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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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Powlekanie żywności proszkami

Marchewka Agnieszka, Domian Ewa

Przemysł Spożywczy

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2019

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T. 73, nr 8

40--43

PL

Zastosowanie technologii powlekania żywności proszkami daje producentom możliwość stworzenia szerokiej gamy produktów o różnorodnych smakach i kolorach. Sztandarowym przykładem wykorzystania tej techniki są przekąski z nanoszoną solą lub różnego rodzaju mieszankami przypraw oraz składnikami funkcjonalnymi. W artykule przedstawiono urządzenia technologiczne wykorzystywane w operacji powlekania, takie jak bębny powlekające i przenośniki taśmowe, z uwzględnieniem systemów dozowania proszków. Scharakteryzowano technikę powlekania elektrostatycznego, która wykazuje lepszą wydajność w porównaniu z metodą konwencjonalną. Zwrócono uwagę na właściwości proszków – rozmiar, kształt, sypkość, gęstość i rozpuszczalność – wpływające na skuteczność procesu. Nakreślono problemy występujące podczas powlekania, jak: niewystarczająca adhezja, pylenie, kohezyjność, zapychanie i wzbieranie, oraz zaproponowano sposoby ich rozwiązania.

EN

The use of food coating technology for powders gives producers the opportunity to create a wide range of products with a variety of flavors and colors. The flagship example of using this technique are snacks with spread salt or various kinds of spice blends and functional ingredients. The article presents technological devices used in coating operations, such as coating drums and belt conveyors, including powder dosing systems. The electrostatic coating technique, which shows a higher coating efficiency compared to the conventional method, was characterized. Attention is paid to the properties of powders – size, shape, flowability, density and solubility – affecting the efficiency of the process. Problems occurring during coating, such as insufficient adhesion, dustiness, cohesiveness, clogging and surging, as well as methods of solving them are outlined.

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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.