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Purification of Chloride Salts for Concentrated Solar Applications...

Publication Type
ORNL Report
Publication Date

The increased interest in high temperature molten salt technology, including concentrated solar power (CSP), has resulted in an increased need for high purity alkali and alkaline earth chloride salts. One lingering question remains in the technoeconomic analysis: ‘How clean is clean enough?’ High-quality corrosion experiments are necessary to design alloys with enhanced corrosion resistance, and ultimately to realize a cost-effective CSP facility. To conduct high-quality, reproducible corrosion experiments, high purity salt with known impurity compositions must be achievable. Commercial high purity salts are qualified on the basis of metal impurity content, with cost increasing significantly as purity increases. However, non-metallic impurities such as oxygen and moisture content are extremely relevant to concentrated solar or nuclear applications are. For this reason, efforts to clean salts at Oak Ridge National Laboratory (ORNL) have centered upon a modified carbochlorination process which addresses oxygen and moisture-based impurities. This report will focus on the modified carbochlorination procedure utilized to purify magnesium chloride-containing salts for concentrated solar power applications.