Fluorite Recovery Research Articles

Flotation Separation of Fluorite from Calcite using an Efficient Depressant Nitrilotriacetic Acid in the NaOL System.

Fluorite and calcite were separated with nitrilotriacetic acid (NTA) as a depressant. The single mineral flotation experiment confirmed that with 40 mg/L NaOL and 80 mg/L NTA, the fluorite recovery and calcite recovery were 24.37 and 94.13%, respectively, at pH 9. Meanwhile, in the fluorite-calcite binary mixed ore flotation experiment, the calcite recovery and fluorite recovery were 75.50 and 26.84%, respectively, and the CaCO3 and CaF2 grade in concentrate was 74.32 and 25.61%, respectively. The results confirmed that NTA could be used as a depressant to selectively inhibit fluorite flotation. The mechanism study illustrated that NTA was selectively reacted with fluorite by chemical interaction between O of NTA and Ca of fluorite. The adsorption of NTA on fluorite will impede the interaction between fluorite and NaOL. NTA could adsorb on fluorite in three ways, while the dominant two ways were the complex between double O of NTA and Ca of fluorite in a vertical model and the complex between double O of NTA and Ca of fluorite in a horizontal model.

Floatability of Fluorite and Calcite Inhibited by Sodium Hexametaphosphate via Ultrasonic Activation

In order to separate fluorite and calcite inhibited in tungsten tailings, the effect and mechanism of using ultrasonic external field activation to separate fluorite and calcite inhibited by sodium hexametaphosphate in a sodium oleate system were investigated. After pretreatment with an ultrasonic external field with a frequency of 40 kHz and sound intensity of 0.56, 0.50 and 0.40 W/cm2, the flotation recovery of calcite could be increased from 16.08% to about 80%, while the flotation recovery of fluorite was only increased from 7.5% to about 20%, with a difference of 60% between the two flotation recoveries, and the larger the sound intensity, the shorter the pretreatment time and the smaller the ultrasonic input energy. The contact angle of the calcite surface increased, sodium oleate adsorption increased, and zeta potential decreased after ultrasonic pretreatment, while the contact angle, sodium oleate adsorption, and zeta potential of fluorite surface were less changed. The results of heat of adsorption and XPS measurements showed that more heat was released from the interaction between sodium hexametaphosphate and fluorite, and the Ca2p peaks on the surface of fluorite were shifted to a greater extent after the interaction, which inferred that the adsorption of fluorite and sodium hexametaphosphate was relatively easier and stronger. It is presumed that the ultrasonic pretreatment can bring the mineral surface to different degrees of desorption according to the adsorption strength of sodium hexametaphosphate, exposing Ca2+ active sites for sodium oleate adsorption, while expanding the floatability difference between fluorite and calcite.

An integrated experimental and computational investigation of N,9,10-trihydroxyoctadecanamide as a potential collector for the flotation separation of fluorite and calcite

Hydrofluoric acid production heavily depends on fluorite (CaF2), a mineral frequently occurring alongside other calcium-rich minerals such as calcite (CaCO3). To separate fluorite from calcite and other associated minerals, flotation is the primary method employed. Oleic acid serves as the most commonly used collector in fluorite flotation. However, oleic acid exhibits poor selectivity and limited solubility at low temperatures. A novel fluorite flotation collector, N,9,10-trihydroxyoctadecanamide (THODA), is developed through the modification of the polar functional group of oleic acid, carboxyl, to an N-hydroxy amide group. Additionally, two hydroxy groups are introduced at the double bond position of oleic acid. Flotation experiments demonstrate that employing THODA as a collector can yield a fluorite recovery of approximately 90%, while the recovery rate of calcite ranges between 10% and 20%. THODA exhibits a superior selectivity in the flotation separation of fluorite and calcite compared to oleic acid. Zeta potential experiments reveal that following the treatment with oleic acid, the zeta potential of calcite surface rapidly decreases, whereas after the treatment with THODA, the zeta potential of calcite surface decreases to a lesser extent. This suggests that, under identical dosage conditions, THODA adsorbs less onto calcite surface compared to oleic acid. Consequently, THODA exhibits a weaker ability to collect calcite in comparison to oleic acid, thereby resulting in its enhanced selectivity over oleic acid.

Potential of low-grade fluorite ore of Landi Kotal, Khyber Pakhtunkhwa Province, Pakistan

This paper describes the results of a beneficiation study conducted on low-grade fluorite ore. The study was aimed at the development of a suitable beneficiation process to produce chemical grade fluorite concentrate. The representative sample of the ore was up-graded by leaching and flotation process. The important parameters of froth flotation process were optimized to obtain highest grade and recovery of fluorite concentrate. A single-factor variation method was applied to get the optimum conditions of the process. The rougher concentrate was reground to liberate fine locked fluorite particles and two cleaning flotation were employed in close circuit to achieve higher grade concentrate. A process flowsheet was designed in the light of these tests. After optimization of process parameters, the fluorite ore containing 62.24% CaF2 could be upgraded to a concentrate assaying 97.55% CaF2 with an overall recovery of 92.73%. The prepared fluorite concentrate meets the specifications of chemical grade and is suitable for production of fluoride based chemicals. Bangladesh J. Sci. Ind. Res. 58(2), 107-118, 2023

Selective Adsorption of Sodium Silicate on the Surface of Bastnaesite and Fluorite in Salicylhydroxamic Acid System under Alkaline Conditions

During the flotation separation process of bastnaesite, it is difficult to separate bastnaesite from fluorite effectively. In this present study, sodium silicate (SS) can effectively improve the flotation separation effect of bastnaesite and fluorite in salicylhydroxamic acid (SHA) systemasa. Through relevant analyses, such as Zeta potential measurements, adsorption capacity tests, Fourier transform infrared (FTIR) spectroscopic analyses and X-ray photoelectron spectroscopy (XPS) tests, the selective suppressor of SS on fluorite was proven. At pH 10, the single mineral flotation results show that with the increase of SS dosage, the flotation recovery of fluorite rapidly decreases from 61.5% to 35.31%, while the flotation rate of bastnaesite is still high (recovery is 80.02%). Then, the experiment of artificial mixed ore proved that the flotation separation of fluorite and bastnaesite was effective under the appropriate dosage of inhibitor. The results of potentiodynamic measurement and an adsorption capacity test showed that the SiOOH3− structure of SS more easily reacted with fluorite, which further prevented the adsorption of SHA on the fluorite surface. FTIR test results and XPS analysis further showed that SS had a strong binding effect with the Ca site on the fluorite surface, but a weak binding effect with the Ce site on the bastnaesite surface. Consequently, SS can be used as an effective inhibitor in the flotation separation of fluorite and bastnaesite.

Selective adsorption of trisodium nitrilotriacetate on calcite and its application for the separation of fluorite minerals

The recovery of fluorite from calcium-bearing carbonate ores by foam flotation is challenging due to low separation efficiency. Herein, we studied the effect of trisodium nitrilotriacetate (TN) addition on the surface properties of calcite and fluorite. For this purpose, we performed micro-flotation tests and carried out zeta potential measurements as well as Fourier transform infrared (FT-IR) and X-ray photoelectron (XPS) spectroscopic measurements to analyze the surface properties of these minerals.The addition of TN as a novel depressor significantly improved the effect of calcite and sodium oleate (NaOl) on the flotation-based fluorite recovery and separation from calcite. TN interacted with fluorite via an electrostatic interaction according to the zeta-potential and XPS analyses. The interaction of TN with calcite was via electrostatic attraction and chemical adsorption. Preferential chemical adsorption of NaOl replaces TN from the fluorite surface. However, calcite preferentially adsorbs TN due to the chemical bonding between carboxyl of TN and the hydrated calcite surface layer, which chemically modifies the original calcite surface. This work also suggests interaction and adsorption mechanisms between TN and calcite.

Combined inhibitors of Fe3+, Cu2+ or Al3+ and sodium silicate on the flotation of fluorite and quartz

Fluorite ore, as an essential raw material in the fluorinated chemical industry, required effective separation and purification. The removal of impurities such as quartz becomes the key point in fluorite flotation. In this work, the fluorite flotation tests via adding the different mass ratios of metal ions (Fe3+, Cu2+, Al3+) and sodium silicate (SS) as a combined inhibitor, were carried out on a laboratory scale. Results indicated that when the mass ratio of SS to Fe3+, Cu2+, and Al3+ was 3:1, 1:1, and 3:1, the fluorite recovery reached 75.01%, 83.56%, and 81.84%, while quartz recovery was only 9.20%, 6.09%, and 4.76%, respectively. In addition, the action mechanisms of the combined inhibitors were investigated and evaluated in-depth. Compared with the single inhibitor of SS, the results of contact angle measurements, Zeta potential measurement, and Fourier transform infrared spectroscopy showed that the combined inhibitor could attenuate the activation of Ca2+ on quartz, and therefore to avoid the quartz mismatching into fluorite concentrates. Therefore, it provides an alternative separation method to realize high-efficient flotation of the fluorite and quartz with the presence of metal ion inhibitors.

Flotation separation of bastnaesite from fluorite with an eco-friendly depressant polyepoxysuccinic acid and its depression mechanism

In this work, an eco-friendly depressant polyepoxysuccinic acid (PESA) was introduced for the flotation separation of bastnaesite from fluorite using octyl hydroxamic acid (OHA) as the collector. The depression effect and mechanism of PESA on the fluorite and bastnaesite were investigated by micro-flotation tests, contact angle, adsorption experiments, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The flotation results showed that the recovery of fluorite decreased by 89.71% when 4 mg/L PESA was added to the flotation system, while the bastnaesite recovery only exhibited a slight reduction of 2.88% under these conditions. Wettability results suggested that the PESA in the presence of OHA could make the fluorite surface hydrophilic, whereas it had a negligible impact on the hydrophobicity of the bastnaesite surface. The addition of PESA could impede the OHA adsorption on fluorite surface, which was revealed by adsorption tests and FT-IR, and the XPS analysis confirmed that the chemisorption of PESA on the Ca sites of fluorite occurred. For bastnaesite, the adsorption of OHA still could be detected, making the bastnaesite well floatable. Therefore, the efficient separation of bastnaesite from fluorite could be achieved with the PESA as a selective depressant.

Selective flotation separation of fluorite and calcite by utilising a novel anionic/nonionic collector

The efficient separation of complex associated fluorite and calcium-containing gangue minerals is difficult to achieve using a traditional fatty acid collector due to the poor selectivity and adaptability of such collector. This study utilised a novel anionic/nonionic collector, namely, a mixture of sodium oleate (NaOL) and oleamide, to investigate selective adsorption onto fluorite and calcite surfaces. Flotation tests were conducted to study the flotation performance of fluorite and calcite, and X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) analyses were performed to identify the reaction mechanism of an anionic/nonionic collector on mineral surfaces. The anionic/nonionic collector exhibited excellent selective capability for fluorite. Calcite recovery decreased to 45% when the molar ratio of NaOL and oleamide was 8:2, whilst fluorite recovery was maintained at 85%. The changes in binding energy and atomic content indicated that the adsorption of NaOL/oleamide onto the fluorite surface was stronger compared with that onto the calcite surface. Adsorption morphology showed that the mixed micelles of NaOL and oleamide were uniformly adsorbed onto the fluorite surface as bulks, demonstrating tight multilayer adsorption. Meanwhile, the adsorption of mixed micelles onto the calcite surface was sparse, which resulted in the poor hydrophobicity of calcite surface and providing a basis for the selective separation of fluorite and calcite.

Resource utilization of waste oil in kitchen waste: preparation of renewable collector for cleaner flotation of high-sulfur fluorite ore

ABSTRACT Waste oils from kitchen waste pose a significant environmental threat. Meanwhile, desulfurization treatment of high-sulfur fluorite ore is also a challenge due to the harmfulness of sulfur. Thus, this study focuses on the preparation of collector from waste oil for the separation of high-sulfur fluorite ore in order to eliminate the environmental threat of the two waste. The flotation kinetic characteristics of pyrite with renewable collectors were studied and the kinetics analysis shows that the rapid flotation of pyrite with different grain sizes could be achieved. Thus, the pre-desulfurization process of high sulfur fluorite ore was proposed. Subsequently, the flotation efficiency of renewable collector on desulfurized fluorite ore was verified. The flotation results illustrate that 83.85% of sulfur can be removed with xanthate dosage of 60 g/t. Further, the sulfur content in the fluorite concentrate can be reduced to 0.02% with 91.52% fluorite recovery by single flotation test with 1.7 kg/t renewable collector dosage. Moreover, the closed-circuit flotation process was designed, fluorite concentrate with CaF2 grade of 97.08% can be obtained, and the sulfur content is only 0.04%. An innovative flotation process of high-sulfur fluorite using renewable collectors prepared from waste oils is proposed, which realized the high-value utilization of waste oils and high-sulfur fluorite.

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.

Effect of Fluoride Ion on the Separation of Fluorite from Calcite Using Flotation with Acidified Water Glass

As a common depressant, acidified water glass (AWG) has strong inhibitory effects on fluorite and calcite. The inhibited fluorite is difficult to be recovered, thus resulting in the waste of resources and low flotation efficiency. In this study, the interaction of fluoride ions with fluorite and calcite surfaces was investigated, and its effects of AWG adsorption on mineral surfaces were evaluated. Micro-flotation experiments indicated that the flotation recovery of fluorite is 88.72% after fluoride ion treatment, that is, approximately fourfold with respect to that without fluoride ion modification. The results of solution chemical calculations showed that SiO(OH)3− is the main component to inhibit fluorite, and Si(OH)4 is the main component to inhibit calcite in AWG solution. XPS and ICP-MS results showed that fluoride ions can improve the floatability of fluorite by converting CaSiO3 on the surface of fluorite into CaF2, but the conversion ability of Si(OH)4 on the surface of calcite is weak, which increases the difference in floatability between fluorite and calcite. The above results were further verified by the analysis of flotation foam image and contact angle measurement. After fluorine ion treatment, the contact angle of fluorite increased, and it was more easily adsorbed on the foam. Therefore, the interaction of the fluoride ion with the fluorite surfaces eliminated the adsorption of AWG on fluorite, thereby resulting in the enhanced hydrophobicity of fluorite. Different from the traditional metal ions modification, the idea of anion modification in this paper is expected to be further studied.

Effect of active substance content and molecular weight of petroleum sulfonate on fluorite flotation: Molecular dynamics simulation

Fluorite is an important non-metallic mineral, and the most efficient way to separate it from gangue is flotation. The commonly used collectors are oleic acid and oxidized paraffin soap, but those two collectors both have a problem of bad solubility, this phenomenon worsens at low temperature. Sodium petroleum sulfonate exhibits a good collecting performance on fluorite, but it has not been systematically studied. In this paper, different types of sodium petroleum sulfonate were used to evaluate the effect of active substance content and average molecular weight. Molecular dynamics simulation was used to understand the mechanism that causes the flotation difference between mono-sulfonate and di-sulfonate. This study identifies that active content has a positive effect on the flotation recovery of fluorite while the molecular weight plays a negative role. The reason why di-sulfonate’s performance is relatively weak at high concentration lies on the steric-hindrance effect, larger cross-sectional area limits the tail–tail interaction between sulfonates.

Flotation behavior and mechanism of styrene phosphonic acid as collector on the flotation separation of fluorite from calcite

SPA was selected as the collector to separate fluorite from calcite. The greatest difference of recovery of fluorite and calcite was achieved with SPA dosage of 20 mg/L and pH 6.0, at which the recovery of fluorite and calcite was 98.79% and 12.55% respectively. The AFM 3D images of fluorite and calcite in the absence and presence of SPA revealed that the amount of SPA adsorbed on fluorite was much more than that on calcite, which accounted for the difference of flotation recovery. The flotation adsorption mechanism of SPA on fluorite was further explored by FT-IR, zeta potential measurements, XPS and first-principles calculation. It was found that SPA was adsorbed on fluorite surface by chemical interaction, and the calcium atom on fluorite was the main active site to react with SPA. The species distribution diagram of SPA in different pH revealed that when pH was 6, the main species of SPA were monovalent ion (C8H7PO3H−) and divalent ion (C8H7PO32−). Thus, there were three possible adsorption models for SPA to be adsorbed on fluorite surface, including coordination between single oxygen and single calcium, coordination between double oxygen and single calcium, and coordination between double oxygen and double calcium. The first-principles calculation demonstrated that among these three possible adsorption models, the adsorption model of coordination between single oxygen and single calcium was the most possible adsorption model.

Hydrophobic behavior of fluorite surface in strongly alkaline solution and its application in flotation

Normally fluorite was collected by fatty acid collectors at pH 5–11, rendering the surface to be hydrophobic. In this study, we found that fluorite surfaces are naturally hydrophobic at high pH without any surfactant, which is beneficial for the selective flotation separation of fluorite from calcite. In a flotation test, fluorite recovery showed a decreasing trend at alkalescent pH but increased at high pH. Sum-frequency generation spectroscopy spectrum confirmed that the orientation and hydrogen bonding structure of the water molecules are dramatically changed at fluorite/water interface. Moreover, a new signal peak, wavenumber of 3657 cm−1, appeared under strongly alkaline conditions; this peak is normally attributed to free OH stretching region and indicates a hydrophobic surface. Meanwhile, the results of contact angle and atomic force microscopy measurements show that the hydrophobicity obviously increases at pH 13. Therefore, the surface structure of fluorite must undergo some significant changes, which will play an important role in the flotation of fluorite.

Flotation separation of fluorite from calcite by using psyllium seed gum as depressant

Separating fluorite and calcite through flotation is difficult due to their similar Ca2+ sites on the adsorption surface of collectors. Psyllium seed gum, a reagent naturally derived from psyllium seed, was used for the first time as an efficient depressant in the flotation separation of fluorite and calcite. Micro-flotation experiments showed that psyllium seed gum had a strong depressing effect on calcite at a wide pH range (8–12). Calcite recovery was significantly and sharply reduced from 97.38% to less than 10% in the presence of psyllium seed gum at pH 9.0. By contrast, fluorite recovery was slightly affected by psyllium seed gum and maintained above 90%. FTIR analysis, XPS analysis, and adsorption test were conducted to determine the selective depression mechanism of psyllium seed gum on these two minerals, and the results show the adsorption effect and capacity of psyllium seed gum were stronger and higher on the calcite surface than on the fluorite surface. Owing to the high electronegativity and powerful electron-gaining ability of CO32−, many electron clouds moved from the hydroxyl groups of psyllium seed gum to the Ca, C, and O elements on the calcite surface. A large amount of psyllium seed gum was chemisorbed on the calcite surface by reacting with Ca2+ site and preventing NaOl adsorption. On the contrary, psyllium seed gum barely affected NaOl adsorption on the fluorite surface. In this case, the efficient flotation separation of fluorite from calcite is realized.

Flotation separation of fluorite from calcite using sulfonated lignite as depressant

In this study, sulfonated lignite (SL) was studied as the depressant in the separation of fluorite and calcite with sodium oleate (NaOL) as the collector. The flotation recovery of fluorite and calcite with and without depressant SL was investigated by micro-flotation test. The mechanism of the depressant was studied through Fourier transform infrared spectroscopy (FTIR) analysis, contact angle analysis and X-ray photoelectron spectroscopy (XPS) analysis. The micro-flotation experiment showed that sulfonated lignite had an effective depression effect on calcite. FTIR results illustrated that sulfonated lignite was selectively absorbed on the calcite surface and NaOL could still be absorbed on fluorite surface with depressant sulfonated lignite. Contact angle analysis demonstrated that depressant sulfonated lignite could significantly increase the hydrophilicity of calcite surface with NaOL as the collector. However, the surface of fluorite was still relatively hydrophobic with depressant SL and collector NaOL. XPS results illustrated that sulfonated lignite was adsorbed on the calcite surface through the interaction of the carboxyl groups of the depressant with the Ca atom on the calcite surface. Therefore, sulfonated lignite could be used as a potential depressant in the flotation system of fluorite and calcite.

Evaluation of the influence of the dispersion-sludge characteristics of the pulp on the beneficiation indicators of technogenic fluorite-containing tailings

The article provides an assessment of the technological features of mature tailings from the processing of finely disseminated fluoritecontaining raw materials of the Yaroslavkaya Mining Company. The prospects for their secondary processing are considered. It has been established that the waste stored in various sectors of the enterprise’s tailings contain from 13 to 23% fluorite, 12-14% calcite. The characteristic is given to the technological features of raw materials. The fluorite grains present in the technogenic tailings are characterized by the presence of thin inclusions and veins of silicate minerals. An obstacle to the selective separation of minerals by the flotation method is the shielding coatings of the surface zone of mineral particles, formed from contact with reagents at the stage of primary ore processing and in the process of interaction with the water-air environment in the tailing dump. The ways of increasing the contrast of the adsorption properties of minerals are proposed. Important factors influencing the process of mineral selection, allowing to influence the quality characteristics of flotation of refractory secondary raw materials is fine grinding of the material in combination with a high degree of dilution of the pulp. The possibility of extracting concentrates with a CaF2 content of 95.2-95.6% with the recovery of fluorite in them of 57-60.7% is shown. The introduction of inter-cycle regrind of foam products into the operation scheme allows to reduce the content of silicone dioxide in concentrates to 0.98%, which meets the requirements of consumers.

Study of the prospects for expanding the range of collectors in the flotation of fluorite from technogenic raw materials

The results of studies on the development of a technology for the extraction of fluorite concentrates from finely disseminated refractory technogenic raw materials from Primorsky deposits were presented. The account of the technological features of the stale tailings of the concentration plant of Yaroslavkaya Mining Company has been given. The necessity of fine grinding of the material and careful selection of reagent compositions providing the required flotation selectivity has been substantiated. The fundamental possibility of obtaining fluorite concentrates containing CaF2 up to 94% and more using several samples of collectors from the group of fatty acids has been established. Fatty acids of tall oil produced by Ust-Ilimsk timber processing complex and a mixture of fatty acids produced in India, branded MASOIL 1880, provide a sufficient level of flotation selectivity. The recovery of fluorite in an open enrichment cycle according to the scheme with seven cleanings of the foam product can be 61.85-63.84%. The use of collectors compositions promotes an increase in the selectivity of the adsorption of reagents, which is accompanied by an increase in the selectivity of their action in comparison with the results obtained with the dosage of certain brands of the tested reagents into the flotation process. The extraction of fluorite into a concentrate obtained using a combination of tall oil and MASOIL-S fatty acids in a 1:1 ratio was 59.55-66.27% with a content of 95.6-94.23% CaF2 in it, respectively.

IMPROVING FLUORITE FLOTATION UNDER LOW TEMPERATURE AND NEUTRAL pH CONDITIONS

The authors provide insight into the problem of selective flotation of fluorite from quartz–fluorite ores. The flotation of fluorite mineral from ores by using acidized water glass as depressant has been studied for substitution of the commonly used depressant. It was found that the acidized water glass could achieve higher selectivity of fluorite minerals against gangue minerals in the fluorite flotation. The experimental results showed that YF collector has high selectivity in the flotation of fluoride for low-grade fluorite ores. The use of the YF collector also made it unnecessary to heat the pulp to a high temperature and achieved an acceptable reduction in the flotation temperature to [Formula: see text]C. The YF collector should be used in neutral pH to separate fluorite from gangue and it could also improve fluorite recovery and flotation rate.