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The floatability of fluorite and calcite exhibit similar properties, rendering their flotation separation challenging. Macromolecular polysaccharide reagents containing the polyhydroxyl group have shown broad promising application. The selectivity of polysaccharide is relatively low. In this study, the introduction of Fe3+ was employed to enhance the selective adsorption capacity of Pullulan polysaccharide towards fluorite and calcite minerals, thereby achieving effective flotation separation. Furthermore, the mechanism underlying intramolecular interactions was elucidated. The DFT calculation and XPS analysis revealed that the adsorption of Fe3+ on the calcite surface was more favorable, leading to the formation of a Ca-O-Fe structure. The MD simulation, XPS analysis, and Zeta potential analysis revealed that the Fe-OH groups on the surface of calcite reacted with the -OH groups in Pullulan and formed bonds, resulting in the formation of a Calcite-Fe-Pullulan structure. This facilitated the attachment of a significant number of Pullulan molecules to the calcite surface. The formation of a hydrophilic layer on the outer surface of calcite by Pullulan, in contrast to the absence of such layer on fluorite's surface, results in an increased disparity in surface floatability between these two minerals, thereby enhancing the efficiency of flotation separation. [ABSTRACT FROM AUTHOR]

The mechanism of electrochemical interaction between chalcopyrite and hexagonal pyrrhotite was analyzed via electrochemical interaction, copper ion concentration testing, and X-ray photoelectron spectroscopy (XPS) characterization. Besides, the effect of electrochemical interaction between the two minerals on the flotation separation was investigated using the mineral flotation tests, adsorption capacity tests, and a microcalorimetric test. Our research results showed that chalcopyrite had higher electrochemical activity than hexagonal pyrrhotite, and when the former acted as an anode during the electrochemical interaction of the two, the corrosion current density was three times higher than that when it acted alone, and the surface oxidation corrosion was intensified. At the same time, the interaction between the two minerals was accompanied by a large number of copper ions dissolved and adsorbed on the surface of the hexagonal pyrrhotite, so that adsorption of butyl xanthate intensified, adsorption increased, and flotation recovery increased by 5%–20%. However, owing to the increase in metal defects and the generation of hydrophilic sulfate, the surface of chalcopyrite hindered the adsorption of butyl xanthate on its surface, and the flotation recovery decreased by nearly 10% compared with that before the occurrence of the electrochemical interaction. This action also significantly weakened the inhibition effect of lime on hexagonal pyrrhotite and increased the difficulty of the flotation separation of the two minerals. The research results of this study provide theoretical guidance for the flotation separation of copper–sulfur ores containing pyrrhotite. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reverse flotation separation of quartz from hematite was difficult. • PASP was firstly utilized as a depressant for the reverse flotation of quartz from hematite. • PASP was hardly adsorb onto the quartz surface. • PASP interacted with Fe(III) species at the hematite surface by chemical adsorption. The depressant polyaspartic acid (PASP) was used to study its selective inhibition behavior in the reverse cationic flotation of hematite from quartz. Microflotation experiments were used to study the flotation behavior of hematite and quartz under different reagents, and artificial mixed mineral experiment was used to verify the separation effect of PASP on the two minerals. The selective adsorption mechanism of PASP on hematite surface was revealed by surface wettability analysis, zeta potential test, adsorption density test and X-ray photoelectron spectroscopy (XPS) analysis. Microflotation experiments showed that PASP was an efficient and selective hematite depressant under alkaline conditions. The artificial mixed mineral experiment proved that PASP can achieve efficient flotation separation of two minerals. Mechanistic experiments (Surface wettability analysis, zeta potential test, adsorption test, and XPS analysis) revealed that the depressant PASP selectively adsorbed on the surface of hematite, which significantly enhanced the hydrophilicity of the hematite surface and significantly negatively shifted its surface zeta potential. The depressant PASP was selectively chemisorbed on the surface of hematite mainly through the complex reaction between polar groups such as –NH- and –COO- in its molecule and the iron ion species on the surface of hematite. [ABSTRACT FROM AUTHOR]

In this work, sodium hypochlorite, hydrogen peroxide, sodium metabisulfite and copper sulfate as activators were investigated to lessen the depression effect of cyanide for deep-depressing chalcopyrite. The experimental results indicate that the copper recovery exceeded 94%, 84% and 97% at the dosage: sodium hypochlorite 3 mL/L, hydrogen peroxide 2 mL/L, sodium metabisulfite 2 × 10 mol/L and copper sulfate 1.67 × 10 mol/L, respectively. According to the results of zeta potential and Fourier transform infrared spectrum, it is suggested that chalcopyrite was depressed because of the chemical adsorption of cyanide on the chalcopyrite surfaces. Sodium hypochlorite, hydrogen peroxide and sodium metabisulfite can destroy Cu-C bond on the deep-depressing chalcopyrite surface by chemical reaction. Copper sulfate can activate deep-depressing chalcopyrite by copper ion adsorption. [ABSTRACT FROM AUTHOR]

The complex disseminated relationship between pyrrhotite and magnetite as well as poor liberation of finely disseminated sulfurous pyrrhotite was revealed through the mineralogy investigation of certain high-sulfurous iron ore. Grinding process and fineness have been found as significant factors influencing the flotation desulfurization performance of high-sulfurous iron ore. Moreover, the separation tests of multi-stage grinding as well as direct one-stage fine grinding were conducted. The results show that desulfurization effect of the former is much better in comparison with the latter. For one thing, sliming losses and slime influences on the separation process were relieved when the separation process of multi-stage grinding was adopted. For another, the grinding circulating load was effectively reduced while the number of high quality particles was increased, which benefits the liberation of valuable minerals. In conclusion, a technological flowsheet was presented. As a first step, one-stage low intensity magnetic separation of mineral particles to produce rough concentrate of magnetic iron was applied under the condition of grinding fineness 65% -0.074 mm. The next step was a fine regrinding of the obtained rough concentrate to 90% -0.045 mm. In succession, an activation of ore pulp with combined activators, as well as a reverse flotation of pyrrhotite with combined collectors to produce magnetite concentrate was employed. The reverse flotation consisted of one-stage roughing, three stages of cleaning and one-stage scavenging. Lastly, another low intensity magnetic separation step on the obtained magnetite concentrate was applied to produce the final iron concentrate. The obtained iron concentrate reaches 64.28% Fe and 0.42% S respectively with iron recovery of 53.62% and desulfurization rate of up to 90%. Technical basis can be provided for the industrial desulfurization application of high-sulfurous iron ore due to the favorable separation efficiency. [ABSTRACT FROM AUTHOR]

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

In this work, we applied the technology of magnetic treatment to the flotation of chalcopyrite. The mechanism of the effect of pre-magnetized butyl xanthate on chalcopyrite flotation was studied using monomineral flotation tests, adsorption tests, conductivity tests, Fourier transform infrared spectroscopy (FTIR), etc. The monomineral flotation test results showed that, after the magnetization pretreatment of butyl xanthate solution, the chalcopyrite flotation recovery was increased by nearly two percentage points, and the dosage was reduced by 4–10 mg/L at the same recovery. The adsorption, FTIR, dissolved oxygen, and conductivity test results all showed that the magnetization pretreatment increased the dissolved oxygen content and promoted the oxidation of butyl xanthate to double xanthate with better selectivity to chalcopyrite. An electrochemical analysis showed that the magnetization pretreatment of butyl xanthate reduced the corrosion potential and corrosion current density of chalcopyrite surface and inhibited the self-corrosion process of chalcopyrite surface. The flotation test results of actual copper sulfide ore showed that pre-magnetized butyl xanthate could increase the copper recovery of copper concentrate by 3.06 percentage points and the sulfur recovery of sulfur concentrate by nearly 3 percentage points, and effectively reduce the mutual content of copper and sulfur concentrates. [ABSTRACT FROM AUTHOR]

The galvanic interaction between chalcopyrite and monoclinic pyrrhotite and its effect on flotation separation were studied using monomineral flotation tests, adsorption capacity tests, X-ray photoelectron spectroscopy (XPS) characterization, and scanning electron microscopy (SEM) test. These results showed that the interaction promoted the reduction of O2 on the cathodic chalcopyrite surface and accelerated the generation of Fe(OH)3, which was not conducive to collector adsorption; hence, the flotation recovery decreased by 10–16%. On the other hand, galvanic interaction accelerated the oxidation of S on the anodic monoclinic pyrrhotite surface to S0 or SO42− and produced a large amount of H+, thus preventing the formation of Fe(OH)3. Meanwhile, the Cu2+ eluted from chalcopyrite surface activated monoclinic pyrrhotite; hence, the flotation recovery increased by 3–10%. Galvanic interaction reduced the floatability difference between the two minerals, and the separation difficulty was significantly increased. Even with an increase in the amount of lime, the separation could not be improved. [ABSTRACT FROM AUTHOR]

• The adsorption structure of Pb(II) on the hydrated surface of wolframite is five ligands. • Mn or Fe site activated by Pb(II) makes it more easily adsorbed by benzo hydroxamic acid. • The primary substance adsorbed on the surface of wolframite is BHA-Mn salt or BHA-Fe salt instead of BHA-Pb salt. Hydration models of wolframite, lead ions, benzo hydroxamic acid ions (BHA), and their co-adsorption models were created to simulate the adsorption processes using the density functional theory (DFT). Pure minerals flotation tests, analysis of reagent adsorption capacity and infrared spectrum of products were carried out. The results indicate that the mechanism of Pb(II) activation in BHA flotation of wolframite in a neutral solution environment was probably due to the traction from Pb(II) on the H 2 Os around the site of the manganese on the wolframite surface reduced the hydration, making them more easily adsorbed by BHA. Therefore, the activation of Pb(II) on BHA adsorption is indirect. [ABSTRACT FROM AUTHOR]

The present research investigates sodium hypochlorite, hydrogen peroxide, sodium metabisulfite and copper sulfate as activators to lessen the depressant effect of cyanide. The results indicate that the zinc recovery exceeded 93%, 90%, 85% and 95% at the dosages: sodium hypochlorite 1.5 ml/L, hydrogen peroxide 2 ml/L, sodium metabisulfite 1.67 × 10 −3 mol/L and copper sulfate 2 × 10 −3 mol/L, respectively. According to the results of FTIR spectrum and zeta potential, it is suggested that the studied marmatite was depressed due to the adsorption of CN − on the surfaces of marmatite by chemical bonds, and moreover the afore enhanced activators can present Zn C N bonds on the surfaces of depressed marmatite by oxidation or ionic adsorption, respectively, and hence activate the depressed marmatite for flotation. [ABSTRACT FROM AUTHOR]

The strengthening effect of fluid force field on the flotation of pyrrhotite from serpentine was revealed through XPS measurements, ICP measurements, zeta potential measurements, turbidity analyses, microscope observation, adsorption capacity measurements and flotation kinetics methods. The results showed that fluid force field can promote the shedding of pyrrhotite surface material(Fe 2 O 3 , SO 4 2-, Fe2+and Fe3+), expose more S0 and form fresh pyrrhotite surface; fluid force field can cause Zeta potential and point of zero charge(PZC) negatively shift on pyrrhotite/serpentine and reduce the value of mutual attraction energy between them, then weaken the hetero-aggregation between serpentine and pyrrhotite; fluid force field can promote the adsorption of butyl xanthate(BX) on pyrrhotite surface, then improve the recovery rate of pyrrhotite from serpentine. By the reaction of fluid force field, the turbidity of artificial mixed minerals slurry increased from 154NTU to 168NTU, the adsorption capacity of BX on pyrrhotite surfaces increased from 0.78 mg/g to 1.08 mg/g, the recovery of pyrrhotite increased from 79.14 % to 82.67 %, and the recovery of serpentine decreased from 23.74 % to 19.43 %. The results of flotation kinetics showed that kinetic model 2 can well reflect the flotation kinetics of pyrrhotite without pre-stirring, while model 1 can well reflect the flotation kinetics of pyrrhotite after pre-stirring by stirring tank. [Display omitted] • A new method to separate pyrrhotite from serpentine was revealed through fluid force field reaction and BX adsorption. • Effects of baffle number, impeller type, stirring time and stirring speed on pyrrhotite flotation were studied. • Flotation resulsts were analyzed by flotation kinetic Model. [ABSTRACT FROM AUTHOR]

Raw ores are mixed with filling materials during mining, which makes it difficult to sort copper‑sulfur resources. Inductively coupled plasma analysis revealed that the primary dissolved metal ions from the filling materials were Ca2+ and Fe3+. Flotation solution chemistry, flotation tests, and X-ray photoelectron spectroscopy measurements confirmed that the dissolved calcium and iron materials were adsorbed onto the chalcopyrite surface in different component forms, which reduced chalcopyrite recovery. Moreover, zeta potential measurements, turbidity analysis, microscope observation, scanning electron microscopy detection, adsorption capacity measurements, and contact angle measurements revealed that the dissolved anions and cations from filling materials can change the surface zeta potential of chalcopyrite and filling materials, weaken the mutual repulsion energy, and strengthen the aggregation effect, thus reducing the adsorption of butyl xanthate on the chalcopyrite surface and its surface hydrophobics. The chalcopyrite recovery eventually decreased from 96.41% to 86.63%. [Display omitted] • The effect of filling materials on chalcopyrite flotation was firstly discussed. • The dissolved metal ions can be adsorbed on the surface of chalcopyrite in the form of hydrophilic hydroxide. • The dissolved materials can strengthen the aggregation between filling materials and chalcopyrite. • The addition of filling materials can weaken the flotation recovery of chalcopyrite. [ABSTRACT FROM AUTHOR]

The strengthen separation mechanism of pyrrhotite and chlorite by ultrasonic pre-treatment was revealed through ICP measurements, XPS measurements, SEM analyses, Zeta potential measurements, turbidity analyses, microscopic observation, adsorption capacity measurements, FTIR analyses and contact angle measurements. The results showed that ultrasonic pre-treatment can promote the dissolution of iron oxide particles on pyrrhotite surface and the desorption of iron ions adsorbed on chlorite surface in mixed minerals, which caused Zeta potential and point of zero charge(PZC) negatively shift on pyrrhotite/chlorite surface and convert mutual attraction energy to mutual repulsive energy, thus weaken the hetero-aggregation and enhance the separation between pyrrhotite and chlorite. Ultrasonic pre-treatment can optimize the adsorption capacity of butyl xanthate(BX) and the surface wettability on pyrrhotite surface, however, it has little effect on BX adsorption and wettability on chlorite surface, hence ultrasonic pre-treatment also can strengthen the separation of pyrrhotite from chlorite. Then the flotation experiment of artificial mixed pyrrhotite and chlorite was carried out, the results show that the recovery of pyrrhotite increases from 77.50 % to 81.72 % and the content of MgO decreases from 6.57 % to 5.74 % by the reaction of ultrasonic pre-treatment. Which further proof that ultrasonic pre-treatment can enhance the flotation separation of pyrrhotite from chlorite. [Display omitted] • Ultrasonic pre-treatment was firstly applied to the separation of pyrrhotite and chlorite. • A new method to separate pyrrhotite from chlorite was revealed through ultrasonic pre-treatment and BX adsorption. • MS calculation had proved that BX molecules can adsorb on the surface of pyrrhotite, but not chlorite. • Ultrasonic pre-treatment can strengthen the separation of pyrrhotite from chlorite. [ABSTRACT FROM AUTHOR]

The diagrammatic sketch of reverse flotation separation of quartz from phosphorite ore by using an emerging Gemini surfactant. • Quartz was separated by reverse flotation using a Gemini surfactant BBD. • In the range of 0 °C to 25 °C, BBD has a stronger collecting ability to quartz than DA. • BBD exhibited excellent selectivity for phosphorite even at 0 °C. • Gemini surfactant is hopeful to the reverse flotation separation of phosphorite ore. Quartz, the gangue of phosphorite ore, is challenging to be separated at low temperatures. In this work, an amine-typed Gemini surfactant, N,N'-bis(dodecyldimethyl)-1,4-butane dibromide (BBD) was recommended as an emerging collector for reverse flotation separation quartz from phosphorite ore. Its collecting ability for quartz and selectivity for phosphorite were also compared with the corresponding unimolecular surfactant 1-dodecylamine (DA) under various experimental conditions. The flotation test results indicated that the BBD, which exhibited a forceful collecting function to quartz and preeminent selectivity for phosphorite at room temperature (25 °C), was a better collector than the conventional DA collector. With 2 × 10-5 mol/L dosage, the quartz recoveries with BBD and DA were 99.0% and 64.5%, respectively. Meanwhile, the phosphorite recoveries of two were not more than 16.0%. When the environment temperature descended, the separating power of the BBD collector for quartz exhibited a more definite stable trend. The recovery of quartz with BBD as a collector raised notably from 61.5% to 93.0% with temperature ranging from 0 °C to 15 °C. However, in the same conditions, the recovery with DA as a collector only raised from 19.5% to 49.5%. At 0 °C, DA lost the vast majority of its collector performance, while BBD still showed high performance. Therefore, BBD presented a better flotation ability for separation of quartz than DA at low temperatures. [ABSTRACT FROM AUTHOR]

Carnallite is a kind of high-quality source of raw material for the production of potash fertilizer (KCl) in industry. However, how to produce potash fertilizer sustainably at low temperature has always been a problem. In this work, we synthesized an emerging morpholine-typed Gemini surfactant, butanediyl-α, ω-bis (morpholino dodeculammonium bromide) (BM), which can be used to collect NaCl in reverse flotation carnallite ores in a low-temperature environment. We compared its ability to collect NaCl and carnallite with the monomeric surfactant 4-laurylmorpholine (LM) at low temperatures. The flotation test results indicated that BM has a stronger collecting ability for NaCl than that of conventional LM collector. At room temperature (25 °C), BM exhibits a forceful collecting function to NaCl and preeminent selectivity for carnallite. The recovery of NaCl ran up to 98.0% when the concentration of BM was 1 × 10−5 mol/L. Under the same condition, the flotation recovery using LM was only 39.0%. The recoveries of carnallite of the two were not more than 3.5%. When the environment temperature descended, the effect of BM for NaCl exhibited a stronger stable trend. The recovery with BM as a collector raised notably from 68.0% to 96.5% with temperature ranging from 0 °C to 15 °C. However, in the same scope of dosage and temperature, the recovery with LM collector only raised from 3.5% to 31.5%. At 0 °C, LM lost the vast majority of its collector performance, while BM still showed high performance. The scheme of a proposal for the reverse flotation of carnallite using LM or BM as the collector. Image 1 • An emerging Gemini surfactant BM was used for production of potassium fertilizer. • In the range of 0 °C–25 °C, BM has a stronger ability to collect NaCl than LM. • BM exhibited surpassing selectivity for carnallite even at 0 °C. • Gemini structure is promising for sustainable potassium fertilizer production. [ABSTRACT FROM AUTHOR]