Aqueous Biphase Extraction for Processing of Fine Coal, 7/97, 27,335

Ever-stringent environmental constraints dictate that future coal cleaning technologies be compatible with micron-size particles. For super-clean coal production, the degree of liberation needed to separate coal from mineral matter, including pyrite, requires grinding to 10 μm or below. In addition, large amounts of fine coal are discharged to refuse ponds because current coal cleaning technology cannot adequately treat such finely divided materials. This research program seeks to develop an advanced coal cleaning technology uniquely suited to micron-size particles, i.e., aqueous biphase extraction. This technique relies on the ability of an aqueous system consisting of a water-soluble organic polymer and an inorganic metal salt to separate into two immiscible aqueous phases. Differences in the hydrophobic/hydrophilic properties of particulates can then be exploited to effect selective transfers to either the upper polymer-rich phase, or the lower salt-rich phase. An experimental program is proposed involving phase diagram determination, phase separation rate measurements, partition measurements, and washing experiments.