N,N′-diisobutyloxycarbonyl-N″,N‴-(1,3-propylene)-bisthiourea (L) and its silver(I) and gold(I) complexes were designed and synthesized. Treatment of 1,3-propanediamine with the isothiocyanate iPrCH2OC(O)NCS yielded bisthiourea L with over 90% yield. Treatment of L with AgNO3 in CH3CN afforded coordination polymer {[Ag(L)(NO3)·CH3CN]}n (1) with layer structure, while with HAuCl4 in CH3CN resulted in reduction of Au3+ to Au+ to yield molecular [Au(L)Cl] (2). Ligand L and complexes 1 and 2 were fully characterized by IR, 1H NMR, UV–Vis, cyclic voltammetry and element analysis. The X-ray diffraction analysis displays that the bisthiourea L behaves as sulfur donor to coordinate to Ag and Au atom with μ3-(S, μ2-S′,S′) and μ2-S, S′ coordination mode in 1 and 2, respectively.The designed bisthiourea ligand acts as neutral sulfur donor, while interestingly its silver complex displays a layer structure and gold complex is a molecular compound.Download high-res image (49KB)Download full-size image

•The CSC of surfactants with metal ions used for design of collectors.•MM selects collectors based on Van der Waals and electrostatic force.•QSAR correlates collector's structures with its flotation performances.•DFT reveals collector's reactivity to design its minerophilic groups.•Log P as criteria to adjust collector's hydrophilic-hydrophobic balance.The nature of froth flotation is to selectively hydrophobize valuable minerals by collector adsorption so that the hydrophobized mineral particles can attach air bubbles. In recent years, the increasing commercial production of refractory complex ores has been urgent to develop special collectors for enhancing flotation separation efficiency of valuable minerals from these ores. Molecular design methods offer an effective way for understanding the structure-property relationship of flotation collectors and developing new ones. The conditional stability constant (CSC), molecular mechanics (MM), quantitative structure-activity relationship (QSAR), and first-principle theory, especially density functional theory (DFT), have been adopted to build the criteria for designing flotation collectors. Azole-thiones, guanidines, acyl thioureas and thionocarbamates, amide-hydroxamates, and double minerophilic-group surfactants such as Gemini, dithiourea and dithionocarbamate molecules have been recently developed as high-performance collectors. To design hydrophobic groups, the hydrophilic-hydrophobic balance parameters have been extensively used as criteria. The replacement of aryl group with aliphatic group or CC single bond(s) with CC double bond(s), reduction of carbon numbers, introduction of oxygen atom(s) and addition of trisiloxane to the tail terminal have been proved to be useful approaches for adjusting the surface activity of collectors. The role of molecular design of collectors in practical flotation applications was also summarized. Based on the critical review, some comments and prospects for further research on molecular design of flotation collectors were also presented in the paper.Download high-res image (368KB)Download full-size image

•S-[(2-hydroxyamino)-2-oxoethyl]-N,N-dibutyl-dithiocarbamate surfactant.•HABTC hydrophobilized copper mineral particles at pH 6–10.•Chalcopyrite adsorbing HABTC is an endothermic chemisorption.•Both dithiocarbamate and hydroxamate of HABTC anchored on chalcopyrite.•Cu(II)-hydroxamate and Cu(I)-dithiocarbamate exist in Cu-HABTC species.In this paper, S-[(2-hydroxyamino)-2-oxoethyl]-N,N-dibutyl-dithiocarbamate (HABTC) was first synthesized and characterized by 1H NMR, 13C NMR and FTIR. The role of HABTC’s hydroxamate and dithiocarbamate groups in chalcopyrite flotation was evaluated by micro-flotation, bench-scale flotation, adsorption experiments, zeta potential and X-ray photoelectron spectroscopy (XPS). HABTC exhibited excellent affinity to chalcopyrite particles under pH 6–10 and achieved superior flotation recovery of copper minerals in comparison with sodium isobutyl xanthate (SIBX). The adsorption thermodynamics and kinetics elucidated that HABTC adsorption on to chalcopyrite surfaces was a spontaneously endothermic chemisorption process. Zeta potential demonstrated that HABTC might chemisorb on to the positive sites of chalcopyrite surfaces. XPS spectra further revealed that both dithiocarbamate and hydroxamate groups of HABTC anchored on chalcopyrite surfaces through Cu(II)-hydroxamate and Cu(I)-dithiocarbamate configurations, resulting in an enhanced collecting power of HABTC to chalcopyrite particles.The adsorption mechanism and flotation performance of S-[(2-hydroxyamino)-2-oxoethyl]-N,N-dibutyl-dithiocarbamate (HABTC) to chalcopyrite (CuFeS2) particles.Download high-res image (92KB)Download full-size image

•Exocyclic S and N atoms of HATT bonded with copper atom on malachite.•HATT-Cu surface complex was formed with reduction of cupric to cuprous.•Hydrophilicity changed to hydrophobicity after HATT adsorption.•The hydrophobized malachite attached selectively to air bubbles.The hydrophobic mechanism of 3-hexyl-4-amino-1, 2, 4-triazole- 5-thione (HATT) to malachite (Cu2CO3(OH)2) was investigated by contact angle, micro-flotation, zeta potential, Fourier transform infrared (FTIR) spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectra (XPS). After HATT modification, the wettability of malachite surfaces was changed from hydrophilicity to hydrophobicity, and its zeta potential moved to more negative values, demonstrating that HATT might adsorb on the positively charged copper species via its anionic amino-triazole-thione group with leaving its hexyl group against malachite surfaces. The hydrophobized malachite particles attached selectively to air bubbles and subsequently moved to the pulp surface with the bubbles. FTIR and ToF-SIMS indicated that HATT might chemisorb on malachite surfaces by formation of Cu-S and Cu-N bonds with the breakage of S-H bond in HATT thiol tautomer. XPS further elucidated that a five- membered-ring HATT-Cu(I) surface complex was formed by bonding the exocyclic S and N atoms of HATT with the copper atom on malachite surfaces.The hydrophobic mechanism of HATT to malachite [2¯01] surfaces (the wettability of malachite surface before (a) and after HATT treatment of 15 min (b), water droplet in the solid/gas interface and air bubble in the solid/water interface).

•In situ AFM and SECM investigate HATT self-assembly on chalcopyrite.•HATT aggregated on chalcopyrite to form self-assembled monolayers.•A five-membered-ring Cu(I)-HATT surface complex was recommended.•HATT’s cover leads to an enhanced hydrophobicity of chalcopyrite.The most engineering application for the molecular self-assembly of sulfydryl compounds on solid surfaces is froth flotation. In this work, the hydrophobic mechanism of 3-hexyl-4-amino-1,2,4-triazole-5-thione (HATT) on chalcopyrite (CuFeS2) was first investigated by in situ atomic force microscopy (AFM), in situ scanning electrochemical microscopy (SECM), time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), contact angle and flotation tests. In situ AFM imaging elucidated that HATT might aggregate on chalcopyrite surface to form self-assembled monolayers. In situ SECM images confirmed the weakened tip current of chalcopyrite region after HATT adsorption. On the self-assembly layers, HATT bound overwhelmingly with copper atoms to form a five-membered-ring Cu(I)-HATT surface complex, accompanying with the reduction of cupric to cuprous. HATT anchored on chalcopyrite surfaces through its exocyclic S and N atoms of 4-amino-1,2,4-triazole-5-thione group and left its hexyl group towards aqueous solutions, resulting in an enhanced surface hydrophobicity to improve the flotation recovery of copper minerals. This fundamental understanding inspired by in situ approaches will promote the innovation and development of novel flotation surfactants.The molecular self-assembly and hydrophobic mechanism of 3-hexyl-4-amino-1,2,4-triazole-5-thione (HATT) to chalcopyrite.

•Molybdenite was depressed in sea water flotation at pH above 9.5.•SEM-AES, XPS and ToF-SIMS were used to study the depression mechanism.•Mg(OH)2 and CaCO3 deposited on the surface of molybdenite in sea water at pH 11.•Colloidal precipitates Mg(OH)2 depressed molybdenite more than crystallized CaCO3.De-ionized water (DI water) and simulated sea water were applied to float molybdenite in this study. Results showed that the flotation recovery of molybdnite was sharply reduced in simulated sea water at pH above 9.5. To find out the exact mechanisms of depression, several advanced apparatuses were applied for surface characterization. Based on the measurements by the scanning electron microscopy (SEM), two kinds of precipitates (colloidal precipitates and crystallized precipitates) were observed on the molybdenite surface which was immersed in the simulated sea water during flotation. It was found that the colloidal precipitates overspread on the surface while the crystallized precipitates randomly scatted on the surface. With the detection by auger electron spectrum (AES), it was found that magnesium and calcium were the main components in the colloidal precipitates and crystallized precipitates, respectively. According to the X-ray photoelectron spectrum (XPS) tests, it was testified that the colloidal precipitates were Mg(OH)2 and the crystallized precipitates were CaCO3, which was confirmed by ToF-SIMS results. These precipitated Mg(OH)2 and CaCO3 particles on the molybdenite surfaces play an important role in inhibiting the flotation of molybdenite in the simulated sea water.Molybdenite is depressed by the colloidal precipitates Mg(OH)2 deposited on the surfaces at pH above 9.5 in sea water flotation.

•iPOPECTU adsorption on chalcopyrite studied by SECM, ToF-SIMS, and XPS.•Preferential adsorption of iPOPECTU on chalcopyrite determined by SECM.•Binding of iPOPECTU with copper, but not with iron identified by ToF-SIMS.•Reduction of cupric to cuprous by iPOPECTU adsorption on chalcopyrite.In situ scanning electrochemical microscopy (SECM) was used to study N-isopropoxypropyl-N’-ethoxycarbonyl thiourea (iPOPECTU) adsorption on chalcopyrite. The in situ SECM images indicated a preferential adsorption of iPOPECTU on chalcopyrite surfaces, resulting in a decrease in the probing electrochemical current response. The surfaces after iPOPECTU adsorption were analyzed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). ToF-SIMS results provided a strong evidence of iPOPECTU binding with copper only. XPS analysis showed the reduction of cupric to cuprous on chalcopyrite surfaces as a result of iPOPECTU adsorption. Our results shed light on adsorption mechanism of iPOPECTU on the surface of chalcopyrite samples.

•A novel surfactant NHOO was first introduced as wolframite flotation collector.•NHOO exhibited a stronger affinity to wolframite than BHA and OHA.•NHOO has two active centers to mineral surfaces and two hydrophobic groups.•NHOO showed self-adapting adsorption forces and hydrophobicity to pH values.•A more hydrophobic and stable surfaces improved wolframite flotation recovery.In this paper, a novel surfactant N-(6-(hydroxyamino)-6-oxohexyl)octanamide (NHOO) was prepared and its flotation performances and adsorption mechanism for wolframite were first investigated by FTIR spectra, flotation tests, zeta potential and adsorption quantity measurements. The flotation results showed that NHOO was a stronger collector than the conventional hydroxamic acid collectors such as benzoyl hydroxamic acid (BHA) and octyl hydroxamic acid (OHA). The adsorption data demonstrated that the adsorption affinity of NHOO to wolframite was far stronger than that of BHA or OHA, and the preferable pH ranges for NHOO adsorption on wolframite surfaces were below 6.69 or above 9.35. The results of FTIR spectra and zeta potential illustrated that NHOO might adsorb on wolframite mainly through hydrogen bonding and electrostatic attraction by its amide C(O)H2N+ group at pH < 6.69 or coordination bonding by its hydroxamic C(O)NHO− group at pH > 9.35. In the pH range between 6.69 and 9.35, NHOO might exist in zwitterion species which was formed through intramolecular electrostatic attraction between its positive amide and negative hydroxamic groups, resulting in mildly weakening interaction force and collecting power to wolframite. NHOO’s unique properties, such as double reactive centers to mineral surfaces, double hydrophobic groups, and self-adapting adsorption manner and hydrophobic geometry to pulp pH values, made it a superior collector for wolframite flotation.The flotation mechanism of NHOO, OHA, or BHA to wolframite.

•An oily alkoxyalkyl thiourea BOPECTU was first introduced as flotation surfactant.•The adsorption mechanism of BOPECTU was studied by SECM, DRIFT and thermodynamics.•The values of ΔG (303 K) and ΔH were −31.02 kJ mol−1 and −27.71 kJ  mol−1, respectively.•BOPECTU might chemisorb on chalcopyrite surfaces by the form of CuS and CuN bonds.•BOPECTU exhibited stronger affinity to chalcopyrite than to sphalerite or pyrite.The adsorption mechanism of N-butoxypropyl-N′-ethoxycarbonyl thiourea (BOPECTU) on chalcopyrite surfaces was investigated by thermodynamics, scanning electrochemical microscopy (SECM), and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. The thermodynamic results demonstrated that the adsorption agreed well with the Langmuir or Freundlich isotherm and the adsorption parameters of thermodynamics were ΔG (303 K) = −31.02 kJ mol−1, ΔS = 10.92 J mol−1 K−1 and ΔH = −27.71 kJ mol−1. It inferred the adsorption of BOPECTU on chalcopyrite was a spontaneously exothermic chemisorption process. The in situ SECM images indicated the adsorption of BOPECTU on chalcopyrite resulted in the decrease of the current response. DRIFT spectra exhibited that after BOPECTU treatment, the characteristic peaks of copper–BOPECTU complex appeared on chalcopyrite surfaces, while on pyrite or sphalerite surfaces, no new peaks appeared. UV–vis and FTIR spectra elucidated that BOPECTU showed more affinities to Cu2+ ions than to Zn2+, Fe3+ or Fe2+ ions, and might bond copper atoms with its sulfur and nitrogen atoms. The results of flotation and adsorption experiments further demonstrated BOPECTU owned stronger collecting ability to chalcopyrite than to sphalerite or pyrite.

Mercaptobenzoheterocyclic compounds: 2-mercaptobenzothiazole (MBT), 2-mercaptobenzoxazole (MBO) and 2-mercaptobenzimidazole (MBI) are widely used as corrosion inhibitors and flotation collectors, but the true nature of the adsorption selectivity and activity to solid surfaces is still unclear. Using density functional theory (DFT) calculations, this study investigates the structure–reactivity relation of MBO, MBI and MBT as flotation collectors with sulfide minerals. The results demonstrate that the O, N and S heteratoms in MBO, MBI and MBT molecules can attend the chemical bond formation with metal atoms on mineral surfaces and significantly impact the chemical reactivity of these mercaptobenzoheterocyclic compounds, and the reactive power of the three compounds to metal and mineral surfaces is predicted to be MBT > MBI ≥ MBO. In addition, the chemical reactivity of the thione, thiol and ionized thiol species of these mercaptobenzoheterocyclic compounds in both vacuum and aqueous phases is also studied. The results show that the thione tautomers of MBO, MBI and MBT is more stable and reactive than their thiol tautomers, and in aqueous solutions, the ionized thiol exhibits the strongest reactivity. The theoretical results of structure–reactivity relations provide an atomic level understanding of the activity and selectivity observed by the experimental investigation of the adsorption of MBO, MBI and MBT on metal and sulfide surfaces. The further pyrite flotation tests indicate that MBT has the highest collecting power to pyrite, followed by MBI and then MBO, which is consistent with the theoretical prediction.Graphical abstractThe relative contribution of the computationally quantum-chemical parameter values: 1 – dipole moment, 2 – Natural group charge of N4C2(S1) group, 3 – HOMO energy, 4 – LUMO energy, 5 – contribution of exocyclic sulfur atom to HOMO, 6 – contribution of N4C2(S1)X3 group to LUMO.Highlights► Quantum-chemical parameters of MBT, MBO and MBI sulfide collectors using DFT. ► Relative chemical reactivity of MBO, MBI or MBT with sulfide in aqueous phase. ► Structure–reactivity relationship of MBT, MBO and MBI. ► Excellent agreement of model prediction with pyrite flotation.

In this paper, three flotation approaches, bulk flotation followed by separation, selective Cu flotation followed by bulk flotation and then separation, and preferential Mo flotation followed by Cu flotation, were investigated to concentrate molybdenite from Dexing (Jiangxi Province, China) porphyry Cu–Mo ores. The bench-scale flotation results demonstrated that compared to other two flotation approaches, the preferential Mo flotation approach using a new non-thiol collector obtained a high recovery of molybdenite in a molybdenum circuit, while the tailing of molybdenum circuit was treated by a copper flotation circuit to obtain a high recovery of other co-present metal values. The industrial flotation tests indicated that compared to the bulk flotation approach, the preferential Mo flotation approach achieved an excellent cleaner concentrate containing 0.655% Mo with 88.49% Mo recovery, and increased Mo recovery and grade over 34.0% and 0.4% in the molybdenum circuit, respectively. For being uncontaminated with thiol collectors, this cleaner concentrate was readily treated to perform the Mo/Cu flotation separation which returned a superior Mo concentrate containing 48.83% Mo with 90.60% Mo operation recovery as well as saved about 1/2 Na2S consumption.Graphical abstractThe principal flowsheet of preferential Mo flotation followed by Cu flotation for recovery of Mo and Cu from a porphyry Cu–Mo ore.Download full-size imageHighlights► Lime impairs the floatability of molybdenite in flotation of a porphyry Cu–Mo ore. ► A novel approach is introduced to reduce the effect of lime on Mo recovery. ► The preferential Mo flotation approach is evaluated and optimized by flotation tests. ► The novel approach achieves a high Mo recovery without the effect of lime.

•2-Amino-6-decanamidohexanoic acid was first introduced as collector.•AHA-10 exhibited superior affinity to diaspore against aluminosilicate.•AHA-10 owned unique bond patterns and double hydrophobic groups.•AHA-10 formed intermolecular hydrogen bonds on diaspore surfaces.In this paper, a novel surfactant, 2-amino-6-decanamidohexanoic acid (AHA-10) was synthesized and used as a collector for flotation separation of diaspore and aluminosilicate minerals. The adsorption mechanism of AHA-10 onto diaspore was also evaluated by FTIR spectra, zeta potential, XPS and solution chemistry. The flotation results demonstrated that AHA-10 exhibited superior collecting power to diaspore and good selectivity against kaolinite and illite, and could effectively recover diaspore from bauxite ores contained aluminosilicate minerals at pH around 10. The analyses of FTIR spectra, zeta potential and solution chemistry inferred that at pH around 10, AHA-10 might chemisorb on diaspore surfaces by formation of AlO and AlN bonds. AHA-10’s unique properties, such as characteristic bond model to Al atoms on diaspore surfaces, double hydrophobic groups and intermolecular hydrogen bonds between neighboring AHA-10 molecules coated on diaspore surfaces, rendering a weakening surface energy and enhancing hydrophobicity of diaspore particles.The potential absorption model of a layer of AHA-10 coated on diaspore.Download high-res image (137KB)Download full-size image

•iPOPECTU exhibits excellent selectivity towards chalcopyrite against pyrite.•Pyrite can be separated from pyrite-including Cu-Mo ore with iPOPECTU in sea water.•ToF-SIMS analysis revealed Cu-iPOPECTU complexes improve chalcopyrite floatability.•iPOPECTU does not impact the floatability of molybdenite.Single mineral flotation of chalcopyrite, molybdenite and pyrite with a regular collector (potassium amyl xanthate) and a selective collector (N-isopropoxypropyl-N′-ethoxycarbonyl thiourea) for chalcopyrite in both de-ionized water and synthetic sea water were investigated in this study. The results indicated a wider effective pH range for separation of pyrite from chalcopyrite and molybdenite with N-isopropoxypropyl-N′-ethoxycarbonyl thiourea than with potassium amyl xanthate in de-ionized water flotation. The separation can be achieved in low alkaline conditions only with the selective thiourea collector in synthetic sea water flotation in this study. The results of the mixed minerals flotation in synthetic sea water confirmed the successful separation of pyrite from chalcopyrite and molybdenite by N-isopropoxypropyl-N′-ethoxycarbonyl thiourea at pH 9. In addition, time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis revealed the mechanism of separation.iPOPECTU can use as selective collector to separate pyrite from chalcopyrite without depressing molybdenite at pH 9 in sea water flotation.Download high-res image (195KB)Download full-size image

•3-Hexyl-4-amino-1,2,4-triazole-5-thione first introduced as a collector.•HATT exhibits excellent performances for chalcopyrite flotation at pH 4–8.•HATT adsorption on chalcopyrite is a spontaneously endothermic process.•HATT–copper surface complexes are formed on chalcopyrite.In this paper, a novel surfactant, 3-hexyl-4-amino-1,2,4-triazole-5-thione (HATT) is first introduced as a collector for chalcopyrite flotation. Its flotation behavior and adsorption mechanism to chalcopyrite has been evaluated by micro-flotation tests, and zeta potential, FTIR spectra and adsorption quantity measurements. The results demonstrate that HATT exhibited excellent flotation performances to chalcopyrite at pH 4–8. The adsorption of HATT on to chalcopyrite agrees well with the pseudo-second-order model and Langmuir isotherm, and is a spontaneously endothermic chemisorption process. FTIR spectra and zeta potential analyses further imply that chalcopyrite might chemisorb HATT by formation of HATT–copper surface complexes.

In this paper, a novel surfactant, N,N-diethyl-N′-cyclohexylthiourea (DECHTU) was synthesized and first introduced as a collector for chalcopyrite flotation. The micro-flotation results demonstrated chalcopyrite with adsorbed DECHTU exhibited good hydrophobicity and was effectively concentrated by nitrogen bubbles under pH 4–8. The adsorption of DECHTU onto chalcopyrite surfaces was fitted well by the pseudo-second-order model and Langmuir isotherm, and was a spontaneously exothermic chemisorption process. The adsorption enthalpy change, entropy change and free energy change were ΔH = −31.10 kJ mol−1, ΔS = −6.32 J mol−1 and ΔG (298 K) = −29.41 kJ mol−1, respectively. The activation energy of the adsorption process was 17.39 kJ mol−1. The zeta potential results implied that DECHTU adsorbed onto chalcopyrite surfaces as its anionic species with the release of H+ ion of NH–C(S)–N group into aqueous solutions. The XPS spectra confirmed that there existed Cu(I)–DECHTU surface complexes on chalcopyrite surface by bonding of copper atom with the sulfur atom of DECHTU, accompanying with the reduction of cupric to cuprous.

•Amide hydroxamate was first introduced as a collector for Ca minerals flotation.•Amide hydroxamates exhibited superior affinity to scheelite against calcite.•Amide hydroxamates owned unique bond patterns and double hydrophobic groups.•Amide hydroxamates formed intermolecular hydrogen bonds on scheelite surfaces.In this paper, novel amide-hydroxamic acid surfactants, such as (N-(6-(hydroxyamino)-6-oxohexyl) benzamide (NHOB), N-(6-(hydroxyamino)-6-oxohexyl) octanamide (NHOO), N-(6-(hydroxyamino)-6-oxohexyl) decanamide (NHOD) and N-(4-(hydroxyamino)-4-oxobutyl) octanamide (NOBO), were introduced as flotation collectors for selective separation of scheelite from calicite. The micro-flotation results demonstrated that compared to NHOO, NOBO and NHOB, NHOD exhibited superior collecting power to scheelite and enabled the separation of scheelite and calcite under pH around 10. The calculation results of density functional theory (DFT) and C log P (octanol–water partition coefficient) indicated that NHOD owned excellent hydrophobicity and affinity to scheelite surfaces. The analyses of FTIR spectra, zeta potential and XPS illustrated that besides the electrostatic attraction with Ca cationic species on scheelite surfaces, NHOD might chemisorb onto scheelite by formation of NHOD-W surface complexes, resulting in a superior selectivity to scheelite compared with calcite. NHOD's unique properties, such as characteristic bond patterns on scheelite surfaces, double hydrophobic groups, and intermolecular hydrogen bonds between neighboring molecules coated on scheelite surfaces, rendered it to be a superior collector for scheelite/calcite flotation separation.Download full-size image

Aliphatic oxime derivatives C7H15CXNOH (X = H, CH3, NH2 or OH) have been commercially used as copper(II) extractants or flotation collectors, but the true nature of their reactivity toward Cu2+ or mineral surfaces still remains elusive. Using density functional theory (DFT) method, the structure–reactivity relationship of these aliphatic oxime derivatives was evaluated at B3LYP/6-311 + G(d, p) level. The results indicated that the O or N atoms in the head group of octanaldoxime (OTAO), methyl n-heptyl ketoxime (MHKO), N-hydroxyoctanimidamide(HOIM) and n-octanohydroxamic acid (OTHA) are the chemical reaction center. The reactivity of the aliphatic oxime ionic species increases successively with the replacement of hydrogen atom by methyl, amino and hydroxyl, suggesting that the affinity of them to copper species is as follows: OTHA > HOIM > OTAO > MHKO, which coincides with the order of their binding energy toward Cu2+. The flotation performance of aliphatic oxime derivatives to malachite was in the order of OTHA > OTAO > HOIM > MHKO, which was in line with the combination effect of their reactivity and hydrophobicity. The established structure–reactivity relationship provides an atomic level understanding of the structural requirements for aliphatic oximes to recover cupric ions or copper oxide minerals.