Occurrence state of fluoride in barite ore and the complexation leaching process

Area of Science:

• Mineral Processing
• Environmental Chemistry
• Hydrometallurgy

Background:

• Barite ore often contains fluoride impurities, mainly fluorite, hindering its commercial use due to high BaSO4 content requirements.
• Efficient removal of fluoride is crucial for improving barite quality and meeting industrial standards.

Purpose of the Study:

• To investigate the occurrence state of fluoride in barite ore.
• To develop and optimize a complexation leaching method for fluoride removal.
• To analyze the leaching kinetics and mechanisms.

Main Methods:

• Analysis of fluoride occurrence using various analytical techniques.
• Complexation leaching experiments with varying HCl and AlCl3 concentrations, temperature, time, and liquid-solid ratio.
• Orthogonal array method for optimizing leaching conditions.
• Leaching kinetics and thermodynamic analysis.

Main Results:

• Elemental fluorine in barite predominantly exists as fluorite.
• Optimized conditions (30 min, 90°C, 3 mol/L HCl, 0.4 mol/L AlCl3, 10:1 mL/g ratio) achieved a 93.11% fluorine leaching rate.
• Leaching kinetics followed solid membrane diffusion control at high temperatures and joint chemical reaction-diffusion control at low temperatures, with an apparent activation energy of 56.88 kJ/mol.

Conclusions:

• The developed complexation approach effectively leaches fluoride from barite ore.
• This method significantly improves barite product quality by increasing BaSO4 content.
• The process offers an environmentally friendly solution for fluoride removal in barite processing.