Bench Flotation Tests Research Articles

Synergism of mixed cationic collectors in the flotation of quartz unveiled by AFM, solution chemistry and quantum chemical calculations

The considerable increase in worldwide demand for iron ore requires more studies for efficiency of silicate gangue flotation. New reagents and synergistic mixtures have been pursued to tackle this technological problem. Although there are several studies of collector mixtures in the literature, very few were dedicated to mixtures of cationic collectors. To fill such gap, the interaction between ethermonoamine (M) and etherdiamine (D) was evaluated using bench flotation tests with a typical Brazilian iron ore, solution chemistry analysis and density functional theory calculations (DFT) for the first time in literature. The combined use of these collectors in the proportion 3 D: 1 M, w/w, at pH 10.5, provided the best recovery and selectivity, showing synergism. The iron recovery was 83.9% with a rougher concentrate presenting an iron and silica content of 64.0% and 4.6%, respectively. Differences in the pKa values of primary and secondary amino groups point to minimization of electrostatic repulsion between adsorbed collectors. Interaction free energy values indicate that the complexes M(0)-D(+) (−8.29 kcal/mol), D(0)-D(+) (−7.74 kcal/mol) and M(+)-D(0) (−8.66 kcal/mol) are the most thermodynamically favored and, therefore, confirm the experimental results and explain the nature of the favorability, which is related to the reorganization of the collectors in order to minimize ether-ether and cation-cation repulsion and maximize ether-amine or amine–amine neighbors, especially when the amino group is protonated.

Collector mixtures and their synergistic effect on quartz floatability

Sinergy is the interaction of two or more agents to produce a combined effect greater than the sum of their separate effects. Etherdiamine yields superior results for quartz floatability in a Hallimond tube and higher selectivity in the reverse bench scale cationic flotation of an iron ore, when compared to ethermonoamine. Blending these collectors yields better results than each one used individually characterizing a synergistic effect. This work evaluated the effects of the collectors ethermonoamine, etherdiamine and the mixture of these at the ratio 1:1 on the flotation of the quartz through the microflotation and bench flotation tests with a typical Brazilian iron ore. The results demonstrated the occurrence of synergistic effects in tests performed at concentrations of 1 and 3 mg/L and pH 10.5, in the absence of a depressant. In the presence of a depressant, the synergy was not observed under the same tested conditions, due to the collector-depressant interaction. On other hand, the bench flotation tests indicated the occurrence of synergy regarding silica content in the concentrate while an additive effect was observed for the iron recovery and Selectivity Index index demonstrating that a feasibility of using collector mixtures in this process, was not clearly achieved on the tested ratio 1:1.

A study on the recovery of fine chromite from UG2 tailings

The recovery of chromite from the tailings streams of South African UG2 platinum concentrators adds significant financial returns to these operations. Whilst the coarser fractions are amenable to processing by physical separation, the focus is now also on the recovery of fine (typically −75 µm) chromite by flotation.This paper describes the results of a series of physical separation, and chromite bench flotation tests that have been carried out at acidic and natural pH respectively, on UG2 tailings from Pilanesberg Platinum Mines (PPM) on the western limb of the Bushveld Complex in South Africa. The objective of the work is to find a route that would best produce, from a feed assaying around 18 % Cr2O3 and with 50 % of the chromite in the −38 µm fraction, a concentrate of at least 40 % Cr2O3 and an overall yield of more than 13 %.Results showed that shaking tables and wet high intensity magnetic separation (WHIMS) alone were not capable of upgrading the tailings to the target grade. However, flotation tests at a pH of 2.5 on a sample that was deslimed at 10 µm by cycloning, as well as a sample that was screened at 25 µm and subjected to WHIMS, demonstrated that a product assaying 42 % Cr2O3 could be attained at yields between 8 and 11 %, with recoveries ranging between 19 and 27 %. The results highlighted the importance of desliming prior to flotation, in reducing the dosage of the Flotinor V-2711 collector by more than 60 %.Subsequent flotation tests at natural pH on hot tailings samples with two stages of cleaning showed good upgrading, where a feed grade of 16.1 % Cr2O3 after desliming was converted to a concentrate of 29.4 % Cr2O3 at a yield, based on deslimed feed, of 28.6 % and a recovery of 52.4 %. The overall upgrade ratio in this case of 1.83 was slightly lower than those of the acidic tests (i.e., 1.87 and 2.31 respectively) but also at lower yields (28.6 % vs 33 %) and recoveries (52.4 % vs 62 %). Further work is underway to investigate various flowsheet options, including the flotation of fines spiral concentrates, staged collector addition to the cleaning stages, and froth washing.

Concentration of oxidized Brazilian zinc ore by flotation: comparative study between anionic and cationic routes

ABSTRACT In this work, a mineralogical characterization by X-ray diffractometry and thermogravimetric analysis of a new Brazilian zinc ore sample was performed. The mineralogical semi-quantification, conducted by normative calculation of the identified minerals, using their theoretical chemical formulas and the contents determined in the chemical analyses was as follows: smithsonite (20.3%), goethite (49.6%), kaolinite (12%), quartz (6.2%), cerussite (3.0%), chlorite (4.0%), dolomite (0.5%) and others (4.4%). Subsequently, bench flotation tests were executed, using sodium oleate (anionic route) and amine (cationic route) as smithsonite collectors. Sodium silicate was used as a depressant of the gangue minerals in both routes tested. These studies showed that the anionic route (30.1% Zn in concentrate and 83% Zn recovery) performed better than the cationic route (17.5% Zn in concentrate and 46.3% Zn recovery). Considering the mineralogical composition of the concentrates obtained in the best flotation results, associated with physicochemical studies published in the literature with the identified minerals, it was evidenced that the difference in performance between the tested routes is due to the influence of ions from the dissolution of carbonates present in the ore on the surface properties of the main gangue minerals (goethite and silicates), especially for the cationic route.

Improved flotation of molybdenite from talc using a selective reagent scheme

Talc is one of the most problematic gangue minerals for molybdenite flotation owing to its strong natural hydrophobicity. In this work, pullulan polysaccharide (PU) was evaluated as a potential depressant in the flotation separation of molybdenite from talc. Bench flotation tests of single mineral samples and multi-mineral samples were carried out to evaluate the performance of PU in flotation. And the results show that under the preferable reagent scheme of 40 mg/L PU, 160 mg/L butyl xanthate (BX) and 25 μL/L MIBC, molybdenite can be effectively separated from talc over a wide pH range (from 2.0 to 8.0). Furthermore, FTIR and XPS analyses demonstrate that BX can desorb the pre-adsorbed PU on the surface of the molybdenite by competitive adsorption, but has only a slight effect on the PU adsorbed on surface of the talc. The results also confirm that PU has a strong and stable adsorption on the surfaces of talc and molybdenite, whereas BX adsorbs more strongly on the surface of molybdenite. Hence, the reagent scheme of PU + BX, with biodegradability, low toxicity, low cost and synergistic selectivity, has great potential for industrial application in the flotation separation of molybdenite from talc.

Flotation separation of molybdenite from chalcopyrite using rhodanine-3-acetic acid as a novel and effective depressant

The selective separation of molybdenite from chalcopyrite is difficult because of their similar floatability in the presence of a collector. In this study, rhodanine-3-acetic acid (3-Rd) was first applied in molybdenite flotation as a novel chalcopyrite depressant, and its depression effect and mechanism were systematically investigated by flotation tests, density functional theory (DFT) calculation, zeta potential measurements, and X-ray photoelectron spectroscopy (XPS) analysis. Single mineral flotation results indicated that 3-Rd can selectively depress chalcopyrite flotation, whereas its effect on molybdenite is negligible. Mixed mineral and bench flotation tests further proved that 3-Rd is an efficient chalcopyrite depressant. The first-principle periodic calculations based on DFT predicted that 3-Rd prefers to adsorb onto Fe rather than Cu because of the more negative adsorption energy of the COO or CSS group on Fe in the chalcopyrite surface. Zeta potential measurements demonstrated that 3-Rd is adsorbed on chalcopyrite surface more selectively, and its adsorption strength is higher than that on molybdenite surface. XPS analysis further confirmed that 3-Rd is chemisorbed on chalcopyrite surface by binding with Fe active site and is adsorbed on molybdenite surface through hydrogen bonding and electrostatic interactions.

The relationship between anion distribution in process water and flotation properties of iron oxides

It is inevitable for the presence of dissolved ions, especially inorganic cations or anions, in the process water of an industrial flotation system. They could alter the chemistry of a flotation system and interfere with the interaction between minerals and reagents. The purpose of this study was to identify the relationship between anion distribution in the process water and the flotation performance of a typical industrial iron ore concentrator when the process conditions were stable. An effort was also made to understand how the anions affect the flotation properties of the iron ore through a series of water chemical analyses by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), ore sample analysis by X-ray Diffraction (XRD), bench flotation tests by using the industrial iron ore, micro-flotation tests by using pure quartz, and zeta potential measurement. The data from water chemical analyses indicated that sulfate ion concentrations in the process water, especially from the roughing stage, are more relevant to the SiO2 content and Fe recovery in concentrate than chloride ion. This can be explained by the results from flotation tests, suggesting that the anions at higher valence tend to have more significant influences on lowering the SiO2 content. But it substantially depends on anion concentration, pulp pH, and type of metal ions. At 8.5–9.2, SO42− ions have promotive effects on the recovery of the quartz pre-modified by FeCl2, or FeCl3 in the water. This is probably due to a shift towards acidic direction on the zeta potential of quartz surfaces in the presence of sulfate ions. These anions, however, have negative effects on the quartz recovery with the occurrence of Ca2+ ions. The precipitation of CaSO4 on the mineral surfaces could be attributed to it.

Dolomitic BIF beneficiation of Conceição - MG mine

Abstract In the Conceicao - MG mine, there are significant reserves of dolomitic itabirite, which is considered overburden material. This study aimed to develop a flotation route for the concentration of this dolomitic BIF according to the requirements of the steel industry. The characterization of samples, comminution, liberation size, microflotation of the pure dolomite and hematite minerals were performed to establish the conditions for selective separation in bench flotation tests. The microflotation tests showed that the soybean oil at pH 6 preferably floats the dolomite in relation to the hematite. The corn starch depressant at a pH higher than10 preferably depresses the hematite relative to the dolomite. The bench flotation tests revealed interactions between the factors pH, percentage of solids in the pulp, soybean oil and starch dosage. The optimal results for bench flotation tests were achieved under the following conditions: pH at 10.5, percentage of solids of 27wt%, dosages of soybean oil and corn starch of 400g/ton and 351g/ton, respectively.

Effects of Cations/Anions in Recycled Tailing Water on Cationic Reverse Flotation of Iron Oxides

It is well known that reverse flotation performance of iron oxides is affected by water quality. Since many potential variations among water sources recycling in a mineral processing plant bring unpredictable effects on the flotation system of iron oxides: disturbing ions/compounds, pH, hardness, residual reagents, etc. In this study, the recycled tailing water from a local plant, characteristically constituting of Ca2+, Mg2+, Na+, K+, Al3+, Fe3+, Cl−, SO42− etc., was introduced into the cationic reverse flotation process of an iron ore. A series of bench flotation tests using iron ores, micro-flotation tests using pure fine quartz, water chemical analyses, and zeta potential measurement were conducted with the objective of identifying the possible influences of both cations and anions in the recycled tailing water on the flotation performance. The flotation results pointed out that the cation with higher valency had more severe influences on the recovery of iron oxides. The formation of the pH-dependent surface complexes on mineral surfaces, for example, Fe(OH)+, Fe(OH)2+, and Fe(OH)3 resulted from Fe3+ ions adsorption, contributed to the less negative zeta potentials of the quartz, and consequently weakened its interaction with the amine collector. It is worthy to note that SO42− ions seem to have a more positive effect on the recovery of iron oxides than Cl− ions. This is probably attributed to the formation of inner/outer- sphere surface complexes on the iron oxides, inhibiting the dissolution of the iron ions/species, and the coordination with these cations from the recycled tailing water, shielding their disturbances in the flotation.

Separation of nickeliferous hexagonal pyrrhotite from pentlandite in Ni-Cu sulphide ores: Recovery by size performance

This study presents results of bench flotation tests on pentlandite-pyrrhotite separation using a Ni-Cu sulphide ore sample, where the crystal structure of pyrrhotite is predominantly hexagonal (e.g., 90–95%). The hexagonal structure of pyrrhotite is known to be more floatable compared to the monoclinic form and is thus recognized as a more challenging separation issue. In order to provide a more complete understanding and capability of the sodium metabisulphite (SMBS)-triethylenetetramine (TETA) reagent systems, particle size effects were investigated. The recovery by size response was compared for SMBS, TETA and their combinations with amyl xanthate as a collector. The pyrrhotite recovery for all sizes are lower than that of pentlandite for the blank case as well as individual cases with SMBS and TETA. For pyrrhotite, the recovery by size relations in the case of individual uses of these reagents were mainly determined by recovery losses at coarser size range (>74 μm), which occurs at a coarser size for pentlandite (>212 μm). The combined use of SMBS and TETA very significantly knocked down the pyrrhotite recovery to less than 7% that was a maximum for the −10 µm size range (attributable to hydraulic entrainment). High recovery of pentlandite in a wide range of intermediate sizes and drastically low recovery of pyrrhotite resulted in a very efficient separation of pentlandite from pyrrhotite in all sizes.

Synthesis of acetic acid-​[(hydrazinylthioxome​thyl)​thio]-sodium and its application on the flotation separation of molybdenite from galena

Abstract A novel organic compound acetic acid-​[(hydrazinylthioxome​thyl)​thio]-sodium was synthesized and characterized. The flotation performance and adsorption mechanism of AHS to galena were investigated by micro, bench flotation tests, UV spectra, zeta potential, FTIR and XPS measurements. The results demonstrated that AHS exhibited superior depressing power to galena and could be used as selective depressant for flotation separation of molybdenite from galena. The results of UV spectra, FTIR, zeta potential and XPS measurements demonstrated that AHS chemisorb on galena surface by forming five-membered cheat ring with releasing of H ions. Therefore, the possible adsorption mode of AHS on galena surface was recommended.

Influence of sodium silicate modulus on iron ore flotation with sodium oleate

This paper presents the influence of sodium silicate modulus on iron ore flotation with sodium oleate collector. Bench flotation tests were performed at pH7 with actual iron ore from Quadrilátero Ferrífero, Brazil, with 42.8% Fe and 37.2% SiO2. Iron recovery averaged above 90% and the Fe contents in the concentrate were above 55%. The highest values of Fe grade and lowest of SiO2 were obtained with low levels of pulp density and sodium silicate dosage and with high level of sodium oleate. Increase of sodium silicate modulus had a small influence on response variables.

Exploiting the Influence of Oxidization on Ultra-Fine Copper and Nickel Sulfide Containing Pt-Pd in Yunnan Mine

It is known that oxidation is one of the most common ways for penlandite to be introducted into tailing during traditional coarse-particle sulfide flotation. However, it could become much more complicated and challenging problems for the low-grade, fine-disseminated Cu-Ni sulfides containing Pt and Pd in Yunnan Mine, accompanied with more than 75% of the content of MgO in the ore sample is. Direct flotation tests had been conducted to extract the metallic values as much as possible by adding traditional depressants and collectors, such as carboxylmethyl cellulose, starch, sodium silicate, butyl xanthate, (BX), butyl ammonium dithophosphate (BA) and etc., the relatively satisfied recoveries of Cu, Ni, Pt and Pd in the concentrate from bench flotation tests were obtained, however, more than 30% of metallic values still lost in the slime. In this study, bench flotation tests for the ore sample fromYunnan Mine, micro-flotation tests of serpentines and pentlandite from Jinchuan Mine and their settling rate tests were conducted to figure out how the oxidation influence the recovery of the ultra-fine nickel sulfide. All the tests results pointed to the presence of over-oxidation on the ultra-fine nickel sulfide surface and lead to the loss of Ni containing Pt and Pd in the slime tailing. Some methods which tried to slow the speed of oxidation on mineral surface during grinding and flotation were introduced in order to recover the values before over-oxidation of sulfides; however, the slime coating of serpentines also may play an important role in disturbing the floatability of ultra-fine sulfide.

The Harmonious Design on the Beneficiability of the Pt-Pd Ores Containing High-MgO Gangues in Yunnan

Flotation characteristics of the fine-disseminated copper-nickel sulfides containing Pt and Pd and thermodynamic properties of high amounts of serpentine gangues by diluted acidic leaching in the ore sample of Yunnan were investigated by bench flotation tests and acidic leaching tests and their combination tests have also been conducted to exploit the harmonious design to extract all the values from the ore sample. Based on the results of bench flotation tests, it has been suggested that traditional flotation with the target of only metallic values in the ore was not available and profitable due to the fact that it was inevitable of the deteriorated dilution of serpentines in the flotation concentration using common various kinds of flocculants or depressants, in which the content of MgO in the concentrate was around 20.0%, while leaching tests by waste acids from producing TiO2 indicated that this may be a promising method to extract MgO andα-Fe2O3 from the ore sample, since it can weaken the disturbance of serpentines significantly and lead a satisfied results of the Cu-Ni sulfide flotation. In this study, a harmonious flow-sheet, which involves leaching by waste acids and traditional flotation process, had been designed with the objective of extracting the metallic values and two non-metallic products, which includesα-Fe2O3 and MgO, from the ore sample. It is worthy noticed that the acidic waste liquids from a TiO2 company in Panzihua was used as leaching agent, which can dissolve 98.81% Mg2+ and 78.43% Fen+ with little Ni2+ and Cu2+. By the comparison of the flotation results and benefits between traditional flotation alone and harmonious design, besides the two more qualified non-metallic products, α-Fe2O3 and MgO, a better concentrate containing a grade of only 2.64% MgO at the grades of 2.58% Cu, 2.97% Ni and 81.02 g/t Pt+Pd with the recoveries of 93.79% Cu, 83.14% Ni and 79.19% Pt+Pd respectively, were harvested from the harmonious design.

Flotation characteristics of magnesite and huntite

Because of similar chemical structures and compositions, huntite and magnesite have similar flotation behaviors and, therefore, cannot be easily separated by flotation infine sizes. This study describes the optimum flotation conditions for the separation of huntite from magnesite by using microflotation and bench flotation tests. Zeta potential measurements and adsorption tests were performed to explain the mechanism of separation. Common ions such as Ca2+ and Mg2+ specifically adsorb on the surface of huntite and magnesite and make the mineral surface positively charged. Experimental findings on run-of-mine ore indicate that magnesite is the floated product and huntite is the rejected product. Carboxymethyl cellulose (CMC) was found to be a strong depressing agent for huntite in the alkaline region, presenting only a slight action on magnesite flotation. In the flotation tests a huntite concentrate containing 97.71 % huntite was produced with an 86.2% recovery and a magnesite concentrate containing 81.28% magnesite was obtained with a 16.9% recovery.

J. Mater. Science Letters

This paper presents the influence of sodium silicate modulus on iron ore flotation with sodium oleate collector. Bench flotation tests were performed at pH 7 with actual iron ore from Quadrilátero Ferrífero, Brazil, with 42.8% Fe and 37.2% SiO2. Iron recovery averaged above 90% and the Fe contents in the concentrate were above 55%. The highest values of Fe grade and lowest of SiO2 were obtained with low levels of pulp density and sodium silicate dosage and with high level of sodium oleate. Increase of sodium silicate modulus had a small influence on response variables.