Flotation Reagents Research Articles

Chemical oxidation co-coagulation-flocculation for the flotation wastewater treatment of lead-zinc oxide ore from Lanping mine

The flotation wastewater produced by "lead preferred flotation-zinc flotation" all-open process with aids of mixed depressants and cationic-anionic collectors has a high turbidity and multitude of reagent contaminants, and fails to meet the discharge standards. This study objective is to remove fine solid particles and flotation reagents in this wastewater by chemical oxidation co-coagulation-flocculation process. Results of chemical oxidation tests indicate peroxymonosulfate (PMS) exhibits superior performance on decreasing COD, and the COD remarkably decreases to 71.8 mg·L<sup>-1</sup> with 100 mg·L<sup>-1</sup> PMS addition after 120 min. Moreover, the combined oxidation of radicals (SO<sub>4</sub><sup>•-</sup> and •OH) are responsible for degradation of flotation reagents (Na<sub>2</sub>S, DCCH, xanthates and amine) in the wastewater. Results of experimental factors confirm that the turbidity of wastewater decreases significantly from 124796 to 71.4 NTU, and the yield of water reaches above 90% with combined usage of lime (500 mg·L<sup>-1</sup>) and polyacrylamide (PAM, 50 mg·L<sup>-1</sup>). Besides, the contents of S, P, N, Zn Pb and Fe decrease, and meet the discharge standards. Results of zeta potential analysis suggest lime reduces the electrostatic repulsion between particles, and PAM plays a bridge link role between particles, accelerating the precipitation of suspended particle.

Development of Reagents - Blowing Agents Based on Local Raw Materials and their Research

The development and search for effective reagents and optimal technological conditions is one of the main factors for improving the coal flotation process. Solving these problems increases the technological and economic efficiency of flotation enrichment. The article discusses methods for producing foaming regents based on waste from the distillation process of cottonseed oil - gossypol resin and methods of flotation of various classes of fine coal. The advantages of this foaming agent include the availability of raw materials, which are a product of domestic industry, produced at the enterprises of the Kattakurgan MJK and amino alcohols (mono- , di- and triethanolamine) , sufficient resources and relative low cost. Conducted research to assess the effectiveness, surface activity and foaming ability of the resulting reagents - in foaming agents, according to the proposed technology of the studied technical products, the resulting product belongs to the surface-active reagents and has high flotation activity. The physico-chemical and foam-forming properties, foam stability, destruction kinetics and other properties of flotation reagents - foaming agents SK-1 and SK-2 - have been studied. The results of studies of the influence of foaming reagents in the process of flotation and extraction of precious and non-ferrous metals are presented. The optimal option for the effective composition of composite chemical flotation reagents - foaming agents and their parameters was selected. The results of scientific research conducted at JSC NMMC on the use of analogues of the foaming agents SK-1 and SK-2 are given in comparison with the reagents (Oxal) currently used at the plant. The elemental composition of man-made waste samples using reagents SK-1 and SK-2 was determined.

Effects of Ca<sup>2+</sup>/Mg<sup>2+</sup> ions in recycled water on the reverse flotation properties of iron oxides

Water quality, particularly hardness, plays an important role in affecting the floatability of minerals as it interferes with the chemical/electro-chemical characteristics of mineral surfaces and their interactions with flotation reagents. It could become unpredictable when water sources characterized by different calcium or magnesium ion distributions were involved. This study aimed to identify the role of Ca<sup>2+</sup>/Mg<sup>2+</sup> ions in the recycled water on the cationic reverse flotation selectivity of iron oxides through a series of bench/micro flotation tests, zeta potential, powder contact angle, and Fourier Transform Infrared (FTIR), etc. The results pointed out that the use of recycled tailing water deteriorates the flotation selectivity and dilutes the concentrates. This can be largely attributed to the presence of Ca<sup>2+</sup> ions at higher concentrations as they induce a drop in the Fe recovery and an increase in SiO2 content while an increase in the content of Mg<sup>2+</sup> ions seems to have little effect on the quality of concentrate. As evidenced by the data from micro-flotation, powder contact angle, zeta potentials, and FTIR, a hydrophilic colloidal layer formed by Ca-based hydrolyzed compounds, such as Ca(OH)<sup>+</sup> or, CaCO<sub>3(s)</sub>, etc., on quartz could change its zeta potentials and disturb its interactions with a cationic collector. They also play a role in weakening the flocculation of starch on hematite probably by pre-locking the acidic groups on the starch remnants and contracting their configurations, thus preventing their adsorption on mineral surfaces. However, magnesium ions seem to be beneficial to in strengthening the flocculation of starch on hematite as magnesium-based species could act as adsorption bridges of between starch and mineral surfaces.

Reactive species identification in KCl activated biochar/persulfate system under different pH condition: Theoretical calculation and column experiments

The challenges of remediating polluted water in mine areas are exacerbated by low emission dispersion and long-lasting pollution, particularly the significant fluctuations in pH value. Notably, the treatment of flotation reagent polluted water with variable pH scenarios remains a challenge. In this study, metal-free biochar-based materials (KBBC)/persulfate system was used for flotation reagent contaminated wastewater treatment with a wide pH range. Regarding the intrinsic nature of the biochar-based materials, ball milling enhanced the degree of graphitization, while introducing a hard template of KCl increased the proportion of carbonyl functional groups on their surface, thereby facilitating persulfate activation. Experimental findings revealed that the KBBC/PS system displayed efficient degradation of aniline aerofloat (AAF) as a representative flotation reagent across a wide pH range (pH = 3.6–10.4 with buffer). Investigations on the mechanism indicated that, under acidic and neutral conditions, superoxide radicals and direct electron transfer processes constituted primary pathways for pollutant degradation. Meanwhile, various active species contributed under alkaline conditions with increased involvement of free radicals (•OH and SO4•−) and singlet oxygen. Furthermore, continuous flow experiments were set up to prove the potential applicability of the KBBC/PS process. This study not only deepens the understanding of persulfate activation by metal-free carbon-based materials across a wide pH range but also expands their potential applications in mine-polluted water purification.

Study on flotation separation of barite fluorite by citric acid under new collector system

Barite and fluorite have similar physical and chemical properties and floatability, and traditional flotation reagents are difficult to effectively separate these two minerals. In order to realize the effective separation of the two minerals, a new system with high selectivity and strong collecting ability, α-BLA ( bromododecanoic acid) system, was selected in this paper. The system can be applied at a wide range of pH values and can greatly eliminate the interference of metal ions. Therefore, this study selected this stable system to explore the effect of citric acid on barite fluorite flotation, in order to more objectively explain the adsorption mechanism of the agent. The results show that the floatability of the two minerals is quite different under the action of citric acid. Barite concentrate with grade of 81.12% and recovery of 87.74% can be obtained by micro-flotation experiment. On this basis, the interaction mechanism between citric acid and mineral surface was further studied by contact angle test, Zeta potential test, Fourier transform infrared ( FTIR), X-ray photoelectron spectroscopy ( XPS) and density functional theory ( DFT) calculation. The results show that when citric acid reacts on the surface of barite, its adsorption energy increases with the increase of bond number. The reaction on the surface of fluorite produces 3-hydroxyglutaric acid, which transfers a certain amount of electrons to Ca1 and Ca2 ions on the surface of fluorite, enhancing the chemical adsorption of citric acid on the surface of fluorite. This paper provides a theoretical basis and effective guidance for the flotation separation of barite fluorite.

Application of exopolysaccharides synthesized by Xanthomonas campestris in an efficient separation system of refractory chalcopyrite and molybdenite

Bacterial polysaccharides get an abundance of attention owing to their distinctive biological activity and promising applications. Recent research found that the specificity of the molecular structure of exopolysaccharides (EPS) can be used to accomplish selective regulation of the physicochemical properties of mineral surfaces. The development and application of novel microbial EPS as a flotation reagent for chalcopyrite and molybdenite separation possesses a promising development prospect. Consequently, we attempted to create effective and sustainable molybdenite depressants in this work by optimizing the strain's fermentation settings and identifying the molecular structure of the generated EPS. Fermentation condition tests revealed patterns of influence of fermentation parameters on EPS yield, the viscosity average molecular weight, and biomass during the fermentation process, and optimized the optimal fermentation conditions. Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and ion chromatography (IC) analyses clarified the structure of the EPS in terms of monosaccharide composition, glycosidic bonding, and functional groups. Mixed mineral flotation tests proved that a low dosage of polysaccharide reagent (100 mg/L) at pH 10 effectively inhibited molybdenite and achieved separation targets of 21.96% Cu and 2.63% Mo in the concentrate, with separation efficiencies (SE) of 72.67% and 55.78% for Cu and Mo, respectively.

A new insight on a novel auxiliary collector 4-MBA synergize with BHA to enhance flotation of scheelite

The hydroxamic acid reagents are extremely pervasive in the collector of scheelite flotation. The high flotation cost is caused by its large dosage and high price. A novel auxiliary collector 4-methodybenzoicacid (4-MBA) was used in combination with benzohydroxamic acid (BHA) to optimize the flotation reagents system for scheelite in the study. A single 4-MBA has weak collection capacity for scheelite. Nevertheless, the combination of 4-MBA and BHA optimized the flotation system of scheelite by ensuring its recovery and reducing the reagent consumption. The results of solution surface tension and contact angle measurements showed that the surface tension of the mixed reagent solution is a relatively lower and the hydrophobicity of the scheelite surface is a relatively higher in the BHA and 4-MBA mixed reagent system. Additionally, a synergistic effect between BHA and 4-MBA on Pb2+ activated scheelite is revealed by the Zeta potential measurements, infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The addition of 4-MBA promoted the physical and chemical adsorption of BHA. The results of molecular dynamics simulation (MDS) further explained that the collector adsorption layer of the surface of scheelite (112) is more compact under BHA and 4-MBA mixed reagent system, which prevents the vertical entry of water phase and improves the hydrophobicity of scheelite. Finally, the bench-scale flotation experiment verified that the addition of 4-MBA enhanced scheelite flotation with BHA, and decrease the flotation cost of scheelite.

Study of selective collecting capacity and mechanism of novel complexes BHA-Ce on fluorite

The selective collecting ability of BHA-Ce complexes on fluorite was investigated through flotation tests, zeta potential, and contact angle measurements, revealing higher selectivity compared to BHA. The adsorption mechanism on the fluorite surface was studied using ultraviolet (UV) spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) tests, and density functional theory (DFT) calculations, showing distinct binding behaviours. BHA exhibited non-selective adsorption on both the calcium of fluorite and calcite surfaces, resulting in the formation of a four-membered ring configuration as -C = O-Ca-NOH-. In contrast, BHA-Ce complexes exhibited selective chemical adsorption on the fluoride atoms of fluorite, forming a five-membered ring configuration as -C = O-Ce-O-NH- with F, while showing no significant adsorption on calcite. Consequently, this phenomenon demonstrates the high selectivity of BHA-Ce complexes for collecting fluorite. This study provides valuable inspiration for the advancement of novel flotation reagents for fluorite within the industry and introduces innovative concepts.

Effects of Au doping on the adsorption of xanthate on pyrite surface in presence of H2O: A DFT study

Despite density functional theory (DFT) has been widely applied in the study of Au-doped pyrite, effects of Au doping on the structural properties and floatability of pyrite still remain uncertain. Most of the previous studies were carried out in vacuum disregarding the existence of water molecules, which were inconsistent with the real flotation system. This work aims to study the adsorption behavior of ethyl xanthate on the surface of perfect pyrite and Au-doped pyrite in presence of water molecules through DFT calculations. It was found that the doped Au expanded the lattice of pyrite (100) surface, with enhanced conductivity and chemical reactivity. After Au-doping, the population and covalence level of Fe-S bond of pyrite was reduced, making Fe atoms prone to interact with water molecules and xanthate. The binding energy and density of states (DOS) analysis indicated that Au-doping enhanced the binding ability of xanthate with pyrite surface more significantly than water molecules. Therefore, Au-doping promoted the adsorption of xanthate on pyrite surface in presence of water molecules. This study is of guiding significance for investigating the flotation behavior of Au-doped pyrite and flotation reagents design.

Electrochemical oxidation degradation of xanthate and its mechanism: Effects of carbon chain length and electrolyte type

There are a lot of residual flotation reagents such as xanthate remaining in the mineral processing wastewater, which must be deeply removed for recycling or discharge. However, there are few studies using electrochemical oxidation to remove xanthate. This article employs the electrochemical oxidation method to treat simulated xanthate-containing wastewater, which investigates the mechanisms involved in removing four xanthate homologues under different electrolyte conditions. Results show that under 1 g/L of Na2SO4, current density of 40 mA/cm2, initial pH of 7.0, and initial concentration of xanthates 1 mM, four alkyl xanthates can be completely removed within 60 min. The COD removal and TOC removal can reach 71.42%–88.61% and 54.23%–81.50%, respectively. By contrast, NaCl electrolyte is more favorable for xanthate degradation. The generated SO42− concentration can reach 145.4 mg/L at 60min, resulting in the sulfur mineralization ratio (ηs) of 75.72%. Regardless of the electrolyte type, as the carbon chain length increases, the xanthate degradation rate accelerates, accompanied by higher COD and TOC removal. The results of UV–vis spectra and LC–MS indicate that intermediate substances such as xanthate peroxides and alcohols are first formed in the process, ultimately leading to the complete mineralization of small molecule substances such as SO42−, CO2, and H2O. The fate of S and Cl elements confirms it. EPR and probe fluorescence spectroscopy results indicate that in Na2SO4 electrolyte, the main active substances are ·OH and a small amount of SO4∙–. Additionally, the production of ·OH increases as the electrolysis time is prolonged. In NaCl electrolyte, ·OH undergoes a series of reactions with Cl− to convert into Cl∙ and active chlorine, which constitute the primary reactive oxygen species.

Enhanced mixed flotation of copper–molybdenum ore using dodecyl dimethyl betaine-emulsified kerosene as environmentally friendly collector

One way to decrease carbon emissions during mineral processing is to reduce reagent dosage. This research focused on utilizing dodecyl dimethyl betaine to emulsify kerosene, which significantly reduced the dosage of mixed flotation reagents for porphyry copper–molybdenum ores. A comparative analysis indicated that the addition of this emulsifier decreased the kerosene dosage by over 50% while enhancing the performance indicators. The analysis also showed that the directional adsorption of dodecyl dimethyl betaine at the oil–water interface increased the negative charge on the oil droplet surface, improving the stability and dispersion of the oil droplets in the solution. Furthermore, the emulsifier strengthened the adsorption stability of kerosene on the hydrophobic mineral surfaces. The emulsified kerosene predominantly exerted a physical adsorption effect on the mineral surfaces, with the highest strengthening effect observed for molybdenite, followed by pyrite and chalcopyrite. The collector, with a lower reagent dosage, improved porphyry copper–molybdenum ore processing and reduced carbon emissions.

An Efficient Peptide Screening Method for Mineral-Binding Peptides

In mineral processing, arsenic-bearing minerals are particularly difficult to separate from their non-arsenic counterparts because they possess similar surface properties. Peptides are well known for their target specificity and can offer a ‘green’ alternative to traditional flotation reagents. However, the use of peptide technologies in mineral processing for developing novel flotation reagents has not been explored. Hence, this work aims to develop a screening method to identify mineral-binding peptides as potential reagent candidates. It is hypothesised that peptides can selectively adsorb onto mineral surfaces, and this method can efficiently identify mineral-binding peptides with high specificity toward the target minerals. The methodology presented involves a selection of peptide candidates from existing literature that show affinity toward arsenic species. These peptides were tested for their adsorption performance onto selected mineral surfaces to evaluate their mineral selectivity under flotation conditions. The study demonstrates that the screening method developed is effective in identifying peptides that have an affinity for target minerals, in this case, arsenic minerals. The screening method can be applied to other minerals, thus, unlocking the potential for developing new reagent chemistries for use in mineral processing.

5-Dodecylsalicylaldoxime as a Novel Collector in Cassiterite Flotation: Performance and Mechanism

Hydroxamic acid and fatty acid collectors are commonly used in cassiterite flotation but face issues like poor selectivity, high dosage, and strict requirements on ore composition and grinding fineness. This study investigates the collecting performance of a novel flotation reagent, 5-dodecylsalicylaldoxime (DSA), in cassiterite flotation. DSA exhibits remarkable selectivity, achieving an impressive 82.5% recovery of Sn at a concentration of only 9 × 10−5 mol/L in single mineral flotation tests. Moreover, DSA significantly outperforms benzohydroxamic acid (BHA), enhancing Sn recovery by 33.55% in artificially mixed ore flotation experiments. In the flotation test of a copper–tin polymetallic ore, compared with the BHA flotation effect, the recovery rate of DSA increased by 12.29% when the Sn grade remained basically unchanged. Analyses such as zeta potential, FT-IR, and XPS indicate that DSA’s superior collecting performance stems from its stable adsorption onto cassiterite surfaces through a chelating ring formation, resembling the adsorption mechanism of hydroxamic acid collectors. Furthermore, DSA’s larger cluster size in the solution compared to BHA contributes to its enhanced selectivity and collectability. Overall, DSA emerges as a promising alternative to traditional cassiterite flotation collectors, offering a combination of enhanced selectivity, lower dosage requirements, and robustness in complex ore systems.

Analysis of the Possibility of Copper Recovery from Flotation Stratiform Copper Ore Tailings

ABSTRACT Flotation tailings produced at three concentrator plants operated by KGHM Polska Miedz SA (SW Poland) are all continuously deposited in the Zelazny Most Tailings Storage Facility. The aim of this study was to analyze the possibility of recovering copper from the stream of final tailings continually produced by the largest of the three KGHM concentrator plants. The tailings sample contained 0.25% of Cu and was characterized by a relatively fine grain size. The tests were performed for three narrow-range size fractions of the tailings sample: −0.040, 0.040–0.160 and +0.160 mm. The findings demonstrate that the coarse and fine fractions are the main carriers of copper-bearing minerals which can be recovered with satisfactory results, if the fractions are processed separately. The coarse grain fraction was milled and then floated in the presence of standard flotation reagents with satisfactory results. The fine fraction was floated in the presence of NaHS with a relatively good efficiency which requires further research. The presented results prove that copper losses in this material can be partially reduced already at the stage of the upgrading processes performed in the concentrator plant.

Intensification of flotation separation process of residual carbon from coal gasification fine slag using ultrafine carbon particles conditioning

ABSTRACT Coal gasification fine slag (CGFS) is a high-ash product with high content of residual carbon. Flotation is a common method to separate residual carbon from CGFS. However, conventional flotation is difficult to effectively remove residual carbon due to the intimate interlock between carbon and ash components in CGFS and the developed pore structure of residual carbon. In this work, a separation method was proposed using ultrafine carbon particles during conditioning to achieve the intensification of ash-carbon flotation separation from CGFS. The flotation results showed that employing ultrafine carbon particles conditioning pulp effectively increase the removal rate of unburned carbon by nearly 20%. To investigate the mechanism of the effect of variable contents of ultrafine carbon particles on the decarburization performance of CGFS, the mercury intrusion porosimeter and a self-made laboratory attachment process observation system were used, indicating that the proposed method reduced the cumulative pore volume of CGFS from 1.27 to 1.09, a 15% decrease. During the conditioning process, the ultrafine carbon particles could follow the fluid flow into the residual carbon pores, which prevented the flotation reagent entering the pores. Thus, this avoids waste of flotation reagents and improves flotation performance.

Retracted: A systematic review of research advances in the interfacial regulation of magnesite flotation: Insights and perspectives

In light of the gradual depletion of high-quality magnesite resources, it becomes paramount to employ flotation as a method for the efficient and cost-effective extraction of magnesium resource from magnesite. Despite an extensive body of research on the interfacial regulation of magnesite flotation, comprehension of various aspects and associated terminologies remains ambiguous. Persistent challenges in the interfacial regulation of magnesite flotation impede its development and industrialization, presenting a pressing obstacle. A comprehensive analysis of the current research status in magnesite flotation is undertaken, encompassing five key aspects: mineral characteristics of magnesite ore and its gangue, interfacial regulation of mineral interactions, interfacial regulation of inevitable metal ions, interfacial regulation of flotation reagents, and progress in flotation process research. Subsequently, proposed are novel directions and technological frameworks for the future of magnesite flotation interface regulation, incorporating mechanisms investigation, reagent design, biological flotation, process enhancement, and tailing utilization. These endeavors aim to update the existing system, offering insights and technological references for efficient desilication and decalcification in industrial production.

Degradation of typical flotation reagents using lead-zinc smelting slag as mediator for persulfate activation: Effect of gallic acid and Cr(VI) on the removal performance and fate of reactive oxygen species

To remediate the Cr(VI)-organic co-contaminants in a non-ferrous mining area, a gallic acid (GA) accelerated lead-zinc smelting slag (LZSS, a mine-sourced waste) mediated peroxodisulfate (PDS) Fenton-like system was constructed for degradation of two typical flotation reagents (benzotriazole and N-hydroxyphthalimide). LZSS acting as an in-situ Fe source in the Fenton-like process, could continuously release Fe species, while GA as a chelate with reducing properties was able to accelerate the rate-limiting step of Fe(III)/Fe(II) cycle to enhance the production of reactive oxygen species (ROS). In the LZSS/PDS/GA system, produced SO4•-, •OH and Fe(IV) jointly contributed to the contaminant removal through radical/nonradical pathways. However, when Cr(VI) coexisted with organic pollutants in the LZSS/PDS/GA system, the reduction of Cr(VI) consumed the electrons that otherwise would have been available for activation of PDS, resulting in fewer different ROS being produced. The increased concentration of GA, as an electron donor, promoted the production of SO4•-, but this promoting effect gradually diminished with increasing Cr(VI). Overall, the dominant ROS gradually transformed from Fe(IV) to SO4•-/•OH as the GA level increased or the Cr(VI) level decreased. Therefore, regulation of the relative roles of ROS by adjusting either the GA dosage or the Cr(VI) levels in the wastewater can improve availability of ROS for further specific removal of pollutants. This study offers an all-in-one solution for utilization of LZSS industrial waste and degradation of flotation reagents, and it also provides a new insight into the advanced environmental application of GA in remediation of Cr(VI)-organic co-contamination.

Совершенствование схемы и режима внутреннего водооборота пенной сепарации алмазосодержащих кимберлитов

The object of this study is the process of enrichment of diamond-containing kimberlites by foam separation. The subject of the research is the recycled water of the foam separation unit. The purpose of the study is to increase the foam separation process efficiency in the enrichment of diamond-containing kimberlites by improving the scheme and regime of internal water circulation. The objectives of the study are to study the effect of sludge on the surface condition and floatability of diamonds, to analyze the composition of sludge products and to establish the causes of the increase in the concentration of sludge in recycled water, to substantiate the approach to the choice of technologies and the development of schemes for desliming recycled waters of the foam separation cycle. To determine the degree of sludge influence on the surface composition and floatability of diamonds, the technique of electron probe X-ray spectral analysis has been used and experiments have been conducted on foam separation of a diamond-kimberlite mixture. Industrial tests of the modes and schemes of clarification of recycled water are carried out at the enrichment plant No. 3 of the Mirninsky Mining and Processing Plant (MPP). The results of X-ray electron spectroscopy show that there is a proportional dependence of the decrease in diamond floatability on the proportion of hydrophilic coatings on the diamond surface. For the destruction of organic-air-mineral aggregates, which are an essential source of sludge, it is proposed to use highly turbulent classification modes in a hydrocyclone, which allows separating grains of hydrophobic kimberlite minerals from drops of apolar collector. In the final stage of clarification of recycled water, it is proposed to use flotation classification technology in a three-product clarifier, which ensures the production of an aqueous phase purified from precipitating and surfacing fractions. The test results of the developed schemes and modes of recycled water desalination in the foam separation department of the processing plant No. 3 of Mirninsky MPP have showed a decrease in the concentration of sludge in recycled water by 2 times, a reduction in the consumption of flotation reagents by 7-10 % and an increase in diamond recovery by 1.2 %.

Performance evaluation of PHGMS technology for superfine chalcopyrite-molybdenite separation

Chalcopyrite (CuFeS2) and molybdenite (MoS2) as typical sulfide minerals are very easy for co-flotation in practice, but their mutual separation consumes a large quantity of flotation reagents, particularly for superfinely associated chalcopyrite and molybdenite as encountered in most porphyry copper deposits. Pulsating high gradient magnetic separation (PHGMS) was effectively applied for pre-concentration of relatively coarse chalcopyrite ore, therefore in this work, its feasibility for separation of superfine chalcopyrite from molybdenite was firstly attempted, with the separation performance under key operating parameters elucidated via a SLon-100 cyclic PHGMS separator in separating a primary superfine chalcopyrite-molybdenite co-flotation concentrate, which assays 8.12 % Cu and 20.00 % Mo, with − 23 μm superfine fraction weighting 79.14 %. The separator achieved a high-selective separation under optimized conditions, producing a copper concentrate of 19.12 % Cu and 6.60 % Mo at 70.90 % Cu recovery, with the Cu content and Mo recovery in the molybdenum concentrate reduced to 3.38 % and reaching 90.88 %, respectively. It was found that low feed weight and velocity, fine matrix, high magnetic induction, and a gentle pulsation were required for producing the effective separation; and the chalcopyrite above 11.4 μm was sufficiently recovered into the copper concentrate, while the high-sufficient recovery for those below 11.4 μm remains a challenge to be overcome, due to its extremely weak magnetic force subjected. This detailed investigation provided a requisite understanding for industrializing the PHGMS technology for fine chalcopyrite-molybdenite separation.

Prediction of Clean Coal Ash Content in Coal Flotation through a Convergent Model Unifying Deep Learning and Likelihood Function, Incorporating Froth Velocity and Reagent Dosage Parameters

This study successfully achieved high-precision detection of the clean coal ash content in the coal froth flotation domain by integrating deep learning with the likelihood function. Methodologically, a novel data processing and prediction framework was established by combining a deep learning Keras neural network with the likelihood function from probability statistics. The SIFT algorithm was utilized to extract key feature points and descriptors from the images, and keypoint matching and mean-shift clustering algorithms were employed to accurately obtain information on foam motion trajectories and velocities. For parameter optimization, the maximum likelihood estimation was applied to find the optimal parameter estimates of the likelihood function, ensuring enhanced model accuracy. By incorporating the optimized likelihood function parameters into the Keras deep neural network, an efficient prediction model was constructed for the dosage of flotation reagents, froth velocity, and clean coal ash content. The model’s evaluation involved six performance metrics. The experimental results were highly significant, with R2 at 0.99997%, RMSE at 0.04458%, MAE at 0.00170%, MAPE at 0.02329%, RRSE at 0.00994%, and MAAPE at 0.00067%.