Demonstration of a Phosphate Recovery Circuit for Existing Waste Streams

72325-Phosphate beneficiation plants currently pump hundreds of thousands of gallons of fine refuse into waste impoundments every minute. This refuse contains not only fine phosphate, considered unrecoverable by current industrial practice, but also coarse phosphate that has been misplaced due to sizing inefficiencies. Unfortunately, this lost phosphate is a large portion of the total valuable mineral extracted during the mining process. Its rejection represents poor separation and energy efficiency, and its recovery would reduce production costs and lessen the amount of waste sent to impoundments. This project will develop a mineral processing circuit for the economical recovery of phosphates that are currently being discarded. This process includes column froth flotation preceded by a combination of advanced hydroclassification techniques. In Phase I, historical records from four primary U.S. phosphate producers were analyzed along with sample characterization data collected directly from a typical fine waste stream. These data indicate that there is a significant amount of valuable phosphate present in a recoverable size range. Preliminary laboratory and on-site testing verified that this material can be concentrated and upgraded. In Phase II, a pilot-scale test circuit will be fabricated and installed at a phosphate beneficiation plant. In conjunction with a major phosphate producer, the mineral processing circuit will be evaluated and optimized in an effort to produce a viable product from current industrial waste. Commercial Applications and Other Benefits as described by awardee: Because no phosphate beneficiation plant incorporates a recovery circuit for the treatment of fine refuse, commercial applications should include the fabrication and installation of the required equipment for every available plant. This circuitry also may be applied to dredging processes that may be used for recovering phosphate directly from refuse impoundments.