Florida Industrial and Phosphate Research Institute, Florida Polytechnic University, Lakeland, United States:

Allaedini G., PhD Chemical Engineering, jiny_ghazaleh@yahoo.com
Zhang P., Director of Beneficiation and Mining

Extra fine sawdust has been utilized as a filter aid for the filtration of the phosphoric acid sludge and recovery of Rare Earth Elements (REE). Results show that the addition of sawdust as a filter aid enhances the filtration in terms of solid residue retained and the quality of either the recovered acid when applied as a precoat or a body feed. It was found that an increase of sawdust dosage above 0.5% reduced REE distribution in the final solid residue with a slight increase in the rate of filtration up to 1%. Application of sawdust as a pre-coat resulted in a final dried solid product containing less phosphorus. This study showed that sawdust could be employed as a low-cost commercial filter aid for treatment of the phosphoric acid sludge for recovery of REE, as well as the phosphoric acid value.

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