组合抑制剂石灰和腐植酸钠在锌砷混合精矿浮选分离中对毒砂的选择性抑制机理

采用石灰和腐植酸钠作为经硫酸铜活化和丁黄药捕收后毒砂的组合抑制剂.纯矿物浮选试验表明,组合抑制剂石灰和腐植酸钠能选择性地抑制毒砂.实验室小型闭路试验结果表明,石灰和腐植酸钠的协同抑制作用能较好地实现闪锌矿和毒砂的浮选分离,得到锌精矿中锌品位为51.21％、锌回收率为92.21％的良好指标.通过接触角测试、吸附量测试和X...     

Flotation evaluation and adsorption mechanism of medialan collector to wolframite

Medialan has preferable flotation performance to wolframite,under the conditions of the best flotation pH value 7.0 and low dosage,wolframite recovery is up to80%.Medialan shows poor flotation performance to quartz,but better to fluorite and calcite.However,fluorite and calcite are inhibited in a certain degree by adding medialan mixed with sodium silicate.Adsorption mechanism of medialan collector on wolfram surface was also studied by using infrared(IR)radiation spectrum,adsorption volume,and zeta potential.The results show that medialan can adsorb on wolfram surface in the form of chemistry adsorption,and as medialan collector dosage changes,change law of adsorption volume is similar with that of wolfram pure mineral flotation.Zeta potential results prove that zeta potential of wolfram surface moves negatively after adsorbing medialan collector.     

樟叶提取物作为新型环境友好抑制剂在白钨矿与方解石浮选分离中的应用（英文）

采用简单的物理方法,直接榨取樟叶汁液作为白钨矿和方解石分离的抑制剂。通过接触角测量、傅里叶转换红外光谱测试和原子力显微镜研究樟叶提取物中活性成分及其抑制机理。浮选试验表明,樟叶提取物对方解石有较强的抑制作用,对白钨矿的抑制作用较小。原子力显微镜检测证实方解石表面吸附有樟叶提取物的有效成分。红外光谱结果表明,吸附在方解石表面的组分含有大量的羟基,这些羟基使方解石疏水。Zeta电位和红外光谱结果表明,樟树叶提取物在方解石表面的吸附量远大于在白钨矿表面的吸附量。樟叶提取物在白钨矿和方解石浮选分离中具有潜在的应用价值。     

TXD as selective depressand of fluorite and calcite

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A novel green depressant for flotation separation of scheelite from calcite

Polyaspartic acid (PASP) was used as a novel environmental-friendly depressant, and its inhibition effect on flotation performance of scheelite and calcite using sodium oleate (NaOL) as a collector was investigated by ways of flotation experiments, zeta potential measurement, contact angle measurement and infrared spectroscopic analysis (IR). The results show that PASP exhibits stronger inhibition capability and selectivity than acidified water glass, and the flotation separation of scheelite from calcite can be realized in the presence of 6 mg/L PASP and 20 mg/L NaOL at pH>6. In the presence of PASP, the zeta potential of calcite surface almost keeps unchanged after adding NaOL, and the contact angle decreases sharply. Therefore, it is indicated that PASP significantly decreases the adsorption of NaOL on calcite surface. By contrast, it has no distinct effect on the adsorption of NaOL on the scheelite surface, which is further confirmed by IR results.     

Hydrophobic intensification flotation: Comparison of collector containing two minerophilic groups with conventional collectors

The surface hydrophobization and flotation of a xanthate−hydroxamate collector toward copper oxide mineral were compared with the combined collectors of xanthate and hydroxamate through water contact angle (WCA) and micro-flotation experiments. The results showed that S-[(2-hydroxyamino)-2-oxoethyl]-O-octyl-dithiocarbonate ester (HAOODE) exhibited stronger hydrophobization and better flotation performance to malachite (Cu₂(OH)₂CO₃) than octyl-hydroxamic acid (OHA) and its combination with S-allyl-O-ethyl xanthate ester (AEXE). To understand the hydrophobic intensification mechanism of HAOODE to malachite, zeta potential, atomic force microscopy (AFM) and XPS measurements were carried out. The results recommended that malachite chemisorbed HAOODE to form Cu—HAOODE complexes in which the hydroxamate—(O,O)—Cu and —O—C(—S—Cu)—S— configurations co-existed. The co-adsorption of HAOODE's hetero-difunctional groups was more stable than the single-functional- group adsorption of OHA and AEXE, which produced the “loop” structure and intensified the self-assembly alignment of HAOODE on malachite surfaces. In addition, the “h” shape steric orientation of the double hydrophobic groups in HAOODE facilitated stronger hydrophobization toward malachite than the “line” or “V” hydrophobic carbon chains of OHA or AEXE. Thus, HAOODE achieved the preferable flotation recovery of malachite particles in comparison with OHA and AEXE.     

A new collector used for flotation of oxide minerals

A surfactant containing a mixed aliphatic structure, with a hydrocarbon chain and a diamine group, has proven to be collector for the flotation of quartz, calamine and calcite. And research about its collecting capability was carried out in laboratory. The test results show that the flotation recovery ascends sharply with increasing the concentration of collector. When the concentration of collector reaches 1.83×10⁻⁴ mol/L, the flotation recoveries of quartz, calamine and calcite get their maximum of 97.64%, 91.04% and 95.99%, respectively. The flotation recoveries of quartz, calamine and calcite rise sharply with the rise of pH. And in a wide range of pH, their flotation recoveries all exceed 90%. And in the whole flotation experiment, the flotation recovery of hematite rises with the increase of collector concentration and pH, while the maximal recovery is not more than 55%. Compared with dodecylamine, the N-dodecylethylenediamine has strong capability to quartz and calamine, while the flotation recoveries of calcite are closely. Hydrogen binding adsorption and electrostatic adsorption occur between the collector and the surface of quartz.     

Mechanism of sodium sulfide on flotation of cyanide-depressed pyrite

The mechanism of sodium sulfide (Na₂S) on the flotation of cyanide-depressed pyrite using potassium amyl xanthate (PAX) as collector was investigated by flotation test and electrochemical measurements. The flotation results show that both PAX and Na₂S can promote the flotation recovery of cyanide-depressed pyrite and their combination can further improve the pyrite flotation recovery. Electrochemical measurements show that PAX and Na₂S interacted with cyanide-depressed pyrite through different mechanisms. PAX competed with cyanide and was adsorbed on the pyrite surface in the form of dixanthogen, thus enhancing the hydrophobicity and flotation of cyanide-depressed pyrite. Unlike PAX, Na₂S rendered the pyrite surface hydrophobic through the reduction of ferricyanide species and the formation of elemental sulfur S⁰ and polysulfide. The combined application of PAX and Na₂S induced superior pyrite flotation recovery because of a synergistic effect between PAX and Na₂S.     

ACTIVATION AND DEPRESSION OF CALCITE IN CALCIUM MINERALS FLOTATION

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Potential-pH diagrams for sulfur and hydroxyl adsorbed on copper surfaces in water containing sulfides, sulfites or thiosulfates

The principle of equilibrium potential-pH (Pourbaix) diagrams can be extended to the case of bidimensional layers of species adsorbed on metal surfaces. It allows us to predict the E-pH conditions of adsorption of sulfur and hydroxyl on copper surfaces immersed in water containing dissolved sulfur species such as sulfides, sulfites or thiosulfates. The E-pH relations associated with the equilibria between water and adsorbed hydroxyl, and between dissolved sulfur species and adsorbed sulfur are given at 25 °C. The E-pH adsorption diagrams are calculated for a sulfur concentration of 10⁻⁴ mol kg⁻¹ and superimposed to the usual Pourbaix diagrams for the S-Cu-H₂O system. It is shown that an adsorbed sulfur monolayer may form on the copper surfaces in E-pH domains in which usual Pourbaix diagrams predict no stability of the bulk copper sulfide. The calculation of stability domains of adsorbed sulfur allows prediction of the corrosion risk for copper-based materials in sulfur-containing aqueous environments.     

Influence of silicon species on the transformation of green rust I(Cl) in aqueous solution by oxidation

X-ray diffraction (XRD) and solution analysis were used for characterizing the influence of different silicon species on oxidation of green rust (GRI(Cl⁻)) suspension. While addition of silicon to metallic iron enhanced the formation of β-FeOOH, GRI(Cl⁻) in aqueous solution oxidized into lepidocrocite and oxidation was delayed in presence of silica and silicate species as noticed from potential, pH, and dissolved oxygen (DO) measurements. Transmission electron micrographs showed that the particle size of lepidocrocite was reduced due to silicate addition. The influence of silicate was attributed to its adsorption on GRI(Cl⁻) and lepidocrocite particles as confirmed from ICP-AES analysis of supernatant solution.     

高铁酸盐(Ⅵ)与毒砂表面的作用机理及其对黄铜矿与毒砂浮选分离的影响（英文）

通过浮选试验、接触角测量、吸附量测试、交流阻抗测试和XPS分析研究一种新型环保抑制剂高铁酸钾(K₂FeO₄)在乙基黄药捕收剂体系下对毒砂和黄铜矿的抑制作用。结果表明,在pH值为4～11的范围内,高铁酸钾强烈抑制毒砂,在pH 8或10时,采用5×10^-4 mol/L K₂FeO₄和5×10⁵ mol/L PEX可以实现黄铜矿与毒砂的浮选分离。在K₂FeO₄和PEX存在时,毒砂的接触角和黄药吸附量显著降低。LEIS测量表明,高铁酸盐的加入可以显著增加毒砂表面的阻抗。XPS分析进一步证实,高铁酸盐加速毒砂表面的氧化。     

Selective flotation of smithsonite,quartz and calcite using alkyl diamine ether as collector

The flotation separation of smithsonite from calcite and quartz using a alkyl diamine ether (GE-609) as the collector was investigated through micro-flotation experiments and the real ore flotation experiments. The results show that GE-609 exhibits good collecting capability to three minerals without selectivity. The presence of sodium sulfide enhances the flotation of smithsonite and calcite while inhibits quartz. Moreover, both sodium silicate and sodium hexametaphosphate exhibit good selective inhibition to calcite. The real ore test results show that a zinc concentrate containing 23.51% Zn with the recovery of 71.02% is obtained in the closed-circuit test. To understand the adsorption of GE-609 on smithsonite surface, zeta potential measurement and FTIR analysis were carried out, and the results indicate that the collector GE-609 can adsorb on smithsonite surface through both electrostatic adsorption and chemical adsorption, and the presence of sodium sulfide enhances the adsorption of GE-609.     

Influence of high concentration Zn2+ on floatability of sphalerite in acidic system

The influence of high concentration Zn²⁺ on the floatability of sphalerite in an acidic system was investigated via flotation experiments, zeta potential measurements, contact angle measurements, and X-ray photoelectron spectroscopy. The results indicated that Zn²⁺ was adsorbed on the sphalerite surface and a Zn-hydroxyl complex was formed at a pH of 4 and a Zn²⁺ concentration of 4×10⁻² mol/L. The zeta potential increased and the contact angle decreased from 84.80° to 36.48°, strongly inhibiting the floatability of sphalerite. When S²⁻ or Cu²⁺ activator was used alone, sphalerite was not activated after Zn²⁺ was adsorbed, and its contact angle did not change significantly. However, by using a combination of S²⁻ and Cu²⁺ activators, its floatability was realized after Zn²⁺ adsorption. This result was attributed to the removal of the Zn-hydroxyl complex on the surface of sphalerite by S²⁻. After this removal, Cu²⁺ was adsorbed on the sphalerite surface to form a Cu₂S·S⁰ hydrophobic film.     

高碱度矿浆中含钙矿物的可浮性

高碱度矿浆中含钙矿物表现出不同的可浮性 ,其变化趋势为白钨矿 >方解石 >萤石 ,白钨矿可浮性好而萤石可浮性差。在高NaOH用量下实验室和工业试验均可实现白钨矿与萤石的浮选分离。捕收剂在矿物表面的吸附量测定表明 ,在高碱度矿浆中 ,捕收剂在白钨矿表面吸附牢固而在萤石表面吸附很差 ;Zeta电位测定表明 ,高碱度下白钨矿与萤石均荷负电 ,由于电荷间相互斥力使白钨矿与萤石处于分散状态 ,从而实现白钨矿与萤石的浮选分离。     

Impedance spectroscopic study of corrosion inhibition of copper by surfactants in the acidic solutions

The inhibitive action of the four surfactants, cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate, sodium oleate and polyoxyethylene sorbitan monooleate (TWEEN-80), on the corrosion behavior of copper was investigated in aerated 0.5 mol dm⁻³ H₂SO₄ solutions, by means of electrochemical impedance spectroscopy. These surfactants acted as the mixed-type inhibitors and lowered the corrosion reactions by blocking the copper surface through electrostatic adsorption or chemisorption. The inhibitor effectiveness increased with the exposure time to aggressive solutions, reached a maximum and then decreased, which implies the orientation change of adsorbed surfactant molecules on the surface. CTAB inhibited most effectively the copper corrosion among the four surfactants. The copper surface was determined to be positively charged in sulfuric acid solutions at the corrosion potential, which is unfavourable for electrostatic adsorption of cationic surfactant, CTAB. The reason why CTAB gave the highest inhibition efficiency was attributed to the synergistic effect between bromide anions and positive quaternary ammonium ions. C₁₆H₃₃N(CH₃)₄⁺ ions may electrostatically adsorbed on the copper surface covered with primarily adsorbed bromide ions. On the basis of the variation of impedance behaviors of copper in the surfactant-containing solutions with the immersion time, the adsorption model of the surfactants on the copper surface was proposed.     

Selective depression of copper-activated sphalerite by polyaspartic acid during chalcopyrite flotation

Environmentally friendly flotation reagent, polyaspartic acid (PAPA), was tested as a potential selective depressant in the flotation separation of chalcopyrite and Cu-activated sphalerite. The depression mechanism of PAPA was revealed by contact angle measurements, Zeta potential measurements, Fourier transform infrared spectroscopy (FT-IR) analysis and inductively coupled plasma (ICP) measurement. The micro-flotation tests with single minerals showed that PAPA selectively depressed Cu-activated sphalerite, while chalcopyrite remained floatable. Moreover, a concentrate containing 31.40% Cu with a recovery of 92.43% was obtained in flotation tests of artificially mixed minerals. Results of contact angle measurements, Zeta potential measurements and FT-IR spectrum revealed that PAPA exerted a much stronger adsorption on Cu-activated sphalerite surface than on chalcopyrite surface, preventing the further adsorption of sodium diethyl dithiocarbamate (DDTC) on its surface. ICP measurements indicated that PAPA had an excellent complexing ability with Cu²⁺ in flotation pulp, weakening the activation of Cu species on sphalerite surface and producing selective depression.     

假乙内酰硫脲酸在铜-钼浮选分离中的抑制性能(英文)

将合成的假乙内酰硫脲酸(PGA)用作铜-钼分离抑制剂。该药剂闭路实验结果表明:假乙内酰硫脲酸在较小的用量下对黄铜矿有较强的抑制作用,经一次粗选、一次扫选、两次精选,可获得Mo品位大于26%、回收率大于89%的浮选指标,而用Na2S做抑制剂时钼的回收率下降了2%。药剂吸附量测试结果表明,PGA与丁基黄药在矿物表面发生竞争吸附,PGA在黄铜矿表面上的吸附量远大于在辉钼矿表面的。红外光谱分析表明,PGA在黄铜矿表面是化学吸附,而在辉钼矿表面属于物理吸附。前线轨道计算结果表明,在PAG分子中,硫原子是反应活性的中心。利用矿物、丁黄药及PGA的费米能级能量大小可以从电化学作用角来度解释PGA的抑制机理。     

Pyrite oxidation in the presence of calcite and dolomite: Alkaline leaching,chemical modeling and surface characterization

The effect of calcite and dolomite on the oxidation of pyrite was studied using batch-leaching experiments complemented with chemical modeling, solution analysis and solid characterization techniques. Leaching tests conducted at 80 °C and p(O₂)=1.013×10⁵ Pa and pH>13 showed that pyrite alkaline oxidation rate decreased in the presence of both calcite and dolomite, while more detrimental effect was observed in the case of calcite. FE–SEM/EDS analysis exhibited a surface layer containing Ca (in the case of calcite) and Mg (in the case of dolomite) on the pyrite surface, which justified the slowdown in pyrite leaching rate. This surface layer was formed due to partial dissolution of carbonate minerals, which was affected dominantly by the pH and temperature of the leaching solution based on the chemical modeling data. The surface layer was characterized as Ca or Mg hydroxide using XRD and FTIR analysis. It was also found that this layer was thin and continuous in the case of calcite while it was thick and discontinuous in the presence of dolomite.     

Effects of sodium carbonate and calcium chloride on calcite depression in cationic flotation of pyrolusite

In the cationic flotation of pyrolusite using dodecyl ammine (DDA), the depressive effect of sodium carbonate and calcium chloride on the calcite mineral was investigated systematically through flotation experiments, FTIR analysis, contact angle measurements and zeta potential tests. The microflotation experiments showed that both depressant agents decrease the flotation recovery of calcite significantly. In addition, sodium carbonate acts as activator agent for pyrolusite, and increases its floatability. The flotation experiments and contact angle measurements indicated that the selective depression effect of sodium carbonate on the calcite mineral is more than that of calcium chloride. As evidenced by zeta potential and FT-IR analysis, sodium carbonate decreases the negative charges on the surface of calcite mineral and subsequently reduces the adsorption of DDA collector through electrostatic forces. At a pH of 7.5, using 2000 g/t DDA and 1500 g/t sodium carbonate, a pyrolusite concentrate containing almost 40% MnO with 71.5% recovery is achieved by carrying out the ore flotation experiments on the tabling pre-concentrate.