Method To Determine MgO and MgOHCl in Chloride Molten Salts

Area of Science:

• Materials Science
• Chemical Engineering
• Renewable Energy

Background:

• Carnallite (KCl·MgCl2·6H2O) is a potential heat transfer fluid for solar thermal applications.
• High operating temperatures (500-720 °C) necessitate addressing the corrosive nature of MgCl2 hydrates.
• Effective chemical monitoring is essential for the stability and performance of carnallite-based heat transfer fluids.

Purpose of the Study:

• To develop and validate an experimental method for separating and quantifying MgO and MgOHCl in solid carnallite.
• To assess the accuracy and error of the developed titration method.
• To enable chemical monitoring of carnallite composition during dehydration and purification processes.

Main Methods:

• Development of a novel experimental procedure for the separation of MgO and MgOHCl from solid carnallite.
• Titration techniques employed for quantitative analysis of separated MgO and MgOHCl.
• Error and accuracy assessment of the developed analytical method.

Main Results:

• The developed method demonstrated a relative error of -7.0% for MgOHCl at 9.0 wt % concentration.
• The method achieved a relative error of less than +1.0% for MgO at 12.0 wt % concentration.
• Titration results successfully tracked changes in MgOHCl concentration during carnallite's dehydration and purification.

Conclusions:

• The validated titration method provides accurate chemical monitoring of key components in carnallite heat transfer fluids.
• This analytical capability is vital for managing carnallite's performance and longevity in solar thermal systems.
• The method supports the successful implementation of carnallite as a next-generation heat transfer fluid.