Rare earth (La, Ce, Nd) and rare metals (Sn, Nb, W) as by-product of kaolin production, Cornwall: Part1: Selection and characterisation of the valuable stream

Rare earths (La, Ce, Nd) and rare metals (Sn, Nb, W) as by-products of kaolin production – Part 3: Processing of fines using gravity and flotation

“…1). The low grade +180 lm fraction was not considered for metal recovery, the 53-180 lm fraction was treated following a gravity processing route (Dehaine et al, 2016a), and the À53 lm fraction constitutes the feed material for the flotation and Falcon tests presented in this study. The mineralogical composition of the feed material is summarized in Table 1.…”

“…The Falcon concentrator used in this work is a Falcon L40 laboratory model (Sepro Mineral Systems, Canada) with a solid capacity inferior at 300 kg/h producing a concentrate of 80-100 g. Tests on the raw micaceous residue product were conducted with the fluidised SB bowl and correspond to the experiments described in Dehaine and Filippov (2015). For the processing of the À53 lm fraction the UF smooth-walled bowl was used with no fluidisation water.…”

“…While REE prices have since dropped due to re-opening of large mining projects outside China, (Mountain Pass, Mount Weld), this situation has stimulated other countries to develop their own rare-earth industry and to look for alternative REE resources such as industrial process residues (Binnemans et al, 2015). A recent study has shown that Light Rare-Earth Elements (LREE) are pre-concentrated in the micaceous residues from the primary processing plant of kaolin deposits in Cornwall (United Kingdom), see Dehaine and Filippov (2015). The main LREEs in terms of grades are in decreasing order Ce, La, Nd, (Pr, Sm), with low overall grades (around 170 ppm LREE) but large volumes.…”

“…The main LREEs in terms of grades are in decreasing order Ce, La, Nd, (Pr, Sm), with low overall grades (around 170 ppm LREE) but large volumes. Mineralogical observations suggest that monazite is the only LREE-bearing mineral which is found free in the micaceous residue stream and sometimes in association with rutile or micas (Dehaine and Filippov, 2015). Typical processing flowsheets of monazite start by physical beneficiation consisting mainly of high-capacity gravity separation steps, to take advantage of the high density of monazite which is between 4.98 and 5.43 g cm À3 (Jordens et al, 2013;Kumari et al, 2015).…”

In Situ Resource Recovery from Waste Repositories: Exploring the Potential for Mobilization and Capture of Metals from Anthropogenic Ores

“…For example, historic Pb-Zn mines in Wales (UK) were originally mined for Pb in the late 19th century and the Zn minerals were discarded; these wastes were later reworked for Zn when Zn prices rose in the early 20th century. There is therefore the possibility that metals that were not originally the target metals for mining, but have since become economically important (e.g., the EU critical metals), maybe be enriched in the waste and become the valuable target (e.g., Dehain and Fillipov [43]). In terms of physical characterization, mine wastes tend to have a larger and wider particle size distribution than tailings which are typically fine (\60 lm), and thus hydraulic conductivity of the materials for in situ leaching is an important consideration.…”