Collector Dosage Research Articles

Flotation of low-rank coal slimes

During coal production, a significant amount of fine coal dust is generated. The utilization of these high-ash coals is of great importance for the national economy. This study aims to recover the slime of the Lavvar facility located in the Kütahya-Tunçbilek region by flotation. The experimental parameters studied include the collector dosage, dispersant dosage, frother dosage, flotation time, air flow rate, and solid ratio. Flotation performance was evaluated by determining the ash, calorific value, sulfur, volatile matter, fixed carbon, and yield values of the products obtained at the end of the experiment. As a result of the experimental studies, the highest yield value was obtained using 2000 g/t sodium silicate, 2000 g/t diesel oil, and 100 g/t MIBC with a solid ratio of 10%, a flotation time of 4 minutes, and an air flow rate of 4 L/min, producing marketable coal with 6312 KCal/kg calorific value, 0.95% sulfur, and 22.4% ash content.

Experimental and Modelling Study of Pt, Pd, and 2E+Au Flotation Kinetics for Platreef Ore by Exploring the Influence of Reagent Dosage Variations

This study investigates the flotation kinetics of individual platinum-group elements (PGEs) and gold, namely Pt, Pd, and 2E+Au (i.e., Pt+Pd+Au), in the context of Platreef ore flotation. Experimental tests were conducted on a Platreef ore feed using various dosages of depressants, frothers, and collectors under controlled agitation and pH conditions. The recoveries of the individual PGEs were analysed using six kinetic models, with the modified Kelsall model identified as the most suitable for accurately describing the flotation kinetics and predicting elemental recovery. Notably, the model incorporates two rate constants (kfast and kslow) to account for the distinct flotation behaviours of the PGEs. The results indicate that Pt has the fastest floatability, followed by Pd and 2E+Au. The modified Kelsall model demonstrates high effectiveness in predicting the recovery of these PGEs. Three empirical correlations for Pt, Pd, and 2E+Au recoveries based on the modified Kelsall model are proposed, enhancing the understanding and optimisation of PGE recovery in Platreef ore flotation.

Study of new commercial collectors for the recovery of coarse quartz particles in iron ore flotation

Currently, a small range of commercial collectors is available for the use in reverse iron ore flotation at Vale. This input represents a considerable unit cost, being essential for the concentration of low content itabiritic iron ores. The present work evaluated the reverse cationic flotation of an itabiritic ore with low iron content (39.6 % Fe) from the Iron Quadrangle (BR) in bench scale tests, focusing on the use of new collectors to remove coarse quartz. The sample presents 19% of its particles as oversize in the 0.150 mm sieve. The poor flotation of coarse quartz particles (>0.150 mm) causes significant problems in various iron ore flotation circuits by contaminating the concentrate. The study evaluated the performance of 10 new collectors from the etheramine family with different degrees of neutralization and at different collector dosages. The flotation process variables were set as industrially practiced at the Cauê iron ore plant (BR). In tests varying the specific collector dosage, the non-neutralized etheramines showed improved performance compared to the current 50% neutralized etheramine used in the plant, achieving industrial targets: concentrate SiO2 content rate lower than 4.5% (1.4%), tailings iron content lower than 23% (18.94%), metallurgical recovery greater than 66% (74,8%), and Gaudin Selectivity Index greater than 6.6 (10.5). The 0.150 mm oversize in the concentrate, mostly coarse quartz particles, was reduced from 5.7% down to 1.2%, indicating the potential for the industrial application of non-neutralized etheramines in the recovery of coarse quartz.

Recovery of residual carbon from coal gasification fine slag by a combined gravity separation-flotation process

Recovering inner residual carbon is important for fully utilizing coal gasification fine slag (CGFS) resources. In this study, we adopted a combined gravity-separation and flotation process to efficiently recover residual carbon by considering the characteristics of the CGFS and optimizing the operating factors of the process. CGFS is principally a mixture of residual carbon and ash, with low-density particles containing more of the former. Accordingly, residual carbon is preliminarily enriched by gravity separation, in which gas velocity (vg) and water velocity (vw) significantly impact separation efficiency, followed by feed volume (m). The residual carbon in the initial concentrate was preliminarily enriched (i.e., loss on ignition (LOI): 55.90%; combustible recovery (Ro): 72.36%) under appropriate operating conditions (i.e., vw = 0.04 m/s, vg = 3 m/s, m = 150 g). Moreover, the quality of the flotation concentrate was most influenced by collector dosage (mc), followed by aeration rate (η), frother dosage (mf), stirring speed (w), and grinding time (t) during flotation of the primary concentrate. The flotation concentrate exhibited LOI and Ro values of 90.95% and 50.34%, respectively, under the optimal flotation conditions (i.e., mc = 20 kg/t, mf = 15 kg/t, w = 2600 rad/min, η = 200 L/h, t = 360 s); it has a high residual carbon content and is an ideal raw material for preparing fuels or carbon materials.

An investigation of nanobubble enhanced flotation for fly ash decarbonization

Froth flotation is often employed to remove unburned carbon in the fly ash produced as a coal combustion by-product before it can be utilized in the cement or similar industries. However, with the deterioration of coal quality and environmental regulations getting stricter, fly ash has become increasingly more difficult to be purified by the flotation process and the limitations of traditional flotation techniques have become more obvious for ultrafine particles such as fly ash. Nanobubbles have proven effective in enhancing the flotation performance with fine and ultrafine particles. In this study the effect of nanobubbles on fly ash flotation decarbonization and underlying mechanisms have been investigated with a flotation column under various experimental conditions using a Chinese fly ash sample. The results have demonstrated that nanobubbles are able to significantly improve the efficiency of decarbonization of fly ash flotation. Typically the use of nanobubbles increased the recovery of unburnt carbon by 3–15 % and reduced the fly ash LOI by 0.2 %–3.5 %. It has also been shown that nanobubble flotation reduced the required dosages of frother and collector by approximately one half. New mechanisms of nanobubbles improving fly ash decarbonization flotation performance were explored from the perspectives of bubble-particle interactions and solution surface tensions.

New insights for improving low-rank coal flotation performance via emulsified waste fried oil collector

A novel emulsified waste fried oil collector (EWFOC) of the oil-in-water (O/W) type was prepared via transesterification and ultrasonic emulsification, and to be used as an alternative collector to improve the flotation performance of low-rank coal while reducing the collector dosage. The preparation process of EWFOC was optimized, and its performance was compared to that of a common collector (diesel) and waste fried oil collector (WFOC) in the flotation of long-flame coal collected from two top coal-producing province (autonomous region) in China. The micrograph, particle size distribution and dispersion of EWFOC were observed under optical microscope. In addition, the functional groups and wettability were also analyzed. The optimized emulsification conditions for EWFOC were determined as HLB = 14.0, emulsifier dosage of 1 %, oil–water ratio of 3:7, ultrasonic time of 5 min, and a NaCl concentration of 0.02 mol/L. Compared to diesel, WFOC improved the recovery of clean coal and reduced the ash content of clean coal. EWFOC, on the other hand, demonstrated better flotation performance, resulting in up to a 70 % reduction in WFOC dosage. This significant improvement is attributed to the cavitation mechanism of phacoemulsification, which renders EWFOC stable in water with homogenous dispersion and enhances its attachment to coal particles. EWFOC showed better performance compared to diesel and WFOC in terms of improved contact angle as well as adherence to oxygen-containing functional groups (especially O=C–O and C–O) on the surface of long-flame coal, thus enhancing the hydrophobicity of the said coal.

Flotation behavior and surface analytical study of synthesized (octylthio)aniline and bis(octylthio)benzene as novel collectors on sulfide minerals

Six novel collectors, 2-(octylthio)aniline (2-OA), 3-(octylthio)aniline (3-OA), 4-(octylthio)aniline (4-OA), 1,2-bis(octylthio)benzene (2-OB), 1,3-bis(octylthio)benzene (3-OB) and 1,4-bis(octylthio)benzene (4-OB) were synthesized and newly introduced as collectors in the flotation of copper sulfide ores. Collector PAX was used as a standard to evaluate the flotation performance of the novel collectors using two kinds of ore samples. The results showed that the novel collectors, especially collector 2-OA, had the strongest flotation capacity, with the highest copper recovery of 95.6% from the chalcopyrite sample at pH 9 and a collector dosage of 100 g/t, while PAX yielded only 66.5% under the same flotation conditions. Likewise in the flotation of copper sulfide ore sample, the flotation performance of the novel collectors was generally improved than that of PAX. The flotation kinetics study showed that the 2-OA novel collector had a faster reaction rate than PAX. The adsorption experiments revealed excellent adsorption characteristics of the novel collectors on the chalcopyrite surface with an adsorption rate of up to 99.3%. UV analysis showed that the novel collectors were more reactive to copper than iron, confirming that the novel collectors enhance the copper recovery in sulfide ore flotation. The infrared spectral analysis exhibited that the novel collectors were adsorbed on the surface of chalcopyrite with the generation of a new substance.

Optimization of spodumene flotation with a fatty acid collector

An increasing demand for lithium-ion batteries is driving the development of new lithium mineral projects. Spodumene, a major lithium-bearing mineral found in pegmatite deposits, is often recovered by froth flotation. The primary collectors in spodumene flotation are fatty acids which are known for their poor selectivity. Fatty acid collectors tend to recover common gangue minerals in spodumene deposits due to their similar surface properties, making it difficult to produce high-grade concentrates with high lithium recovery. The ionic collector behavior is sensitive to pulp conditions like pH and concentration, but there is a weak understanding of this behavior during conditioning. There is a consensus that the conditioning stage is vital to flotation performance and should be conducted at high pulp-density (∼60% solids) to ensure proper collector adsorption. If not executed properly, rougher flotation suffers, making it challenging to achieve high final concentrate grades and recovery. This study uses a central composite experimental design and linear regression analysis to investigate and model the effects of four parameters of high-density conditioning with fatty acids on the responses of rougher concentrate grade and recovery: initial pulp pH, collector dosage, conditioning time, and power density. The models developed for both responses were determined to be statistically significant in the tested region. Initial pulp pH, collector dosage, and power density were significant terms in both models, while conditioning time was insignificant. Increased power density, ∼31 W/L, was necessary to achieve high rougher concentrate grades but increasing beyond 37 W/L was harmful to recovery. In general, higher collector dosages (>500 g/t) resulted in high recoveries, but initial pH must be adjusted accordingly to maintain concentrate grade. The most robust conditions to achieve > 90% recovery at a concentrate grade > 5.5% Li2O with this material were determined to be 31 W/L energy input and 625 g/t collector at an initial pH of 8.25. The flotation performance in this study is strongly connected to the behavior of fatty acid collectors reported in the literature and the findings provide good insight for operators and researchers aiming to improve spodumene flotation performance with fatty acids.

Studying the influence of cationized pyrolysis oil on the flotation of a bituminous coal using historical data design

ABSTRACT This investigation assessed the influence of a cationized pyrolysis oil (PO) produced by the pyrolysis of used car tires on coal flotation using an extended Historical Data (HD) design. The effect of operating factors, including pulp solid content, diesel oil, pine oil, and pyrolysis oil dosages, was examined using experimental and statistical analyses. Fourier Transform Infrared Spectroscopy (FTIR) measurement showed that PO contains hydrocarbons and their oxides (alkane, ester, or carboxylic acid). Statistical analysis using analysis of variance (ANOVA) revealed that concentrate ash content is influenced by solid content and pyrolysis oil concentration through a non-linear trend such that maximum ash removal may be obtained at the middle level of solid content and in the absence of PO. The solid content and diesel oil had a significant impact on process yield. Maximum yield was achieved at the low and middle levels of solid content and collector dosage, respectively. A comparison of individual and interaction effects of significant operating variables showed their complicated effects on process responses. Overall, the PO affected the coal flotation efficiency adversely, which can be due to the interaction between hydrophilic groups in the PO structure and the oxide nature of non-combustible materials in coal particles.

Development of magnetic flotation hybrid separation process for cleaner coal preparation

The magnetic flotation hybrid separation process, which combines column flotation and magnetic separation, was anticipated to beneficiate a representative coal sample acquired from the El-Maghara coal mine with a relatively high ash percentage of 27.21%. The system was designed to introduce a high gradient magnetic field to a flotation column to hinder the flotation of magnetic particles even if attached to flotation bubbles, improving the coal demineralization process and producing high quality coal. The Box-Behnken design and response surface methodology were employed to investigate and optimize the combined influence of various operating parameters on the process performance. The effects of the main operating parameters such as magnetic field strength, slurry circulation flow rate, air flow rate, collector dosage, and frother concentration were investigated. Ash percentage, combustible recovery, and separation efficiency were defined as process responses. Upgrading the coal sample under the optimum conditions of 1.2 T magnetic field strength, 1500 ml/min circulation flow rate, 11.64 ml/min air flow rate, 0.87 kg/ton diesel collector, and 42 ppm methyl isobutyl carbinol frother, the predicted and two confirmation experiments data were 7.78%, 7.89%, 7.71% ash percentages with maximum recoveries of 75.86%, 76.37%, 75.94%, and maximum separation efficiencies of 77.17%, 78.51%, 78.71% respectively.

Understanding adsorption mechanism of a novel “Y” structure carboxylate-hydroxamate surfactant towards rhodochrosite

High consumption and low selectivity of traditional collectors limit the efficient flotation recovery of rhodochrosite particles from finely disseminated complex ores. Herein, a novel “Y” structure multi-functional surfactant, 2-decanoylamino-4-hydroxycarbamoyl-butyric acid (DHBA) was developed for flotation recovery of rhodochrosite. The micro-flotation results showed that DHBA exhibited an excellent collecting ability for rhodochrosite than common collector octanohydroxamic acid (OHA) (the recovery reached 85.7% for 7 × 10–5 mol·L–1 DHBA, while only 27.9% for OHA). Meanwhile, DHBA can selectively separated rhodochrosite from quartz at neutral pH and low collector dosages. The experimental analysis combined with the density functional theory calculations revealed that DHBA was lattice matched to the rhodochrosite via the oxygen atoms of carboxyl and hydroxamate groups chelating with two Mn atoms, conferring strong adsorption affinity of DHBA. In addition, intermolecular hydrogen bonds coexist through the amide groups, promoting the collectors' self-assembly on the rhodochrosite surface, improving surface hydrophobicity. This research provides a feasible collector design protocol for the separation and enrichment of manganese carbonate ore.

Statistical analysis and optimization studies on recovery of carbon from steel plant sludge

Steel-making industries that produce sludge as a by-product in their operations contain valuable mineral phases and carbon which can be recovered for primary and secondary usage. The present study aims to recover carbon values from the sludge, adopting flotation technique by altering the surface hydrophobicity of carbon values and optimizing its process parameters for effective separation. Laboratory scale studies were carried out in a D12 Denver flotation cell using a laboratory-synthesized flotation reagent as the collector for carbon recovery and Methyl Isobutyl Carbinol (MIBC) as the frother. The experimental study was statistically designed using the Taguchi method with three input variables, i.e., frother dosage, cell revolutions per minute (rpm), and collector dosage at mixed levels for process parameter optimization and for interpretation of the importance of process parameters on the mean and variation of responses. Experimental designing and statistical analysis were used to study the effects of input parameters on outputs and determine the order of significance. Among L18 (2^1*3^2) orthogonal array experiments performed, the one with operating conditions at 1400 rotations per minute (rpm) of the cell, frother dosage of 54 g per tonne (gpt), and collector dosage of 3400 g per tonne (gpt) of feed, 83.05% carbon recovery was optimally obtained. Based on the flotation experimental test results, one-way analysis of variance (ANOVA) was used to predict the order of significance of three input variables for each response variable namely, carbon grade and carbon recovery. The order of significance for the response parameter, carbon recovery, was observed to be in the order of Collector dosage > Frother dosage > Cell rpm indicating the impact of the laboratory-synthesized collector on recovering the carbon values from the sludge.

A beneficiation study to recover xenotime minerals from rich‐iron‐silicate ores

AbstractThe Yen Phu (YP) rare‐earth mine, located in Yen Bai, Vietnam, currently reserves 28,000 tons of total rare earth oxides (TREO) with a TREO grade of about 1.16%. A mineralogy study shows the dominance of iron‐oxide‐ and silicate‐bearing minerals in YP ore, whereas xenotime presents as the major rare‐earth metal (REM) bearing mineral. Chemical analyses also exhibit a relatively high proportion of heavy rare earth metals (HREMs) at 41.2%, which suggests the high economic value of YP ores. The factors influencing the flotation involving the pH, the depressant, and the collector dosage were first assessed. Then, a beneficiation flowsheet including grinding, wet magnetic separation, and flotation was recommended and practically conducted to enrich the TREO. The proposed process successfully promoted the TREO grade from 1.16% to 29.70% with a high recovery of 80.31% in the REM concentrates, while a tiny loss of TREO was exhibited in the tailing. The chemical analysis of REM concentrates also demonstrated the conservation of REM composition throughout the beneficiation.

Enhancing Flotation Performance of Low-Rank Coal Using Environment-Friendly Vegetable Oil

Flotation is widely used for low-rank coal upgrading, although it is always inefficient due to its rough surface morphology and rich oxygen-containing functional groups. In this study, the environment-friendly vegetable oil 1030# was used to enhance the flotation performance of low-rank coal. The mechanism of 1030# enhancing the flotation of low-rank coal was revealed through surface property analysis of coal particles and bubble–particle adhesion tests. The flotation results showed that the flotation yield of low-rank coal increased with the increase in the collector dosage, and the flotation yield of 1030# as a collector is obviously higher than that of diesel. Scanning electron microscopy (SEM) and chromatography–mass spectrometry (GC-MS) were used to analyze the surface morphology of coal particles and components of the reagent. The SEM results showed that the surface of low-rank coal is loose and contains a large number of pores and cracks, which is not conducive to the spreading of chemicals on the coal surface and the mineralization of bubbles and particles. GC-MS results showed that 1030# mainly contained methyl oleate with more unsaturated double bonds than diesel. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to analyze the surface functional groups of the low-rank coal before and after reagent treatment. The results of FTIR and XPS showed that the coal surface of low-rank coal before reagent treatment contained a large number of oxygen-containing functional groups with poor surface hydrophobicity, while the surface of low-rank coal after reagent treatment had reduced oxygen-containing functional groups and increased hydrophobicity. The contact angle of the low-rank coal surface also showed the same variation trend as the FTIR and XPS results. The adhesion force between the bubble and coal surface in different collector solutions was measured. The maximum adhesion between the bubble and coal surface increased with the increase in the collector, and the maximum adhesion force with 1030# treatment was higher than that of diesel. This indicated that 1030# with a large number of polar components is more easily spread on the surface of low-rank coal, thus improving the hydrophobicity of low-rank coal.

Effect of nanobubbles on flotation of El-Maghara coal

ABSTRACT To extensively explore the advantage of using nanobubbles in the El-Maghara coal flotation process, the effect of nanobubbles on both column and mechanical flotation was investigated under different operating parameters such as diesel oil collector dosage, MIBC frother concentration, superficial feed velocity, superficial air velocity, and superficial wash water velocity in column flotation; besides the slurry flow rate through nanobubbles generator into a 25-liter mechanical flotation cell. The representative coal flotation feed acquired from the El-Maghara deposit located in Sinai, Egypt with chemical characterization using proximate analysis containing 25.27% mineral matter forming ash during coal combustion and with particle size distribution measurement using laser particle size analyzer is 57 µm d90. Also, the flotation kinetic experiments were done to show the influence of nanobubbles on the flotation time required to obtain high-quality coal products with high combustible recovery. Nanobubbles enhanced the flotation performance and kinetics by up to 24% combustible recovery based on the operation parameters reducing flotation time from 4 to 2.25 min for 80% combustible recovery.

Investigating the selective flotation of auriferous arsenian pyrite from refractory ores using thionocarbamate

Thionocarbamate, specifically modified Isopropyl Ethyl Thionocarbamate (IPETC) is selective in the separation of pyrite from arsenopyrite, following copper activation. In this work, the flotation response of a refractory gold (Au) ore containing arsenic (As) mainly in the form of arsenian pyrite is investigated to reject gold-barren sulphidic phases. The recovery of Au increased with an increase in CuSO4 concentration to 0.3 kg/t, beyond which further increase in concentration yielded no significant recovery. Variations of IPETC concentration between 0.2 and 1.5 kg /t of ore influenced both gold and arsenic recovery. It was surmised that the high collector dosage may have resulted from competitive adsorption between arsenian pyrite and other gangue minerals in the ore. 0.3 kg/t CuSO4 and 1.2 kg/t IPETC concentration at pH 11 gave the best results of 86% Au and 83% As recovery at an Au and As grade of 8.14 g/t and 2436 ppm respectively. LA-ICP-MS analysis of the concentrate showed a positive correlation between gold and arsenic. The technique also revealed arsenic-rich zones in pyrite which was further confirmed by SEM/BSD imaging to be rims of arsenian pyrite encapsulating Au-barren pyrite. MLA mineral maps of concentrates obtained at different times also showed that there is no relationship between the arsenic content of pyrite and the flotation rate. The deportment of arsenic in the rims of pyrite presents a complex mineralogical association which results in a decrease in concentrate grade.

A Collector Promoter for Apatite Flotation in the Serra do Salitre Complex

The concern about enhancing the productivity of Salitre phosphate mines has led to an extensive research and development program on new reagents, aimed at the sustainable processing of the ore, with greater production of phosphate concentrate and, consequently, less waste disposal in the tailings dam. Flotation is the most widely applied technique for processing of phosphate rocks, using mainly fatty acids and their salts as collectors. In partnership with BASF Mining Solutions, a new collector system was developed based on soy oil fatty acid (SOFA) and BASF’s co-collector Lupromin® FP A 1210 Base (L.1210, a mix of synthetic surfactants). The laboratory scale flotation results showed that most effective performance was achieved with a ratio SOFA:L.1210 of 70:30, while in the industrial application the ideal proportion was 90:10. This difference in reagent ratio is directly related to the surface tension of the bulk, making the apatite more or less hydrophobic, directly affecting the flotation performance. These proportions were tested by comparing different reagent conditions and pH, while contact angle and surface tension studies provided a theoretical framework to indicate a more effective collector adsorption, allowing for further process optimization. Applying 10% of L.1210 on an industrial scale, a more stable industrial process was observed to the oscillations of the processing plant, corroborating that by using the collector promoter there is a significant performance increase in this circuit of the Serra do Salitre Complex, which increased, on an industrial scale, at least 7.1% in P2O5 recovery and reduced 12.5% of the collector dosage compared to the use of only fatty acid. In this study, it was possible to identify two main process conditions to further optimize the current reagent system applied in industrial scale: pH 9.5 with the mixture SOFA/L.1210 90/10 (θ = 75.8°); and pH 7.5 with SOFA/L.1210 70/30 (θ = 76.8°).

The removal of dolomite from collophane using reverse flotation process enhanced by compound collector

To improve the magnesia removal effect of collophane and increase the P2O5 grade of phosphorus concentrate, the fatty acid collector mixed with sodium dodecyl sulfate (SDS) was used as the compound collector in reverse flotation for magnesia removal in acid system. Solution surface tension measurement, Zeta potential test and infrared spectrum analysis were conducted to analyze the intensified effect of compound collector for dolomite removal. The results showed that under the conditions of grinding fineness -0.074 mm accounted for 89.8%, sulfuric acid dosage 12.0 kg/t, phosphoric acid dosage 3.0 kg/t, SDS compound proportion 3%, collector dosage 1.0 kg/t, the P2O5 grade of concentrate is increased from 25.7% to 29.94%. SDS can reduce the surface tension of slurry, which is conducive to the formation and stability of flotation foam. Zeta potential became negative due to the compound collector adsorbed on the mineral surface. Moreover, the -CH2 antisymmetric stretching vibration peak originated from fatty acid and SDS were detected after the interaction of collectors with dolomite. The compound collector was effectively adsorbed on the surface of dolomite, enhancing the magnesium removal effect of collophane.

Innovative flotation separation considering pores blocking to facilitate residual carbon recovery from coal gasification fine slag

The conventional flotation of coal gasification fine slag has the dilemma of large collector dosage and low carbon recovery due to the developed porosity of the residual carbon. In this study, an innovative method to enhance the flotation recovery of residual carbon was proposed by pores blocking with pulverized coal. Flotation experiments were carried out to verify the effect of pore blocking on the recovery of residual carbon, and scanning electron microscope, X-ray photoelectron spectroscopy, and mercury intrusion porosimetry were used for mechanism analysis. The results showed that the addition of pulverized coal did play a role in pores blocking in the novel flotation, and its carbon recovery rate was improved by 14.11% (absolute value) compared to that of conventional flotation at the same ash content of the concentrates. On the one hand, the pulverized coal adheres on the pore openings on the residual carbon surface, thus preventing the collector adsorption into the pore channels; on the other hand, the adhesion of pulverized coal to the residual carbon surface increases the adsorption sites for collector. Therefore, pores blocking is beneficial for more adsorption of the collector on the outer surface of the residual carbon and thus improving its flotation recovery. This paper provides significant inspiration for efficient flotation of coal gasification fine slag.

Development of a novel biocollector for flotation of low grade graphite ore

ABSTRACT Mineral processing plants operate in capacity of hundreds/thousands of tons per day. Accordingly, chemical reagents’ usage also increases proportionally. Stringent norms toward environment sustainability question the usage of chemical reagents, especially in large quantities and tailings disposal in open areas. Hence, bioreagents have gained great interest. Froth flotation is by far the most practiced processing route for fines beneficiation and low-grade ore upgradation especially for naturally hydrophobic minerals. Flotation being a physico-chemical separation technique, flotation reagents selection plays a pivotal role in the process performance. A novel environmental-friendly biocollector, an extract from the leaves of Vitex negundo, was used as flotation collector in the present investigation for beneficiating a low-grade graphite ore with 8.67% fixed carbon. A three-factor and three-level Box-Behnken Design (BBD) under Response Surface Methodology (RSM) was employed to study the effects of important process variables such as grinding time, depressant dosage, and collector dosage on the responses, namely, ash percent of final concentrate and its recovery. A final graphite concentrate with 4.24% ash and 14.42% yield was obtained using the developed biocollector by flotation of low-grade graphite ore with 89.47% ash content. The degree of significance of input variables was determined using ANOVA. Regression models for ash content, % of final concentrate, and its %recovery was obtained from BBD analysis. It showed that the grinding time has a significant influence on the process followed by depressant dosage on the grade of final concentrate and collector dosage on its recovery.