Earth Addition ◽  
Residual Elements ◽  
Initial Content ◽  
Removal Of Arsenic ◽  
High Initial Content

Cleanliness control is an eternal theme to improve the properties of steel products. With the increasing recycling rates of scrap steel, the removal and stabilization of residual elements have become a vital issue for improving the performance of steel products. Thermodynamic and mismatch calculations plus laboratory experiments were carried out to study the heterogeneous nucleation phenomena of inclusions when lanthanum was employed to remove arsenic from molten steel and stabilize arsenic in solid steel. The effect of heterogeneous nucleation on the mechanism of arsenic removal was discussed. A series of heterogeneous nucleation phenomena of inclusions in the La-O-S-As system were discovered, and the heterogeneous nucleation among the inclusions turned out to be selective. As the vital product of arsenic removal, La-S-As is most likely to generate with LaS as heterogeneous nucleation cores, and its possible chemical formula turned out to be 3LaS⸱LaAs. Sulfur plays an essential role in removing arsenic from molten steel by adding lanthanum. It needs to control the initial sulfur content in an appropriate range, because the high initial content causes too much loss of rare earth, and the low initial content cannot produce LaS and La-S-As.

Flame spectra of the rare-earth elements*

1962 ◽  
Vol 18 (4) ◽  
pp. 1127-1153
Author(s):  
V FASSEL ◽  
R CURRY ◽  
R KNISELEY
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
The Rare Earth

ESTIMATION OF THE ABUNDANCE AND DISTRIBUTION OF RARE EARTH ELEMENTS IN SOIL AROUND KADUNA REFINING AND PETROCHEMICAL COMPANY USING NUCLEAR TECHNIQUE

2020 ◽  
Vol 4 (2) ◽  
pp. 599-604
Author(s):  
Michael A. Onoja ◽  
P. H. Bukar ◽  
C. U. Omeje ◽  
A. M. Adamu
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Nuclear Technique ◽  
Flood Plains ◽  
Economic Exploitation ◽  
Rare Elements ◽  
Petrochemical Company ◽  
The Moment ◽  
Abundance And Distribution ◽  
Natural Pattern

Instrumental neutron activation analysis (INAA) technique was used to investigate the abundance and distribution of rare earth elements (REE) in soil around Kaduna Refinery. The aim of the study is to assess the rare elements potential of Nigeria for economic exploitation. Five REEs (La, Dy, Eu, Yb, and Lu) were detected in varying concentrations ranging from a minimum of 0.6 µg/g (Lu) to a maximum of 249.0 µg/g (La). The elements existed with trends consistent with the natural pattern of REEs in soil, showing significant Eu and Dy anomalies which characterize upper plains and flood plains. The levels of REEs in soil in the study area were generally slightly above background levels, with minimal (La, Dy, and Eu), moderate (Yb), and significant (Lu) enrichments and trending: Lu ˃Yb ˃ Eu ˃ Dy ˃ La. The abundance of the REEs investigated cannot establish a potential of Nigeria for economic exploitation of the mineral, hence, rare earth project in the study area is not viable at the moment.

Sc, Y, La-Lu Rare Earth Elements

1986 ◽  
Author(s):  
Ingeborg Hinz ◽  
Peter Kuhn ◽  
Ursula Vetter ◽  
Eberhard Warkentin
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements
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