As a by-product from the phosphate fertilizer industry Phosphogypsum (PG) was considered a potentially valuable source of the rare earth elements (REEs). Because of trace concentration of REEs in the PG (normally <0.1% wt) and also their tiny and complex occurrence phases the recovery process would be highly challenging in both technology and economy. The studies on occurrences of REEs, REE recovery by physical methods and leaching using different lixiviants such as inorganic acids, H 2 SO 4 ,

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... Cl and HNO 3 , and organic chemicals, the effects of mechanical treatment of PG by microwaving and grinding on leaching efficiency of REEs, and resin-in-leach process were reviewed in the paper.