Flotation Of Dolomite Research Articles

CO<sub>2</sub> bubble formation on dolomite surface and its influence on surface wettability and flotation of dolomite

CO<sub>2</sub> bubble formation on dolomite surface and its influence on surface wettability and flotation of dolomite

Flotation Separation of Magnesite from Dolomite Using Sodium Silicate Modified with Zinc Sulfate as a Selective Depressant

Flotation separation of magnesite from dolomite in the presence of SSZS (sodium silicate modified with zinc sulfate) as an inhibitor and NaOL (sodium oleate) as a collector has been studied via flotation tests, zeta potential measurements, contact angle measurements, and Fourier transformation infrared spectroscopy analysis (FT-IR). The flotation tests show that NaOL has strong collecting capacity in magnesite and dolomite flotation, so it is difficult to separate two minerals via flotation without inhibitors. SSZS is used as the depressant, which can selectively inhibit dolomite flotation and has little depression effect on magnesite. Zeta potential measurements, contact angle measurements, and FT-IR analysis indicate that SSZS can adsorb strongly onto dolomite’s surface and has a weak adsorption effect on magnesite. The adsorption of SSZS prevents NaOL from acting on the surface of dolomite. On the contrary, because there is little adsorption of SSZS onto magnesite, NaOL can still adsorb onto magnesite’s surface.

Flotation separation of magnesite and dolomite regulated by synergistic effect of acid etching and inhibitors

ABSTRACT In this work, the synergistic effect of hydrochloric-acid etching and inhibitors on the flotation separation of magnesite and dolomite in the sodium oleate (NaOL) system was studied. Flotation tests revealed that the synergistic effect of acid etching and sodium hexametaphosphate, sodium alginate, and sodium lignosulfonate on the separation of magnesite and dolomite was poor. Meanwhile, the synergistic effect of acid etching with sodium carboxymethyl cellulose (CMC) could regulate the flotation separation of magnesite and dolomite over a wide pH range. Moreover, the synergistic effect of acid etching and CMC increased the flotation difference between magnesite and dolomite from 15.73% to 67.17%, and the selective separation index increased from 1.38 to 2.89. Characterization by atomic force microscopy revealed that acid etching altered the surface morphology of magnesite and dolomite, roughening their surfaces. Contact angle measurements, Fourier transform infrared spectroscopy analysis, and zeta potential measurements indicated that the synergistic effect of acid etching and CMC changed the wettability, charge, and adsorption performance of dolomite, selectively inhibiting the adsorption of NaOL onto the surface of dolomite, thereby inhibiting dolomite flotation. However, it has minimal effect on the floatability of magnesite.

Enhancing selective calcite and dolomite flotation in the phosphate ores: Investigation, modeling, and automated mineralogy assessment

This paper presents a comprehensive study on the selective flotation of a multi calcium-bearing minerals ore, focusing on the efficient removal of dolomite and calcite impurities from a carbonaceous sedimentary phosphate ore. Commercial fatty acid (FA) and phosphate ester collectors were investigated in a reverse flotation process, assessing the impact of flotation pH, collector dosage, and type on the selectivity and recovery of calcite and dolomite. The efficiency of FA-based collectors was recognized as they provided higher quality concentrates with reduced carbonated-fluorapatite contents. The response surface methodology was employed to review and model the effects of pH and dosage of each fatty acid collector on flotation performance. Accurate regression models were developed, forming the basis for an optimization study to determine the optimal operating conditions for achieving selective carbonate flotation with high carbonate grade and recovery while minimizing the carbonated-fluorapatite (CFA) content. Automated mineralogical microscopy was conducted on the phosphate ore and the recovered carbonate and phosphate concentrates, confirming the success of flotation while attributing the presence of 12% CFA (≈ 4 % de P2O5) in the carbonate concentrate to mineral associations and fines entrainment.

Reverse flotation separation of calcite/dolomite from hemimorphite based on their surface sulphophile and oxyphile affinity differences

This study attempts to selectively inhibit hemimorphite flotation using sodium sulphide and uncover the mechanisms behind it. With the use of a fatty acid collector, the flotation test results showed that sodium sulphide had a strong inhibition performance on hemimorphite flotation while having no adverse impact on calcite and dolomite flotation, which were consistent with the contact angle measurement results. According to the results of attenuated total reflectance-Fourier transform infrared spectroscopy and adsorption proportion measurement of sodium oleate, sodium sulphide can inhibit sodium oleate binding on hemimorphite surfaces while having no effect on calcite and dolomite surfaces. The sulphide species exhibited an extremely high binding affinity for the hemimorphite surface but not for the surfaces of the calcium/magnesium-bearing gangue minerals, as demonstrated by the X-ray photoelectron spectroscopy measurements. Because of the strong sulphophile affinity of zinc, when the sodium sulphide concentration was sufficiently high, an interface boundary layer of a liquid solution with the remaining sulphide species formed on the hemimorphite surface, preventing sodium oleate from binding on the hemimorphite surfaces and thus selectively inhibiting the hemimorphite flotation.

Effect of SO42- and PO43- on flotation and surface adsorption of dolomite: Experimental and molecular dynamics simulation studies

H2SO4 and H3PO4 are commonly used as depressants for flotation of dolomite from apatite. Unsatisfactorily, the dissociated anions such as SO42- and PO43- may cause trouble to the flotation. In this study, the effect of SO42-, PO43- on the floatability and surface adsorption of dolomite were revealed by experimental and molecular dynamics simulation studies. The results show that SO42- and PO43-, especially PO43-, have a negative effect on flotation of dolomite. The mechanism is that the presence of SO42- and PO43- could inhibit the adsorption of sodium oleate collector on the dolomite surface, and decrease its adsorption capacity. In addition, SO42- and PO43- could react with Ca2+ to form the hydrophilic CaSO4·2H2O and Ca(H2PO4)2, respectively, the synergistic effect resulted in a decrease in the surface hydrophobicity. As a result, the flotation of dolomite was inhibited. This study clarifies the adverse effects of dissociated anions on dolomite flotation, which also lays a foundation for the targeted removal of these ions in the next step.

Selective depression by using environment-friendly depressant pectin in apatite and dolomite flotation system

The difficulty of apatite and dolomite to be efficiently separated by froth flotation due to similar physical and chemical properties of both minerals in using fatty acid collectors without any depressants. In this study, pectin was explored as an efficient and environment-friendly depressant in flotation to separate apatite and dolomite. In the micro-flotation experiments, pectin displayed an intense depressing effect in dolomite flotation and slightly affected apatite flotation. Quantum chemical calculation was used to predicated the reactive site of pectin, the results demonstrated that oxygen atoms of COO, OH and COC in pectin display the most negative regions. The Zeta potential results indicated pectin was adsorbed on the dolomite surface selectively and depressed the adsorption of sodium oleate on the dolomite surface due to electrostatic repulsion effect. The Fourier transform infrared (FTIR) spectrum measurements uncovered that the selective separation of pectin was due to OH of pectin molecules. The Raman spectrum demonstrated that weak adsorption of pectin on the apatite surface was due to CO of pectin molecule, while the strong adsorption is regard as COO and COC of pectin for dolomite. XPS results indicated that COO of pectin can chelate with Ca2+ and Mg2+ of dolomite surface and depress dolomite flotation. Hence, pectin was be utilised as an eco-friendly and highly selective depressant.

Adsorption mechanism of green efficient chelating poly-L-aspartic acid in flotation separation of brucite and dolomite

Green and efficient reagents have gained considerable attention in flotation research, where poly-L-aspartic acid (PASP) is an effective reagent to realize the flotation separation of brucite and dolomite. The effect of PASP on the flotation of brucite and dolomite and its mechanism were studied using flotation tests and modern detection methods. Microflotation tests show that PASP can considerably reduce the flotation recovery of dolomite in the Sodium dodecyl sulfonate (‘SDS) system, whereas it only slightly affects the flotation recovery of brucite. Under ‘SDS, PASP can selectively reduce the contact angle of dolomite but only slightly affect that of brucite. Furthermore, atomic force microscopy detection and zeta potential tests demonstrate that PASP can strongly adsorb on the dolomite surface, considerably changing its roughness and potential value but slightly affecting brucite. The infrared spectrum analysis shows that PASP is selectively strongly adsorbed on dolomite, causing strong and weak ‘SDS adsorption on the surfaces of brucite and dolomite, respectively. Moreover, X-ray photoelectron spectroscopy demonstrates that PASP strongly impacts the Ca site of dolomite, and selective chelation of Ca is a key factor in inhibiting dolomite flotation.

Selective adsorption of the activator diammonium hydrogen phosphate in the reverse flotation separation of brucite and dolomite

To achieve efficient purification of brucite resources, diammonium hydrogen phosphate (DAP) was used as an activator to realize the reverse flotation separation of brucite and dolomite in a flotation system with dodecylamine (DDA) as the collector. The microflotation test reveals only a small difference between the flotation recovery of brucite and dolomite in the DDA system. The presence of DAP considerably improve the flotation recovery of dolomite and increase the flotation difference between the two minerals. The adsorption capacity measurements indicate that DAP selectively increase the adsorption capacity of dolomite for DDA but do not affect the adsorption capacity of brucite for DDA. Contact angle measurements reveals that DAP enhances the floatability of dolomite in DDA system and the difference in contact angle between brucite and dolomite. Zeta potential detection and Fourier transform infrared spectroscopy analysis reveal that the strong adsorption of DAP on dolomite is conducive to the adsorption of DDA on the dolomite surface but the presence of DAP do not affect the weak adsorption of DDA on the brucite surface. X-ray photoelectron spectroscopy results reveal that DAP strongly adsorbs on the characteristic Ca sites on the dolomite surface and that DDA has a strong adsorption ability on dolomite after DAP adsorption, which is beneficial for the targeted activation of dolomite flotation.

A novel depressant N,N-bis(phosphonomethyl)glycine for magnesite-dolomite separation and its mechanism

In this study a novel depressant, N,N-bis(phosphonomethyl)glycine (BPMG), is proposed for the beneficiation of magnesite from dolomite using sodium oleate (NaOL) as the collector. Laboratory flotation results show that BPMG selectively depresses the flotation of dolomite but has almost no effect on magnesite at an approximate pH of 10.0. In addition, wettability analysis reveals that differences in the NaOL adsorption characteristics due to BPMG pre-adsorption are responsible for the different flotation characteristics of the two minerals. According to the zeta potential and Fourier transform infrared spectra analysis, BPMG is adsorbed onto both magnesite and dolomite surfaces, with dolomite adsorbing strength considerably more than magnesite. Moreover, X-ray photoelectron spectroscopy results confirm that BPMG is adsorbed onto the dolomite surface by chelation between the calcium sites and the phosphonyl structure of BPMG, and on the magnesite surface by weak adsorption. As a result, BPMG is preferentially adsorbed firmly onto the dolomite surface rather than the magnesite surface. BPMG dominates the selective depression of dolomite when NaOL is used as the collector.

Insight into the inhibition mechanism of carboxymethyl cellulose for flotation of dolomite and fluorapatite: Experimental and DFT studies

The flotation separation of dolomite and fluorapatite is difficult due to the similar surface properties. In this study, carboxymethyl cellulose (CMC) was introduced as a depressant for flotation of dolomite and fluorapatite, the adsorption mechanism of CMC on the mineral surfaces was clarified by DFT calculations, XPS analysis, zeta potential and contact angle measurements. The results showed that CMC exhibited a strong inhibitory effect for dolomite under alkaline conditions due to the surface adsorption. Compared with the adsorption of CMC on two Ca sites or two Mg sites of dolomite (104) surface, CMC preferred to simultaneously adsorb at Ca site and Mg site to form a more stable bridge adsorption, the two O in carboxyl group of CMC could bond with Ca and Mg to form chemical adsorption. However, CMC could not be adsorbed on the surface of fluorapatite, and the presence of CMC did not affect the adsorption of collector on fluorapatite surface to make it hydrophobic. Thus, CMC can be used as an alternative depressant for the selective flotation separation of dolomite and fluorapatite.

An environment-friendly and highly effective inhibitor for flotation separation of brucite and dolomite in SDS system

ABSTRACT Brucite is a type of mineral resource containing structural water and high contents of Mg, and is popular in refractory and flame-retardant materials. Dolomite is a common mineral associated with brucite, and its presence reduces the purity of brucite and utilization efficiency of resources. Therefore, in the flotation system of sodium dodecyl sulfonate, the selective inhibition characteristic and inhibition mechanism of environment-friendly and highly effective inhibitor sodium alginate (SA) on dolomite in the flotation separation of brucite and dolomite were investigated. The flotation test shows that an SA dosage of 8 mg/L can achieve 77.92% difference in floatability between brucite and dolomite, and the flotation effect was verified using the selectivity index. The measurement of contact angle shows the stability of the SA effect, thereby demonstrating significant SA effect on dolomite and a small effect on brucite. Zeta potential detection and infrared spectrum analysis show that the adsorption capacity between SA and dolomite is considerably stronger than that between SA and brucite, which is another critical reason for the inhibition of SA on dolomite flotation. In addition, the interaction of SA with the two minerals and the reasons for its selective interaction with dolomite were analyzed using X-ray photoelectron spectroscopic detection. SA shows strong interaction with Ca sites and the O in the carboxyl group of the SA structure can chelate Ca.

Investigation of the effect of phosphoric acid as an acidic medium in flotation separation of dolomite from magnesite

Flotation separation of carbonate minerals is difficult because of their similar surface properties. A variety of collectors and depressants have been previously used to improve their separation in acidic or alkaline media. In the present study, the flotation of dolomite and magnesite in acidic to neutral pH was investigated using oleate as collector and hydrochloric acid or phosphoric acid as pH regulator. It was found that the recovery of dolomite was high and independent of pH while that of magnesite decreased with acid addition, especially when phosphoric acid was used. Results of mineral dissolution showed a higher dissolution of dolomite than magnesite in acidic pH, which therefore provides more calcium (than magnesium) ions to interact with the oleate collector. These results are in agreement with the larger quantity of oleate adsorbed/precipitated on dolomite than on magnesite revealed by the infrared spectroscopic study. Furthermore, the new PO4 species observed in the Raman and infrared spectra of these minerals at acidic pH when phosphoric acid was used may prevent mineral dissolution and/or collector adsorption. The surface passivation of magnesite therefore explain the decrease in magnesite flotation when using phosphoric acid as pH control.

The utilization of tamarind seed gum as a novel dolomite depressant in the selective flotation of apatite from dolomite

In this study, the separation of apatite from dolomite was first investigated by using tamarind seed gum (TSG) to depress the flotation of dolomite in sodium oleate (NaOL) collector system. The effects of pH and flotation reagents concentration were studied, and the results indicated that TSG could strongly depress the dolomite floatability rather than apatite floatability. A satisfactory separation effect was realized when pH was 9.0, TSG dosage was 10 mg/L and NaOL dosage was 40 mg/L, at which the recovery of single apatite and dolomite was 80.28 % and 3.46 % respectively, and the grade of P2O5 and the recovery of P2O5 of the concentrate was 35.86 % and 76 % respectively in mixed ore flotation experiments. To reveal the adsorption mechanism, the flotation reagents adsorption morphology, adsorption type, and adsorption site were analyzed through AFM images, zeta potential measurements, FT-IR spectra, and XPS spectra, respectively. It was found that TSG was adsorbed on apatite by hydrogen bond while adsorbed on dolomite by chemical bond. Hydrogen bond was weaker than chemical bond, thus NaOL could still express the strong adsorption on apatite surface when TSG was used as depressant, while TSG could impede NaOL to be adsorbed on dolomite. Therefore, TSG selectively restrained the flotation of dolomite, achieving the separation. Furthermore, the XPS results uncovered that the Ca and Mg of dolomite were the main active sites that react with TSG.

Activation of Dolomite Flotation by Ferrous Hydroxide and Carbonate

The major problem with Carlin-type gold deposit flotation is that the high dolomite content in the concentrate decreases the quality of gold. Further, the activation mechanisms involved in dolomite flotation are still not fully understood. Herein, the correlation of Fe2+ conversion with xanthate adsorption and dolomite flotation was investigated to reveal the effect of dolomite embedded with pyrite. Flotation tests suggested that Fe2+ rather than Fe3+ improved the floatability of dolomite from 20% to 45%. Contact angles and thermodynamic tests indicated that the hydrophobicity of Fe2+-modified dolomite corresponds to the adsorption of xanthate. Importantly, time-of-flight secondary ion mass spectroscopy (Tof-SIMS) and x-ray photoelectron spectroscopy (XPS) attributed the activation of dolomite flotation to the formation of Fe(OH)2 and FeCO3. The coordination model of flotation successfully elucidated the selective adsorption of xanthate between Fe(OH)2, FeCO3 and FeOOH surfaces. The density function theory (DFT) simulation calculation was performed to identify the reaction rate at the atomic level, and the density of states (DOS) was also conducted to verify the conclusions at the electronic level. This study presents important surface chemistry evidence for understanding and regulating the poor selectivity in the flotation of Carlin-type gold deposits.

Interaction of Ca2+, Mg2+ with dolomite (1 0 4) surface and its effect on caproic acid adsorption: DFT calculation

Ca2+ and Mg2+ are unavoidable ions in the flotation pulp of phosphate ore, but its influence mechanism on flotation of dolomite is unclear. In this study, the adsorption of caproic acid on dolomite (104) surface in the absence and presence of Ca2+ and Mg2+ was investigated by density functional theory (DFT) calculation. The results show that the caproic acid could stably adsorb on the surface of dolomite by chemical adsorption and hydrogen bond. Ca2+ could be adsorbed on dolomite surface by bonding with O(surf), meanwhile the O(surf) experienced a significant relaxation. The caproic acid could interact with O(surf) using Ca2+ as the medium to form a more stable structure, both O of caproic acid and O(surf) could form σ bond and a weak π bond with Ca2+, respectively. The zeta potential and contact angle measurements further showed Ca2+ could promote the adsorption of the fatty acid on the surface of dolomite and increase the surface hydrophobicity to enhance the flotation effect. Mg2+ did not bond with O(surf), and not affect the adsorption of the fatty acid on dolomite surface and the flotation effect.

Selective Flotation Behavior of Dolomite from Fluorapatite Using Hydroxy Ethylene Diphosphonic Acid as High-Efficiency Depressant

In the reverse flotation of fluorapatite and dolomite, high-efficiency depressors of fluorapatite have received considerable attention. In this paper, the depression mechanism of hydroxy ethylene diphosphonic acid (HEDP) was studied for the first time as a novel fluorapatite depressant on the surface of fluorapatite. The effect of HEDP on the flotation behavior of the two minerals was studied by single and mixed minerals in flotation tests. HEDP exhibited an excellent depression effect on fluorapatite flotation, whereas its adsorption on dolomite surface was minimal. Fluorapatite and dolomite were effectively separated by applying sodium oleate as a collector and HEDP as a depressant at pH 6.0. The depression mechanism of HEDP on fluorapatite was further analyzed via contact angle measurement, zeta potential and X-ray photoelectron spectroscopic (XPS) analysis. We found that HEDP seriously hindered the adsorption of sodium oleate (NaOL) on the fluorapatite surface and had a minimal effect on the dolomite surface. XPS analysis results indicate that the strong adsorption of HEDP on the fluorapatite surface can be attributed to the strong chelation between the electron-rich groups of HEDP and Ca ions on the fluorapatite surface. Therefore, HEDP is used as a selective depressant of fluorapatite in the fluorapatite–dolomite flotation–separation process.

New insights on depressive mechanism of citric acid in the selective flotation of dolomite from apatite

The effective separation of apatite and dolomite is always the focus of phosphate ore flotation research. The effect of citric acid (CA) on the flotation reaction of apatite and dolomite was studied. The flotation behavior of these two minerals was evaluated through micro-flotation experiment. The results of micro-flotation experiment indicate that CA has selective depression for apatite, but has no obvious depression for dolomite The depression mechanism of CA on apatite and dolomite was analyzed by infrared spectroscopy (FTIR), Zeta potential measurement and XPS analysis. CA adsorbed on apatite and dolomite to varying degrees via FTIR test and Zeta potential measurement. The results from XPS test showed that CA formed chemisorption on apatite surface to form organic complex, but not on dolomite surface. In addition, the results of adsorption amounts and mineral dissolution experiments further support the selective depression mechanism of apatite. Through adsorption amounts test and surface dissolution test, it is found that the surface of dolomite dissolves strongly, and a large amount of calcium ions are generated in the solution. Calcium ions can chelate with citric acid and consume citric acid. At the same time, the calcium density on the surface of dolomite is higher than that of apatite, and a large amount of dissolution occurs on the surface of dolomite. However, the density of remaining active sites on the surface of dolomite is still high, and sodium oleate can still be adsorbed on the surface of dolomite. The degree of surface dissolution of apatite is less. CA occupies the active sites on the surface of apatite, making it difficult for sodium oleate to adsorb on the surface of apatite, resulting in poor apatite floatability.

Flaxseed gum as new depressant in the separation of apatite and dolomite and its mechanism

Apatite was firstly separated from dolomite by utilizing flaxseed gum as depressant and NaOL as collector. Single mineral and apatite-dolomite binary mixed ore flotation experiments were performed. The results revealed that under the conditions of pH 8, flaxseed gum 40 mg/L and NaOL 40 mg/L, single apatite and dolomite recovery was 78.47% and 1.98% respectively. For the apatite-dolomite binary mixed ore flotation experiments, the P2O5 recovery and P2O5 grade of the concentrate was 76.43% and 39.39% respectively. Flaxseed gum could selectively depress dolomite flotation and achieve the separation of apatite from dolomite. Atomic force microscope (AFM), zeta potential measurements, Fourier transformed infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) were carried out to reveal the mechanism. The results revealed that flaxseed gum could not be adsorbed on apatite at pH 8, while it was chemisorbed on dolomite by the sites of Ca and Mg. Therefore, the NaOL could still be adsorbed on apatite at pH 8 and flaxseed gum could not impede it, but the further adsorption of NaOL on dolomite was hindered by flaxseed gum. Thus, flaxseed gum selectively depressed the flotation of dolomite and realized the separation of apatite from dolomite.

The Effect of Oleic Acid Emulsification using SPE on Fluorite and Dolomite Flotation.

Collector OA, oleic acid, is widely used industrially for fluorite flotation. Low selectivity, dispersibility and collecting capability of the OA collector are always observed. In this study, compared with flotation of dolomite, a collector mixture of OA and SPE (styrylphenol polyoxyethylene ether) demonstrated significantly better performances for the fluorite. An optimal mass ratio 4 : 1 OA : SPE was found, and the recovery of fluorite was increased from over 85 % to more than 94 % compared with pure OA. Furthermore, the dosage of the collector agent was reduced from 50 mg mL−1 to 20 mg mL−1, which did not negatively impact the recovery of dolomite. The results from the contact angle tests indicated that SPE selectively increased the surface hydrophobicity of fluorite but had little effect on dolomite. Besides, zeta potential measurements and IR analyses revealed that the addition of SPE led to strong chemical adsorption on the surface of fluorite, resulting in a significant difference in the flotation performances of the two minerals. Therefore, SPE‐emulsified OA is corroborated to prompt more selectivity and collecting capability on flotation of fluorite over dolomite.