extraction comparison (IMAGE) DOE/Sandia National Laboratories Caption A comparison of Sandia National Laboratories method for extracting rare-earth metals to existing methods shows how using citric acid is more efficient. Credit (Images courtesy of Guangping Xu Usage Restrictions news media only; License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.