Fluorite Flotation Research Articles

The anionic flotation of fluorite from barite using gelatinized starch as the depressant

As an important non-metallic mineral widely used in industry, fluorite is normally associate with barite in nature. Anionic flotation is the most efficient method to separate fluorite from barite in mineral processing while the critical point of successful separation lies on the depressant. A cheap and eco-friendly depressant, corn starch, has been gelatinized and introduced in this study. Microflotation experiments showed that the fluorite and barite presented non-selectivity in flotation with the addition of anionic collector, sodium oleate (NaOl). By use of the gelatinized starch (GS), barite was selective depressed, leading to the high separation efficiency. The phenomenon was confirmed by the flotation of artificial mixed minerals. Zeta potential measurements demonstrated that NaOl can be adsorbed on the fluorite surface while it cannot interact with the barite in the presence of GS. X-ray photoelectron spectroscopy (XPS) indicated that the adsorption of GS on the fluorite surface mainly through physical bonding while the stronger hydrogen bonding may determine the interaction between GS and barite surface.

The Role of Gangue Mineralogy on Flowsheet Development in Fluorite Processing

Fluorite, CaF2, is considered a strategically important mineral as it is a raw material for many strategic industries. Froth flotation is reported to be the most efficient and economically viable process for the production of an acid-grade product with a CaF2 content of at least 97%. Selective flotation of fluorite from gangue minerals, e.g., calcite and barite, is challenging because these minerals have similar physicochemical properties. This study employed batch flotation tests coupled with mineralogical analysis to design suitable customised flowsheets and efficiently optimised reagent regimes for optimum production of acid-grade fluorite concentrate from two different fluorite ores by the froth flotation process. The effect of pulp temperature on fluorite flotation was investigated in this study with the objective of lowering pulp temperatures in fluorite flotation. The results showed that an acid-grade CaF2 concentrate could be obtained from the flotation of both ores at ambient pulp temperatures. This eliminates the requirement for high-temperature pulp treatment, which would result in a significant reduction in thermal energy costs. This study showed that an understanding of gangue mineralogy is key to process optimisation for acid-grade CaF2 production. Although an acid-grade CaF2 concentrate could be produced from both ores, the flowsheets and reagent regimes were markedly different. For instance, the production of an acid-grade CaF2 product from a high quartz and calcite ore was achieved by employing a simple rougher–multiple cleaner flotation circuit using tannin and sodium silicate as calcite and quartz depressants, respectively. On the other hand, the production of an acid-grade CaF2 product from the flotation of the pyritic ore required a pre-sulphide flotation stage for upfront sulphur removal and the use of a sulphide depressant. Multiple stages of cleaning were required for improved selectivity in the flotation of both ores.

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.

Flotation mechanism of a novel synthesized collector from Evodiaefructus onto fluorite surfaces

In this study, a new collector for fluorite flotation was synthesized from EvodiaeFructus oil and comprised by mixing sodium fatty acid and fatty acid amide. The relationship between the flotation behavior and mechanism of the collector onto fluorite was evaluated using micro-flotation tests, zeta potential, AFM measurements and quantum mechanics simulation. The flotation results showed that this synthesized collector could float fluorite very well in a pH range of 8.5–9.5 at the acid number of 120 mgKOH/g and it exhibits excellent collecting capacity for fluorite even at low slurry temperature (6.5 °C). The zeta potential of fluorite becomes more negatively-charged at around pH 8.5, indicating that the adsorption of hydrophobic anions in the collector onto fluorite surfaces. AFM analysis data correlated with quantum mechanics simulation results showed that compared to sodium oleic acid or oleamide, their mixture has a better chemical adsorption ability on fluorite surfaces.

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.

1-Hydroxyethylidene-1,1-diphosphonic acid used as pH-dependent switch to depress and activate fluorite flotation I: Depressing behavior and mechanism

Fluorite is usually separated from calcite by froth flotation method using large amounts of sodium silicate depressant, which can cause trouble in the loss of fluorite and wastewater treatment. In this study, green and low-cost 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP or H4L) was used as pH-dependent switch to initially depress fluorite for calcite pre-removal at pH 6.0, and then activate fluorite for further upgrading fluorite concentrate at pH 8.0. The depressing behavior and mechanism were reported in this work. H2L2− was the dominant form of HEDP, and a stronger chemical adsorption of H2L2− on fluorite hindered the subsequent adsorption of sodium oleate (NaOL), while that of the calcite showed the opposite result. Two active O atoms in H2L2− could well match in interatom distance with two Ca sites on fluorite to form Ca-H2L complexes. The pH-dependent switch reagent reported here may open a new avenue for more selective separation among mixed mineral systems.

Clean utilization of waste oil: Soap collectors prepared by alkaline hydrolysis for fluorite flotation

Abstract An innovative approach of clean utilization of waste oil is proposed to reduce the risk of environmental pollution and achieve cleaner production of fluorite. The waste oil in kitchen waste was first separated from solid waste and waste water. Further, alkaline hydrolysis was succeeded in preparing soap collectors by saponification reaction. Further, the fluorite flotation was conducted to verify the applicability of the renewable collectors. The results of FT-IR show that the characteristic peaks of the renewable collector appear on the particle surface after the adsorption treatment, which indicates that the collector can be effectively adsorbed. Effect of renewable collector on the charge properties of fluorite surface was analyzed and results show that the electronegativity of particle surface is enhanced after adsorption, which indicates that chemisorption can occur under alkaline conditions. The flotation test results show that the renewable collector has excellent separation effect on fluorite. The flotation kinetic analysis indicates that the four kinetic models have ideal applicability for describing the flotation behavior of renewable collectors for fluorite. The research results reveal the optimistic prospect of harmful waste oil transformation into collectors, and have potential industrial application prospects.

Impact of gypsum on flotation of scheelite and fluorite using sodium oleate as collector

ABSTRACT In this study, effect of calcium and gypsum on scheelite and fluorite was investigated using sodium oleate as collector. Micro-flotation and contact angle results showed that the adsorption of calcium could inhibit the hydrophobicity of scheelite and fluorite. Moreover, sulfate could enhance the inhibition. FT-IR results showed that calcium could be priori precipitated into calcium oleate and adsorb on mineral surface. The adsorption of calcium could increase the scheelite potential to IEP, while it showed limited effect on fluorite potential. However, the interaction of calcium on scheelite and fluorite in gypsum solution was more complex than that in calcium solution.

Rheological investigations on the hetero-coagulation between the fine fluorite and quartz under fluorite flotation-related conditions

In this paper, the particle interaction between the fine fluorite and quartz (all less than 10 μm) and its effect on the fluorite flotation were studied mainly by rheological measurements, optical observation and micro-flotation tests. Sodium oleate was used as the fluorite collector. The yield stress, which is a rheology parameter, was utilized to quantify the aggregation degree of the particles and evaluate the strength of the net-work structures in flotation slurry. The yield stress value of fine fluorite slurry as a function of the solid concentration, pH, percentage of the fine quartz and collector concentration was measured. The rheological measurements and the optical observation results show that the fluorite particles could partially aggregate into flocs in the pH range of 5–10 and form net-work structure in suspensions, while quartz particles could not aggregate across the whole pH range tested. When quartz and fluorite particles were mixed in water, the yield stress of the mixed mineral slurry was much higher than that of the single mineral slurry, demonstrating a strong hetero-coagulation between the two minerals. The flotation performance of the fine fluorite particles with different degree of hetero-coagulation (caused by the different percentage of fine quartz) was tested. The hetero-coagulation exhibited a detrimental effect on the fluorite flotation, manifesting as decreased flotation recovery and decreased flotation rate. It was found that the hetero-coagulation deteriorated the fine fluorite flotation by forming strong net-work structures that could interfere with the rising processes of the bubbles carrying valuable mineral particles. The research provides a new way for quantifying the particle interactions and may potentially be used for regulating the flotation operations in the fluorite flotation plants.

Use of Al2(SO4)3 and acidified water glass as mixture depressants in flotation separation of fluorite from calcite and celestite

To cope with the increase of sulfate gangue minerals in fluorite ores, flotation separation of fluorite from calcite and celestite using Al2(SO4)3 and acidified water glass (AWG) as mixture depressants was studied in this paper. The flotation separation performance and underlying mechanism were studied by flotation experiments, zeta potential measurements, microcalorimetric analysis, adsorption measurements, and X-ray photoelectron spectroscopy (XPS). The flotation results show that under optimum conditions, the inhibition effect of AWG on celestite is more remarkable with the assistance of Al2(SO4)3, but has no obvious effect on the flotation of fluorite. Zeta potential measurements show that both positively charged Al species and negatively charged Si species are adsorbed on the surface of the minerals. Microcalorimetric analysis confirms that the interaction between Al2(SO4)3 and celestite is more intense than that of calcite and fluorite, while AWG is more likely to be adsorbed on the calcite surface. Adsorption measurements reVeal that there is competitive adsorption between the depressant and collector and that the adsorption of the depressant AWG prevents the collector NaOL from adsorbing on the surface of the minerals. The XPS results show that Al species and Si species are chemically adsorbed on the surface of the minerals and change the chemical surroundings of the elements on the mineral surface. Moreover, compared with fluorite, Al species can more clearly enhance the adsorption of Si species on the celestite surface.

Mitigating the coating of fine quartz in fluorite flotation using a triblock copolymer

Slime coating is a common problem in mineral flotation and this study explored a novel idea to mitigate slime coating to improve mineral flotation. Guided by the previous work, Pluronic triblock copolymer F-127 (PEO100PPO65PEO100) was chosen to mitigate fine quartz coating in fluorite flotation. Then the mechanism underpinning the mitigation of fine quartz coating on fluorite surface by F-127 and the interaction of F-127 with collector sodium oleate on quartz and fluorite surfaces were studied. It was found that F-127 adsorbed on both quartz and fluorite surfaces and therefore mitigated fine quartz coating on fluorite surface through steric repulsion. The adsorbed F-127 on fluorite surface also enhanced the adsorption of sodium oleate but had little effect on the adsorption of sodium oleate on quartz surface. The mitigation of fine quartz coating and enhanced adsorption of sodium oleate on fluorite surface explain the significantly improved fluorite flotation in the presence of fine quartz particles after the addition of F-127.

Application of Raman spectroscopy to the flotation process of fluorite

Exact knowledge of the content of the various components in a flotation system is critical in both product analysis and process control. In the present work, FT Raman spectroscopy was successfully applied to an industrial fluorite flotation system for quantification of calcium fluoride (CaF2). In a first step, an artificial model system consisting of CaF2, barium sulphate and silica was set up to test feasibility of FT Raman spectroscopy and to generate a calibration curve. An empirical model was developed, which incorporates effects of particle size on Raman shift and peak area, so that a CaF2 quantification is feasible independent of particle size. Conversely, the empirical model provides information about the approximate particle size in the analysed sample. A cross-validation using X-ray fluorescence spectroscopy showed excellent quantification of CaF2 in seven industrial fluorite samples with CaF2 weight fraction in a range from 7% to 98% with absolute differences of less than 5%. In a first laboratory batch-flotation experiment, the CaF2 content of the froth product could be quantified successfully providing additional information about the approximate median particle size of the concentrate, making FT Raman spectroscopy superior to commonly applied X-ray fluorescence spectroscopy.

Selective flotation of fluorite from barite using trisodium phosphate as a depressant

In this paper, trisodium phosphate (TSP) was utilized for the flotation separation of fluorite from barite. Micro-flotation results showed that good floatability of both fluorite and barite was obtained at around pH 8.5 using sodium oleate (NaOL) as a collector. TSP showed a selective depression for barite, and flotation separation of fluorite from barite was achieved using TSP as a depressant and NaOL as a collector. Zeta potential measurements indicated that the addition of TSP prior to NaOL did not prevent the adsorption of NaOL on fluorite surface while it prevented NaOL to adsorb on barite surface.

Separation of bastnäsite from fluorite using ethylenediamine tetraacetic acid as depressant

Bastnäsite is an important mineral resource in the production of rare earth materials and is usually beneficiated by flotation. The flotation of bastnäsite is problematic due to the competitive adsorption of hydroxamate collector on bastnäsite and its associated calcium-bearing gangue minerals such as fluorite. One strategy to solve this problem is to use effective depressants to depress the gangue minerals. However, the current depressants all have some drawbacks. In this study, the effect of ethylenediamine tetraacetic acid (EDTA) as a depressant was tested in the flotation of single mineral of bastnäsite and fluorite and their mixture. The mechanism underpinning the role of EDTA was investigated through theoretical thermodynamic calculation, zeta potential and X-ray photoelectron spectroscopy (XPS) measurements. The results show that fluorite was significantly depressed, while the flotation of bastnäsite was almost unaffected when EDTA was present. The separation index between bastnäsite and fluorite increased from 1.18 to 12.66 with the increase of EDTA concentration from 0 to 7.79 kg/t. It was found that EDTA could dissolve the chemically adsorbed octyl hydroxamic acid (OHA) on fluorite through the formation of soluble Ca-EDTA complexes, whereas the chemically adsorbed OHA on bastnäsite was more stable and could not be transformed into Ce-EDTA spontaneously. Therefore, the flotation of fluorite was selectively depressed by EDTA. The results show that EDTA was a promising depressant for fluorite gangue mineral in bastnäsite flotation.

Optimal Depressants and Collector Dosage in Fluorite Flotation Process Based on DoE Methodology

Alternative processes have been proposed for selective separation of fluorite and gangue minerals (carbonates and silicates) present in fluorspar ores. Calcination and gravity separation processes are methods that have low efficiency and high cost. Flotation is a chemical process that becomes important when high ore grades are required; however, the selectivity is inhibited by the superficial similarity of the chemical composition of minerals. Accordingly, interactions between dissolved ionic species of fluorite, carbonates, and silicates with some reagents under determinate conditions obstruct the flotation process. In order to optimize the flotation process of a Spanish fluorite ore, this research uses a mathematical model. In this study, the variables were the dose of potato starch, quebracho tree, white dextrine, oleic acid, and sodium silicate. On the other hand, the factors studied were the law of carbonates, silica, and fluorite, in addition to the metallurgical recovery of fluorite. The statistical technique of factor analysis that relates the variables and factors allowed to the optimization of the reagent dosage. Maximum metallurgical recovery was achieved without sacrificing the fluorite grade. The mathematical model adjusts satisfactorily to the results with a correlation coefficient of 91.58% for metallurgical recovery and 98.51% for fluorite grade. Optimizing the process 60.45% of metallurgical recovery and 68.99% of fluorite grade are achieve in the roughing step, using a dosage of 1.68 g·kg−1 of potato starch, 0.86 g·kg−1 of quebracho tree, 1.25 g·kg−1 of dextrin, 3 g·kg−1 of oleic acid, and 0.85 g·kg−1 of water glass.

Inhibition performance and adsorption of polycarboxylic acids in calcite flotation

As a common gangue mineral, the inhibition of calcite is very important to enrich the valuable minerals by flotation. With the increasing complexity of mineral properties and higher requirements for environmental protection, developing a newly eco-friendly depressant for calcite flotation is necessary. In this study, the effects of polyaspartic acid (PASP), polyepoxysuccinic acid (PESA), and hydrolytic polymaleic anhydride (HPMA) on the flotation performance of calcite using sodium oleate as the collector were investigated through flotation experiments. The results showed that all the three depressants exhibited strong inhibition to calcite, and the inhibition capabilities decreased in the order of PASP > HPMA > PESA. The results of zeta potential measurement, contact angle measurement and X-ray photoelectron spectroscopy indicated that the adsorption of sodium oleate on calcite surface was greatly decreased as the addition of the depressant. To investigate the inhibition selectivity, three depressants were used in fluorite flotation, and the results suggested that sodium oleate could still adsorb on fluorite surface in the presence of PASP. The flotation separation of fluorite from calcite could be therefore realized with PASP on the basis of the best selectivity among the three depressants.

Reducing environmental threats of gutter oil: application in fluorite flotation by saponification

ABSTRACTIn order to reduce the environmental threat of kitchen waste, the gutter oil was transformed into renewable collector by saponification and used for flotation of fluorite. The adsorption characteristics of the collector on fluorite surface were analyzed by X-ray photoelectron spectroscopy (XPS). The influence of the collector dosage and inhibitor dosage on the separation efficiency was analyzed by the flotation test. XPS results show that collector can change the charge characteristics of calcium ions, indicating that the collector has significant adsorption on the fluorite surface. Separation results show that the renewable collector has achieved an excellent effect on fluorite flotation.

Reverse Flotation Separation of Fluorite from Calcite: A Novel Reagent Scheme

Fluorite (CaF2), as an important strategic mineral source, is usually separated from calcite by the common froth flotation method, but this separation is still not selective enough. The development of a selective collector and/or depressant is the key to achieving high selective separation. 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP or H4L) is widely used as an environmentally friendly water treatment reagent due to its low cost and excellent anti-scaling performance in an aqueous solution. In this study, a novel reagent scheme was developed using HEDP as a fluorite depressant and sodium oleate (NaOL) as a calcite collector for the first time. When 3 × 10−5 mol/L of HEDP and 6 × 10−5 mol/L of NaOL were used at pH 6, the optimal selective separation for single minerals and mixed binary minerals was obtained. Zeta potential measurements indicated that HEDP possessed a stronger adsorption on fluorite than calcite, while NaOL did the opposite. This novel reagent scheme is of low cost, uses a small dosage, and is friendly to the environment, which makes it a promising reagent scheme for fluorite flotation in industrial application.

Effects of crystal chemistry on sodium oleate adsorption on fluorite surface investigated by molecular dynamics simulation

The surface properties of minerals are governed by the crystal chemistry of their cleaved and exposed surfaces, which will vary with the reduction of particle size under mechanical crushing or grinding. Molecular dynamics (MD) simulations were used to study the adsorption conformations and interaction energies of sodium oleate (NaOL) on different fluorite (CaF2) surfaces in an explicit solution system. Three fluorite crystal planes, namely, the (1 1 1) surface, the (1 1 0) surface and the (3 1 1) surface, were considered. Anisotropic surface energies and broken bond densities were calculated based on density function theory (DFT) to confirm the cleavage plane of fluorite and to investigate the crystal-chemical characteristics of fluorite crystal planes. It was demonstrated that NaOL preferentially combined in a bridged ring complex configuration with the most stable plane of fluorite, the (1 1 1) surface, which bears a Ca┄F broken bond density of 100%. The exposure of the (1 1 0) surface of fluorite limited its flotation response to NaOL collectors, as this surface exhibited a lower affinity for NaOL, agreeing well with the results of the fluorite flotation experiments performed with different size distributions. The anisotropy of fluorite with different size fractions was further verified by X-ray diffraction (XRD) analyses. The findings in this work suggest that the flotability of fluorite could be further improved if a selective grinding process is applied to favour the exposure of the (1 1 1) surface.

Investigation of two-stage depressing by using hydrophilic polymer to improve the process of fluorite flotation

Abstract Fluorite is a non-renewable mineral that is used for anhydrous hydrofluoric acid and aluminum fluoride purposes. In China, along with the excellent fluorite resource, which is over-exploited, many off-specification fluorites (CaF2 > 93, under 97%; SiO2 > 1.5%) are produced. Improving the grade of fluorite instead of costly technologies of the Buss and CHEMCO are conducted. To improve the grade of fluorite, an excessive amount of sodium silicate is commonly used. However, this approach cannot stably produce high-quality fluorite and result in excessive reagent consumption, poor selectivity and high-water content of the fluorite concentrate. To solve these problems, suitable hydrophilic polymer depressants, which are highly stable, safe, non-toxic, hydrophilic, biodegradable and low processing cost because of abundant in nature, are selected to replace sodium silicate. To make the study practical, the testing location chosen was in Chenzhou (Hunan, China) and was operated by Xinyuan mining Co. Ltd., the largest monolithic fluorite ore producer in Asia. Meanwhile, to prevent the above problems from occurring, the focus throughout this study was achieving separation in the flotation process through the successful occurrence of two sub-processes. The first process was desilicication using dextrin, and the second process was decalcification using tannin. A tech-economic assessment based on the pilot program showed that compared with sodium silicate, the new technology (dextrin + tannin) improved fluorite recovery by 19.23%, removal rate of CaCO3 by 13.43% and SiO2 by 8.93% and reduced production costs by $2914.8 per day. The technology (dextrin + tannin) produced an excellent result, simplifying the flow during fluorite flotation, which can led to a reduction in power consumption as well as reduction in production costs for each ton of 105% sulfuric acid of $3.24 (t/t) for the entire production chain lifecycle. The new technology was an efficient, economic and environmentally friendly and has widespread applications and promising market prospects.