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Herein we present the use of a Gemini surfactant and reverse froth flotation to efficiently separate magnetite from quartz and produce iron ore at 273 K. This surfactant achieved an obviously superior flotation performance (TFe recovery increased by 48.18%), and the dosage of the Gemini surfactant was three times less than that of a conventional monomeric surfactant. Our findings are expected to serve as a general guide to design a new and excellent collector for high-efficiency mineral flotation and to lead to an efficient and clean development of mineral resources. [ABSTRACT FROM AUTHOR]

Abstract An effective collector plays a vital role in the reverse flotation of phosphate ore as well as sustainable production of phosphate fertilizer. Phosphate fertilizer is used to achieve the sustainable increase in the production of food. Phosphate ore is concentrated by reverse froth flotation and used as a raw material to produce phosphate fertilizer in industry. However, all the surfactants used in the phosphate ore reverse flotation process are conventional monomeric surfactants contain a single similar hydrophobic group in the molecule, which results in a low production efficiency and severe environmental contamination. In this work, a novel Gemini surfactant, N,N′-bis(dodecyldimethyl)-1,4-butane diammonium dibromide (BDBD) was prepared, and originally recommended as a collector for reverse froth flotation separation of silicoide from phosphate ore. The performance of BDBD was compared with the results acquired using its conventional monomeric surfactant dodecylamine hydrochloride (DAH). The bench-scale flotation results showed that BDBD had excellent collecting power for silicoide and significant selectivity against apatite at pH 9. Moreover, BDBD presented stronger desilication efficiency than DAH. Achieving the superior flotation performance (P 2 O 5 recovery increased by 2.41%, P 2 O 5 content increased by 0.26%, and SiO 2 content reduced by 2.52%), the dosage of Gemini type BDBD collector (100 g/t) is four times less than that of monomeric DAH collector (400 g/t). Therefore, this work provides a promising approach to the sustainable phosphate fertilizer production and to address global food security concerns. Graphical abstract Gemini surfactant as a collector for reverse froth flotation separation of silicoide from phosphate ore for sustainable phosphate fertilizer production. Image 10888 Highlights • A novel Gemini surfactant BDBD was introduced in phosphate fertilizer production. • BDBD exhibited superior selectivity for silicoide against apatite. • BDBD displayed superior flotation performances than conventional surfactant DAH. • Gemini is a promising collector for sustainable phosphate fertilizer production. [ABSTRACT FROM AUTHOR]

Herein, we report that a gemini surfactant can efficiently separate KCl from NaCl by froth flotation to produce potassium fertilizer (KCl). For achieving the obviously superior flotation performance (KCl recovery increased by 14.51%), the dosage of the gemini surfactant should be three times less than that of the conventional monomeric surfactant. Its unique properties, such as double active centers to mineral surfaces, double hydrophobic groups, and stronger surface tension reducing ability, make it a superior flotation collector for separation of KCl from NaCl in potassium fertilizer production. [ABSTRACT FROM AUTHOR]

Highlights • A novel Gemini surfactant BOBD was introduced in potash ore flotation. • BOBD exhibited superior selectivity for sylvite against halite. • BOBD displayed superior flotation performances than conventional surfactant OAH. • Gemini BOBD is a promising collector for cleaner production of potash fertilizer. Abstract Potash fertilizer ensures the necessary agricultural yields to feed an increasing world population. Over 80% of the world's potash fertilizer is produced by the selective froth flotation of KCl (sylvite) from NaCl (halite). However, all the surfactants used in the potash froth flotation process are traditional monomeric surfactants contain a single similar hydrophobic group in the molecule, which leads to a low production efficiency. In this work, a novel Gemini surfactant, N,N'-bis (octadecyldimethyl)-1,4-butane diammonium dibromide (BOBD) was prepared, and originally recommended as a collector for froth flotation separation of sylvite from halite for potash ore. The performance of BOBD was compared with the results acquired using its traditional monomeric surfactant octadecylamine hydrochloride (OAH). The bench-scale flotation results showed that BOBD had excellent collecting power for sylvite and significant selectivity against halite at natural pH. Moreover, BOBD presented stronger desalination efficiency than OAH. The results gained with the Gemini collector were better in terms of KCl recovery and NaCl content than those gained with four times higher dosages of the conventional monomeric surfactant. [ABSTRACT FROM AUTHOR]

Drilling fluid contacts with the surface of coal and fractures fully during the drilling process for CBM, its pH value has direct impact on the wettability of coal, affecting the seepage of CBM further. Therefore, the research about the effect of drilling fluid’s pH value on the coal’s wettability has important practical significance. The influence law of drilling fluid’s pH value on the coal’s wettability was studied through lots of experiments, the results showed that the wettability was related to the pH value of drilling fluid, decreases firstly, increases secondly and decreases at last, the coal’s hydrophilicity was the weakest at the pH value of 9, and the hydrophilicity of coal was weaken further after the addition of surfactants. The conclusions provide strong technical guidance for selecting drilling fluid and optimizing fluid performance, and it helps to protect the reservoir and increase CBM production. [ABSTRACT FROM AUTHOR]

Comparison diagram of reverse flotation behavior of Phosphorite by a novel hammer-like amidoxime surfactant DPA and traditional collector DA. [Display omitted] • A novel amidoxime surfactant DPA was introduced in phosphate fertilizer production. • DPA exhibited superior selectivity for quartz against phosphorite. • DPA displayed superior flotation performances than conventional surfactant DA. • Amidoxime is a promising collector for sustainable phosphate fertilizer production. Phosphate fertilizer, as a necessary nutrient for crops in agriculture, plays a vital role in addressing global food security concerns. The source of phosphate fertilizer is mainly obtained through the production of phosphate ore, which has caused widespread concern. However, in the traditional process, the low production efficiency and high dosage of common surfactants have severely restricted the development and utilization of phosphate rock resources. In this work, a new designed hammer-like amidoxime surfactant (DPA) was characterized and introduced as an outstanding collector to recover high quality phosphate ore. The micro-flotation tests indicated that DPA had more excellent collecting ability and selectivity(The phosphorite recovery was always lower than 15%) than common monomolecular collector 1-dodecylamine (DA). Bench-scale flotation tests showed that a high quality phosphorite concentrate with higher grade and recovery (33.65% and 79.46%, respectively) could be enriched using lower dosage DPA. Economic estimate for a 5000 t/d phosphorite ore concentrator would result in an annual profit increase of approximately $8675330.65 by DPA collector. Density functional theory(DFT) calculations revealed that DPA reacted with Nucleophilic reagent (Phosphorite) by the reactive site of –CH 2 NH(CH 2) 2 C(NOH)N+H 3 group and more easily absorbed on the surface of Phosphorite than DA. Therefore, the above results prove that amidoxime surfactant DPA is an efficient and economic collector to recover high quality phosphate ore, which provides an important guarantee for the production of phosphate fertilizer. [ABSTRACT FROM AUTHOR]

Separation of scheelite from calcite by froth flotation using a new amidoxime surfactant - 3-dodecylamine propyl amidoxime (DPA). [Display omitted] • A new amidoxime surfactant DPA was used to flotation separate scheelite and calcite. • Scheelite and calcite recovery were 92% and 4.5% respectively. • DPA exhibited preferable selectivity than NaOL in the absence of depressant. • The interaction of DPA surfactant on scheelite surface is electrostatic adsorption. With its high electrical conductivity, thermal creep resistance and compression modulus, tungsten take an irreplaceable position in modern industry, defense, and high technology. Scheelite, as the main raw material of tungsten resources, usually adopts Petrov' process: steam heating 80 °C-90 °C, stirring in a tank containing 2%-4% sodium silicate solution for more than half an hour to make sodium oleate desorbed on the calcite surface, and repeated cleaning. Herein, a new amidoxime surfactant 3-dodecylamine propyl amidoxime (DPA), had been synthesized and used as a collector for the first time in the flotation separation of scheelite and calcite at room temperature without any sodium silicate, and compared with the traditional collector sodium oleate (NaOL). The flotation behavior of DPA was studied by micro-flotation and mixed binary mineral flotation tests, which showed that DPA has good collection ability and excellent selectivity for scheelite. Meanwhile, the interaction mechanism of DPA on the mineral surface was discussed by FTIR analysis, zeta potential test, contact angle measurement and density functional theory (DFT). FTIR analysis and zeta potential test confirmed that DPA collector had adsorption on scheelite surface but had little effect on calcite. DFT calculation further confirmed that the positively charged –C(NOH)N+H 3 group in DPA had electrostatic adsorption on the negatively charged scheelite surface. The contact angle measurement results revealed that DPA can enhance the surface hydrophobicity of the scheelite particles. Therefore, this highly selective DPA surfactant can achieve effective separation of scheelite and calcite, contributing to environmental protection and sustainable green development of resources. [ABSTRACT FROM AUTHOR]

Wolframite was separated and extracted from calcite by using a new type of amidoxime surfactant − 3-dodecylamine propyl amidoxime (DPA) as a flotation collector. [Display omitted] • A novel amidoxime surfactant DPA was synthesized by lab. • DPA was first introduced in flotation for separation of wolframite from calcite. • DPA has superior selective adsorption performance at wolframite interface. • The wolframite recovery was 96% and calcite only 2 % at pH 7 and 2 × 10-4mol/L DPA. This study concentrated on the adsorption features and mechanism of a novel amidoxime surfactant 3-dodecylamine propyl amidoxime (DPA) used as a new wolframite collector on wolframite and calcite surfaces. The flotation experiment showed that DPA collector has a remarkable flotation separation effect on wolframite and calcite. Additionally, the results of the contact angle and zeta potential measurements, and FTIR spectral analysis revealed that the DPA had produced strong electrostatic adsorption on the surface of wolframite, but almost no adsorption on calcite. The results of the DFT calculation showed that DPA had a strong effect on the wolframite surface mainly through the positive charged –C(NOH)N+H 3 group. It provides a new idea for the flotation separation of wolframite and calcite. [ABSTRACT FROM AUTHOR]

In this paper, a Gemini surfactant, ethane-1,2-bis(dimethyl-dodecyl-ammonium bromide) (EBAB), was introduced as a collector for reverse cationic flotation separation of quartz from magnetite, and its adsorption mechanisms on the two minerals and air/water interface were also investigated by FTIR spectra, zeta potential, density functional theory (DFT) calculation and surface tension. The flotation results showed that EBAB presented stronger collecting power than the conventional monomeric surfactant dodecylammonium chloride (DAC) and superior selectivity for quartz against magnetite. The results of FTIR spectra and zeta potential measurements demonstrated that the interaction of EBAB with quartz and magnetite was mainly through electrostatic attraction, which was further confirmed by DFT calculation. EBAB was preferred to adsorb on the negatively charged surface of quartz, increasing its zeta potentials and improving its hydrophobicity. Adsorption of EBAB at the quartz/water interface could be divided into four stages as the concentration of EBAB was increased in solution. At low concentrations, adsorption was controlled primarily by electrostatic interactions, but when the zeta potential of quartz was reversed from negative to positive, hydrophobic chain interactions controlled the adsorption process. EBAB’s unique properties, such as high positive grouping Mulliken charge of –CH 2 N + (CH 3 ) 2 (CH 2 ) 2 (CH 3 ) 2 N + CH 2 –, and strong “surface activity” at the air–water interface, made it be a superior cationic collector for reverse flotation desilication from iron ores. [ABSTRACT FROM AUTHOR]

Highlights: [•] An amino-trisiloxane Gemini surfactant BBAB was introduced and synthesized. [•] BBAB showed strong collecting ability for aluminosilicates even at high pHs. [•] Structure–property relationship of BBAB, DTAB and DDA. [•] High Mulliken charge of –CH2N+(CH3)2(CH2)4(CH3)2N+CH2– group in BBAB. [•] “Parachute” structure of hydrophobic siloxane groups in BBAB. [Copyright &y& Elsevier]

Comparison diagram of flotation behavior of lepidolite by new Gemini collector HBDB and traditional monomolecular collector DA. [Display omitted] • A novel amine-based Gemini surfactant HBDB was synthesized in our lab. • HBDB was introduced as an efficient collector of lepidolite flotation. • HBDB has better collecting ability and selectivity than traditional collector DA. • Using less dosage HBDB obtained a higher quality lepidolite concentrate. The global lithium supply and demand in this century is accelerated by the energy transition from carbon-based fossil fuels to renewable energy where electrical energy storage and electric vehicles heavily depend on the lithium-ion battery. The lepidolite is one of the main resources for extracting lithium, and it is usually enriched by froth flotation separation technology. However, the traditional lepidolite collector is monomer surfactant with only a single hydrophobic group and hydrophilic group, which usually leads to the low flotation separation efficiency. Therefore, to achieve the flotation separation of lepidolite ore more efficiently, in this work, an amine-based Gemini surfactant, hexanediyl-α, ω-bis (Dimethyldodecylammonium bromide) (HBDB), was synthesized, and compared with the conventional single molecule collector dodecylamine (DA). The experimental results show that the optimum pH value of flotation is 3, and the optimum dosage of HBDB and DA are 150 g/t and 300 g/t respectively. In bench-scale flotation experiments, compared with the conventional monomer DA collector (350 g/t), the Gemini HBDB with only 1/2 dosage of DA (175 g/t) increased the recovery of lepidolite by 16.18%. Economic calculation for a lepidolite ore plant, 1500 t/d, demonstrating that using Gemini HBDB can gain more about $ 8.2 million USD per year than using traditional unimolecular DA. Accordingly, this study provides a new and highly efficient collector for the flotation separation of lepidolite ore. [ABSTRACT FROM AUTHOR]

In froth flotation separation process, the collector molecular design has a crucial effect on potash processing to ensure sustainable production of potassium fertilizer (KCl) that is important to secure food supply in human society. Carnallite is an important source of KCl fertilizer production in industry. Reverse flotation has been used to separate halite (NaCl) impurities from carnallite (KCl · MgCl 2 · 6H 2 O) for carnallite resources. However, progress in the carnallite resource reverse froth flotation has been constrained by the inherent limitation of traditional collector molecules with a single hydrophilic head and single hydrophobic chain per molecule. Herein, a novel morpholine-based Gemini molecule with double hydrophilic heads and hydrophobic chains, butanediyl-α, ω-bis (morpholino tetradecylammonium bromide) (BMTB) was synthesized and applied as the flotation collector in the reverse flotation separation for carnallite mineral. The better flotation performance of Gemini BMTB was achieved, compared to the traditional monomeric surfactant N-(n-Tetradecyl) morpholine (TDM). The bench-scale froth flotation separation results revealed that BMTB exhibited outstanding affinity and selectivity for NaCl crystals from carnallite at natural pH, resulting in less collector dosages – only 1/3 of TDM molecules. In contrast with traditional monomeric surfactant TDM (120 g/t), less amount of Gemini BMTB (40 g/t) – only one third of TDM molecules, was needed to obtain higher KCl recovery (KCl recovery raised by 4.69%). Meanwhile, the grade of NaCl with 40 g/t BMTB collector (2.19%) was lower than that with 120 g/t TDM collector (3.91%), and the grade of KCl with BMTB collector (22.59%) was higher than that with TDM collector (22.12%). Therefore, this work demonstrated the next-generation of flotation collector for the reverse froth flotation separation of the carnallite resources. Gemini surfactant as a collector for reverse froth flotation separation of halite from carnallite ore for potassium fertilizer production. Unlabelled Image • Halite was separated by reverse flotation using a Gemini surfactant BMTB. • BMTB exhibited superior selectivity for halite against carnallite. • BMTB displayed superior flotation performances than conventional surfactant TDM. • Gemini surfactant is hopeful to the reverse flotation separation of carnallite ore. [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]

Abstract: The first use of a Gemini cationic surfactant, butane-α,ω-bis(dimethyl dodeculammonium bromide) (BDDA), as a collector for reverse flotation to separate illite, pyrophyllite and kaolinite from diaspore is reported in this study. Micro-flotation tests of the pure minerals are employed to detect the minerals'' flotation behaviors with the Gemini and to comparatively investigate the collecting ability both with the dimeric surfactant and the corresponding monomeric. The results show that the Gemini surfactant demonstrates a stronger collecting power than the monomer. Moreover, with the Gemini, the floatability of kaolinite is better than that of illite and pyrophyllite in the entire pH range. When corn starch was used as a depressant, flotation separation of the artificial mixed-mineral samples and the bauxite ore were conducted by using BDDA as a collector at pH around 9–10. The Gemini presents a significant selectivity for illite, pyrophyllite and kaolinite against diaspore. Mass ratio of Al to Si of the concentrate was 9.72 for the bench-scale separation, and the recovery of Al was 81.25%. To understand mechanisms of the Gemini adsorption on the mineral surfaces, we employed FTIR spectra analysis, density functional theory (DFT) calculation, electrokinetic measurements and surfactant property studies as well. In addition, the role of corn starch in the selective depression of diaspore was also explained. [Copyright &y& Elsevier]

• 2-decanoylamino-pentanedioic acid was first introduced as collector. • DPA exhibited superior affinity to ilmenite. • DPA owned two unique hydrophobic groups and three hydrophilic groups. In this work, 2-decanoylamino-pentanedioic acid (DPA), a novel dendritic surfactant, was designed, synthesized, and exploited as a collector for the flotation of ilmenite. The experimental froth flotation results illustrated that DPA had a superior collecting activity, adsorbed better on the ilmenite surface than oleic acid, and could effectively recover ilmenite from titanomagnetite at a pH of approximately 7. DPA's unique properties, including two hydrophobic groups and three hydrophilic groups, allowed it to coat the ilmenite surface, rendering it a superior collector. [ABSTRACT FROM AUTHOR]