Mixed Minerals Flotation Research Articles

Minimizing entrainment recovery of ultrafine silicate minerals in pentlandite flotation using carboxymethyl cellulose

The presence of silicate minerals is a common occurrence in various ore types, including nickel sulphide ores. These silicate minerals dilute the grade of flotation concentrates through recovery by entrainment which leads to poor flotation performance and subsequently loss of values. Flotation by entrainment is further enhanced as the particle size of the feed becomes finer. The present work investigates the entrainment characteristics of silicate minerals in the flotation of pentlandite. Within the context of the selective flotation of pentlandite from silicate gangue minerals, the influence of different particle sizes on entrainment flotation was also carried out. PAX was used as a collector for recovering pentlandite, whereas carboxymethyl cellulose (CMC) was employed as a dispersant for the silicate gangue mineral. Microflotation experiment was conducted on a pentlandite-quartz mixture of different particle sizes including − 106 + 75 µm, − 75 + 38 µm, − 38 + 20 µm, and − 20 µm. Electroacoustic zeta potential measurements, Fourier-Transform Infrared (FTIR) Spectroscopy, and Ultraviolet–Visible (UV–Vis) spectroscopy were used to characterise the interaction between pentlandite and quartz and in the presence of PAX and CMC. It was observed during the mixed minerals flotation tests that flotation by entrainment increased with a decrease in feed particle size irrespective of the dosage of CMC. Notwithstanding, the addition of CMC led to notable reduction in entrained silica flotation from 58 % to 38 % in the −20 µm size fraction attributed to improved particle drainage from the froth layer in the presence of CMC. Furthermore, UV–Vis spectroscopy and FTIR results gave further evidence that PAX adsorbed onto pentlandite and quartz minerals surfaces in the presence of CMC, which is consistent with the flotation response observed. Overall, this study confirms entrainment of gangue species is dominant within fine or ultra-fine mineral particles and proposes the use of CMC as a dispersant to limit gangue flotation by entrainment.

Study on expanding flotation performance differentiation of quartz and magnesite by amino-trimethylphosphonic acid in dodecylamine system

In this paper, amino trimethylene phosphonic acid (ATMP) was introduced into the separation process of magnesite and quartz, in order to reduce the content of associated minerals in magnesite and improve the industrial utilization value of magnesite. Micro-flotation tests showed that under the system of dodecylamine as collector, ATMP can selectively depress magnesite within the alkaline pulp environment. When the dosage of ATMP was 100 mg/L and the pulp pH was 11, the flotation recovery of magnesite was 12.65 % and that of quartz was 91.00 %. Additionally, the findings of the artificial mixed mineral flotation showed that a concentrate with a grade of 43.53 % MgO and a recovery of 91.03 % was achieved. Zeta potential, FTIR and XPS analyses demonstrated that ATMP chelated with the active site Mg2+ on the surface of magnesite through –PO3 group. In addition, DFT calculation indicated that the adsorbed ATMP increased the distance of N atom in dodecylamine (DDA) to the surface of magnesite from 2.671 Å to 5.106 Å. The interaction energy between DDA and magnesite increased from −201.28 kJ/mol to −136.75 kJ/mol, resulting in it difficult for DDA to adsorb on the magnesite surface. However, ATMP was difficult to adsorb on the quartz surface and had no effect on the interaction between DDA and quartz. Therefore, the selective depression effect of ATMP on magnesite was realized.

An eco-friendly depressant derived from grape seed extract (GSE) as depressant for flotation separation of pyrite from chalcopyrite under low-alkalinity conditions

This study explores the selective depression mechanism of pyrite by proanthocyanidins (PC) during chalcopyrite-pyrite flotation separation. The selective inhibition effect of inhibitor PC was examined through flotation experiments. The depression mechanism of PC on pyrite was analyzed employing X-ray photoelectron spectroscopy (XPS) analysis, selective adsorption tests, adsorption experiments, contact angle measurement, and zeta potential measurement. The artificial mixed mineral flotation test of chalcopyrite-pyrite at a ratio of 1:12 was conducted under pH 7, PC concentration of 75 mg/L, and PAX concentration of 18.75 mg/L. The copper concentrate exhibited a recovery rate of 88.97%, with a copper grade of 29.43%. The sulfur grade in copper concentrate was 40.35%, and the pyrite recovery rate was 1.97%. PC can be used as a potential depressant of pyrite. adsorption experiments and Zeta potential measurement indicated that PC treatment significantly impeded PAX adsorption on the pyrite surface, as confirmed by XPS test results and Ion adsorption analysis.

A new application of Cu2+ on differential modification to promote copper-molybdenum separation with a novel chalcopyrite depressant amidinothiourea

The separation of chalcopyrite and molybdenite has always been a challenge in mineral processing because of their similar floatability and close association. This study proposes a new chalcopyrite depressant named amidinothiourea (ADT) and a new application of Cu2+ on differentially modifying chalcopyrite and molybdenite. It is found that small dosage of ADT is insufficient to depress chalcopyrite, although there is ADT adsorption on chalcopyrite surface at this time. While after Cu2+ modification on chalcopyrite and molybdenite, a small dosage of ADT can strongly depress chalcopyrite, and has no effect on molybdenite. The largest difference of grade and recovery between chalcopyrite and molybdenite were 45.32 and 70.79 % in mixed-mineral flotation with 2.0 × 10−4 mol/L of Cu2+ and 1.6 × 10−4 mol/L of ADT. The mechanisms of ADT depression and Cu2+ modification were investigated through LEIS, XPS, ToF-SIMS and ICP-OES tests. LEIS experiments show that ADT can adsorb on chalcopyrite surface, and particularly pronounced after the modification of Cu2+ on chalcopyrite. XPS and ToF-SIMS confirm that N is the site of action for ADT, and Cu is the site of action for minerals. XPS, ToF-SIMS and ICP-OES tests reveal that Cu2+ modifies chalcopyrite by promoting the dissolution of iron ions and firmly binding with the exposed unsaturated S. While Cu2+ modifies molybdenite by binding with saturated S atoms weakly.

The utilization of 1-Dodecyl-3-methylimidazolium bromine ionic liquid in the reverse flotation separation of feldspar from apatite

The utilization of a new collector 1-Dodecyl-3-methylimidazolium bromine (DMB) ionic liquid in the reverse flotation of feldspar from apatite was researched through a series of experiments. The micro-flotation results exhibited that DMB had a good collecting for feldspar while it had little floatability for apatite, and the artificial mixed minerals flotation presented the reverse flotation separation of feldspar from apatite can be realized well by adding the DMB collector. The foam collapse results illustrated that DMB has better foam properties for reverse flotation compared to dodecylamine (DDA). The zeta potential and Fourier Transform Infrared Spectroscopy (FT-IR) measurements indicated that the interaction of DMB with the feldspar surface was much stronger than that of DMB with the apatite surface. The XPS analysis further suggested that the interaction between DMB and apatite surface was weak while that between DMB and feldspar surface was hydrogen-bonding adsorption. As such, this work is expected to provide a meaningful guide for the selection/design of a cationic collector in reverse flotation of feldspar from apatite.

Effect and mechanism of environmentally friendly depressant 2, 4-Diamino-6-hydroxypyrimidine in separation of chalcopyrite and molybdenite

It is challenging to separate between molybdenite and chalcopyrite due to their comparable hydrophobic characteristics. Inorganic depressants were previously used to separate two minerals, but the results were unsatisfactory and polluted the environment. In this study, the molybdenite and chalcopyrite were separated using a highly effective and ecologically safe depressant, 2,4-Diamino-6-hydroxypyrimidine (DAHP). According to the single mineral experiment, chalcopyrite is totally depressed while molybdenite has superior floatability. The efficacy of DAHP as the depressant was validated by further artificially mixed mineral flotation experiments, indicating the possibility of separating chalcopyrite and molybdenite. The adsorption capacity experiment results showed that the adsorption capacity of DAHP on the surface of chalcopyrite was greater than that on the surface of molybdenite. Zeta potential experiment results show that DAHP is adsorbed on the surface of chalcopyrite and molybdenite through static electrostatic interactions. X-ray photoelectron spectroscopy (XPS) experiment results show that DAHP is mainly adsorbed on chalcopyrite surface through –NH3+ group, which hinders the adsorption of kerosene. The electrostatic contact between DAHP and molybdenite has the least effect on kerosene adsorption. This study shows that DAHP has the potential to separate chalcopyrite and molybdenite as an efficient and environmentally friendly depressant.

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.

Exploration of a novel depressant pullulan gum for the flotation separation of specularite from aegirite

The successful separation of specularite and aegirite in the flotation process heavily relies on efficient depressants due to their closely similar physical and chemical properties. This study focuses on investigating the specific depressive impact and mechanism of pullulan gum (PG) on specularite and aegirite. The findings from single mineral flotation tests revealed the maximum floatability difference was 49.7 percentage point when pH was 8 and the dosage of PG and DDA were 90 mg/L and 30 mg/L respectively, which indicated that PG selectively depressed specularite while displaying a notably weaker depression effect on aegirite. The selective depressive impact of PG was further affirmed through artificial mineral mixed mineral flotation tests. Additionally, results derived from contact angle measurement, adsorption capacity measurement, Zeta potential measurement, and FT-IR analysis collectively highlighted the significantly higher affinity of PG to the surface of specularite compared to aegirite. This stronger interaction between PG and specularite obstructed the adsorption of DDA onto the latter mineral. Moreover, XPS analysis provided insights indicating that PG chemically adsorbs onto the specularite surface, forming a Fe-O complex via a potential reaction between OH and Fe site. As a result of these comprehensive findings, PG emerges as a promising novel depressant for effectively separating specularite from aegirite.

New insights into the influence of mineral surface transformation on the flotation behavior of anhydrite/apatite

Apatite is generally associated with calcium-containing minerals such as anhydrite, which are difficult to separate due to their similar surface characteristics. In this study, the influence of anhydrite on the flotation behavior of apatite in a fatty acid system was systematically investigated using micro-flotation tests, solution chemical calculations, and surface chemical analyses based on the theory of flotation solution chemistry. The single and mixed mineral flotation experiments revealed that an increasing concentration of anhydrite in the mixed ore system rises, apatite flotation is inhibited while anhydrite flotation is activated. The solution chemical calculation results demonstrated that in the mixed system of anhydrite/apatite, the surface dissolution of anhydrite in the pulp will change the solution chemistry environment, resulting in a drastic decrease in the number of surfaces located ions on the apatite surface and inhibiting its flotation. Furthermore, when the pH of the solution exceeds 4.3, the surface of anhydrite transformed to apatite, promoting anhydrite flotation. The results of the X-ray photoelectron spectroscopy (XPS) analysis further confirmed that the phosphate ions dissolved by apatite were adsorbed on the anhydrite surface at pH= 9, forming calcium phosphate films. Based on the above test results, a novel flotation process was designed to realize the selective flotation of apatite from anhydrite-rich phosphate ores. This study can serve as a theoretical foundation and a practical reference for the separation of calcium-containing minerals.

Selective depressing mechanism of H-acid monosodium salt on flotation separation of graphite and sphalerite

Micro-flotation experiments, Fourier transform infrared spectroscopy (FT-IR) tests, Zeta potential tests, X-ray photoelectron spectroscopy (XPS) analysis and molecular dynamics simulation were used to study the flotation behavior, separation and depressing mechanisms of graphite and sphalerite in the presence of H-acid monosodium salt (HAMS). Under the optimum flotation conditions, the recovery of sphalerite and graphite in the concentrate of mixed mineral flotation was 93.37% and 4.98%, respectively. Zeta potential tests and XPS analysis indicated that HAMS was considerably adsorbed on graphite surfaces but virtually absent on sphalerite surfaces. The FT-IR tests revealed that HAMS had no significant chemisorption on graphite surfaces. Molecular dynamics simulation inferred that the hydrophobic interaction between the naphthalene ring in HAMS and graphite was responsible for the adsorption of HAMS on the graphite surface.

The combination of calcium hypochlorite and fulvic acid as an efficient arsenopyrite depressant in Cu-As separation

In this work, fulvic acid (FA) was tested as a novel arsenopyrite depressant in the flotation separation of chalcopyrite from arsenopyrite with or without calcium hypochlorite (Ca(ClO)2). The flotation behaviors were investigated by single and artificial mixed mineral flotation tests. The depression mechanism of FA and Ca(ClO)2 on mineral surface was uncovered by electrochemical measurement, Zeta potential, contact angle, adsorption capacity, Raman, Fourier Transform Infrared spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). Flotation tests illustrated that FA had strong depression action on arsenopyrite but hardly influenced the flotation of chalcopyrite with or without Ca(ClO)2. Electrochemical measurement and Raman spectra results showed that the oxidation degree of arsenopyrite surface was higher than that of chalcopyrite. Zeta potential, FTIR and adsorption capacity results illustrated that FA preferred to adsorb on arsenopyrite surface than chalcopyrite surface, and the introduction of Ca(ClO)2 facilitated the adsorption of FA on arsenopyrite surface. XPS results indicated that Ca(ClO)2 promoted the oxidation of arsenopyrite surface to form more iron oxide products. In addition, FA strongly absorbed on arsenopyrite surface via the complexing between hydroxyl groups and Fe oxidized product to form Fe-OH species, preventing the adsorption of sodium isobutyl xanthate (SIBX) on arsenopyrite and rendering it hydrophilic. While FA weakly adsorbed on chalcopyrite surface, which could be substituted by SIBX and regain hydrophobicity.

Biodegradable ether amines for reverse cationic flotation separation of ultrafine quartz from magnetite

A considerable amount of ultrafine magnetite as the iron source will end up in the tailing dams since the magnetic separation process markedly drops as the particle size. Cationic reverse flotation could be one of the main alternatives for recovering ultrafine magnetite. As a systematic approach, this study explored the flotation efficiency and interaction mechanisms of two biodegradable ether amines (diamine and monoamine) to separate ultrafine quartz from magnetite (− 20 µm). Several assessments (single and mixed mineral flotation, zeta potential, contact angle, surface tension measurement, turbidity, and Fourier transform infrared) were conducted to explore the efficiency of the process and the interaction mechanisms. Results indicated that ether diamine and monoamine could highly float ultrafine quartz particles (95.9 and 97.7%, respectively) and efficiently separate them from ultrafine magnetite particles. Turbidity assessments highlighted that these cationic collectors could aggregate magnetite particles (potentially hydrophobic coagulation) and enhance their depression. Surface analyses revealed that the collector mainly adsorbed on the quartz particles, while it was essentially a weak interaction on magnetite.

Flotation behavior and mechanism of tannic acid as a depressant on Cu-Mo flotation separation

The similar flotation performance of chalcopyrite and molybdenite in the bulk concentrate made their separation a challenge. Therefore, selective depression of them was required. Previous studies had tended to focus on chalcopyrite depression. Tannic acid (TA), a macromolecular organic compound, has been used as a molybdenite depressant to separate chalcopyrite from molybdenite in flotation. Micro-flotation experiments showed that the TA demonstrated a stronger depression for molybdenite. The Cu and Mo recovery of 95.01% and 3.34% was achieved with the TA in mixed mineral flotation, respectively. The UV spectroscopy measurements suggested that TA had a greater adsorption amount on the molybdenite surface. XPS analysis showed that there was chemisorption between iron ions on chalcopyrite and TA and non-chemisorption between molybdenite and TA. The molecular dynamics simulation indicated that the hydrophobic interaction caused TA to be adsorbed on the molybdenite surface. The hydrophobic interaction between TA and the molybdenite surface was more favorable for adsorption than the chemical interaction of TA with the chalcopyrite surface. Additionally, it was confirmed by infrared spectroscopy analysis that TA adsorbed on the chalcopyrite surface would prevent the subsequent adsorption of PBX (potassium n-butyl xanthate), while PBX significantly weakens the adsorption of TA on the chalcopyrite surface.

Application of Diethylenetriaminepenta pentasodium salt as an eco-friendly depressant to effectively improve the flotation separation of scheelite and calcite

Diethylenetriaminepenta (methylene-phosphonic acid) pentasodium salt (DTPMPA), an eco-friendly reagent, was tried for the first time as a depressant for flotation separation of scheelite from calcite. Micro-flotation tests show that DTPMPA can selectively depress the floatability of calcite. In contrast, DTPMPA barely affects the flotation behavior of scheelite. Based on the selective depress effect, floatation separation of scheelite and calcite can be effectively achieved by using DTPMPA as depressant in artificially mixed minerals flotation tests. Based on a series of measurements, it found the surface of calcite was positively charged due to the existence of Ca ion site, which can be chelated with -PO<sub>3</sub>H- functional group on the surface of DTPMPA. In the flotation process, DTPMPA can be chemically absorbed on the surface of calcite to inhibit further collector adsorption. On contrast, little DTPMPA was adsorbed on the surface of scheelite due to the spatial site resistance and electrostatic repulsion induced by surface WO<sub>4</sub><sup>2+</sup>. All in all, these results exhibit DTPMPA has excellent selective depression ability on calcite, which can be potentially applied in the actual scheelite flotation process.

Considering the mechanism of a depressant 2-Amino-5-mercapto-1,3,4-thiadiazole in the flotation of chalcopyrite and molybdenite

Separating chalcopyrite and molybdenite is difficult owing to their similarly high floatability. Accordingly, this paper considers the depressant 2-Amino-5-mercapto-1,3,4-thiadiazole (AMT), in order to separate chalcopyrite and molybdenite and investigate the relevant mechanism of AMT depression. Single-mineral flotation tests showed that when kerosene was used as the collector and AMT as the depressant, molybdenite showed excellent flotation while chalcopyrite was completely depressed. Mixed mineral flotation tests showed that separation of these two minerals could be achieved when AMT was applied as the depressant. Combining the test results of adsorption, Zeta potential, and XPS, the mechanism of AMT depression is suggested. Therefore, the adsorption mechanism of AMT on the chalcopyrite and molybdenite can be revealed. The adsorption of AMT on the chalcopyrite surface is unquestionably greater than that on the molybdenite surface. The results suggest that AMT is chemisorbed on chalcopyrite surfaces through the Cu-S bonds. By contrast, physisorption on molybdenite surfaces is through electrostatic action. Thus, selective depression of chalcopyrite can be achieved with the use of AMT. This study promises a more environmentally friendly flotation separation process for chalcopyrite and molybdenite.

Separation of molybdenite from chalcopyrite with thiolactic acid depressant: Flotation behavior and mechanism

The separation of molybdenite and chalcopyrite is a major challenge because of their similar floatability. It is essential to discover a depressant for selectively inhibiting chalcopyrite in a profitable and sustainable way. A novel chalcopyrite depressant, thiolactic acid (TLA), was proposed. The flotation behaviors were studied through micro-flotation and artificial mixed minerals flotation. Micro-flotation experiments indicated that thiolactic acid could significantly suppress chalcopyrite recovery from 81% to 9.7%, along with molybdenite recovery always more than 71%. Artificial mixed minerals flotation experiments showed a distinct separation behavior between chalcopyrite and molybdenite with an optimal Gaudin's selectivity index of 12.9. The reactivity mechanism of TLA on molybdenite and chalcopyrite surfaces was determined by FT-IR, XPS, and AFM with a possible adsorption model presented. The results revealed that —SH and —COOH groups of TLA preferentially occupied the active copper site on chalcopyrite surface, inhibiting subsequent sodium n-butyl xanthate chemisorption.

Selective depression action of sesbania gum in flotation separation of specularite and chlorite

Specularite and chlorite have similar physical and chemical characteristics, making it challenging to separate from each other. To solve the dilemma, sesbania gum (SG) was firstly utilized as a depressant in the flotation process of specularite and chlorite. Flotation experiments were employed for investigation into the selective depression of SG on the two minerals. The results of single-mineral flotation displayed that SG selectively depressed specularite and floatability difference between the two minerals reached 57.0 percentage point. Artificial mixed mineral flotation experiments further verified the selective depression effect of SG on specularite. Characterization experiments including adsorption experiments, contact angle measurement, Zeta potential detection, FT-IR measurement and XPS analysis revealed the adsorption mechanism of SG on the surface of specularite. Overall, SG adsorbed selectively on the surface of specularite, but rarely on chlorite. In addition, SG acts with surface metal ions of specularite mainly through chemisorption to form metal complexes. Finally, the adsorption schematic diagram of SG on the surface of specularite and chlorite was presented.

Synthesis and utilization of a novel oleate hydroxamic acid collector for the flotation separation of bastnaesite from barite

Hydroxamic acid collectors display excellent selectivity but poor collecting ability in bastnaesite flotation. Improving the collecting capacity of hydroxamic acid collector appropriately become an effective method to enhance the performance of flotation reagents. A novel oleate hydroxamic acid (OLHA) as a collector was synthesized and applied to bastnaesite flotation in this work. The structure of OLHA was characterized by Fourier transform infrared spectrometry (FTIR) and nuclear magnetic resonance spectroscopy (NMR). The single mineral and artificial mixed minerals flotation experiments results show that OLHA achieved efficient flotation separation of bastnaesite and barite when odium hexametaphosphate (SHMP) was used as depressant. The contact angle, zeta potential, FTIR and X-ray Photoelectron Spectroscopy (XPS) measurements were performed to investigate the adsorption mechanism of OLHA. The contact angle results show that OLHA significantly improved the surface hydrophobicity of bastnaesite. Zeta potential and FTIR results show that in the presence of SHMP, OLHA selectively adsorbs to the surface of bastnaesite. Over all, OLHA adsorbs on the surface of bastnaesite through chemically adsorption, and strengthen the hydrophobicity of bastnaesite surface. Therefore, OLHA is a promising collector for bastnaesite flotation.

Using ML8 to achieve the lime-free separation of sphalerite-pyrrhotite under the copper activation system

Sphalerite flotation is conducted under Cu2+ activation system, whereas the selective separation of pyrrhotite is difficult due to the inevitable activation effect of Cu2+, which requires a large amount of lime to depress pyrrhotite flotation. In this study, the conventional collector butyl xanthate and a novel collector ML8 were compared to the selectivity of the flotation separation of sphalerite and pyrrhotite. The ML8 was investigated as an effective sphalerite collector to achieve the lime-free separation of sphalerite and pyrrhotite. Single mineral flotation indicated that sphalerite exhibited good floatability under low-alkaline conditions, whereas pyrrhotite was almost non-floatable, and their selective separation could be achieved using a low dosage of ML8. Mixed mineral flotation further confirmed that the ZnS separation could be achieved under low-alkaline conditions (pH = 9) using ML8 as a sphalerite collector. Reagents adsorption measurements demonstrated that ML8 possessed greater affinity to sphalerite than pyrrhotite, thus the contact angle of sphalerite increased from 51° to 76° after treatment with ML8 while that of pyrrhotite only increased from 67° to 70°. XPS detection results illustrated that the adsorption sites of ML8 on sphalerite were the adsorbed Cu site on the mineral surface rather than the Zn site of sphalerite crystal. The amount of Cu sites located on sphalerite was much greater than on pyrrhotite after the activation with copper sulfate.

Selective adsorption of 1-hydroxyethylidene-1,1-diphosphonic acid on calcite surface in smithsonite flotation system

Removing calcite is a tricky problem in smithsonite flotation because of its better floatability. 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP), a scale inhibitor in water treatment industry, was chosen as a calcite depressant. This study validated the effectiveness of HEDP in separating smithsonite from calcite by flotation using sodium oleate (NaOL) as the collector, and obtained a 70% recovery difference in a single mineral flotation. Artificial mixed mineral flotation obtained a concentrate with a grade of 44% and a recovery of more than 80%. Zeta potential, Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) tests were conducted to obtained some crucial information on the adsorption of NaOL and HEDP, demonstrating that the adsorption of HEDP on calcite surfaces was stronger than smithsonite. The intense adsorption of HEDP on calcite surfaces was attributed to chelation with surface calcium sites. Quantum chemical calculations suggested that the selectivity of HEDP was closely related to the phosphate groups. HEDP was chemically adsorbed on calcite surface by complexing with calcium sites to form six-membered ring chelate. Partial oxygen atoms of phosphate groups dominated in the reaction with calcium sites, and the deprotonation of phosphate groups enhanced the reactivity.