In-Situ Recovery of Critical Technology Elements

G.U.B. Ingenieur AG in Dresden, Germany, is developing optimized in-situ extraction technologies for critical technology elements, including Rare Earth Elements (REE) Nd, Eu, Tb, Dy, and Y and Cu. We discuss some selected examples of ongoing GUB R&D projects including: (1) In-situ bioleaching of Cu shale-sandstone in an active ∼1 km deep shaft mine in Poland, (2) In-situ (bio)leaching and near-surface extraction of REE from ion-adsorption clays (IAC) in Madagascar, and a new project scope (3) REE extraction from secondary phosphate streams. In-situ bioleaching of Cu from deep Cu-shale deposits in Europe allows to retrieve metals like Cu (among other metals) from deep European ore deposits at lower costs. In-situ recovery of REE from IAC deposits is important as such deposits in southern China are the main source of critical technology elements Nd, Eu, Tb, Dy and Y. REE-recovery from secondary phosphate streams is a potential major value-adding step in optimizing the phosphate recovery processing chain, yet it is essential to understand the partitioning of REEs (and NORM including U, Th and their progenies) between phosphogypsum and phosphoric acid in the fertilizer production process. We identified three main REE sinks based on existing phosphate processing chains: (1) Sand, clay and phosphoric tailings hosting ∼40-50% of total REE, (2) phosphogypsum ponds with ∼40% of total REE, and (3) phosphoric acid with dissolved ∼10-20% of total REE. In-situ recovery may potentially recover ∼80-90% of total REE from secondary streams (phosphate tailings and phosphogypsum ponds) whereas ∼10-20% of total REE may potentially be recovered from phosphoric acid and/or tailings eluate by biocomplexation of REE. Modification of the phosphate processing chain may provide additional REE extraction points. The most suitable REE extraction points may also be controlled by NORM separation. We propose a customized R&D program to develop an in-situ recovery technology for in-situ REE recovery from secondary (ex-phosphate) streams, in the framework of a joint company and/or EU-funded R&D project.