Researchers at ISTC have successfully demonstrated a process for dewatering coal mining slurry, showing significant potential for reducing the ecological impact of mining.
For several years, Nandakishore Rajagopalan, associate director, and ISTC colleagues Hafiz Salih and Vinod Patel have been studying forward osmosis as an alternative to slurry ponds for dealing with tailings from coal mining. The work added to previous evidence that osmotic dewatering presents a simple, reliable and economical alternative with strong sustainability characteristics. The modular nature of the technology allows it to be tested at a small scale with the results being transferable to larger scales readily.
"This compares favorably with other technologies and the level of dewatering was higher," said principal investigator Rajagopalan, who also serves as Illinois' State Pollution Prevention Scientist. Moreover, the process can be used to solve similar sludge problems arising from manufacturing, water treatment, and bioprocessing, he said.
Modern coal preparation plants use water washing to separate coal from refuse. The washing releases a hodgepodge of fine mineral particles (tailings) that poses a substantial threat to the environment when held in ponds. Dewatering using osmosis enables the production of dry cake that can be handled in a beneficial manner within mines.
Building on past proof-of-concept studies at ISTC, the engineers have charted a pathway to scaling up the technology in a simple manner and hope to build a continuously operating system to study long-term performance. Rajagopalan is currently seeking engineering companies to partner with to build and test the technology. The work prepares the way for additional testing over a longer period under real world conditions.
The research was supported by the Illinois Clean Coal Institute (ICCI).