Mechanochemistry and agglomeration

Juhász, Zoltan; Opoczky, Ludmilla

doi:10.14382/epitoanyag-jsbcm.2003.16

Cited by 8 publications

(7 citation statements)

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“…In the second stage, the slope of the specific surface area decreases (section of aggregation), while in the third stage, the specific surface area decreases drastically with the milling time (which can be explained by the phenomenon of agglomeration) down to 16 000 cm 2 cm -3 . However, from the cumulative undersize curves, no tendency can be observed; the specific surface are calculated from it shows the general trend [25] that was to be expected with brittle materials. Figure 8 shows the variation of the characteristic particles size values as a function of milling time for (NbC+Si) powder mixture, specifically with the median and 80% passing size plots.…”

Section: Materials Finenessmentioning

confidence: 72%

Mechanical alloying of iron-coated NbC and Si in stirred media mill

Al-Azzawi

Kristály

Rácz

et al. 2019

J min metall B Metall

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In the current research, the effect of mechanical alloying (MA) of iron-coated NbC and Si on the material's fineness and crystal structure was investigated. The MA experiments were carried out in a batch-type laboratory scale stirred media mill for various residence times up to 240 min in isopropanol. During MA, milling energy was measured, and stress energy (SE) was calculated. Morphology and material structural changes, during the mechanical alloying process, were determined by means of scanning electron microscopy (SEM) and powder X-ray diffraction (XRD), respectively. The particle size distribution of the product was measured by a Horiba 950 LA laser particle size analyser. Evolution of phases during highenergy milling of NbC, Al-Fe-carbide, Fe, and Si was studied as a function of specific milling energy. Transformations in the crystal structure were revealed, namely the generation of cementite and Nb-Si-carbide, which was proved by XRD results and thermodynamic calculations. As result of the experiments, optimum MA conditions were determined. The application of the mechanical alloying method gives the opportunity to produce nanocrystalline phase from the initial ironcoated NbC and Si powder.

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Section: Materials Finenessmentioning

confidence: 72%

Mechanical alloying of iron-coated NbC and Si in stirred media mill

Al-Azzawi

Kristály

Rácz

et al. 2019

J min metall B Metall

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“…cement clinker, quartz, fly ash, slags) are susceptible to aggregation and agglomeration. Therefore, it is crucial to eliminate the adhesion forces between particles which can be realized by various surface-active materials, by dosing so called grinding aids [3,39].…”

Section: Mechanical Activationmentioning

confidence: 99%

“…In a study [40] authors investigated the synergetic application of fly ash based geopolymer binder and steel making converter slag as aggregate. They established that the secondary raw materials were successfully applied collectively in the geopolymer concrete, thus creating a product for construction industrial purposes with a nearly 20 MPa compressive strength after 7 days.…”

Section: Applications Of Mechanically Activated Famentioning

confidence: 99%

Mechanical activation of power station fl y ash by grinding – A review

Mucsi¹

2016

Epitoanyag - JSBCM

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Power station fly ash has good application possibilities mainly in the construction industry, nevertheless, significant amount is landfilled due to their relatively low reactivity and heterogeneity. Hydraulic properties of fly ashes can be tailored by mechanical activation achieving a higher added value product, for example supplementary cementing materials (scms). the improved properties are higher specific surface area and desired particle size distribution (containing submicron size particles) as well as higher amount of reactive components that can be optimized by grinding. the objective of this paper is to investigate the effect of mechanical activation of fly ash by grinding on physico-chemical and minerological properties. it can be established that there are numerous techniques for mechanical activation of fly ash, e.g. planetary ball mill, vibratory mill or stirred media mill. on the other hand, most of the results reported in the literature are focusing on material related investigations, but beside this, from energetic point of view the process related evaluation has even higher importance. keywords: mechanical activation, grinding, power station fly ash, reactivity, energy efficiency.Gábor Mucsi Associate Professor and Deputy Dean at the university of miskolc, Faculty of earth science and engineering, institute of raw material Preparation and environmental Processing. His main fields in education and research are mechanical processes -comminution, especially fine grinding, mechanical activation -and utilization of industrial by-products and waste materials. He has more than 100 publications.

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“…Hosszabb ideig tartó őrlés után a finomság növekedése minimumra csökken, majd teljesen megszűnik, sőt a diszperzitásfok csökkenése, azaz az őrlemény durvulása következik be. Ezen a szakaszon a rideg anyagok ál-talában kristályszerkezeti, illetve mechanokémiai változásokat is szenvednek, ezt az agglomeráció szakaszának nevezzük [7]. A szükséges őrlési időt úgy érdemes meghatározni, hogy az őrlés a Rittinger vagy aggregációs szakaszban fejeződjön be, ha a minél nagyobb diszperzitásfok, vagy fajlagos felület elérése a cél.…”

Section: őRlési Időunclassified

“…Az őrlést segítő anyagok vizsgálatával hazánkban Opoczky és Juhász [5,6,7] munkái foglalkoznak átfogóan, ennek eredményeképpen a szilikátipari fi nomőrléshez használatos őrlési segédanyagok hatásmechanizmusáról átfogó képet kaptunk. Nyilvánvalóvá vált, hogy száraz fi nomőrlés területén nagyfokú kapacitásnövekedés és szemcseméret-csökkenés érhető el a megfelelő őrlést segítő anyagok használatával.…”

Section: őRlést Segítő Anyag Adagolásaunclassified

Possibilities and problems of the submicron dry grinding in stirred ball mill (Part I)

Rácz¹

2010

Epitoanyag-JSBCM

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Mechanochemistry and agglomeration

Abstract: /1. ábra. Repedés kialakulása a csúszósíkok metszésénél (a) és a repedés terjedése (b) 1/2. ábra. A törésnél a repedéscsúcsnál fellépõ hõmérsékletek 1/3. ábra. Erõ-deformáció összefüggése egyedi részecske törésénél 1. ábra. A törés folyamata

Cited by 8 publications

References 0 publications

Mechanical alloying of iron-coated NbC and Si in stirred media mill

Mechanical alloying of iron-coated NbC and Si in stirred media mill

Mechanical activation of power station fl y ash by grinding – A review

Possibilities and problems of the submicron dry grinding in stirred ball mill (Part I)

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