The Problem with Traditional Settling Tests

Flocculant selection, dosage, and dilution characterization are important parameters necessary to optimize thickener design and operation. For existing operations improvements can be made by comparing current operational parameters with a large number of alternate parameters to investigate improved performance and potential cost savings. These type of experiments are normally referred to as “Jar Tests” and their accuracy depends entirely on the operator, the generic laboratory equipment used, and visual observations of how the slurry settles with time. There is no normalization to control the quality of these tests, and this presents a challenge when trying to compare conditions for an in-depth sample investigation. Simply put, the test method is outdated and both the test accuracy and the data recovery can be improved.


The SedScan Test

SedScan is the first automated settling test developed to take away the technician and reduce the test error through the use of precision instrumentation. The test consists of a transparent tube and sensors to measure the interface position as a function of time, using a sample size of less than 400 g of tailings feed material. The sensors also measure the supernatant turbidity. The system is constructed so that twelve tests can be conducted simultaneously, each with different flocculants dosage, pH, or other client-specific conditions. The results are logged electronically, processed and a report sheet is generated. The test results are interpreted in multiple formats including the Kynch, the Coe-Clevenger, the modified Coe-Clevenger, and the Willhem-Naide methods. The total cost per test is less than $40 for large volumes. This is a huge cost savings over traditional settling tests.


Other Successful Applications

  • Rapid screening of thickener feed conditions, including pH, flocculant dosage, coagulant dosage, and % solids
  • Ore variability tests following pilot plant trials
  • Prediction of supernatant/overflow clarity giving real NTU values with time.