The Physical Preparation of Geologic Samples For Chemical Analysis Using Laboratory Robotics

Abstract

Abstract An automated system to grind geologic samples has been successfully tested. A Zymate II robotic system, along with specially designed or modified hardware, was used to process partially pulverized geologic samples. the system is capable of processing samples on a 24-hour basis with an average per-samples grinding time of 12.4 minutes. A sample grinding period is followed by a cleanout sequence of air purges, vacuuming and grinding for surface cleaning with quartz sand. Routine operator involvement is limited to adjusting the grinding plates on the Bico vertical grinder at the beginning of each preparation interval. Studies conducted using variable amounts of cleaning sand between grinding of samples indicate that the adjustment interval can be extended to 50 samples (25g cleaning sand) using an acceptance criteria of 80% of sample passing 80 mesh. the processed samples are suitable for direct geochemical analysis using a variety of standard chemical digestions. Cross contamination studies using soil, chromite, and galena/sphalerite samples have revealed that the grinding system is capable of clean-out efficiencies exceeding 99% using as little as 25g of cleaning sand.