Dual X-Ray and Optical System for In Situ Monitoring of Solids Fraction in Tailings

Abstract

Highlights What are the main findings? A full operational system was successfully demonstrated for in situ measurements of solids content in a large pilot-scale settling column. In situ hybrid optical and gamma-ray techniques provide accurate solids content measurements that agree well with conventional laboratory gravimetric measurements. What are the implications of the main findings? The technology enables rapid measurement of solids’ depth profiles in settling ponds without the need for time-consuming and costly sampling followed by subsequent laboratory analysis. The technology can facilitate better monitoring and management of oil sands tailings, resulting in improved process efficiency and improved environmental performance. Abstract A sensing apparatus was developed to quantify solids fraction within a 3 m test column, demonstrating real-time monitoring of tailings sedimentation. This integrated system employs a low-power infrared laser coupled with scattering detectors alongside a low-activity radioactive source and detector. Both methodologies utilize non-destructive principles to evaluate the concentration of solids. Specifically, X-ray transmission through the medium provides a measure of the solids fraction, as X-ray attenuation corresponds to the solids percentage. Concurrently, the optical component detects radiation backscatter from the sample. To ensure precision, both instruments underwent calibration using reference materials. Experimental evaluations were conducted using two configurations: a fixed array and a depth-profiling setup. The former utilized a 2.5 m plastic column with integrated sensors placed within a settling vessel to acquire data at discrete depths. Conversely, the depth-profiling configuration involved a submersible mobile unit lowered into the column to characterize the solids profile at arbitrary depths.