Wyniki wyszukiwania - BazTech

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Practical guidelines for predicting the proper conditions of high-energy mixing in a planetary ball mill towards powder flow improvement

Leś Karolina M., Opaliński Ireneusz

Chemical and Process Engineering

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2022

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Vol. 43, nr 3

419-–433

EN

In this work Response Surface Methodology and Central Composite Rotatable Design were applied to find high-energy mixing process parameters enabling flow properties of highly cohesive Disulfiram powder to be improved. Experiments were conducted in a planetary ball mill. The response functions were created for an angle of repose and compressibility index as measures of powder flowability. To accomplish an optimisation procedure of mixing process parameters according to a desirability function approach, the results obtained earlier for potato starch, as another cohesive coarse powder, were also employed. Coupling these results with those achieved in a previous work, it was possible to develop some guidelines of practical importance allowing mixing conditions to be predicted towards flow improvement of fine and coarse powders.

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Prospective Application of Response Surface Methodology for Predicting High-Energy Mixing Process Conditions towards Fine Powders Flow Improvement

Leś Karolina, Opaliński Ireneusz

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 1

134--143

EN

Planetary ball mill was proposed as an intensive high-energy mixer to obtain flowability improvement of industrially exploited, cohesive and finely comminuted powders via dry coating. Response surface methodology (RSM) coupled with central composite rotatable design (CCRD) was applied as an effective method for the prediction of high-energy mixing conditions. The use of this procedure allows identifying relatively narrow ranges of high-energy mixing parameters (rotating speed of planetary ball mill and mixing time) and the amount of additives used (nanosilica and isopropyl alcohol) providing substantial improvement of the flowability of Aluminium hydroxide (Apyral) and Calcium carbonate powders. In order to find the optimal values of the process parameters, enabling to obtain the lowest values of flowability indices (angle of repose, compressibility index), the desirability function approach was applied. The obtained results may be a basis for developing a general routine allowing mixing parameters to be successfully predicted regarding some physical properties of powders only with no experiments needed.

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Optimisation Of Process Parameters In High Energy Mixing As A Method Of Cohesive Powder Flowability Improvement

Leś K., Kowalski K., Opaliński I.

Chemical and Process Engineering

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2015

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Vol. 36, nr 4

449--460

EN

Flowability of fine, highly cohesive calcium carbonate powder was improved using high energy mixing (dry coating) method consisting in coating of CaCO3 particles with a small amount of Aerosil nanoparticles in a planetary ball mill. As measures of flowability theangle of repose and compressibility index were used. As process variables the mixing speed, mixing time, and the amount of Aerosil and amount of isopropanol were chosen. To obtain optimal values of the process variables, a Response Surface Methodology (RSM) based on Central Composite Rotatable Design (CCRD) was applied. To match the RSM requirements it was necessary to perform a total of 31 experimental tests needed to complete mathematical model equations. The equations that are second-order response functions representing the angle of repose and compressibility index wereexpressed as functions of all the process variables. Predicted values of the responses were found to be in a g ood agreement with experimental values. The models were presented as 3-D response surface plots from which the optimal values of the process variables could be correctly assigned. The proposed, mechanochemical method of powder treatment coupled with response surface methodology is a new, effective approach to flowability of cohesive powder improvement and powder processing optimisation.

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The influence of ball milling conditions on the mechanical decomposition of Cu-hydroxycarbonate

Powałka E., Jagosz M., Gamrat K., Janicka E., Wieczorek-Ciurowa K.

Czasopismo Techniczne. Środowisko

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2004

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R. 101, z. 9-Ś

70--76

EN

The quantity of copper oxide formed from Cu2(OH)2CO3 during mechanical activation using planetary ball mill (FRITSCH Pulverissette 6) was calculated on the basis of TG/DTG-DTA curves of milling products. The effects of different milling circumstances such as: ball size and ball-to-powder mass ratio are presented. For obtaining the highest level of degree decomposition of Cu2(OH)2CO3 the following parameters can be recommended: 10-mm balls, BPR = 10:1 milling time - 180 min at maximum speed of 600 rpm.

PL

Ilości tlenku miedzi powstającego z rozkładu Cu2(OH)2CO3 podczas mechanicznej aktywacji przy użyciu młynka planetarnego (FRITSCH Pulverissette 6) były określone na podstawie analizy krzywych TG/DTG-DTA produktów mielenia. Wykazano różne efekty mielenia w zależności od zastosowanychwarunków, takich jak: średnica mielników, stosunek mas mielników do materiału mielonego. Dla uzyskania najwyższego stopnia rozkładu Cu2(OH)2CO3 zalecane jest użycie: mielników 10 mm, BPR = 10:1, czasu mielenia - 180 min i maksymalnej liczby obrotów = 600 rpm.