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Mineralogical factors affecting the separation behavior of Ta-Nbbearing minerals in the gravity field : mineral grain size, liberation, and association relationship

Cheng Hongwei, Xu Jian, Wang Shoujing, Lv Zihu, Wei Fushuai, Zhao Dengkui, Wu Dongyin

Physicochemical Problems of Mineral Processing

2023

Vol. 59, iss. 6

art. no. 174504

Gravity separation is the primary method used to beneficiate Ta-Nb-bearing minerals, however, it performs poorly in low-grade and fine-grained ores. A comparative study of gravity separation products (concentrate, middlings, and tailings) reveals the factors affecting the separation behavior of Ta-Nb-bearing minerals in the process combined with a spiral chute and shaking table from the perspective of mineralogy. The results reveal that columbite-tantalite is the principal Ta-Nb-bearing mineral. As the grinding time increases, the grade of Ta and Nb in concentrate increases significantly. The grain size of columbite-tantalite in the concentrate is the coarsest, followed by that in the middlings, and the finest in the tailings, which are mainly distributed in the range of -150+38 μm, -75+20 μm, and -38 μm, respectively. The liberation degree of columbite-tantalite in the concentrate and tailings is positively correlated with grinding time, while that in the middlings is negatively correlated with grinding time. The density of columbite-tantalite-bearing particles in concentrate is mainly distributed above 3 or even 4, due to the high liberation degree of the columbite-tantalite in the concentrate, as well as the high amount of rich intergrowth associated with heavy minerals. The density of Ta-Nb-bearing mineral particles in the middlings and tailings is predominantly distributed in D<3, owing to columbite-tantalite mainly associated with lighter gangue minerals such as quartz, albite, and orthoclase. It demonstrates that the liberation degree is not the most essential factor in determining columbite-tantalite separation behavior in the gravity field, and the mineralogical characteristics of columbite-tantalite including grain size, association relationship, and particle density, may be more important. The results of this investigation can provide theoretical support for the strengthening separation of low-grade tantalum-niobium ore.

Extraction and sensitive spectrophotometeric determination of niobium in silicate rocks and columbite-tantalite minerals

Tarafder P. K., Mondal R. K., Chattopadhaya S.

Chemia Analityczna

2009

Vol. 54, No. 2

231-246

A new and simple method for separation of niobium by solvent extraction has been described. Niobium has been determined in the form of colored mixed-ligand complex with 2,3-dihydroxynaphthalene and acetate ion applying selective and sensitive spectrophoto-metric method. Molar absorptivity was 4.6 š 0.05 x104 L mol cm-1 at 397 nm (λmax) and detection limit equaled to 20 ng mL~l. A comparative study on extraction of niobium(V) using different organic solvents has shown that extractability, sensitivity, and selectivity of the proposed method depend on the nature of solvents and hetero-ligands used. Niobium has been successfully separated in the presence of Ti, V, Mo, Zr, Ta, W, Fe, Al, Cr, U, Th, Ni, Co, Zn, Cd, Cu, and Mn, thereby eliminating the interference of these ions during its spectrophotometric determination. The designed method has been applied to the recovery of niobium from silicate rocks, ores, and columbite-tantalite minerals.

Opisano nową, prostą ekstrakcyjną metodę wydzielania niobu. Niob oznaczano w postaci barwnego kompleksu z mieszanymi ligandami tj. 2,3-dihydroksynaftalenem i jonem octanowym co stanowi podstawę czułej i selektywnej metody spektrofotometrycznej. Molowy współczynnik absorpcji wynosił4,6 š 0,05 x 104Lmol cm-1 przy 397 nm(Xniax) a granica wykrywalności wynosiła 20 ng mLcm-1 . Porównawcze badania ekstrakcji niobu(V) przy zastosowaniu różnych ekstrahentów organicznych wykazały, że zdolność do ekstrakcji, a także czułość i selektywność proponowanej metody zależy od rodzaju hetero-ligandów oraz wyboru rozpuszczalnika. Niob można było wydzielić w obecności Ti, V, Mo, Zr, Ta, W, Fe, Al., Cr, U, Th, Ni, Co, Zn, Cd, Cu i Mn eliminując w ten sposób możliwe interferencje ze strony tych jonów w trakcie spektrofotometrycznego oznaczania. Opracowaną metodę zastosowano do oznaczania niobu w skałach krzemianowych, rudach i minerałach kolum-bitowo-tantalitowych.