Scanning Electron Microscope Equipped With An Energy Dispersive Spectrometer Research Articles

Experimental phase equilibria of the Mg–Sn–Ce ternary system at 800 K

The phase equilibria of the Mg–Sn–Ce ternary system at 800 K were investigated by means of X-ray powder diffraction (XRD) and scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS). Six stable ternary phases (τ1-τ6) and one suspected ternary compound (A2) were observed in the section. Three known ternary compounds τ1 (MgSnCe, Pnma, oP12), τ2 (MgSn2Ce, I-42m, tI32) and τ3 (Mg23SnCe6, Fm-3m, cF120) were confirmed at 800 K. The new ternary phase τ4 (Mg40+4Sn26–4Ce34) has the iso-structure of Mg3·9Sn2·1La3 (Cu4Si2Zr3 prototype, P-62m, hP9). The crystal structures of the two additional new ternary compounds τ5 (Mg44Sn34Ce22) and τ6 (Mg40Sn36Ce24) have not been determined. It has not been identified that A2 (Mg10Sn39Ce51) is a ternary compound or a Ce–Sn binary compound with a solubility of Mg. CeSn3, Ce3Sn5, αCe5Sn3 and Ce3Sn were detected to contain solubility of Mg as 13.6, 1.0, 2.0 and 2.7 at.%, respectively. The Mg3Ce and MgCe contain small solubility of Sn as 1.0 and 4.5 at.% Sn. The tie-triangles of the ternary system have been identified.

The effect of short-term annealing in an Ar environment on microstructure and adhesion property of Cr-coated Zircaloy-4 claddings

Short-term annealing tests were conducted at 700, 900, 1100, 1200 and 1300 °C in an Ar environment to investigate the microstructure and adhesion property of the Cr-coated Zircaloy-4 cladding by arc ion plating. Scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS), electron backscatter diffusion (EBSD), and scanning transmission electron microscopy fitted with an energy dispersive spectrometer (STEM-EDS) were used to study the microstructural evolution between the coating and the substrate. The adhesion properties of the samples before and after short-term annealing tests were evaluated by combining scratch tests and SEM-EDS analysis. The results showed that when the annealing temperature increased, the diffusion of chemical elements became more intense, leading to the formation of an intermetallic Zr(Cr,Fe)2 layer at the interfacial region; the critical load between the coating and the substrate decreased, however, there was no sign of coating breaking or spalling during the process. Therefore, the arc ion plated Cr coating exhibited good adhesion properties below 1300 °C.

Phase equilibria of the Mg–Sn-Nd ternary system at 400 °C

The phase equilibria of the Mg–Sn-Nd ternary at 400 °C were investigated by X-ray powder diffraction (XRD), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS). Seven stable ternary compounds and one eutectoid decomposed structure (A1) were observed in the section. The crystal structure for the phases: τ1 (MgSnNd, I4/mmm, tI12) and τ2 (MgSn2Nd, I42 m, tI32) were confirmed. τ3 (Mg75Sn3.5Nd21.5) is the iso-structure of Mg23SnLa6 (Zn23SiZr6 prototype, cF120 Pearson's code) and τ4 (Mg40+3Sn26.7-3Nd33.3) has the same structure and homogeneity range of Mg4-xSn2+xLa3(0.12 < x ≤ 0.4) (Cu4Si2Zr3 prototype, hP9 Pearson's code). The crystal structure of τ5 (Mg44Sn34Nd22), τ6 (Mg40Sn36Nd24) and τ7 (Mg16+3Sn45Nd39-3) are not determined. Two binary compounds Nd3Sn and Nd2Sn3, which were not included in the Nd–Sn binary phase diagram, were detected in this work. All detected Nd–Sn binary compounds show different amounts of Mg solubility, among which NdSn3 and Nd5Sn4 dissolve up to 10 and 6.8 at.% Mg and the rest Nd–Sn binary phases contain 1–3 at.% Mg. The MgNd phase dissolves up to 6.0 at. % Sn.

CO Oxidation over Pd Catalyst Supported on Porous TiO2 Prepared by Plasma Electrolytic Oxidation (PEO) of a Ti Metallic Carrier.

A porous TiO2 layer was prepared with the plasma electrolytic oxidation (PEO) of Ti. In a further step, Pd was deposited on the TiO2 surface layer using the adsorption method. The activity of the Pd/TiO2/Ti catalyst was investigated during the oxidation of CO to CO2 in a mixture of air with 5% CO. The structure of the catalytic active layer was studied using a scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), inductively coupled plasma mass spectrometry (ICP-MS), and X-ray diffraction (XRD). The PEO process provided a porous TiO2 layer with a uniform thickness in the range of 5–10 µm, which is desirable for the production of Pd-supported catalysts. A TOF-SIMS analysis showed the formation of Pd nanoparticles after the adsorption treatment. The conversion of CO to CO2 in all samples was achieved at 150–280 °C, depending on the concentration of Pd. The composition of Pd/ TiO2/Ti was determined using ICP-MS. The optimum concentration of Pd on the surface of the catalyst was approximately 0.14% wt. This concentration was obtained when a 0.4% PdCl2 solution was used in the adsorption process. Increasing the concentration of PdCl2 did not lead to a further improvement in the activity of Pd/ TiO2/Ti.

Valorization of seashell waste in polypropylene composites: An accessible solution to overcome marine landfilling

Waste mussel (Mytilus galloprovencis) and clam (Ruditapes philippinarum) shells can be used as a bio-filler in polymeric composites. In this work, powdered shell wastes were incorporated into a polypropylene (PP) matrix. The powdered shell wastes were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS). DSC analysis of the PP composites indicates that both fillers did not act as nucleating agents but partially interfere with the formation of the crystalline phase of the polymer matrix. Moreover, by increasing the filler content, the elastic modulus of PP enhanced from ∼450 to ∼510 MPa. Finally, it was evidenced that mussels and clams shell powders enhanced the solar reflectance features of PP.

Efficient phosphorus removal by a novel halotolerant fungus Aureobasidium sp. MSP8 and the application potential in saline industrial wastewater treatment

Efficient halotolerant phosphorus accumulation microorganisms are of great significance for the treatment of high-salt wastewater. In this study, a halotolerant fungus strain named MSP8 was isolated and identified as Aureobasidium sp. Salinity resistance results showed that strain MSP8 can resist the salinity from 0% to 17%, and 77.2% phosphorus removal was achieved at the optimal salinity of 5%. The strain also showed wide environmental adaptability (pH of 3–7; temperature of 20–30 °C). Batch tests and scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) characterization results verified the key role of extracellular polymeric substance (EPS) secreted by MSP8 in phosphorus removal. The actual brewery and chemical wastewater treatments exhibited that above 53.5% of phosphorus can be removed by MSP8. The excellent adaptation of MSP8 made it a potential candidate for phosphorus removal especially in saline wastewater treatment.

Scavenging Effects of Kaolin on Fine Ash Formation during Zhundong Coal Combustion

The previous work found that the additive kaolin could scavenge not only sodium (Na) but also calcium (Ca) and magnesium (Mg), which is the important ash fluxing agents in low rank coal combustion. Such scavenging effects of kaolin on fine ash formation were studied in the present work. A typical Zhundong coal and its blends with kaolin at dosages of 1, 2 and 4 wt% were combusted in an electrically heated drop tube furnace (DTF) at 1300°C. The fine ashes generated were collected and size segregated by a low pressure impactor (LPI). The morphology and chemical composition of fine ash were analyzed by scanning electron microscopy equipped with an energy-dispersive spectrometer (SEM-EDS). In addition, char/ash particles were sampled at various positions of DTF to elucidate how kaolin additive affected the fine ash formation process. The results further showed that apart from the scavenging of volatile Na, kaolin additive could also strongly scavenge the refractory Ca, Mg and Fe in the fine ash during Zhundong coal combustion, which transformed the sintered particles with irregular shape into melted spherical particles, and finally resulted in the considerable decrease of these elements in both PM_0.4 and PM_0.4-10 by melting and agglomeration. The close contacts between kaolin particles and coal resulted from physically mixing were a key factor responsible for the reaction of kaolin with the refractory Ca, Mg and Fe.

Preparation of electrospun polyvinylidene fluoride/amidoximized polyacrylonitrile nanofibers for trace metal ions removal from contaminated water

In this study, a mixture of polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), and dimethylformamide (DMF) as solvent were reacted with hydroxylamine hydrochloride to produce polyvinylidene fluoride (PVDF)/amidoximized polyacrylonitrile (AOPAN) spinning solution, and then a novel composite PVDF/AOPAN was fabricated by electrospinning technique. Later the electrospun PVDF/AOPAN nanofibers (NFs) were treated with KOH and pitched in (plunged in) mini-column to be used as an adsorbent material under continuous flow. The structural and morphological characterization of nanofibers membrane was determined using scanning electron microscope equipped with an energy dispersive spectrometer(SEM/EDS), Fourier transform infrared spectrometer (FTIR), and goniometer, the inductively coupled plasma optical emission spectrometer (ICP-OES) analysis was used to evaluate the adsorption capability. The effects of pH and metal ions concentration on the transport properties of PVDF/AOPAN nanofibers were also studied. The Langmuir model fits well with isotherm data for lead and copper and the Redlich–Peterson model for nickel, whereas pseudo-second order was the best to clearly delineate the investigated kinetics. The modified PVDF/AOPAN NFs showed excellent adsorption capability with very fast kinetics reaching the equilibrium in 90 min for lead, copper, and 60 min for nickel. EDS analysis of PVDF/AOPAN after metal adsorption confirmed the attachment of the metals. Obtained results illustrate that converting PAN to AOPAN enhanced the hydrophilicity drastically. The removal rate for lead, copper, and nickel reached 99.5% 99.5% 99.6% under 10 mg L−1 respectively, more interestingly for lead, even the concentration was 100 mg L−1, the removal rate still reached 98.1%. Moreover, the adsorbent displayed an excellent regeneration ability by using 0.5 M HCl. This study showed that PVDF/AOPAN is an effective adsorbent for Pb(II), Cu(II), and Ni(II) removal in trace amount.

Inhibition performances of spirocyclopropane derivatives for mild steel protection in HCl

The use of green and environmentally friendly substances is a contemporary scientific challenge and a key task for today's specialists in chemistry and technology-related fields. In this context, this research work involves the study of two new compounds named 1-benzoyl-2-(3,4-dimethoxyphenyl)-6,6-dimethyl-5,7-dioxaspiro [2.5]octane-4,8-dione (2-MPOD) and 1-benzoyl-6,6-dimethyl-2-(3,4,5-trimethoxyphenyl)-5,7-dioxaspiro [2.5]octane-4,8-dione (3-MPOD). The two compounds were synthesized and their inhibition properties for mild steel (MS) corrosion in 1.0 M HCl were first evaluated by means of experimental methods such as electrochemical impedance spectroscopy (EIS), weight loss (WL), in addition to potentiodynamic polarization (PDP) techniques, and also utilizing quantum chemistry studies and molecular dynamics (MD) simulations. For a description of the impact of molecules on the MS surface, the X-ray photoelectron spectroscopy (XPS) and scanning electron microscope equipped with an energy-dispersive spectrometer (SEM-EDS) have been performed. 2-MPOD and 3-MPOD were confirmed to be effective inhibitors in acidic solution and the highest resistance was achieved at 10-3 M concentration and 303 K. The adsorption of inhibitors on MS has been linked to both physical and chemical processes. The adsorption is in accordance with the Langmuir isotherm model. Quantum mechanical calculation results suggest that π-electrons in the aromatic ring and the lone-pair electrons in the methoxy group contribute to enhanced adsorption onto iron surface, leading to effective corrosion inhibition.

Effect of processing conditions on (Ba1-xCax)(Ti0.9Sn0.1)O3 lead-free ceramics for the enhancement of structural, humidity sensing and dielectric properties

The present study reports detailed guidelines for the preparation of high-quality perovskite (Ba1-xCax)(Ti0.9Sn0.1)O3 (BCTS) (x = 0.0–0.1) lead-free ceramics by solid state reaction. The compositions (x = 0.0–0.04) exhibit orthorhombic–tetragonal phase transition (TO-T), except x ≥ 0.06 that shows a pure tetragonal structure phase which conformed by X-ray diffraction (XRD). The microstructure and purity of the sintered ceramics were examined using scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS). Some pores existing in the grain boundary were observed at high concentrations of Ca content. Field emission scanning electron microscope (FE-SEM) was used to examine the morphology of sensing film of the calcined powder and it was prepared as a humidity sensor using screen-printing technique. All the compositions exhibited poor sensitivity toward the humidity sensing in the range of 0–98% RH at room temperature. Hot-stage microscope (HSM) has been used to investigate the sintering curve of the pure calcined powder and it was found that the suitable sintering temperature for obtaining a fully dense microstructure is 1400 °C. The highest values of permittivity (er = 46,515, at 10 kHz) and piezoelectric coefficient (d33 = 510 pC/N) were achieved in the composition x = 0.02. The difference between alumina and platinum crucibles for the processing of the powders has been introduced, and by the aid of dispersive spectrometer analysis and it was indicated that use of alumina crucibles leads to the undesired presence of Al in the ceramics, which can be prevented by using a capped platinum crucibles.

Insights into removal of tetracycline by persulfate activation with peanut shell biochar coupled with amorphous Cu-doped FeOOH composite in aqueous solution

Peanut shell biochar (BC) supported on Cu-doped FeOOH composite (Cu-FeOOH/BC) was synthesized using a facile and scalable method. The Cu-FeOOH/BC samples were characterized by Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy equipped with an energy-dispersive spectrometer (SEM-EDS), x-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) techniques. Novel catalytic composites with different Cu/Fe molar ratios were compared systematically by activating persulfate (PS) for the tetracycline (TC) degradation. 0.5Cu-1FeOOH/BC (Cu/Fe molar ratio = 0.5:1) was confirmed as the optimum activation material and the removal of TC reached 98.0% after 120min by combining with 20mM PS at pH 7.0 and 25°C. The influencing factors including catalyst loading, PS dosage, water matrix species, and pH on the performance system of 0.5Cu-1FeOOH/BC-PS were investigated, respectively. Reaction rate constants (Kobs) on catalyst dosages (0.05, 0.10, 0.20, and 0.30gL-1) were 0.0072, 0.0101, 0.0244, and 0.0144min-1, and 0.0090, 0.0146, 0.0244, and 0.0178min-1 for the change of PS concentrations (5, 10, 20, and 30mM), which indicated that increasing the concentrations of catalyst and PS appropriately improved TC degradation, but excessive dosages inhibited the reaction process of TC removal. The TC removal rate was inhibited by inorganic anions with the following order of HCO3- > Cl- > HPO42- > SO42- > NO3-. Free radical quenching and capture experiments under different pH values revealed that sulfate radicals existed predominantly in acidic conditions and hydroxyl radicals in alkaline conditions. The catalyst showed an excellent recyclability and stability and the removal efficiency of TC still remained over 90% after five consecutive uses. To conclude, coupling of 0.5Cu-1FeOOH/BC and PS can be successfully applied as an effective and stable technique for the treatment of refractory organic pollutants in wastewater.

Study on the Electrochemical Co-Reduction of Gd(III) and Al(III) in LiF-CaF2 Melt

This paper describes the co-reduction process of Gd-Al alloys and the electrochemical extraction of gadolinium from gadolinium oxide in LiF-CaF2 melt. Gd2O3 was fluorinated by adding AlF3, and dissolved into the melt as Gd(III). The electrochemical behaviors and alloy forming mechanisms of Gd(III) and Al(III) were analyzed through cyclic voltammetry, square wave voltammetry, chronopotentiometry, and open circuit chronopotentiometry. Potentiostatic electrolyses in the LiF-CaF2-Gd2O3-AlF3 system were conducted for three hours under −1.60 V and −2.20 V, respectively, and at least three kinds of Gd-Al alloys were obtained. The GdAl3 phase was identified through a scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) and X-ray diffraction analysis, and GdAl2 and GdAl were characterized by SEM-EDS.

Removal of copper and nickel from water using nanocomposite of magnetic hydroxyapatite nanorods

A nanocomposite of magnetic hydroxyapatite was synthesized and tested as an adsorbent for the removal of copper (Cu (II)) and nickel (Ni(II)) from aqueous solution. The adsorbent was investigated using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy equipped with an Energy Dispersive Spectrometer (SEM/EDS), X-ray powder diffraction (XRD) and the Brunauer–Elmet–Teller nitrogen adsorption technique (BET-N2 adsorption). Batch experiments were carried out to determine and compare the adsorption parameters of Fe3O4 and its composite with hydroxyapatite. It was found that the adsorbent is nanostructured and has a specific surface area of 101.2 m2 g−1. The Langmuir adsorption isotherm was found to be an appropriate model to describe the adsorption processes, showing the adsorption capacities of Cu(II) and Ni(II) of 48.78 mg g−1 and 29.07 mg g−1, respectively. In addition to the high adsorption capacity, the fully-adsorbed material could be easily separated from aqueous media using an external magnetic field. These results suggested that the utilization of new hydroxyapatite – Fe3O4 nanocomposite for the removal of Cu(II) and Ni(II) is a promising method in water technology.

Anti-H-factor autoantibodies in inflammatory myopathies

To improve the wear resistance of a C45E4 steel substrate, a Mo coating was deposited by plasma transferred arc (PTA) process. The phase and microstructure of the coating were characterized by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS) and transmission electron microscopy (TEM), respectively. The hardness and wear resistance were investigated by Vickers hardness and pin-on-disk wear testers. It was found that the metastable Fe63Mo37, Fe solid solution, Fe7Mo6, and a certain amount of amorphous phases co-existed in the as-deposited Mo coating. The peritectic coupled growth in Fe-Mo alloys was observed. Based on the undercooling and eutectic growth theory, the possibility of the Fe63Mo37/α-Fess peritectic coupled growth has been discussed. The microhardness was much higher than that of the C45E4 steel substrate. The results showed that the coating exhibited higher wear resistance ascribed to the high hardness phases and low-friction MoO3 film on the worn surface of the coating under dry sliding wear test against ZrO2 disc at room temperature.

Impact of carbamylation on IgG mediated complement activation

To improve the wear resistance of a C45E4 steel substrate, a Mo coating was deposited by plasma transferred arc (PTA) process. The phase and microstructure of the coating were characterized by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS) and transmission electron microscopy (TEM), respectively. The hardness and wear resistance were investigated by Vickers hardness and pin-on-disk wear testers. It was found that the metastable Fe63Mo37, Fe solid solution, Fe7Mo6, and a certain amount of amorphous phases co-existed in the as-deposited Mo coating. The peritectic coupled growth in Fe-Mo alloys was observed. Based on the undercooling and eutectic growth theory, the possibility of the Fe63Mo37/α-Fess peritectic coupled growth has been discussed. The microhardness was much higher than that of the C45E4 steel substrate. The results showed that the coating exhibited higher wear resistance ascribed to the high hardness phases and low-friction MoO3 film on the worn surface of the coating under dry sliding wear test against ZrO2 disc at room temperature.

Human c1q induces apoptosis in an ovarian cancer cell line via tumor necrosis factor pathway

To improve the wear resistance of a C45E4 steel substrate, a Mo coating was deposited by plasma transferred arc (PTA) process. The phase and microstructure of the coating were characterized by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS) and transmission electron microscopy (TEM), respectively. The hardness and wear resistance were investigated by Vickers hardness and pin-on-disk wear testers. It was found that the metastable Fe63Mo37, Fe solid solution, Fe7Mo6, and a certain amount of amorphous phases co-existed in the as-deposited Mo coating. The peritectic coupled growth in Fe-Mo alloys was observed. Based on the undercooling and eutectic growth theory, the possibility of the Fe63Mo37/α-Fess peritectic coupled growth has been discussed. The microhardness was much higher than that of the C45E4 steel substrate. The results showed that the coating exhibited higher wear resistance ascribed to the high hardness phases and low-friction MoO3 film on the worn surface of the coating under dry sliding wear test against ZrO2 disc at room temperature.

Forms of contact-activated C3 associated with AP convertase formation

To improve the wear resistance of a C45E4 steel substrate, a Mo coating was deposited by plasma transferred arc (PTA) process. The phase and microstructure of the coating were characterized by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS) and transmission electron microscopy (TEM), respectively. The hardness and wear resistance were investigated by Vickers hardness and pin-on-disk wear testers. It was found that the metastable Fe63Mo37, Fe solid solution, Fe7Mo6, and a certain amount of amorphous phases co-existed in the as-deposited Mo coating. The peritectic coupled growth in Fe-Mo alloys was observed. Based on the undercooling and eutectic growth theory, the possibility of the Fe63Mo37/α-Fess peritectic coupled growth has been discussed. The microhardness was much higher than that of the C45E4 steel substrate. The results showed that the coating exhibited higher wear resistance ascribed to the high hardness phases and low-friction MoO3 film on the worn surface of the coating under dry sliding wear test against ZrO2 disc at room temperature.

The C5a/C5aR1 axis controls the development of Epidermolysis bullosa acquisita through its impact on IgG autoantibody formation and glycosylation

To improve the wear resistance of a C45E4 steel substrate, a Mo coating was deposited by plasma transferred arc (PTA) process. The phase and microstructure of the coating were characterized by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS) and transmission electron microscopy (TEM), respectively. The hardness and wear resistance were investigated by Vickers hardness and pin-on-disk wear testers. It was found that the metastable Fe63Mo37, Fe solid solution, Fe7Mo6, and a certain amount of amorphous phases co-existed in the as-deposited Mo coating. The peritectic coupled growth in Fe-Mo alloys was observed. Based on the undercooling and eutectic growth theory, the possibility of the Fe63Mo37/α-Fess peritectic coupled growth has been discussed. The microhardness was much higher than that of the C45E4 steel substrate. The results showed that the coating exhibited higher wear resistance ascribed to the high hardness phases and low-friction MoO3 film on the worn surface of the coating under dry sliding wear test against ZrO2 disc at room temperature.

Microstructure and wear resistance of Mo coating deposited by plasma transferred arc process

To improve the wear resistance of a C45E4 steel substrate, a Mo coating was deposited by plasma transferred arc (PTA) process. The phase and microstructure of the coating were characterized by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS) and transmission electron microscopy (TEM), respectively. The hardness and wear resistance were investigated by Vickers hardness and pin-on-disk wear testers. It was found that the metastable Fe63Mo37, Fe solid solution, Fe7Mo6, and a certain amount of amorphous phases co-existed in the as-deposited Mo coating. The peritectic coupled growth in Fe-Mo alloys was observed. Based on the undercooling and eutectic growth theory, the possibility of the Fe63Mo37/α-Fess peritectic coupled growth has been discussed. The microhardness was much higher than that of the C45E4 steel substrate. The results showed that the coating exhibited higher wear resistance ascribed to the high hardness phases and low-friction MoO3 film on the worn surface of the coating under dry sliding wear test against ZrO2 disc at room temperature.

Removal of fine quartz from coal-series kaolin by flotation

Coal-series kaolin (CSK) in Xuzhou, Jiangsu Province of Eastern China was characterized by chemical analyses, X-ray diffraction (XRD) and zeta potential measurement as well as by scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS). The authigenic ultrafine quartz grains (d90=15.8μm) closely associated with this CSK sample was the major impurity mineral, which cannot be separated from kaolin by screening and size classification process. This work investigated the separation of fine quartz from kaolin by flotation. Single mineral flotation tests indicated that effective separation of quartz from kaolin was possible with acidic pH value (pH=3), depressant of starch and collector of dodecyl amine (DDA). Rougher flotation tests of coal-series kaolin revealed that the SiO2/Al2O3 weight ratio of the concentrate was qualified for industrial applications in the presence of 160g/t starch and 100g/t DDA, at acidic pH pulp. A specially designed two-stage cleaner flotation flowsheet increased the concentrate recovery from 37.26% to 46.55% compared to a rougher flotation process.