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1

Influence of pH and salt solution on the sedimentation properties of finebauxite tailings

Yu Haihao, Bai Zhixiao

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 2

art. no. 186326

EN

Bauxite tailings slurry is a type of solid waste produced in the process of bauxite washing and beneficiation. It has poor engineering properties, that is, self-consolidation settlement unusually cannot be completed during several decades. To investigate the sedimentation properties of bauxite tailings, bauxite tailings slurry, phyllite residual soil, and kaolinite, we conduct sedimentation tests on these materials in varying pH and salt solution environments. The influence mechanism of the surface electrical properties of clay particles on the settlement of tailings slurry is investigated using the zeta potential test. The findings reveal that increases in the cation concentration and valence state lead to compression of the electric double layer on the surface of three types of soil particles, resulting in a decline in the repulsive potential energy and an increase in the gravitational potential energy. This in turn contributes to a reduction in the settling stable void ratio. As the pH increases, the zeta potentials of the three soils gradually decrease from positive to negative. A change in the pH at the isoelectric point, PZCedge, triggers the transformation of the kaolinite mineral arrangement. When the pH is either greater than or less than the isoelectric point, an increase or decrease in the pH results in expansion of the electric double layer of the clay particles and an increase in the pore content. The resultsof this study suggest that bauxite tailings mud is more likely to settle in an acidic environment than in an alkaline environment, thus an acidic settling environment should be utilized for bauxite tailings produced in industrial production.

2

Surface chemistry and flotation properties of galena and pyrite particles in the presence of xanthate- monothiophosphate- thiocarbamate collectors

Ercelik Gokhan, Terzi Mert, Kursun Ilgin, Ozdemir Orhan

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 5

art. no. 167947

EN

In this study, surface chemistry and flotation properties of the gold-bearing galena and pyrite minerals of Menderes region, Izmir, Turkey were investigated with the use of xanthate-thiocarbamate-monothiophosphate collectors. In this context, the micro-flotation experiments, the zeta potential, and bubble-particle attachment time measurements were conducted in the presence of Thiophosphate (Aero S-8045), Xanthate (SIBX), and Thiocarbamate (Aero float MX-505) collectors. In the case of micro-flotation experiments, the MX-505 exhibited higher flotation efficiency for both minerals compared to SIBX and S-8045 collectors. In the micro-flotation tests conducted on galena and pyrite, while the flotation recovery of 99.82% and 81.96% were obtained with MX-505, the flotation recovery of 89.64% and 62.50% were reached in the case of using SIBX. Furthermore, the S-8045 resulted in the flotation recovery s of 75.09% and 25.45% for galena and pyrite, respectively. In the case of zeta potential experiments as a function of pH, the galena mineral showed a negative charge between -17.22 to -41.42 mV at pH 5 - 11, no point of zero charge (pzc) was determined, and the pzc of pyrite was determined as pH≈8. The bubble-particle attachment time experiments performed in the presence of S-8045, SIBX, and MX-505 collectors indicated that the attachment efficiency was 100% in the presence of MX-505 at 12.5-75 g/Mg dosages and 1-1000 ms contact times. These results revealed that there was an extraordinarily strong interaction between the galena/pyrite and the air bubbles in the presence of MX-505. The results obtained within this study indicated that galena and pyrite minerals showed inherently less than 25% natural floatability which can only be enhanced under specific conditions. The results obtained within this study indicated that galena and pyrite minerals showed inherently low natural floatability which can only be enhanced under specific conditions. In the tests conducted on these minerals, galena mineral showed higher than %20 natural floatability compared to pyrite mineral, and collectors produced from thiocarbamates have shown greater effectiveness compared to xanthate and thiophosphate.

3

Flotation of copper-bearing shale at different pH values of solutions and sodium chloride concentrations

Sajewicz Jakub, Ratajczak Tomasz

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 6

art. no. 176242

EN

Flotation of copper-bearing shale in aqueous solutions of NaCl at their different pH values was investigated. The tests were carried out in a laboratory flotation machine. The pH range was between 5 and 10 while NaCl concentrations were 0.5M, 1.0M and 2.0M. It was observed that the flotation recovery of the copper shale was increasing with the increase of pH and concentration of the salt solution. On the basis of thermodynamic and hydrodynamic considerations it was postulated that the increasing surface tension was responsible for better shale flotation observed with increasing salt concentration. The observed improved shale flotation caused by increasing pH is most likely due to changes in the properties of the thin film between particle and bubble including mosaic structure of water on the surface of shale. It was shown that the zeta potential of shale particles, zeta potential of air bubbles, solution surface tension, and shale hydrophobicity were not responsible for the increasing with pH recoveries.

4

Electrokinetic and surface properties of some methacrylate-based copolymers

Ersoy Bahri, Çiftçi Hakan, Evcin Atilla, Merdivenci Yılmaz

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 152162

EN

In this study, some electrokinetic and surface properties of MBAOM-GMA copolymers synthesized from 2-[(methoxy-1,3-benzothiazole-2-yl) amino]-2oxoethyl methacrylate (MBAOM) and glycidyl methacrylate (GMA) monomers were investigated. Accordingly, (i) pH-dependent zeta (ζ) potential changes of the copolymers were investigated under a constant ionic strength (in 1.10-3mol/dm3 NaCl) and the corresponding isoelectric points (iep) were determined, (ii) zeta potential changes depending on the salt concentration in the presence of mono-, di- and tri-valent metal salts were examined, (iii) contact angles (θ) of the copolymers with water were measured and their wetting behavior was assessed, and (iv) surface free energies (SFE) of the copolymers were determined by Acid-Base approach using Van Oss-Chaudhury-Good method. The compositions of the copolymers were 77% MBAOM - 23% GMA, 45% MBAOM - 55% GMA, and 19% MBAOM - 81% GMA. FeCl3, CaCl2, and KCl salts were used for the salt solutions for the zeta potential measurements. As a result, (i) it was determined that the chemical structure of methacrylate copolymers showed a decisive effect on both electrokinetic and surface properties, (ii) the hydrophobic character of copolymer increased with the increase of the GMA ratio, and correspondingly, the SFE decreased, and (iii) the iep of the copolymers varied between pH 3.1-3.7 depending on composition.

5

Control of glass surface wettability via esterification with n-alkyl alcohols

Kruszelnicki Mateusz, Polowczyk Izabela, Kowalczuk Przemyslaw B.

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 2

art. no. 145147

EN

Surface wettability plays an essential role in many processes and materials applications. It depends mainly on the surface roughness and chemical composition, thus through a controlled modification of these parameters, the wettability can be restrained. Glass is an inorganic solid material, composed mainly of amorphous silica, which surface, due to the presence of reactive hydroxyl groups, can be quite easily chemically modified. This feature can be used to control the wettability of glass by reaction with organic compounds. In this study, the esterification of glass silanol groups with n-alkyl alcohols (Cn/H2n+1/OH, n=3, 4, 6, 8, 10) was employed to modify its wettability. The effect of such modification on the physicochemical properties of glass surface was comprehensively investigated and characterised by the water contact angle, surface free energy, zeta potential, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) measurements. We demonstrate that the wettability of the esterified glass surface is strongly dependent on both the chain length of used alcohol and modification time. The alcohol molecule binds to the glass surface through a Si-O-C bond, leading to the formation of a monolayer that does not significantly affect the surface morphology and zeta potential. Conducted studies provided a broader view of the influence of this technique for modifying surface wettability on its physicochemical properties.

6

Bioleaching of sulfide containing material from the Wiśniówka Quarry: stability and adhesion of secondary products

Pawlowska Agnieszka, Sadowski Zygmunt, Winiarska Katarzyna

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 4

art. no. 149884

EN

Secondary products (minerals) formed during bioleaching play an essential role in this process. Their adhesion to the surface of leached grains can inhibit bioleaching. For this reason, it is crucial to know the physicochemical conditions of adhesion. Selected material from the Wiśniówka Quarry (Kielce, Poland) with increased content of sulfides was subjected to microbial leaching. A precipitate collected from a bacterial culture was used as a secondary product (mainly jarosite). Adhesion and bio-extraction tests were carried out in a column reactor with a mineral bed (particle size 0.8 - 1.2 mm). The cationic surfactant (CTAB), anionic surfactant (SDS), and rhamnolipids (RL) were used to modify the surface of minerals and secondary products. Changes in the surface properties were determined with zeta potential measurements. The cationic surfactant above the 0.5 mM caused stability of jarosite suspension. Also, bioleaching efficiency was the highest for mineral surfaces modified by CTAB. The quantitative interpretation of the adhesion of the secondary product to bioleach mineral material was carried out.

7

Activated biocarbons obtained from post-fermentation residue as potential adsorbents of organic pollutants from the liquid chase

Nowicki Piotr, Gruszczyńska Karolina, Urban Teresa, Wiśniewska Małgorzata

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 2

art. no. 146357

EN

A series of new synthetic carbonaceous adsorbents has been prepared via physical and chemical activation of residue of alcoholic fermentation of corn starch. Two different variants of thermal treatment procedure - microwave and conventional heating have been applied for preparing of the activated biocarbons. All the samples under investigation were characterised by elementary analysis, surface area measurements as well as determination of the number of surface functional groups. The electrokinetic properties of examined materials were studied using potentiometric titration and electrophoresis methods, which enabled determination of the surface charge density and zeta potential of activated biocarbon particles. Moreover, sorption properties of the carbonaceous materials towards two organic dyes - methylene blue and malachite green were tested. The final products were activated biocarbons of medium developed surface area ranging from 21 to 879 m2/g, showing acidic character of the surface and various content of surface functional groups. More favourable textural parameters as well as sorption properties toward both organic dyes were revealed by chemically activated samples. The obtained results indicated also considerable effect of adsorbed dye molecules on the structure of electrical double layer formed at the solid/liquid interface.

8

Separation of fine beryl from quartz via magnetic carriers by the aiding of non-ionic surfactant

Fawzy Mona M.

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 2

14--23

EN

This study demonstrated the possibility of separating fine beryl from quartz by using magnetic carrier technology with the presence of non-ionic surfactant (Sorbitan monooleate). Oleatecoated magnetite was used as a magnetic carrier for enhancing the magnetic properties of fine beryl to be separated and get rid of the most common associated gangue mineral "quartz". This study proved that the most important factors affecting this separation process is the pH, as the study showed that the efficiency of the separation process is the maximum possible when pH at the isoelectric point (IEP) of beryl. Where at IEP, beryl is ready to adsorb oleate-coated maginetite onto its surface and the presence of sorbitan monooleate helps this adsorption and strengthens. To demonstrate the separation process, physico-chemical surface characterization for beryl, quartz, magnetite and oleate-coated magnetite was studied before and after treatment with sorbitan monooleate using zeta potential measurements and Fourier Transform Infrared (FTIR). Mineralogical characterization was take place for separated minerals of beryl, quartz and magnetite using x-ray diffraction (XRD) analyses and scanning electron microscope (SEM) with energy-dispersive spectrometer (EDS) unit. The magnetic carrier separation tests were performed in this study in the case of separate minerals investigated that fine beryl (94% recovery) could be recovered under optimum test conditions of 2.5 pH, 4.29 g/L sorbitan monooleate and 1:0.5 beryl to oleate-coated magnetite ratio, while quartz under the same conditions was recovered by 9.8%. FTIR measurements for the investigated minerals before and after treatment with sorbitan monooleate confirmed that the adsorption of sorbitan monooleate on the surface of beryl far exceeds that of the surface of quartz at beryl IEP.

9

Flotation separation of dravite from phlogopite using a combination of anionic/nonionic surfactants

Fawzy Mona M.

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 4

87--95

EN

In the present study, the effect of a mixture of anionic collector (sodium oleate)/ non-ionic surfactant (sorbitan monooleate) on the flotation separation of dravite from the main associated gangue phlogopite was investigated in comparison of using single sodium oleate as a collector. The flotation experiments were conducted on pure single minerals of dravite and phlogopite. The flotation results demonstrated that adding sorbitan monooleate to Na-oleate at a dose of 5.64 kg/Mg Na-oleate with 0.43 kg/Mg sorbitan monooleate in the presence of methyl isobutyl carbinol (MIBC) as a frother (0.12 Kg/Mg) at pH 7.7 improved the flotation efficiency of dravite from 73.5% by using sodium oleate as a single collector to 96.9% using the mixture. Whereas, the flotation recovery of phlogopite in the same conditions reached 26.3%. The zeta potential measurements and Fourier transform infrared (FTIR) spectroscopy analysis were also implemented to investigate and predict the mechanism of collector adsorption on the mineral surfaces. As a result of flotation experiments and the zeta potential measurements of FTIR analysis, high chemisorption of the mixed collector on the surface of dravite was obtained, on the contrary, a little amount of the collector mixture adsorbed on the phlogopite surface.

10

Impact of cationic-anionic surfactants on selective oil agglomeration of oil shale

Abdel-Khalek Mohamed A., Amin Rasha, Hassan El-Sayed R. E.

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 6

137--144

EN

Egyptian oil shale from Red Sea area is upgraded via oil agglomeration technique to achieve a clean fuel. A representative sample is characterized to identify its undesirable components and its liberation size. The quartz, apatite, calcite, siderite and anhydrite are the main gangue minerals. The sample was pulverized to less than 20 µm for efficient liberation. The impact of anionic (Calcium dodecyl benzene sulfonate, CDBS) or/and cationic (Cetrimonium bromide, CTAB) surfactants on the zeta-potential and agglomeration process was investigated in presence of different kerosene concentrations. A concentrate of 62% kerogen with 95% recovery was obtained from feed of 29% kerogen using 0.1% CTAB/CDBS mixture in 2% kerosene emulsion.

11

Electrokinetic properties of silica-titania mixed oxide particles dispersed in aqueous solution of C.I. Direct Yellow 142 dye – effects of surfactant and electrolyte presence

Chibowski Stanisław, Wiśniewska Małgorzata, Wawrzkiewicz Monika, Hubicki Zbigniew, Goncharuk Olena

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 6

6--13

EN

The mixed SiO2-TiO2 oxide obtained by the pyrogenic method with the silica:titanium percentage ratio equal to 20:80 (ST80) was used in the experiments. The influence of azo dye C.I. Direct Yellow 142 (DY) adsorption at the mixed oxide-solution interface on the electrokinetic properties of solid particles was studied. To determine solid surface charge density and zeta potential of examined suspensions the potentiometric titration and Doppler laser electrophoresis techniques were applied. The changes in structure of electrical double layer formed on the mixed oxide surface in the dye presence were specified as a function of DY concentration, inorganic salt addition and surfactant introduction. The effects of surfactant type and its concentration were determined. Three surfactants of different ionic character (anionic SDS, cationic CTAB and nonionic Triton X-100) were used in measurements. The obtained electrokinetic characteristics of ST80 mixed oxide dispersed in aqueous solutions with various adsorbate compositions is essential for such suspensions stability.

12

Effect of sulfidization on the stability of adsorption of isoamyl xanthate on malachite

Xiong Kun, Wen Shuming, Liu Zilong, Deng Jiushuai, Mao Yingbo

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 3

493--503

EN

The activity and stability of adsorbed isoamyl xanthate (IX) on a malachite surface before and after sulfidization were studied by calculating the malachite dissolved component and adsorption energy and performing experiments pertaining to the zeta potential, adsorption and desorption experiments, and flotation experiments. In the malachite slurry solution, the main components of copper are Cu2+, CuCO3, HCuO2-, CuO2-, and Cu(CO3)22-, and the concentration distribution of these components is related to the slurry pH value. Between pH 5 to 9, the main copper component in the slurry is CuCO3. The malachite surface is negatively charged; however, the sulfur ions or hydrosulfide ions can still adsorb on the surface at a pH of more than 8.2, which indicates that the sulfidization of malachite corresponds to the chemical adsorption, and the surface electrical properties of the malachite are not obvious to the sulfidization. The adsorption activity of malachite on IX is stronger than that of the sulfide malachite; however, the desorption ratio of IX with respect to the malachite is higher than that pertaining to the sulfide malachite. The adsorption energy of IX on the malachite and sulfide malachite surface was -449.6 kJ/mol and -1134.7 kJ/mol, respectively, and the IX adsorbed on the sulfide malachite surface was more stable. The flotation experiments indicated that the sulfidization of malachite reduced the consumption of IX; however, the recovery of malachite was improved.

13

Adsorption and electrokinetic studies of sodalite/lithium/poly(acrylic acid) aqueous system

Wiśniewska Małgorzata, Franus Wojciech, Fijałkowska Gracja, Ostolska Iwona, Wójcik Grzegorz, Nosal-Wiercińska Agnieszka, Gościańska Joanna

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 6

158--166

EN

The synthetic zeolite-sodalite obtained by the hydrothermal conversion of fly ash with aqueous sodium hydroxide was used in the experiments. Its adsorption properties in relation to lithium ions were examined. The effects of: solution pH, presence of polymeric substance – poly(acrylic acid) and order of individual adsorbates addition were determined. To specify the binding mechanism of lithium ions on the sodalite surface, besides adsorption experiments, the measurements leading to the solid surface charge density and zeta potential determination, were performed. As a result, the structure of mixed adsorption layer composed of polymer+metal complexes was characterized. The presented study concerns two important issues: management of environmentally harmful wastes such as coal combustion products as well as searching for new sources of lithium and effective methods of its acquisition.

14

The use of Zeta Potential Measurement as a Control Tool of Surface Water Coagulation

Mroczko Dominik, Zimoch Izabela

Journal of Ecological Engineering

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2020

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Vol. 21, nr 3

237--242

EN

The implementation or optimization of the coagulation process requires prior preliminary tests. Standard Jar-Test method is time-consuming, inaccurate and may not work well, especially for the waters characterized by high variability of quality parameters. Zeta Potential Isoelectric Point (IEP) analysis may give fast and precise data on the coagulant type and dose required for maintaining an efficient coagulation process. The research objects included the surface waters taken directly from the Mała Panew and Odra rivers. The zeta potential and set coagulant dose dependence was measured for each sample. Four aluminum-based coagulants with different characteristics were used in this research: aluminum sulfate (Alum), polyaluminum chloride (PAC), dialuminum chloride pantahydroxide (PACl), polyaluminum chloride hydroxide sulfate (PACS). Charge neutralization effectiveness, by means of Zeta Potential IEP analysis, was the basis for the choice of the most effective coagulant doses. The coagulation process efficacy was based on the parameters of the treated water (pH, turbidity, color, alkalinity), reduction of organic matter (Abs254, Total Organic Carbon (TOC), Dissolved Organic Carbon (DOC)) and residual aluminum contamination. The Zeta Potential utility evaluation was based on the DOC reduction.

15

Nickel Composite Coatings Reinforced Nano SiC Particles

Nowak M., Mizera J., Kłyszewski A., Dobkowska A., Boczkal S., Kozik A., Koprowski P.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

935--940

EN

The paper presents the results of the electrodeposition of nickel composite coatings reinforced with the nano size SiC ceramic particles. The type and size of the ceramic particles or organic additives used play a important role during electrodeposition processes. A Watts type galvanic bath with various organic additives was used. These additives were: 2-sulfobenzoic acid imide, dioctyl sulfosuccinate sodium salt (DSS), sodium dodecyl sulfate, tris (hydroxymethyl) aminomethane and hexamethyldisilizane. The nickel composite coating was electrodeposited on a 2xxx aluminum alloy series substrate (EN-AW 2017) with zinc interlayer. The work concerns the determination of the impact of the change in the zeta potential of SiC nanoceramic particles used on properties of composite coatings (wear resistance, corrosion, etc.). The paper characterized the composite nickel coatings on aluminum alloy using SEM techniques, wear resistance tests by TABER method and coating adhesion to the substrate using the “scratch test” method. The corrosion resistance of coatings was also tested using electrochemical methods. The research allowed to determine the effect of SiC nanoceramic particle size on the value of the zeta potential in the model KCl solution.

16

Otrzymywanie i charakterystyka wodnych zawiesin węglika krzemu przeznaczonych do wytwarzania wyrobów metodą odlewania

Gnyla Joanna, Gubernat Agnieszka, Zych Łukasz, Lach Radosław, Zientara Dariusz

Szkło i Ceramika

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2019

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R. 70, nr 3

10--15

PL

W pracy przedstawiono wyniki badań właściwości zawiesin o 30% udziale objętościowym fazy stałej, którą stanowiły proszki: SiC, Al2O3 i Y2O3 w funkcji dodatku upłynniaczy, tj. TMAH i NaOH w ilości od 0,0 do 1,0% mas. w przeliczeniu na masę fazy stałej. Na podstawie wyznaczonych krzywych lepkości i szybkości sedymentacji stwierdzono, że optymalna ilość upłynniaczy wynosi 0,4–0,6% mas. Wówczas zawiesiny wykazują pH z zakresu 10–11, a wartość potencjału dzeta cząstek gwarantuje ich stabilizację. Uzyskane wyniki badań dały podstawy do zaproponowania elektrostatycznego mechanizmu stabilizacji zawiesin przez oba upłynniacze. Do zawiesin wprowadzono dodatki tlenkowe i spoiwo, a następnie uformowano z nich wyroby (tygle) techniką odlewania. Celem wprowadzenia dodatków tlenkowych było aktywowanie spiekania węglika krzemu. Aktywatorami spiekania była mieszanina tlenków glinu i itru w stosunku masowym 3:2 i w ilości 10% mas. Jako dodatek ułatwiający formowanie zastosowano spoiwo akrylowe w ilości 0,5, 2, 5 i 10% mas. w odniesieniu do masy proszku SiC. Wyroby spiekano w temperaturze 2050 i 2150°C. Wytworzono w ten sposób materiały SiC o wysokiej gęstości i jednorodnej mikrostrukturze.

EN

The paper presents the results of investigations on the properties of suspensions with 30% volume fraction of solid phase which consisted of SiC, Al2O3 and Y2O3 powders as a function of dispersing agents i.e. TMAH and NaOH additive in the amount from 0.0 to 1.0 wt. % calculated on the basis of the solid phase mass. Based on the determined viscosity curves and sedimentation rate measurements, the optimum amount of dispersing agents was found to be 0.4–0.6 wt. %. The suspensions showed pH from the range 10–11 and the value of the zeta potential of particles guaranteed their stabilization. The obtained results gave rise to the proposal of an electrostatic mechanism of stabilization of the suspensions by both dispersing agents. Oxide additives and binders were added to the suspensions and then the products (crucibles) were formed using the slip casting technique. The purpose of introducing the oxide additives was to activate sintering of silicon carbide. The sintering activators were a mixture of aluminium and yttrium oxides in a mass ratio of 3:2 and in the amount of 10% by weight. Acrylic binder in the amount of 0,5, 2, 5 and 10 wt. % was used as an additive facilitating the formation of SiC powder. The products were sintered at 2050 and 2150°C. SiC materials of high density and homogeneous microstructure were produced in this way.

17

Physicochemical Properties of Copper Modified Zeolite

Świderska-Dąbrowska Renata, Schmidt Rafał, Dąbrowski Tomasz

Rocznik Ochrona Środowiska

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2019

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Tom 21, cz. 2

810--824

EN

Zeolites have been used in environmental engineering mainly in catalytic processes and as ion exchangers in water and wastewater treatment. Selective modified zeolites allow significant improvement in the effectiveness of impurities’ removal without introducing additional reagents to the environment. The final effect of treatment of water solutions is determined by the catalyst used, its physicochemical properties and the process parameters. In this work effectiveness of zeolite modification methods as well as their physical and chemical stability, taking into account the changes that take place during the process of calcination within the temperature range of 250°C to 650°C is presented. A natural clinoptilolite used in the experiment was transformed into the hydrogenous form and subsequently modified with copper (II) ions by coprecipitation with NaOH and Na2CO3. The effect of the method of the zeolite modification on Cu content, the zeolite Leaching capacity and surface charge was evaluated. An analysis of experimental results has shown that calcination temperature does not significantly change the surface charge, but does affect copper speciation. Analysis of EDS spectra by a scanning microscope, which showed that new and regular forms of copper compounds had been formed along the zeolite lattice structure is also presented. The experimental results show that retention of Cu in zeolites was caused by electrostatic interactions between Cu(II) cations and the electronegative surface of the zeolite and coprecipitation of Cu(II) complexes. Physicochemical properties of examined zeolites were affected by processes of hydration, hydrolysis and complexing of Cu with the zeolite matrix as a function of the solution’s pH. Results show that the process of impurities’ removal from water and wastewater depends on the method of zeolite modification and on the solution’s pH.

PL

W inżynierii środowiska zeolity stosowane są przede wszystkim jako wymieniacze jonowe w oczyszczaniu wody i ścieków oraz w procesach katalitycznych. Selektywne modyfikowane zeolity pozwalają na znaczące zwiększenie skuteczności usuwania zanieczyszczeń, jednocześnie nie wprowadzając dodatkowych reagentów do środowiska. O końcowym efekcie decyduje rodzaj zastosowanego katalizatora, jego właściwości fizykochemiczne oraz parametry prowadzenia procesu. W pracy przedstawiono efektywność metod modyfikacji zeolitów oraz ich stabilność fizyczną i chemiczną, z uwzględnieniem zmian zachodzących podczas procesu kalcynacji w zakresie temperatur od 250°C do 650°C. W badaniach zastosowano zeolit naturalny klinoptylolit, który przeprowadzono w formę wodorową roztworem HCl, a następnie poddawano modyfikacji jonami miedzi (II) metodą współstrącania z użyciem NaOH i Na2CO3. Oceniono wpływ sposobu prowadzenia modyfikacji zeolitu na zawartość Cu, jego rozmywalność oraz ładunek powierzchniowy. Analiza wyników badań wykazała, że temperatura kalcynacji nie wpływa istotnie na zmianę ładunku powierzchniowego, ale na formę występowania związków miedzi. W pracy przedstawiono również analizę widm EDS wykonanych mikroskopem skaningowym, która pokazała, że wzdłuż struktury krystalicznej zeolitu zostały utworzone nowe i regularne formy związków miedzi. Wyniki badań wykazały, że zatrzymywanie Cu w zeolitach zachodziło na skutek oddziaływań elektrostatycznych między kationami Cu(II) i elektroujemną powierzchnią zeolitu oraz w wyniku strącania i współstrącania kompleksów Cu(II). Czynnikami wpływającymi na właściwości fizykochemiczne badanych zeolitów są procesy hydratacji, hydrolizy i kompleksowania Cu z matrycą zeolitu w funkcji pH roztworu. Przedstawiona w pracy analiza wyników badań wykazała, że proces usuwania zanieczyszczeń z wód i ścieków uzależniony jest od sposobu modyfikacji zeolitu oraz od pH roztworu.

18

Zeta potential of Teflon in presence of monovalent and divalent ions

Gulgonul Ilhan

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 3

792--801

EN

In this study, the specific effects of Na+ and Ca2+ ions on natural hydrophobic Teflon particles and flat Teflon surfaces were investigated using zeta potential and contact angle measurements, respectively. The zeta potential measurements showed that the surface charge of Teflon was negative at all pH values in the absence of salt ions, and became the positive with the increased salt concentration, and obtained an iso electric point (iep) between pH 3 and 4. The results also indicated that Ca+2 ions more adsorbed on the Teflon surface compared to Na+ ions in the case of the compression of the electrical double layer. The contact angle measurements with Teflon sample showed that while the flat Teflon had a contact angle of 107° at pure water, and the contact angle considerably reduced as a function of salt concentration. This decrease was more effective in the presence of Ca2+ ions rather than Na+ ions. While calcium is a strong water structure maker cation, sodium is a weak structure maker cation, but the role of calcium is more effective at the Teflon-water interface according to zeta potential and contact angle measurements. It is revealed that the Ca+2 ions have a specific effect on Teflon surface due to low salt concentrations and ion charges. The different effects of these cations on Teflon-water interface can be attributed to use in mineral processing, especially in flotation enrichment.

19

Physicochemical parameters effect on biosynthesis and properties of copper nanoparticles

Pawlowska Agnieszka, Kazmierczak Michal, Sadowski Zygmunt

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 6

1460--1466

EN

Plant extract obtained from green tea was used for the synthesis of nanoparticles under anaerobic and aerobic conditions at various ratios of the copper solution to the extract used. The smallest nanoparticles were obtained at a ratio of 1:10. The nanoparticles showed the maximum negative value of the zeta potential around pH 6. An increase in the temperature of reaction caused a decrease in the negative zeta potential value. Synthesis under nitrogen atmosphere favours the formation of smaller copper nanoparticles.

20

Effect of Various Organic Additives in Galvanic Bath on Properties of Ni-SiC Composite Coatings

Nowak M., Mizera J., Kłyszewski A., Dobkowska A., Boczkal S., Kozik A., Koprowski P.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 4

1327--1333

EN

The paper presents the results of the electrodeposition of nickel composite coatings reinforced with the ceramic SiC particles. A Watts type galvanic bath modified with various organic additives was used. These additives were: 2-sulfobenzoic acid imide (LSA), dioctyl sulfosuccinate sodium salt (DSS), sodium dodecyl sulfate (SDS), tris (hydroxymethyl) aminomethane (THAM) and hexamethyldisilizane (HMDS). The nickel composite coating was electrodeposited on a 2xxx aluminum alloy series substrate (EN-AW 2017) with zinc interlayer. Studies concerned the effect of the applied organic additives on properties of composite coatings such as: microstructure, microhardness, adhesion to the substrate, corrosion resistance and roughness. The structure of the coatings was assessed by scanning electron microscopy and light microscopy. Based on the studies of zeta potential it was found that the bath modification had a significant impact on the amount of the ceramic phase embedded in metal matrix. The tests conducted in a model 0.01 M KCl solution were not fully representative of the true behavior of particles in a Watts bath.