New Insights on Sodium Oleate Adsorption on Quartz for Iron Direct Flotation under Weak-Acidic Condition

2021 ◽  
Vol 58 (3) ◽  
pp. 237-242
Author(s):  
Ying Hou ◽  
Ahmed Sobhy
Keyword(s):  
Molecular Dynamics ◽  
Fourier Transform ◽  
Sodium Oleate ◽  
Dynamics Simulation ◽  
Chemical Calculation ◽  
Calculation Results ◽  
Acidic Conditions ◽  
Verification Test ◽  
Materials Studio ◽  
Weak Acidic Condition

Abstract To study the sodium oleate (NaOL) adsorption on quartz and its effect on flotation under weak-acidic conditions, the adsorption characteristics of NaOL on the surface of quartz were determined at pH = 6.5 by Fourier transform infrared spectroscopy (FTIR). The solution chemical calculation results show that NaOL exists as oleic acid (HOL) under weakly acidic conditions. The existence form and charge distribution of quartz and HOL were analyzed by Molecular Dynamics Simulation (MDS) using Materials Studio (MS) software, and the results showed that HOL is prone to the (101) and (100) surfaces of quartz under weak-acidic conditions by hydrogen bonding. The flotation verification test with NaOL as a collector was also performed under weak-acidic conditions. The flotation test led to a partial flotation of quartz into the froth products, reducing the grade of hematite direct flotation concentrate, which is consistent with industrial production.

Sputtering of Graphite by Hydrogen Isotopes in the Fusion Environment: A Molecular Dynamics Simulation Study

2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Qiang Zhao ◽  
Yang Li ◽  
Zheng Zhang ◽  
Xiaoping Ouyang
Keyword(s):  
Molecular Dynamics ◽  
Incident Energy ◽  
Large Scale ◽  
Incident Angle ◽  
Hydrogen Isotopes ◽  
Dynamics Simulation ◽  
Calculation Results ◽  
Sputtering Yield ◽  
Increasing Temperature ◽  
Sputtering Yields

The sputtering of graphite due to the bombardment of hydrogen isotopes is crucial to successfully using graphite in the fusion environment. In this work, we use molecular dynamics to simulate the sputtering using the large-scale atomic/molecular massively parallel simulator (lammps). The calculation results show that the peak values of the sputtering yield are between 25 eV and 50 eV. When the incident energy is greater than the energy corresponding to the peak value, a lower carbon sputtering yield is obtained. The temperature that is most likely to sputter is approximately 800 K for hydrogen, deuterium, and tritium. Below the 800 K, the sputtering yields increase with temperature. By contrast, above the 800 K, the yields decrease with increasing temperature. Under the same temperature and incident energy, the sputtering rate of tritium is greater than that of deuterium, which in turn is greater than that of hydrogen. When the incident energy is 25 eV, the sputtering yield at 300 K increases below an incident angle at 30 deg and remains steady after that.

Molecular Dynamics Simulation of the Sputtering of Graphite due to Bombardment With Deuterium and Tritium in Fusion Environment

2017 ◽  
Author(s):  
Qiang Zhao ◽  
Yang Li ◽  
Zheng Zhang ◽  
Xiaoping Ouyang
Keyword(s):  
Molecular Dynamics ◽  
Temperature Increase ◽  
Incident Energy ◽  
Dynamics Simulation ◽  
Critical Issues ◽  
Calculation Results ◽  
Hydrogen Deuterium ◽  
Sputtering Yield ◽  
Dynamics Method ◽  
Lower Carbon

The sputtering of graphite due to the bombardment of hydrogen isotopes is one of the critical issues in successfully using graphite in the fusion environment. In this work, we use molecular dynamics method to simulate the sputtering by using the LAMMPS. Calculation results show that the peak values of the sputtering yield are located between 25 eV to 50 eV. After the energy of 25 eV, the higher incident energy cause the lower carbon sputtering yield. The temperature which is most likely to sputter is about 800 K for hydrogen, deuterium and tritium. Before the 800 K, the sputtering rates increase when the temperature increase. After the 800 K, they decrease with the temperature increase. Under the same temperature and energy, the sputtering rate of tritium is bigger than that of deuterium, the sputtering rate of deuterium is bigger than that of hydrogen.

Molecular Dynamics Simulation on Crack Propagation for Magnesium

2009 ◽  
Vol 417-418 ◽  
pp. 21-24
Author(s):  
Shu Sheng Xu ◽  
Xiang Guo Zeng ◽  
Hua Yan Chen
Keyword(s):  
Molecular Dynamics ◽  
Crack Propagation ◽  
Crack Tip ◽  
Pure Magnesium ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
External Loading ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Calculation Results

The crack propagation for pure Magnesium at an atomic scale level under external loading was carried out by using a molecular dynamics method. In this study, the Modified Embedded Atom Method (MEAM) was used to characterize the interactions of atoms and the Newtonian equations were solved by Velocity-Verlet algorithm. The crack propagation and failure processes were observed around the crack tip. The calculation results reveal that vacancies were formed near the crack tip during the failure processes for pure Magnesium, and the coalescence between crack tip and vacancies induced the crack growth with the increase in loading.

Sign in / Sign up

Export Citation Format

Share Document