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1

Froth flotation of Aljustrel sulphide complex ore

100%

Sousa R. , Futuro A. , Pires C. S. , Leite M. M.

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2017

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tom Vol. 53, iss. 2

758--769

EN

Froth flotation of copper-zinc-lead ores is a complex process based on similar metallurgy processing and strong interactions between chalcopyrite and sphalerite. These types of ores represent 15% of the world production and 7.5% of copper deposits all over the world. In the present study, an attempt is made to assess the feasibility of froth flotation of a complex sulphide ore, where the effect of liberation grade as well as depressant, collector and frother dosage was studied. Copper flotation is dependent on the mineral liberation grade, which is significantly related with the size distribution. It was shown that longer grinding time increased the Cu grade but decreased the copper recovery due to the presence of very fine particles. Lime and sodium metabisulphite, used as depressants, allowed to achieve a good flotation performance. It was shown that for this type of ore lower dosage of the collector should be applied. Finally, a higher frother dosage led to a greater selectivity and reduced entrainment of very fine particles, but also caused low kinetic ratio and low recovery of valuable minerals. A well-defined flotation objective was imperative for a good liberation grade and reagents dosage selection, mainly for complex sulphide ores. A useful contribute was given to a better technical understanding of flotation of a complex sulphide ore from the Moinho deposit.

2

Flotation separation of enargite from complex copper concentrates by selective surface oxidation

88%

Li T. , Zhang Y. , Zhang B. , Jiao F. , Qin W.

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tom Vol. 55, iss. 4

852--864

EN

In previous study, the promising results of separating enargite from non-arsenic copper sulfides were obtained using selective surface oxidation in pure mineral systems. However, this technology was not well understood in real ores or concentrates. In this study, the flotation separation of enargite from complex copper concentrates by selective surface oxidation was investigated. The effects of regrinding, pulp pH, NaClO concentration, conditioning time and flotation time on separation of enargite from NECu minerals were studied. The mineralogical characteristics of the flotation feed and products were showed as an instructive tool to understand the separation results. According to the results of EDTA extraction, the possible mechanism for separation of enargite from NECu minerals is that enargite is more resistant to oxidized compared to NECu minerals. The following order for the oxidation of NECu minerals and enargite is obtained: chalcopyrite (chalcocite, digenite)> enargite (covellite).

3

Optimization of flotation efficiency of phosphate minerals in mine tailings using polymeric depressants : experiments and machine learning

88%

Alsafasfeh A. , Alagha L. , Alzidaneen A. , Nadendla V. S. S.

Physicochemical Problems of Mineral Processing

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2022

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tom Vol. 58, iss. 4

art. no. 150477

EN

In this study, direct froth flotation experiments were conducted on silicate-rich phosphate tailing samples. The average grade of P2O5 in the flotation feed was 21.6% as determined using a combination of spectroscopic techniques including X-ray powder diffraction (XRD), mineral liberation analysis (MLA), and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Two polymers were selected to promote the depression of silicates and enhance the flotation of phosphates: in-house synthesized hybrid polyacrylamide (Hy-PAM) and chitosan. Flotation efficiency of phosphates was evaluated at different flotation conditions including depressant type, depressant dosage, pH, and the flotation time. Results indicated that the optimum flotation efficiency of phosphate minerals (84.6% recovery at 28.6% grade of P2O5) was obtained when Hy-PAM was utilized at the studied range of pH and flotation time. All datasets produced from the flotation experiments were integrated within the framework of machine learning (ML) using artificial neural networks (ANNs). The ANN platform was trained, validated, and successfully employed to predict the process outcomes in relation to the pulp and reagents characteristics, which in turn were used to determine the optimum values of process variables. Coefficient of determination (R2), mean absolute error (MAE), and root-mean-square error (RMSE) were used as model indicators. Optimization results showed that the peak flotation performance could be achieved at higher dosages of both polymers. However, lower pH and shorter flotation time for Hy-PAM, and higher pH and longer flotation time for chitosan, were predicted to give the optimum process efficiency.

4

Effect of the foaming performance of ammonium dibutyl dithiophosphate on the flotation of slime-containing copper sulfide ore

88%

Deng R. , Duan W. , Wang Y. , Hu Y.

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tom Vol. 58, iss. 6

art. no. 153492

EN

The use of ammonium dibutyl dithiophosphate (ADD) as a collector in the flotation of slimecontaining copper sulfide ore typically produces a sticky froth, which results in poor flotation. The mechanism and effects of copper sulfide ore flotation in synergistic systems comprising ADD and terpenic oil reagents have been systematically investigated to solve this problem. A high ratio of ADD to terpenic oil is not conducive to the flotation of fine-grained copper sulfide ores; however, adjusting this ratio may improve floatation by reducing the effect of the slime. Lowering the ratio from 5:1 to 1:1 increased the copper grade from 17.7% to 20.8%, while the recovery was largely unchanged. Notably, adjusting this ratio also reduced the cost of the flotation reagent. To study the mechanism by which the ADD–to–terpenic oil ratio affects the foam performance, the froth stability tests of the gas–liquid twophase and gas–liquid–solid three-phase systems were performed. Reducing the proportion of ADD reduced the froth water content and weakened the ability of the froth to collect gangue by adsorbtion with copper ions; this reduced gangue entrainment and maximized recovery and product quality.

5

Mechanism of the combined effects of air rate and froth depth on entrainment factor in copper flotation

88%

Wang L. , Xing Y. , Wang J.

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tom Vol. 56, iss. 1

43--53

EN

The effect of air rate and froth depth on the entrainment factor in flotation has been extensively studied, but further investigation on the underlying mechanism for their effect is still required. In this study, flotation tests were performed at different air rates and froth depths in a 3 dm3 continuously operated cell using an artificial copper ore. The results showed that entrainment factor was affected by both air rate and froth depth, and the combined effect of these variables on entrainment factor depended strongly on the particle size. The entrainment factor increased with either increasing air rate at a relatively shallow froth or decreasing froth depth at a relatively high air rate. At a very low air rate and deep froth, higher entrainment factor was observed for mid-size and coarse particles. When the entrainment factor was correlated to the effective liquid velocity at the pulp/froth interface, the results indicated that multiple mechanisms were responsible for the effect on entrainment factor. At a relatively high air rate and shallow froth depth, entrainment factor had a linear relationship with the interface effective liquid velocity, suggesting that drag force dominated the change in the entrainment factor when air rate and froth depth were varied. At a very low air rate and deep froth, the entrainment factor for fine particles was found to correlate strongly with the interface effective liquid velocity, while the entrapment of solid particles may be the main reason for the high entrainment factor for mid-size and coarse particles under this condition.

6

Role of calcium and magnesium cations in the interactions between kaolinite and chalcopyrite in seawater

75%

Uribe L. , Gutierrez L. , Laskowski J. S. , Castro S.

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2017

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tom Vol. 53, iss. 2

737--749

EN

A number of flotation plants around the world have increased the use of seawater due to limited sources of fresh water. The aim of this research work is to study the role that Mg2+ and Ca2+ ions play in the interactions between kaolinite and chalcopyrite in seawater. In order to achieve this objective, the effect of kaolinite on flotation of chalcopyrite is studied over the pH range from 8 to 11, when flotation is carried out in seawater and in a 0.01M NaCl solution. The influence of calcium, magnesium, sodium, and potassium ions on the extent of depression by kaolinite is evaluated. The micro-flotation results indicate that chalcopyrite is depressed by kaolinite in both 0.01 NaCl solution and seawater. In the 0.01 NaCl solution, the depressing effect of kaolinite decreases as the pH increases from 8 to 11. However, the results obtained using seawater show that the depressing effect of kaolinite is similar to what is observed in a 0.01 NaCl solution only at pH values below 9, but above this pH kaolinite significantly affects the recovery of chalcopyrite. The results from experiments with using solutions containing individual cations show that the depressing action of kaolinite in the presence of Mg2+ and Ca2+ is more obvious at pH values of 9 and 10, respectively, which correlates with the pH values at which the first hydroxy-complexes of these divalent cations start forming. This seems to indicate that depressing effect of kaolinite on chalcopyrite in seawater may be related to formation of hydrolyzed species of calcium and magnesium. These species can induce heterocoagulation between kaolinite and chalcopyrite. The trends observed in the micro-flotation experiments are in good agreement with the results of the induction time measurements and slime coating tests.