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The management of tailings streams has taken an increasingly important role in the minerals industry in recent years. The global issue of water scarcity and tightening of regulations governing the disposal of waste waters has significantly contributed to a focus on the development of thickener technologies that is not only widely accepted but also economically advantageous. The operational desire for high density paste thickeners involves dewatering (water re-use), underflow density (pipeline transport), and stacking (deposition processes), all of which are governed by rheology. Although thickener technology has proved to be effective, in many cases, it is not efficient by itself.
The addition of chemical agents known as rheology modifiers or flocculants has shown to be instrumental in improving the overall performance efficiency of the thickening process. These flocculants are generally high molecular weight water soluble polymers that adsorb onto particle surfaces and bridge them together to form large aggregates, thus facilitating flocculation. Most of the commercially available flocculants are generically designed to perform across a broad range of mineral solids (mineralogy), but are not capable of targeting multiple performance criteria. However, a range of next-generation flocculants has been developed; these excel at multiple performance criteria for a particular mineralogy. This paper discusses the dewatering performance, stacking capability, and changes in the underflow rheology of processed gold tailings when treated with various flocculants (traditional versus next-generation).
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