TAILINGS DEWATERING
Various mining and extraction processes produce a tailings stream consisting of a slurry of particulate matter in water. These tailings often contain hazardous components that cannot be discharged directly into rivers and streams.
A common practice is to store tailings in ponds, which can be very large or encompass numerous sites. For example, recent estimates state Canadian oil-sands tailings ponds cover an area of about 200 square kilometers.
In the US, the Environmental Protection Agency has identified more than 500 ash and coal slurry ponds, mostly in the Appalachian coal-mining region. In Florida, phosphate mining results in the production of approximately 100,000 tons a day of phosphatic clays in the form of pond-stored slurry. It is very difficult to dewater, and the phosphate industry leaves about 40% of mined land in unstable clay settling areas.
Extrakt has developed the technology to meet the challenges faced by operators.
Extrakt Process Solutions has a process to dewater and consolidate tailings. Unlike other methods used so far, this process achieves a solids content of greater than 75% quite easily.
Originally, this was achieved through the use of ionic liquids (ILs). A more recent form of the process uses solutions of ILs together with small amounts of an additive. Patent applications for the new process have been filed in the US and Canada, and other filings are imminent. Six new patent applications were also filed in 2016, describing processes based on inexpensive ionic solutions.
Direct Filtration of Phosphate Tailings (250mm Pilot Recessed Chamber Pressure Filter)
Comparative Cylinder Settling of Copper Tailings
Flocculation Canadian Oil Sands Tailing Dewatering in USA Pilot Facility
Chamber Filter Cake
Inline Pilot Flocculation of Canadian Oil Sands Tailings at High River (SFR=1, 65 gpm, 3” diameter, 550 ft HDPE Piping)
