Flotation de-silicating from diasporic-bauxite with cetyl trimethylammonium bromide

1　INTRODUCTIONTheZetapotentialsofkaolinite ,illiteandchlo riteweremeasuredforthecoalflotation ,allthesethreeclaymineralswerenegativelychargedinthepHrangeof 2 .5 11.0 [1] .Theadsorptionofsodiumdode cylsulfateanddodecyltrimethylammoniumchlorideontokaolinitewasstudiedintheabsenceandpresenceofsodiumhexametaphosphate .Itwasfoundthatthepresenceofthelongchainphosphatedecreasedad sorptionoftheanionicsurfactantbutincreasedthead sorptionofthecationicsurfactant[2 ] .Acommercialmonoetheramineandac…     

Effect of galvanic contact on the flotability of galena in the presence and absence of a collector

In this paper, the effect of various electrochemical environments in the galena flotation is investigated. The electrochemical environments consisted of a ball mill for grinding of galena ore and a Denver flotation cell for flotation of galena in the laboratory scale. In order to achieve the maximum recovery with sodium hyposulfite, the concentrations of 0.06 and 0.12 M of air and nitrogen gases have been used to control the pulp potential in the Denver flotation cell. The galena sample was from the “Era mine” which is located in the Kiyasar area, north of Iran. This mine contains: Galena (PbS) at least 22%, Fluorite (CaF₂) 73.37%, Quartz (SiO₂) 2.54% and other minerals such as Cerussite (PbCO₃) and Kaolinite (Al₂Si₂O₅(OH)₄). Flotation of Galena was conducted in a 0.12 M of sodium hyposulfite solution. It was found that the amount of recovery by this process was 85% and 63% in the presence and absence of potassium amyl xanthate (KAX) and at an estimated potential of 280 to 350 mV respectively while the recovery was 70% and 52% at an approximate potential of 175 to 210 mV in water in the presence and absence of collector (KAX).     

A new technology for processing niobite ore found in Jiangxi province

A new process is proposed for refining niobite ore that is found in Jiangxi province of China. Niobite, also known as columbite or niobite–tantalite, is a mineral that contains tantalum and niobium. The separation process includes two-stage grinding, gravity concentration, magnetic separation, and flotation. The tantalum/niobium concentrate obtained had a grade of Ta₂O₅ 18.28%, Nb₂O₅ 41.62% at a recovery rate of Ta₂O₅ 49.08%, Nb₂O₅ 70.77%. Other minerals occurring along with the niobite, such as zinnwaldite, feldspar, and quartz, were also recovered to comprehensively utilize this ore.     

Prospects of utilization of waste dumped low-grade limestone for iron making: A case study

Low grade dumped limestone sample having high silica of 8.1%, 36.8% CaO, and 3% Al_2O_3 has been studied with the aim to reduce the silica level to below 3% for its utilization in iron making. Beneficiation study of the sample was initiated with desliming of the feed sample of -100 μm to remove the siliceous ultrafine particles and to improve the feed quality. Flotation study was carried out by column flotation technique varying the collector dosage, superficial air flow velocity and froth depth to assess their effect on silica reduction and CaO recovery. It was observed that increased collector dosage and superficial air velocity increases the recovery of CaO, and increase in the froth depth reduces the mass flow and silica content in the concentrate. The best result was found at 1.25 cm/sec superficial air velocity, 25 cm froth depth, 1.25 kgpt collector dosage and concentrate assayed 47.3% CaO, 2.8% silica with 72% CaO recovery.     

Effect of deep oxidation of chalcopyrite on surface properties and flotation performance

In this study, chalcopyrite was oxidized in hydrogen peroxide (H₂O₂) solutions of different concentrations to simulate different degrees of oxidation in real ores, and the effects of H₂O₂ treatment on chalcopyrite surface properties and flotation performance were investigated by surface analysis techniques and floatation experiments, which implied the reason for the poor grade and recovery of oxidized chalcopyrite concentrate in the production process of the ore. Flotation results showed that when the concentration of H₂O₂ increased from 0% (by weight) to 5%, the flotation recovery of chalcopyrite decreased sharply. However, with increasing H₂O₂ concentration from 5% to 30%, chalcopyrite recovery improved relatively to different degrees with different collector concentrations. Analyses of X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma-atomic optical emission spectrophotometry (ICP-OES) results indicated that the pretreatment with H₂O₂ caused that hydrophilic substance formed on chalcopyrite surface with the dissolution of copper ions, and the dissolution amount of copper increased with the increase of H₂O₂ concentration. UV–visible spectrophotometer and Fourier transform infrared spectrum (FTIR) studies indicated that the pretreatment of chalcopyrite with H₂O₂ had little effect on the adsorption amount of potassium butyl xanthate (PBX) on chalcopyrite surface. However, due to the dissolution of copper ions, PBX interacted with chalcopyrite mainly as buthyl dixanthogen (BX)₂.     

Comparative studies on phosphate ore flotation collectors prepared by hogwash oil from different regions

In order to compare the differences between variations of phosphate ore flotation collectors prepared by hogwash oils, JZQ-F collectors were prepared by the hydrolysis method using four types of hogwash oils from different regions in China. The components of the hogwash oils were determined using Fourier transform infrared spectroscopy(FIIR) spectra analysis, while the components of the JZQ-F were determined through gas chromatography–mass spectrometry(GC–MS). The flotation effects of the JZQ-F collectors were investigated by flotation experiments and the adsorption characteristics were determined through the quartz crystal microbalance(QCM-D). Results show that the JZQ-F collector from the Ordos area has 27.43% unsaturated fatty acids. JZQ-F collectors from Beijing, Qingdao, and Dongguan areas contain over 62% of unsaturated fatty acids, which can acquire phosphorous concentrates with a the grade of P_2O_5 above 31.96% and the recovery higher than 91.52%. These three collectors have a larger adsorption capacity, faster adsorption rate, and stronger adsorption structure on apatite surface, which contributed to a good adsorption performance and a favorable flotation effect.     

Effects of different factors during the de-silication of diaspore by direct flotation

Most of the bauxite resources in China are kaolinite-diaspore bauxite of middle to low grade, with a fine dissemination, and are difficultly separated. Direct flotation de-silication has been shown to be an effective method for de-silication of diaspore. In this study the effect of different factors, including pulp temperature, density, pH value, depressant, and collector dosage, on direct flotation of diaspore were investigated by laboratory experiments. The optimum conditions were identified and the flotation performance was improved. The results show that under optimum conditions (a pulp temperature around 40 °C, a pulp density from 30% to 33%, a pH value from 9.0 to 10.0, an air flow rate of 0.5 m³/(m² min), a dispersant level from 35 to 70 g/t, and a collector level around 1000 g/t) an Al/Si ratio of 6.97 is obtained starting from an initial Al/Si ratio of about 4.71. The recovery of Al₂O₃ under these conditions was 86.94%.     

胶磷矿浮选技术的改进

胶磷矿浮选过程选择性差的根本原因,是由于矿物组分尤其镁离子的溶解,造成矿物表面性质相互转化和捕收剂皂盐在矿物表面无选择性沉积. 通过控制浮选条件和药剂制度,尽可能避免捕收剂和溶解组份在矿物表面无选择性吸附或沉积,是选择性调控胶磷矿浮选性质的重要手段. 此外,采用机柱联合浮选装置来改善胶磷矿的浮选分离环境,对提高其浮选效率也非常重要. 实验表明:对原矿含五氧化二磷22.16%、氧化镁3.15%、二氧化硅25.41%的湖北远安磷矿石,通过采取以上改进措施,采用简单的单一浮选工艺,可获得磷精矿五氧化二磷品位＞30%、回收率＞80%和氧化镁品位1%左右的分选指标     

Modification of nano-TiO2 by Al2O3 in-situ coating

A novel technology of in-situ coating Al₂O₃ on the surface of H₄TiO₄ was developed to prevent the aggregation of nano-TiO₂ powders and improve the dispersibility and thermal stability in the way of forming a uniform coating layer. The heterogeneous nucleation was conducted to prepare the precursor of nano-TiO₂ and then Al₂O₃ was coated on the surface of precursor. The effects of Al₂O₃ in-situ coating on the properties of nano-TiO₂ were investigated. The results show that H₄TiO₄ can be dispersed well under alkaline condition (pH 8.5) and the heterogeneous nucleation can be controlled easily. The optimized uniform coating layer is obtained by adding 5% (mass fraction) and 10% of Al₂O₃ and the aggregation of nano-TiO₂ powders is effectively inhibited and the dispersibility is obviously improved. The crystal sizes of TiO₂ powders are 12.3, 11.4 and 8.7 nm after coating 0,5% and 10% of Al₂O₃ respectively. Al₂O₃ on the surface of particulates in amorphous phase could increase the thermal stability of nano-particles after calcined at 550 °C. Foundation item: Project(04GK2007) supported by Hunan Industrial Key Project of Science and Technology     

铝硅酸盐矿物新型浮选捕收剂的研究

考察了自行合成的新型阳离子表面活性剂QAS222对高岭石、叶蜡石和伊利石等铝硅酸盐矿物的浮选行为,试验研究结果表明：广泛矿浆pH范围内,新型阳离子表面活性剂QAS222对铝硅酸盐矿物既表现出较强的捕收力,又显示良好的选择性,是铝硅酸盐矿物的有效捕收剂,可应用于铝硅酸盐矿物的浮选富集,同样也可用于铝土矿、铁矿、萤石矿等选别过程的反浮选脱硅;在矿浆pH=11时,以QAS222为捕收剂,不添加其它任何抑制剂,成功地实现不同铝硅比的人工混合矿的反浮选脱硅,并获得较好的选别指标——当给矿A/S仅有2．7时,仍能获得精矿A／S为12．82,其中Al2O3品位77．79％、回收率69．91％的较好指标,且当给矿A／S不断增大时,精矿中的A/S,Al2O3的品位和回收率都有所提高．     

Assessment of pH-responsive nanoparticles performance on laboratory column flotation cell applying a real ore feed

Nanoparticles(NPs) can promote the column flotation process in mining industry. Nanoparticles' effects on column flotation process(copper recovery, grade and flotation rate constant) are assessed in Sarcheshmeh Copper Complex, Iran, through response surface methodology(RSM) optimization technique. The c-Al_2O_3, a-Fe_2O_3, SiO_2, and TiO_2 nanoparticles are selected for these experiments. A flotation rate constant is chosen as a response to assess the effect of nanoparticles on flotation in its kinetic sense.The process p H and nanoparticle dosage are selected as the influential parameters. Results obtained from RSM indicated that the maximum percentage of Cu recovery and grade is obtained at p H of 12 and nanoparticle dosage of 6 kg/t, through a-Fe_2O_3 and c-Al_2O_3 nanoparticles, respectively. Applying nanoparticles in particular c-Al_2O_3 and a-Fe_2O_3 increases the Cu recovery by 8–10% together with the grade by 3–6% in a significant manner. It is revealed that nanoparticles could effectively be applied in enhancing the flotation performance.     

Synthesis of glycerine-xanthate and its depressing mechanism in separation of marmatite from arsenopyrite

A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glycerine-xanthate through flotation experiments in the presence and absence of Cu^2＋. The results show that glycerinee-xanthate has a strong dressing effect on marmatite at pH〉6 and on arsenopyrite in weak acid and base conditions with butyl-xanthate as collector. In the presence of glycerine -xanthate, marmatite is activated by addition of Cu^2＋, but arsenopyrite cannot be activated and remains unfloatable. So the selective separation can be achieved for two minerals. The depression of glycerine-xanthate on sulfide minerals was discussed based on the radical electronegative calculation and the theory of HSAB. Infrared spectrum shows that there are some -OH and-CSS-in glycedne-xanthate molecule, which competes with butyl-xanthate on the mineral surface. As a result of many hydrophilic groups in glycerine-xanthate, the surfaces of marmatite and arsenopyrite become hydrophilic, thus the flotation of marmatite and arsenopyrite is depressed. The collector is adsorbed preferentially on the surface of marmatite and it shows a better floatability in the presence of Cu^2＋, whereas, the surface of arsenopyrite absorbs glycerine-xanthate and the flotation of arsenopyrite is depressed by glycerine-xanthate.     

Potential control flotation of galena in strong alkaline media

The electrochemical oxidation of galena in collectorless and collector flotation systems, particularly in strong alkaline media, was studied. The results show that, with pH value higher than 12.5 and potentials below 0.17 V, the oxidation products of galena are elemental sulfur and HPbO2^- . Elemental sulfur was present on the mineral surface in excess of oxidized lead species due to dissolution of HPbO2^- , which is beneficial to the flotation of galena. Under the same conditions, sphalerite and pyrite were depressed as a result of significant surface oxidation. Diethyldithioearbamate (DDTC) was found to be the most suitable collector for galena flotation in strongly alkaline media. The very potential produced hydrophobic PbD2-the surface reaction produet of DDTC with galena, is 0 to 0.2 V. Meantime DDTC can depress the surface over-oxidation of galena.Investigations also indicate that, in the range of - 0.9 V to 0.6 V, hydrophobic PbD2 can be firmly adsorbed on galena.     

Thermodynamics of chromite ore oxidative roasting process

To explicate the thermodynamics of the chromite ore lime-free roasting process,the thermodynamics of reactions involved in this process was calculated and the phrases of sinter with different roasting times were studied.The thermodynamics calculation shows that all the standard Gibbs free energy changes of the reactions to form Na2CrO4,Na2O·Fe2O3,Na2O·Al2O3 and Na2O·SiO2 via chromite ore and Na2CO3 are negative,and the standard Gibbs free energy changes of the reactions between MgO,Fe2O3 and SiO2 released f...     

Depressing effect of phenoxyl acetic acids on flotation of minerals containing Ca^2＋/Mg^2＋ gangues

Phenoxyl acetic acids were applied to determine their depressing effect on minerals containing Ca2 /Mg2 gangues. Calcite, mixture of calcite and fluorite, and nickel ore were used in the flotation. And the depression mechanism was studied by the determination of contact angle, zeta potential, adsorptive capacity of collector, and IR analysis as well. It is found that 0.1 mmol/L of phenoxyl acetic acid derived from pyrogallol or gallic acid exhibits strong depressing ability on calcite in almost zero yields at pH value of 9.8, and calcite can be depressed in the flotation of calcite/fluorite mixture for approximate 87% yield of fluorite. The flotation result of practical nickel ore containing serpentine indicates that these two depressants may also show better depression performance to serpentine than traditional depressants such as sodium fluosilicate and carboxylmethyl cellulose. Analysis for the depression mechanism reveals that there exists strong chemical interaction between the depressants and minerals.     

The pulp electrochemistry of flotation separation for stibnite-arsenopyrite bulk concentrate

In the thermodynamics, for flotation separation of the Sb-As bulk concentrate system there is no potential extent using butyl xanthate as collector. However in the kinetics, there exists 150 mV in reducing potential of butyl dixanthogen on the surface of stibnite and arsenopyrite. In this paper, their reducing kinetic difference of electrochemistry was confirmed by pure mineral flotation under controlled potential, the artificial Sb-As bulk concentrate flotation separation and UV-spectrophotometic analysis. The electrochemical separation of Sb-As bulk concentrate has been carried out. qualified concentrate has been obtained. Sb-concentrate contains Sb 49.44 %, As 0.44 %, Sb-recovery is 87.83 % and As-concentrate contains As 10.96 %, As-recovery is 94.66 %. Synopsis of the first author Ou Leming, Doctoral student, born in May 1964, majoring in the flotation electrochemistry of sulphide minerals and the potential-control flotation column.     

胶磷矿柱式双反浮选工艺研究

针对我国西南地区难选硅-钙质胶磷矿,采用旋流-静态微泡浮选柱对其进行了柱式双反浮选工艺的研究.以硫酸和磷酸作为磷矿物抑制剂,脂肪酸类药剂PA-64作为碳酸盐矿物捕收剂,胺类药剂GE-601作为硅酸盐矿物捕收剂,考察了磨矿细度、药剂用量、循环泵工作压力等因素对浮选指标的影响.研究结果表明,采用旋流-静态微泡浮选柱双反浮选工艺,可以得到精矿P_2O_5品位30.49%,MgO含量0.73%,磷回收率81.03%的浮选指标,简化了胶磷矿浮选工艺流程.     

Effect of cobalt loading on reducibility, dispersion and crystallite size of Co／Al2O3 Fischer-Tropsch catalyst

Co/Al2O3 Fischer-Tropsch synthesis catalysts with different cobalt loadings were prepared using incipient wetness impregnation method. The effects of cobalt loading on the properties of catalysts were studied by means of X-ray diffraction (XRD), temperature programmed reduction (TPR), hydrogen temperature programmed desorption (H2-TPD) and O2 titration. Co-support compound formation can be detected in catalyst system by XRD.For the Co/Al2O3 catalysts with low cobalt loading, CoAl2O3 phase appears visibly. Two different reduction regions can be presented for Co/Al2O3 catalysts, which belong to Co3 O4 crystallites (reduction at 320 ““C) and cobalt oxidealumina interaction species (reduction at above 400℃). Increasing Co loading results in the increase of Co3 O4 crystallite size. The reduced Co/Al2O3 catalysts have two adsorption sites, and cobalt loading greatly influences the adsorption behavior. With the increase of cobalt loading, the amount of low temperature adsorption is increased, the amount of high temperature adsorption is decreased, and the percentage reduction and cobalt crystallite size are increased.     

New technique of comprehensive utilization of spent Al2O3 -based catalyst

A new technology was developed to recover multiple valuable elements from the spent Al2O3-based catalyst by X-ray phase analysis and exploratory experiments. The experimental results show that in the condition of roasting temperature of 750 ℃ and roasting time of 30 min, molar ratio of Na2O to Al2O3 of 1.2, the leaching rates of alumina, vanadium and molybdenum in the spent catalyst are 97.2%, 95.8% and 98.9%, respectively. Vanadium and molybdenum in sodium aluminate solution can be recovered by precipitators A and B, and the precipitation rates of vanadium and molybdenum are 94. 8% and 92. 6%. Al（OH）3 was prepared from sodium aluminate solution in the carbonation decomposition process, and the purity of Al2O3 is 99. 9% after calcination, the recovery of alumina reaches 90. 6% in the whole process; the Ni-Co concentrate was leached by sulfuric acid, a nickel recovery of 98. 2% and cobalt recovery over 98.5% can be obtained under the experimental condition of 30% H2SO4, 80 ℃, reaction time 4 h, mass ratio of liquid to solid 8, stirring rate 800 r/min.     

Antibiotic properties of Al2O3 doping silver

The preparation technique and properties of Ag-type inorganic antibiotic material carried by Al₂O₃ were studied. The results show that the material has good antibiotic and safety properties, the acute toxicity taken by stomata is LD ₅₀>8 000 mg/kg (little and big white rats), and the normal quantity in subacute toxicity test is 80 mg/(kg · d). The better mass fraction of doping Ag₂O in antibiotic material carried by Al₂O₃ is 4%–8%, and the optimal sintering temperature is from 1 000 °C to 1 100 °C. Foundation item: Project (2002AA327090) supported by National High Technology Research and Development Program of China