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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

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2023

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Vol. 59, iss. 6

art. no. 174504

EN

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.

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Exploring the characterization, liberation and flotation response of a Nigerian low-grade copper ore

Nheta Willie, Ola-Omole Omoyemi O.

Journal of Sustainable Mining

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2023

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Vol. 22, iss. 1

20--32

EN

This study explores the characterization, liberation and flotation response of low-grade copper ore from Anka area, Zamfara state Nigeria. The ore was crushed, milled and sieved in accordance with BS 410 standard. It was characterized with XRD, XRF, SEM-EDS and AAS. Froth flotation was carried out with varying %solids, pH, retention time and collector dosages using SEX and sodium oleate. Particle size distribution of the ore shows its economic liberation between -150 and +106 µm while 80% passing corresponds to 175.7 µm using the Gaudin Schuhmann equation. However, according to metallurgical balance calculation, 63 µm proved to have the highest metal content. Identified peaks of the copper ore by XRD revealed the presence of pyrite and chalcopyrite as the major mineral content at 47 and 36%, respectively, while other elements were present in traces. XRF shows Fe and Cu as the major elements and others in traces. Morphology, according to SEM-EDS, revealed that Fe is the major impurity while the presence of Cu and S confirmed chalcopyrite is present in the ore minerals. AAS shows an average of 25.87% Cu and 32% Fe in the ore. Optimum recoveries of copper were recorded at 30% solids, pH of 8, 30 minutes retention time. The highest recovery of 95.94% was recorded with SEX at 0.25 mol/dm3, while recoveries were lower with PAX, the highest recovery being 33% at 0.20 mol/dm3. 0.25 mol/dm3 of SEX recorded the highest yield and enrichment ratio of 40.38 and 2.38, respectively.

3

Impeller radial velocity and air flow rate influence on copper rougher flotation recovery

Bazan B., Potulskia-Bazan A., Witecki K.

Civil and Environmental Engineering Reports

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2018

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Vol. 28, no. 1

40--53

EN

A rougher flotation study has been done to analyze the effects of copper feed mineralogy, air flow rate and impeller radial velocity on metallurgical performance. During the performance testing the trials were exposed to metallurgical examining and computerised mineral analysis to establish a size-by-size mineralogy. The mineralogical and metallurgical information was compared to the material balance for rougher flotation results. These samples showed that copper recovery optimization should focus on the losses of liberated Cu-minerals and how they are associated with fine particles. The result of variable impeller radial velocity for each flotation cell cascade on metallurgical performance has been explored on a known-sized and an unknown-sized base, to gauge the input from the fine particles. An industrial application is discussed in this paper, and it validates that divergence of the impeller radial velocity and air flow has positive influence on the recovery.

PL

W pracy przeprowadzono analizę wpływu składu mineralogicznego nadawy kierowanej do procesu flotacji głównej, wielkości przepływu dozowanego powietrza i prędkości obrotowej wirników na wyniki flotacji miedzi. Produkty procesu zostały poddane analizom chemicznym oraz mineralogicznym z wykorzystaniem systemu MLA. Przeprowadzone analizy wykazały, ze optymalizacja uzysku miedzi flotacji głównej w warunkach przemysłowych, limitowana jest obecnością w nadawie uwolnionych minerałów miedzi w skrajnych klasach ziarnowych. W artykule przedstawiono wyniki eksperymentów realizowanych w warunkach przemysłowych i pozytywny wpływ modyfikacji prędkości obrotowej wirników oraz stopnia napowietrzenia zawiesiny flotacyjnej na uzysk miedzi.

4

Effect of intergrown particle liberation on difficult-to-separate coking coal flotation

Gui X., Liu J., Cao Y., Xing Y., Deng Y., Li S.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

279--294

EN

Flotation tests with intergrown particle liberation were conducted to explore a separation method of difficult-to-separate coking coal from the Tangshan Kailuan mine in China. The particle size distribution, density and coal petrography were investigated. The difficult-to-separate coking coal sample resulted in intergrown particles, such as non-liberated coal and rocks. Thus, intergrown coal particle liberation and re-separation tests were conducted. The results showed that grinding time had a great effect on the flotation performance. Grinding prompted coal to dissociate and improve the surface hydrophobic properties of minerals. However, heterogeneous fine silt covered the surface of coal particles when coal was ground too long. The inorganic mineral particles were over-ground and reduced the contact angle of coal. The results of coal rock dissociation and laboratory re-separation tests showed that clean coal combustible recovery increased through intergrown particle liberation and re-separation.

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The use of continuous centrifugal gravity concentration in grinding circuit. Modified approach for improved metallurgical performance and reduced grinding requirements

Altun N. E., Sakuhuni G., Klein B.

Physicochemical Problems of Mineral Processing

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2015

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Vol. 51, iss. 1

115--126

EN

The use of centrifugal gravity concentration in the closed-grinding circuit of a gold-containing massive sulphide ore was tested on classifier underflow and overflow. A continuous Knelson CVD6 was retrofitted to the hydrocyclone underflow for recovery of Au and Pb at a coarser feed size. The objective of treatment of overflow was recovering unliberated Au prior to flotation. The tests were performed in actual operating conditions at Nyrstar’s Myra Falls Mine. The results of the tests on the cyclone underflow revealed that both liberated and unliberated Au and Pb were recovered by the Centrifugal Variable Discharge (CVD) concentrator. Concentrate grades <60g/Mg Au were attainable at a more than 20% recovery. This application also allowed early and increased Pb recovery before it became gravity unrecoverable by over-grinding. Other benefits included capturing middlings for regrinding as well as potential coarser grinding and increase in mill throughput. A coarse grind also corresponds to a reduction in deformation of Au-particles, and is beneficial for increased Au recovery in downstream processing. Treatment of cyclone overflow by the CVD also provided favourable results. The outcomes included capturing unliberated gold prior to flotation and potentially reducing pumping requirements and reagent consumption. A comparison of the metallurgical performances showed that CVD application on classifier underflow was more effective. The CVD was capable of recovering unliberated gold in sulphides and performed better at a coarser particle size. Therefore, when used with the grinding circuit, a coarser grind can be applied and the CVD could be used to reject gangue at a coarser size.