Currently, diamonds can only be detected at the surface of an ore. To find gems inside rocks, the igneous rock has to be breaken up into very small pieces. This consumes large quantities of water and energy, and there is the risk of damaging the larger – and, therefore, more valuable – diamonds.
Scientists around Jörg Mühlbauer, Development Center for X-ray Technology EZRT, Fürth, Germany, a division of the Fraunhofer Institute for Integrated Circuits IIS, have developed a demonstrator that detects diamonds hiding inside rocks of volcanic origin.
The crushed rocks pass through an X-ray machine at a speed of 3 m/s. Two images of the same object are produced using two different X-ray spectra. A new algorithm filters out the data of chemical atomic numbers of the materials from both images, and, thus, the technology is capable of detecting diamonds of just a few millimeters in size in kimberlite ore of grain sizes up to 50 mm.
Together with colleagues from the Fraunhofer Institute for Optronics, System Technologies and Image Exploitation IOSB, Karlsruhe, Germany, the researchers are working on the advanced engineering of this demo model. The objective is to achieve a prototype that can inspect the ore on a fully-automated basis. They also want to develop an industrial testing process that allows several tons of bulk material per hour to run through the system and be analyzed.
The use of this method is possible anywhere that materials have to be identified and cleanly separated.
- Fraunhofer-Gesellschaft, Munich, Germany