LKAB are planning to invest 45 million kronor in pilot plants for recovery of phosphorus and Rare Earth Minerals (REE) from the waste rock from their iron ore mining operation. This development was announced on 20 February 2019, read more here
The pilot plant trial is based on the CleanMAP process developed by Easy Mining, a daughter company of the waste treatment company RagnSells. Details of the CleanMAP process are given here. This seems to be based on the US Patent 8658117 B2, which however only refers to “known processes” for the digestion of apatite with sulfuric acid, hence presumably the traditional use of concentrated sulfuric acid. This patent does not mention the procedure for separation and purification of the rare earth elements. An example of a method to recover rare earth elements from digestion of apatite with strong acid is given in the patent by Genkin et al US 1001 1891.