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1

Petrographic assessment of the occurrence of potentially alkali-reactive silica in post-glacial gravels of North-Western Poland and North-Eastern Germany

Dubiniewicz Andrzej K.

Roads and Bridges - Drogi i Mosty

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2023

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Vol. 22, no. 3

259--273

EN

The paper presents the results of petrographic assessment of the occurrence of potentially alkali-reactive silica in gravels from post-glacial deposits located in north-western Poland and north-eastern Germany. The petrographic examination consisted in identifying alkali-reactive minerals and determining the form of their occurrence and content. The post-glacial gravels, which have a varied petrographic composition, are dominated by fragments of crystalline rocks. There are also fragments of lime- stones and sandstones, as well as lesser quantities of siliceous rocks and opal. Gravel grains contain various forms of reactive silica – opal, chalcedony, cryptocrystalline and microcrystalline quartz and strained quartz. Mineral components of the rocks displayed traces of secondary processes, mainly plagioclase kaolinitization and biotite chloritization. The post-glacial gravels were classified as potentially reactive according to the RILEM AAR-1 document. The conducted research confirmed that the petrographic examination is a method that allows one to quickly determine the presence of harmful components, however, when testing aggregates for alkali-reactivity, it should be used in conjunction with other methods.

PL

W pracy przedstawiono wyniki petrograficznej oceny obecności potencjalnie reaktywnej alkalicznie krzemionki w żwirach ze złóż polodowcowych północno-zachodniej Polski i północno-wschodnich Niemiec. Analiza petrograficzna polegała na identyfikacji minerałów alkalicznie reaktywnych oraz ustaleniu formy ich występowania i zawartości. W kruszywach polodowcowych, które mają zróżnicowany skład, dominują okruchy skał krystalicznych. Obecne są w nich także okruchy wapieni i piaskowców oraz podrzędnie skał krzemionkowych i opalu. W ziarnach żwirów znajdują się różne formy reaktywnej krzemionki – opal, chalcedon, kwarc kryptokrystaliczny i mikrokrystaliczny oraz kwarc w stanie naprężeń. W składnikach mineralnych skał zaobserwowano przejawy procesów wtórnych, głównie kaolinityzacji plagioklazów i chlorytyzacji biotytu. Żwiry polodowcowe zaliczono do kruszyw potencjalnie reaktywnych według dokumentu RILEM AAR-1. Przeprowadzone badania potwierdziły, że analiza petrograficzna jest metodą pozwalającą w krótkim czasie stwierdzić występowanie składników szkodliwych, powinna ona jednak być stosowana w ocenie reaktywności alkalicznej kruszyw w połączeniu z innymi metodami.

2

Zastosowanie trójparametrowych modelowych izoterm do opisu procesu adsorpcji cynaryzyny na mezoporowatej krzemionce MCM-41

Geszke-Moritz Małgorzata, Chmiel Krystian, Moritz Michał

Przemysł Chemiczny

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2023

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T. 102, nr 8

799--802

PL

Przedstawiono wyniki badań dotyczących właściwości adsorpcyjnych mezoporowatego sita molekularnego MCM-41 wobec cynaryzyny (modelowy lek) w środowisku acetonitrylu. Przeprowadzono modelowanie procesu adsorpcji z zastosowaniem trójparametrowych modeli matematycznych: Sipsa, Redlicha i Petersona oraz Dubinina i Astachowa. Parametry izoterm adsorpcji oszacowano metodą optymalizacji nieliniowej. Maksymalna pojemność adsorpcyjna krzemionki MCM-41 wyniosła 212,2 mg/g (równanie Dubinina i Astachowa), zaś obliczona energia adsorpcji wskazuje na fizyczny charakter oddziaływań leku z powierzchnią adsorbentu.

EN

Cinnarizine was adsorbed from its solns. in MeCN on MCM-41 mesoporous silica. The adsorption process was described using three-parameter math. models: Sips, Redlich and Peterson as well as Dubinin and Astakhov. Nonlinear fiting anal. was used to estimate the parameters of adsorption isotherms. MCM-41 silica was characterized by max. adsorption capacity of 212.2 mg/g (Dubinin-Astakhov model). The calculated adsorption energy indicated the phys. nature of cinnarizine adsorption onto MCM-41 mesoporous silica

3

Zastosowanie mezoporowatej krzemionki MCM-41 w procesie adsorpcji boldyny

Geszke-Moritz Małgorzata, Stoińska Aleksandra, Moritz Michał

Przemysł Chemiczny

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2023

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T. 102, nr 7

722--725

PL

Przedstawiono wyniki badań dotyczących właściwości adsorpcyjnych niemodyfikowanej krzemionki MCM-41 wobec boldyny w środowisku acetonitrylu. Proces adsorpcji opisano za pomocą równań modelowych izoterm: Langmuira, Sipsa oraz Dubinina i Astachowa. Parametry modeli matematycznych oszacowano metodą optymalizacji nieliniowej. Oszacowana maksymalna pojemność adsorpcyjna krzemionki MCM-41 mieściła się w przedziale 213,5-235,5 mg/g w zależności od zastosowanej izotermy adsorpcji. Adsorpcja boldyny na krzemionce MCM-41 miała fizyczny charakter.

EN

Boldine was adsorbed from its solns. in MeCN on MCM-41 mesoporous silica. Nonlinear fiting anal. was used to estimate the parameters of the Langmuir, Sips and Dubinin-Astakhov isotherm. MCM-41 silica was characterized by max. adsorption capacity of 213,5-235,5 mg/g depending on used isotherm model. Physisorption process was the main force of boldine adsorption onto MCM-41 mesoporous silica.

4

Modelowanie procesu adsorpcji boldyny na mezoporowatej krzemionce MCM-48

Moritz Michał, Lis Weronika, Geszke-Moritz Małgorzata

Przemysł Chemiczny

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2023

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T. 102, nr 9

947--950

PL

Przedstawiono wyniki badań dotyczących oceny właściwości adsorpcyjnych krzemionki MCM-48 wobec boldyny jako modelowego adsorbatu. Dokonano opisu zjawiska adsorpcji z zastosowaniem modelowych izoterm: Freundlicha, Langmuira oraz Redlicha i Petersona. Parametry modeli matematycznych oszacowano metodą optymalizacji nieliniowej, stosując różne funkcje błędu. Pojemność adsorpcyjna krzemionki MCM-48 oszacowana wg modelu Langmuira wyniosła 405,2 mg/g (funkcja błędu ARE). Izoterma Freundlicha wykazała najlepsze dopasowanie.

EN

MCM-48 mesoporous silica was used as adsorbent for boldine alkaloid in MeCN soln. Nonlinear fitting anal. was used to estimate the parameters of the Freundlich, Langmuir and Redlich-Peterson isotherm. MCM-48 silica was characterized by max. adsorption capacity of 405,2 mg/g (Langmuir model, ARE error function). Freundlich isotherm was the best fitted adsorption model.

5

Polymer composites for obtaining human anatomic structures

Oleksy Małgorzata, Dynarowicz Klaudia, Aebisher David

Polimery

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2023

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Vol. 68, nr 6

323--329

EN

Composites based on PLA with the addition of 3, 6 and 10 wt% silica, hydroxyapatite and bentonite were obtained by twin-screw extrusion. Maleic anhydride grafted polyethylene was used to enhance interface interactions. The influence of the fillers used on the Charpy impact strength, Rockwell hardness, tensile properties and processing shrinkage was investigated. Test samples were obtained by 3D printing. The highest impact strength and hardness were obtained for the composite containing 10 wt% hydroxyapatite. PLA with 10 wt% hydroxyapatite and 3 wt% bentonite was used to obtain anatomical structures by 3D printing.

PL

Metodą dwuślimakowego wytłaczania otrzymano kompozyty na osnowie PLA z dodatkiem 3, 6 i 10% mas. krzemionki, hydroksyapatytu oraz bentonitu. W celu zwiększenia oddziaływań na granicy faz użyto polietylenu szczepionego bezwodnikiem maleinowym. Zbadano wpływ stosowanych napełniaczy na udarność Charpy’ego, twardość Rockwella, właściwości mechaniczne przy statycznym rozciąganiu oraz skurcz przetwórczy. Próbki do badań otrzymano za pomocą druku 3D. Największą udarność i twardość uzyskano w przypadku kompozytu zawierającego 10% mas. hydroksyapatytu. Do otrzymywania struktur anatomicznych metodą druku 3D zastosowano hybrydowy kompozyt PLA zawierający 10% mas. hydroksyapatytu i 3% mas. bentonitu.

6

Effectiveness of polyethylene glycol-coated silica on ions adsorption in industrial wastewater

Maryudi Maryudi, Rahayu Aster, Hakika Dhias Cahya

Polimery

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2023

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Vol. 68, nr 5

259--263

EN

The effect of coating silica with polyethylene glycol on the adsorption of iron and phosphate ions in industrial wastewater was investigated. Variable factors were temperature and time of coating, PEG concentration, and PEG to silica ratio. Infrared spectroscopy and scanning electron microscopy were used to evaluate the chemical structure and morphology of PEG-coated silica. Optimum iron and phosphate ions removal efficiency was obtained using a coating temperature of 50°C, a coating time of 15 min, a PEG concentration of 20%, and a PEG to silica ratio of 1:3.

PL

Zbadano wpływ powlekania krzemionki glikolem polietylenowym na adsorpcję jonów żelaza i fosforanów ze ścieków przemysłowych. Czynnikami zmiennymi były temperatura i czas powlekania, stężenie PEG oraz stosunek PEG do krzemionki. Do oceny budowy chemicznej i struktury krzemionki powlekanej PEG stosowano spektroskopię w podczerwieni i skaningową mikroskopię elektronową. Optymalną skuteczność usuwania jonów żelaza i fosforanów uzyskano stosując temperaturę powlekania 50°C, czas powlekania 15 minut, stężenie PEG 20% oraz stosunek PEG do krzemionki 1:3.

7

A new environmentally friendly chemical mechanical polishing method applied for surface finishing Ti-6Al-4V alloy

Quang Nguyen Minh, Quan Nguyen Ngoc, Mai Nguyen Trong, Thanh Le Thi Phuong, Tung Nguyen Tien, Tan Tran Ngoc, Hai Ha Thanh, Trinh Nguyen Duy

Journal of Machine Engineering

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2023

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Vol. 23, No. 4

64--76

EN

A new eco-friendly slurry has been developed for the chemical mechanical polishing process with a solution of malic acid, deionized water, and an oxidizing agent hydrogen peroxide (H2O2). The surface quality of Ti-6Al-4V workpieces with the proposed chemical mechanical polishing slurry with optimal parameters include oxidizers (H2O2), colloidal (SiO2) slurry, and deionized water by weight 8%, 45%, and 47% respectively, the pH concentration is adjusted 4 through the malic acid content present in the slurry. Experimental results obtained with the proposed chemical mechanical polishing method show a more improved surface quality than previous studies when applying for polishing Ti-6Al-4V alloy. The developed chemical mechanical polishing method's polishing results under optimal conditions obtain an ultra-fine surface quality with Ra = 0.696 nm over a measuring area of 53×70 μm2. X-ray photoelectron (XPS) and electrochemical measurements were used to study the chemical reaction mechanisms in the proposed chemical mechanical polishing process. The chemical mechanical polishing processes for the surface of the Ti-6Al-4V alloy workpiece with the H2O2 oxidizing agent showed high suitability with the reactants formed on the surface such as Ti, V, and Al oxide. With the proposed oxidant and the established chemical mechanical polishing slurry, the feasibility and surface quality of the super smooth Ti-6Al-4V workpiece formed after polishing were demonstrated. The established chemical mechanical polishing method shows high applicability in environmental protection and Ti-6Al-4V alloy ultra-precision machining industries.

8

Performance of Modified Slow Sand Filter to Reduce Turbidity, Total Suspended Solids, and Iron in River Water as Water Treatment in Disaster Areas

Fitriani Nurina, Wahyudianto Febri Eko, Salsabila Nada Fikna, Mohamed Radin Maya Saphira Radin, Kurniawan Setyo Budi

Journal of Ecological Engineering

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2023

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Vol. 24, nr 1

1--18

EN

This study aimed to determine the ability to modify slow sand filter (SSF) media with silica sand or Anadara granosa shells on the efficiency of removal of turbidity, total suspended solids (TSS), and iron in the water of Kali Jagir Surabaya as an effort to achieve clean water in disaster areas, to obtain the influence of variables, and to optimize the obtained results. The research data was processed using Design Expert 11 Software which factors consisted of media type, filtering speed, and running time, for the responses of removal efficiencies for each parameter. The reactor was operated continuously for 6 days, and samples were analyzed for turbidity parameters based on Indonesian standard (SNI 06-6989.25-2005); TSS and Iron Standard Method 23rd 3500A. In addition, the results of the parameters were processed using the Analysis of Variance (ANOVA) to show the significant effect of the variables on the efficiency of the elimination of all parameters. Optimal research was achieved in the SSF reactor unit with silica sand media type and filtering speed of 0.1 m/hour turbidity removal efficiency of 82.07%; TSS 89.5%; and 50.14% iron. However, the reactor that was chosen was the filtering speed of 0.1 m/hour with a flow rate of 22.8 L/day, while the SSF was suitable to be applied in disaster areas, which had a large discharge. Hence, the reactor is suitable for use in water sanitation in disaster areas, namely with a filtering speed of 0.3 m/hour which produces a discharge of 68.4 L/day with variations of sand, geotextile, and silica sand media.

9

New Material Nanocomposite Thermoplastic Elastomer with Low Cost Hybrid Filler Oil Palm Boiler Ash/Carbon Black

Frida Erna, Bukit Nurdin, Sinuhaji Perdinan, Bukit Ferry Rahmat Astianta, Bukit Bunga Fisikanta

Journal of Ecological Engineering

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2023

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Vol. 24, nr 2

302--308

EN

This study aimed to prepare thermoplastic elastomeric nanocomposites with Low-Cost Hybrid Filler Oil Palm Boiler Ash/Carbon Black as New Material. Hybrid filler composites promise to overcome the limitations of composites. The effects offered by the matrix and filler are responsible for improving the properties of the composite. The preparation of thermoplastic elastomer was carried out in two stages. The first stage involves mixing a rubber compound with filler. The second stage is blending the compound, HDPE, and PE-g-MA using an Internal Mixer. The results show that the peak intensity increased along with the amount of OPBA in TPE. The increase in peak intensity was caused by the rise in the number of crystalline phases in the nanocomposite. In general, the absorption bands are almost the same. The samples analyzed showed absorption band vibrations (Si-O-Si), in-plane strain vibrations (Si-OH), and symmetric strain vibrations (Si-O-Si), C―H deformation, –CH symmetrical stretching of the CH2 group appeared on each sample that FTIR has analyzed. Thermoplastics show good interaction between filler and matrix, so it can be assumed that these interactions can improve the mechanical properties of TPE. Differential Scanning Calorimetry (DSC) shows an increase in the number of peaks in the sample with 60/40 phr filler.

10

Silica ash from waste palm fronds used as an eco-friendly, sustainable adsorbent for the Removal of cupper (II)

Al-Qadri Fatima A., Alsaiari Raiedhah

Archives of Environmental Protection

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2023

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Vol. 49, no 2

30--39

EN

This study describes the creation of a low-cost silica material using a silicate extract as a precursor. This precursor is made from inexpensive palm frond waste ash through a simple calcination process at 500°C and a green extraction with water. Nitrogen adsorption-desorption, FTIR analyses, and transmission electron microscopy were used to characterize the samples. The surface area of the obtained mesoporous silica ash material was 282 m2/g1, and the pore size was 5.7 nm. For the adsorption of copper ions, an excellent adsorbent was obtained. The maximum copper ion adsorption capacity of this inexpensive silica ash-based adsorbent for removing heavy metal ions Cu(II) from aqueous solutions was 20 mg/g, and the eff ect of pH, temperature, and time on its adsorption capacity were also investigated. In addition, The adsorption isotherms were fi tted using Langmuir and Freundlich models, and the adsorption kinetics were evaluated using pseudo-first-order and pseudo-second-order models The results demonstrated that the synthesized adsorbent could effectively remove heavy metal ions from aqueous solutions at pH levels ranging from 2 to 5. The adsorption isotherms followed the Langmuir model, and the kinetic data fit the pseudo-second-order mode well. The thermodynamic results Negative values of G° indicate that the adsorption process was spontaneous, and negative values of entropy S° indicate that the state of the adsorbate at the solid/solution interface became less random during the adsorption process. According to the findings, prepared silica from palm waste ash has a high potential for removing heavy contaminating metal ions Cu (II) from aqueous solutions as a low-cost alternative to commercial adsorbents.

11

Układy hybrydowe na bazie krzemionki i haloizytu do zastosowań środowiskowych i biomedycznych

Kurczewska Joanna

Wiadomości Chemiczne

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2022

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[Z] 76, 7-8

529--550

EN

Silica and halloysite are inorganic materials of great importance in various areas of industry. Inorganic-organic hybrid systems obtained on their basis allow for the expansion of potential applications to new directions and improve their properties in the context of possible applications. Silica is characterized by good selectivity and mechanical stability. It consists of siloxane and silanol functional groups that can be functionalized with different organic units. Halloysite is an aluminosilicate clay mineral with silica and alumina sheets. It is often characterized by tubular structure, and its internal and external surfaces can be easily functionalized. Two large areas of application for hybrid materials based on silica and halloysite are environmental protection and medicine. Herein, the exemplary materials dedicated to the adsorption of impurities and drug delivery systems are presented.

12

Zastosowanie mezoporowatej krzemionki SBA-16 w procesie adsorpcji terfenadyny

Geszke-Moritz Małgorzata, Moritz Michał

Przemysł Chemiczny

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2022

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T. 101, nr 7

491--494

PL

Przedstawiono wyniki badań dotyczących oceny właściwości adsorpcyjnych niemodyfikowanej krzemionki SBA-16 wobec terfenadyny. Przeprowadzono modelowanie procesu adsorpcji z zastosowaniem izoterm: Freundlicha, Dubinina i Raduszkiewicza oraz Dubinina i Astachowa. Parametry modeli matematycznych oszacowano metodą dopasowania nieliniowego. Wykazano znaczną pojemność adsorpcyjną krzemionki SBA-16 wobec leku (155,9 mg/g, izoterma Dubinina i Astachowa) oraz fizyczną naturę procesu adsorpcji. Wydajność adsorpcji terfenadyny w środowisku acetonitrylu wyniosła 87,7%.

EN

Terfenadine was adsorbed from its solns. in MeCN on SBA-16 silica. Model isotherms such as Freundlich, Dubinin-Radushkevich and Dubinin-Astakhov were used. Non-linear fitting anal. was employed for estn. of isotherm parameters. The significant adsorption capacity of SBA-16 silica was shown (155.9 mg/g, Dubinin-Astakhov model). The phys. nature of adsorption process was disclosed. The adsorption efficiency of terfenadine in MeCN soln. reached 87.7%.

13

Zastosowanie mezoporowatej krzemionki SBA-15 oraz krzemionki koloidalnej jako adsorbentów terfenadyny : studium porównawcze

Geszke-Moritz Małgorzata, Moritz Michał

Przemysł Chemiczny

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2022

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T. 101, nr 6

404--408

PL

Porównano właściwości adsorpcyjne krzemionki SBA-15 oraz Aerosil wobec terfenadyny jako modelowej substancji leczniczej. Dowiedziono, że krzemionka mezoporowata odznacza się prawie dwukrotnie większą pojemnością adsorpcyjną (160,4 mg/g) wobec leku aniżeli krzemionka koloidalna (85,7 mg/g) przy jednocześnie dwukrotnie mniejszej wartości ilości adsorbatu przypadającej na jednostkę powierzchni adsorbentu. Przeprowadzono matematyczną interpretację procesu adsorpcji, stosując modelowe izotermy: Freundlicha, Langmuira, Jovanovicia, Dubinina i Astachowa oraz Redlicha i Petersona. Wykazano, że dominującą siłą oddziaływania leku z powierzchnią krzemionek jest adsorpcja fizyczna.

EN

Terfenadine was adsorbed from its solns. in MeCN on a SBA-15 and Aerosil SiO2. Nonlinear fitting anal. was used to estimate the parameters of the Freundlich, Langmuir, Jovanovic, Dubinin-Astakhov and Redlich-Peterson isotherms. The max. adsorption capacity was 160.4 mg/g and 85.7 mg/g (Dubinin-Astakhov model) for SBA-15 and Aerosil silicas resp. It was shown that phys. adsorption was the main force of drug-SiO2 surface interactions.

14

Zastosowanie mezokomórkowej pianki jako adsorbentu dla cynaryzyny

Geszke-Moritz Małgorzata, Pyć Agnieszka, Moritz Michał

Przemysł Chemiczny

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2022

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T. 101, nr 12

1127--1129

PL

Przedstawiono wyniki badań dotyczących adsorpcji cynaryzyny na krzemionce MCF w środowisku acetonitrylu. Proces adsorpcji opisano za pomocą modelowych izoterm Freundlicha, Langmuira oraz Dubinina i Astachowa. Wykazano fizyczny charakter oddziaływania leku z powierzchnią adsorbentu MCF, którego pojemność adsorpcyjna wyniosła 116,7 mg/g (model Dubinina i Astachowa).

EN

Cinnarizine was adsorbed from its solns. in MeCN on MCF silica. Non-linear fitting anal. was used to estimate the parameters of the Freundlich, Langmuir and Dubinin-Astakhov isotherm. Physical nature of adsorption process was the main force of cinnarizine adsorption onto MCF silica. The adsorption capacity of MCF silica reached 116.7 mg/g (Dubinin-Astakhov model).

15

Modelowanie procesu adsorpcji terfenadyny na mezoporowatej krzemionce MCM-41

Geszke-Moritz Małgorzata, Moritz Michał

Przemysł Chemiczny

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2022

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T. 101, nr 7

470--473

PL

Przedstawiono wyniki badań dotyczących właściwości adsorpcyjnych niemodyfikowanej krzemionki MCM-41 wobec terfenadyny w środowisku acetonitrylu. Dokonano opisu procesu adsorpcji z zastosowaniem modelowych izoterm: Freundlicha, Langmuira oraz Dubinina i Astachowa. Parametry modeli matematycznych oszacowano metodą optymalizacji nieliniowej, stosując różne funkcje błędu. Maksymalna pojemność adsorpcyjna krzemionki MCM-41 oszacowana wg modelu Dubinina i Astachowa mieściła się w przedziale 220,7–229,3 mg/g w zależności od zastosowanej funkcji błędu. Adsorpcja terfenadyny na adsorbencie MCM-41 miała charakter fizyczny.

EN

Terfenadine was adsorbed from its solns. in MeCN on MCM-41 mesoporous silica. Nonlinear fitting anal. was used to estimate the parameters of the Freundlich, Langmuir and Dubinin-Astakhov isotherm. MCM-41 silica was characterized by max. adsorption capacity of 220.7–229.3 mg/g (Dubinin-Astakhov model, various error function). Physisorption process was the main force of terfenadine adsorption onto MCM-41 mesoporous silica.

16

Optimization of Palm Oil Boiler Ash Biomass Waste as a Source of Silica with Various Preparation Methods

Bukit Bunga Fisikanta, Frida Erna, Humaidi Syahrul, Sinuhaji Perdinan, Bukit Nurdin

Journal of Ecological Engineering

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2022

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Vol. 23, nr 8

193--199

EN

Several studies have synthesized silica from waste. The silica synthesis method from agricultural waste aims to produce high purity silica with low contaminants at an affordable cost. This study synthesized silica from oil palm boiler ash (OPBA) by means of various methods, such as ball milling, coprecipitation, and modification with methyl trichlorosilane (MTCS). XRD characterization results showed that the OPBA synthesized with ballmill and coprecipitation method has the smallest particle size of 14.90 nm. Morphology showed the OPBA obtained by using the ballmill method, the OPBA synthesized with ballmill and coprecipitation method, as well as the OPBA synthesized with ballmill, coprecipitation, and modified with methyl trichlorosilane as spherical particles. At the same time, the FTIR results show an absorption peak which is a characteristic of silica confirmed by the XRF results, where silica content is dominant.

17

Digital image processing (DIP) application on the evaluation of ironrich heavy mineral concentrates produced from river sand using a sequential mineral processing approach

Terzi Mert, Kursun Ilgin, Cinar Mustafa, Ozdemir Orhan

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 3

21--35

EN

In this study, the iron-rich heavy mineral concentrate production from river sand as a byproduct of an alternative resource by gravity, magnetic separation, and flotation methods were investigated in detail. For the physical separation of the sample and increasing the Fe2O3 content, a shaking table and a wet high-intensity magnetic separator were used, respectively. The gravity and magnetic separation experiments included rougher, cleaner, and scavenger circuits. In the flotation experiments, cationic flotation with ethylenediamine under acidic conditions, and anionic flotation with sodium oleate under alkaline conditions were performed. The iron and silica content of the products obtained were determined by digital image processing (DIP) methods and compared with the classical analytical procedures. Finally, a flow chart was proposed for the processing of the ore according to the optimum enrichment parameters were determined from the experiments. The results obtained in this study show that it is possible to produce an iron-rich heavy mineral concentrate with Fe2O3 grade and recovery rate of 79.13% and 57.81%, respectively, in addition to a potential feed for the production of quartz sand and feldspar concentrates.

18

Perspective of sol-gel hydrophobic silica deposited using low-pressure cold spray and ultrasonic atomizing for automotive coatings

Gibas Anna, Gąsiorek Jolanta

Journal of TransLogistics

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2021

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Vol. 7, nr 1

113--128

EN

The automotive sector is under constant pressure to minimize fuel consumption and reduce pollution emissions while maintaining a declining tendency for weight and cost reduction. This makes the material selection process a major of engineering design considerations. In the paper, the main automotive requirements were formulated to analyze the potential of selected deposition (low pressure cold spray and ultrasonic atomizing) and material fabrication (sol-gel method) techniques for application in the automotive industry.

PL

Sektor motoryzacyjny znajduje się pod ciągłą presją, aby minimalizować zużycie paliwa i redukować emisję zanieczyszczeń przy jednoczesnym utrzymaniu dotychczasowego tempa redukcji masy i kosztów. To sprawia, że dobór materiału jest szczególnie ważny podczas procesu projektowania wybranego elementu. W artykule sformułowano główne wymagania branży automotive do analizy potencjału wybranych technik osadzania (niskociśnieniowego natryskiwania na zimno i atomizacji ultradźwiękowej) oraz wytwarzania materiału (metoda zol-żel) do zastosowań jako powłoki ochronne w przemyśle samochodowym.

19

Microstructure Formation of Al-5 mass%Mg Alloy Melts by Interaction with Silica

Kim Sun-Ki, Ha Seong-Ho, Kim Bong-Hwan, Yoon Young-Ok, Lim Hyun-Kyu, Kim Shae K., Kim Yong-Jig

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 4

947--950

EN

Dissolution of Si in Al-5 mass%Mg alloy melt by the reduction of SiO2 and its effect on microstructure formation of the alloy after solidification were investigated. Al-5 mass%Mg alloy without silica powder had approximately 0.05 mass%Si as an impurity. No significant difference in Si content was observed after the reaction with silica for 10 min, while the Si content increased up to about 0.12 mass% after 30 min. From the microstructure analysis and calculation of Scheil-Gulliver cooling, it was considered that as-cast microstructures of Al-5 mass%Mg-1 mass% SiO2 alloys had the distribution of eutectic phase particles, which are comprised of β-Al3Mg2 and Mg2Si phases. Based on the phase diagrams, only limited amount of Mg can be selectively removed by silica depending on the ratio of Si and Mg. Addition of silica of more than approximately 1.5 mass% in Al-5 mass%Mg alloy led to the formation of spinel and removal of both mg and Al from the melt.

20

Microstructure silica leached by NaOH from semi-burned rice husk ash for moisture adsorbent

A’yuni D.Q., Subagio A., Hadiyanto H., Kumoro A.C., Djaeni M.

Archives of Materials Science and Engineering

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2021

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Vol. 108, nr 1

5--15

EN

Purpose: This work aims to study the water vapor adsorption property of fine silica particles from semi-burned rice husk ash. The semi-burned rice husk ash is selected as the raw material since it contains high silica and is easily found as a by-product of pottery furnace combustion. Design/methodology/approach: The silica adsorbent from semi-burned rice husk ash was prepared through a sol-gel method using various NaOH concentrations. In doing so, the different pH precipitation was also observed. Here, the fine silica powder was obtained by pulverizing dry sol-gel. The product characterizations were conducted based on water adsorption capacity at different air relative humidity. Findings: The results show no significant effects of different treatments in the extraction and gelation process. The fine silica particles exhibit large porous surfaces with agglomerated nano-sized particles that formed pores. This porous structure is related to the distributions of pore size of each sample, which mostly obey the mesoporous characteristics. From sorption isotherm, weak adsorbent-adsorbate bonding was observed and demonstrated multilayer adsorption of mesoporous materials. Research limitations/implications: The study of water adsorption was carried out at room temperature, which can change at any time, even though has no significant effect on the humidity. However, it is needed to study the adsorption in an incubated area to receive a constant temperature. Practical implications: The products namely silica prepared from semi-burned rice husk ash show a high moisture uptake, especially at a high relative humidity region. This property can be comparable with the other silica preparation methods. So, this product can be a highly potential adsorbent for air or gas dehumidification systems. Originality/value: The silica-based semi-burned rice husk ash as a water adsorbent is more sustainable than commercial silica. This is a positive contribution to find a potentially develop water vapor adsorbent with good adsorption capacity. Besides, the synthesis process is a simple and low-cost process.