Purification process to save billions of litres

A process that once took 25-50 years now takes hours thanks to a new purification technique developed at the University of Florida.

Using electromagnetic fields, professor of chemical engineering Mark Orazem, separated clay and water particles around 200,000 times faster than current processes.

The technique is of great interest to phosphate miners, who use water for the transport of slurries, dust suppression and mineral processing. This produces an electrically charged clay effluent, a highly concentrated mix of clay and water that must be separated before being reused. It is the electrical charge that slows down the rate of settling.

“It looks like a solid, but if you throw a stone into it, it’ll splash,” says Orazem

By creating a magnetic field, the charged clay particles are drawn to the bottom purifying the mix in two to three hours. The solid “cake” left over can be used to plug mining holes while the water can be put back into the system.

“Instead of having the water tied up in these clay settling areas, water is sent back through the process and then reused and reused and reused,” says Orazem. 

The process will be highly beneficial in water scarce areas such as Morocco and the Western Sahara, where 85% of phosphate mining takes place.