Maps showing distribution of anomalous concentrations of trace elements in the magnetic fraction of heavy-mineral concentrates, Domeland Wilderness and contiguous roadless areas, Kern and Tulare counties, California

1985 ◽  
2020 ◽  
Vol 18 ◽  
pp. 63-73
Author(s):  
C. I. Adamu ◽  
E.E. Okon ◽  
D.O. Inyang

Active stream sediments generally consist of broken-down fragments of pre-existing rocks by the action of river (stream) flow. This makes them target materials for routine geochemical surveys and provenance analysis. Fifteen (15) stream sediment samples were collected in some parts of Bula and its environs, northeastern Nigeria, in order to determine their textural characteristics, heavy mineral and elemental composition. The sediments were subjected to granulometric, heavy mineral and elemental analyses. The result of granulometric analysis show that the streamsediments are poorly to moderately well sorted, very platykurtic to leptokurtic, fine to medium grained and positively skewed. Zircon, rutile and tourmaline are the dominant heavy mineral species occurring in the sediments. The computed Zircon-Tourmaline-Rutile (ZTR) index values for the samples range from 59.18 - 83.53, indicating mineralogical maturity. The geochemical data of the stream sediment samples show that the mean contents of the trace elements [Ti (0.73 ± 0.74%), Fe (0.39±0.19%), Cr (816±639ppm), Ni (258±108ppm), Pb (48±12.37ppm) and Zn (502±126ppm)] were higher than their respective average crustal values except for Fe. Computed threshold values indicate possible mineralization containing Fe and Ti. The elements have variable spatial distribution. The study shows that the trace elements composition of the stream sediments is majorly lithogenic. Because mineralization in rocks and sediments are often characterized by considerable variation in their trace elements contents, the metal concentrations in these sediments are large enough for Ilmenite and Rutile mineralization to be suspected within the study area.


Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 387 ◽  
Author(s):  
Christina Stouraiti ◽  
Vassiliki Angelatou ◽  
Sofia Petushok ◽  
Konstantinos Soukis ◽  
Demetrios Eliopoulos

Beneficiation of a rare earth element (REE) ore from heavy mineral (HM) sands by particle size classification in conjunction with high-intensity magnetic separation (HIMS) was investigated. The HM sands of Nea Peramos, Kavala, Northern Greece, contain high concentrations of REE accommodated mainly in silicate minerals, such as allanite. However, the potential of the Northern Greek placer for REE exploitation has not been fully evaluated due to limited on-shore and off-shore exploration drilling data. Characterization of the magnetic separation fractions using XRD and bulk ICP-MS chemical analysis showed that the magnetic products at high intensities were strongly enriched in the light REE (LREE), relative to the non-magnetic fraction. Allanite and titanite are the major host mineral for REE in the magnetic products but mainly allanite controls the REE budget due its high concentration in LREE. SEM/EDS and ICP-MS analysis of the different particle size fractions showed LREE enrichment in the fractions −0.425 + 0.212 mm, and a maximum enrichment in the −0.425 + 0.300 mm. The maximum enrichment is achieved after magnetic separation of the particle size fractions. Mass balance calculations showed that the maximum REE recovery is achieved after magnetic separation of each particle size fraction separately, i.e., 92 wt.% La, 91 wt.% Ce, and 87 wt.% Nd. This new information can contribute to the optimization of beneficiation process to be applied for REE recovery from HM black sands.


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