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1

The numerical techniques application in the ball mill comminution process modelling

Pawlos Witold, Dominiczak Przemysław

Cuprum : czasopismo naukowo-techniczne górnictwa rud

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2023

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nr 1-2

47--53

EN

The preliminary results of comminution process numerical simulations have been presented in this paper. The numerical prediction has been based on discrete elements method (DEM) for solid modelling and smoothed particles hydrodynamics method (SPH) for modelling a continuous medium – liquid. The one way numerical coupling between solid and liquid has been applied. The ball mill working in production line in O/ZWR has been modelled. The considered ball mill is used to copper ore comminution process. The numerical calculations have been carried out for different mill rotation speed.

PL

W artykule przedstawiono wstępne wyniki numerycznych symulacji procesu rozdrabniania. Prognozowanie numeryczne zostało oparte na metodzie elementów dyskretnych (DEM), wykorzystanej dla modelowania cząstek stałych, oraz na metodzie symulacji hydrodynamicznej (SPH) dla modelowania w ośrodku ciągłym – ciecz. Zastosowano jednokierunkowe sprzężenie numeryczne pomiędzy fazą stałą a ciekłą. Młyn kulowy, zainstalowany w ciągu technologicznym ZWR, został wytypowany jako obiekt modelowania. Rozpatrywany młyn pracuje jako urządzenie rozdrabniające rudę miedzi. Obliczenia numeryczne przeprowadzono dla różnych prędkości obrotowych młyna.

2

Improvement of the accuracy of Hogg and Fuerstenau's model in predicting the power draw of ball mills based on determining the grinding media’s dynamic voidage

Golpayegani Mohammad Hasan, Rezai Bahram

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 153380

EN

In the development of tumbling mills' power models, the voidage of grinding media is assumed to be static and equal to 40%. While the grinding media’s voidage is dynamic; and hence is varied by changing the operating parameters. In this paper, to improve the Hogg and Fuerstenau model's accuracy in predicting the ball mills' power draw, the grinding media's static and dynamic voidage was studied for Bond's proposed ball size distributions (BSD) for the ball mills' first filling. To this end, by scaling down balls to one-tenth of actual size, developing a novel method to measure the dynamic voidage, and employing the three-level factorial method, a separate empirical model was developed for determining the dynamic voidage of each Bond's BSD with respect to mill's fractional filling and rotating speed. Moreover, using the multiple regression method, a general empirical model was derived to determine the dynamic voidage of each supposed BSD based on calculating the mean absolute deviation of balls diameter (MAD). Results indicated that grinding media's dynamic voidage increases with an increase in rotating speed and a decrease in fractional filling and balls diameter's MAD. The maximum and minimum static and dynamic voidage occurred for the seventh and first Bond's BSDs. By employing an industrial database and analyzing the mean absolute percentage error (MAPE) of predicted ball mills' power draw, it was found that the Hogg and Fuerstenau model's accuracy enhances by calculating the load's bulk density based on the grinding media's dynamic voidage.

3

Effect of grinding media on the flotation of copper-activated marmatite

Long Tao, Chen Yao, Shi Juanjuan, Chen Wei, Zhu Yangge, Zhang Chonghui, Bu Xianzhong

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 2

229--237

EN

How to avoid the shortage of floatability and non-purpose flotation in marmatite flotation is a big problem. This paper innovatively studies how to reduce these two negative phenomena from the perspective of grinding media. The effects of steel and stainless-steel balls on the flotation performance of copper-activated marmatite were investigated mainly through flotation tests, redox potential measurements, ion concentration tests, and XPS and FT-IR spectrum studies. The flotation results showed that the floatability of copper-activated marmatite remarkably decreased by using the steel ball in the grinding process, but it had a mere influence when stainless-steel medium was used. Redox potential measurements showed that the grinding environment of stainless-steel medium could exhibit a higher oxidizing potential than the steel grinding environment. Results from FTIR, XPS, and ion concentration measurements demonstrated that more ferric ions existed on the copper activated marmatite surface in the steel grinding environment than that in the stainless-steel environment. Ferric ions could further hinder the activation effect of copper ions on marmatite and result in decreased marmatite flotation. This research could potentially explain the mechanism of ferric ions in the grinding process, and it can be utilized to improve the flotation performance of marmatite ore through selecting suitable grinding media in ball mill operations.

4

Effect of grinding media on the flotation behavior of fluorite using sodium oleate as a collector

Yao Wei, Li Maolin, Zhang Ming, Qian Gongming, Cui Rui, Ning Jiangfeng

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 3

556--565

EN

Grinding, an essential procedure before flotation, to some extent, determines the flotation behavior of minerals. In this study, the effect of grinding media on the flotation behavior of fluorite using sodium oleate (NaOl) as a collector was investigated via micro-flotation experiments, zeta potential measurements, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) analyses. The results indicated that, compared with the fluorite particles ground by ceramic media, the ones ground by cast iron media adsorbed less NaOl, resulting in lower flotation recovery. The lower flotation recovery of fluorite particles ground by cast iron media resulted from the coating of the hydrophilic Fe precipitates generated in the grinding, including Fe(0), Fe(OH)2, and Fe(OH)3on their surfaces. These Fe precipitates may cover the Ca active sites and increase the hydration membrane which can inhibit the further NaOl adsorption. This research reveals the effect of grinding media on the flotation behavior of fluorite and guides for media selection in disposing of fluorite ore.

5

Modern grinding balls sorting machines

Piekaj Paweł

New Trends in Production Engineering

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2019

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Vol. 2, Iss. 1

86--95

EN

Raw materials produced in large quantities are ground in ball, vibratory and stirred ball mills. In mills, the working parts are grinding balls. During grinding, grinding balls wear, change their diameter and lose their shape. The effect of this is the unfavourable change in the grinding balls parameters, which results in deterioration of the technological conditions of the milling process. Relevant parameters of the grinding balls set are restored during maintenance shutdowns. Grinding balls are sorted into appropriate size classes; grinding balls that are not suitable for further use are rejected, and then a set of grinding balls with appropriate parameters is used again. The time needed to prepare the required set depends mainly on the sorting time. To reduce this time, appropriate grinding balls sorting machines are used. The paper presents major problems associated with the grinding balls sorting process, a comparison of modern types of grinding balls sorting machines, a description of their construction and technological parameters.

6

Analysis of Possibilities of Obtaining the Fine Particle Size in Mills of Various Designs

Wołosiewicz-Głąb M., Foszcz D., Gawenda T.

Inżynieria Mineralna

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2016

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R. 17, nr 1

223--231

EN

The paper presents the problem of obtaining the fine grained material in mills of different constructions. Various types of mills have been characterized, taking into account the type of grinding media used. Characteristics of selected mills and grinding media used were presented and the movement of the particles in the drum of the ball mill has been shown. Mills with mixed grinding media have been described. Model of "transport energy pulses" for free grinding media in the Kurrer’s tubular chamber of the vibratory mill were described. Paper discusses the advantages and opportunities for fine grinding in the electromagnetic mill, performance and in particular the energy cost of commimtion, that is achievable in this device.

PL

W artykule przedstawiono problematykę uzyskiwania drobno uziarnionych materiałów w młynach o różnych konstrukcjach. Dokonano charakterystyki różnych rodzajów młynów z uwzględnieniem typu stosowanych mielników. Pokazano charakterystykę wybranych młynów i użytych w nich mielników. Opisano ruch ziarna w bębnie młyna kulowego, a także model „transportu impulsów energii” ku mielnikom w rurowej komorze młyna wibracyjnego według Kurrera. Omówiono zalety i możliwości w zakresie drobnego mielenia w młynie elektromagnetycznym w szczególności wydajność oraz wydatek energii na rozdrabnianie, jakie możliwe jest do uzyskania w tym urządzeniu.

7

Kinetyka laboratoryjnej flotacji rudy miedzi z ZWR Polkowice po mieleniu w obecności mielników o różnym składzie chemicznym

Bakalarz A., Duchnowska M., Konieczny A., Kasińska-Pilut E., Pawlos W., Kaleta R., Kowalczuk P., Drzymała J., Łuszczkiewicz A.

Cuprum : czasopismo naukowo-techniczne górnictwa rud

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2015

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nr 2

55--70

PL

Wiele danych w literaturze potwierdza, że rodzaj, skład chemiczny i ścieralność mielników użytych do przygotowania nadawy flotacyjnej wpływa na właściwości elektrochemiczne zawiesiny flotacyjnej, a tym samym na efektywność procesu wzbogacania. W pracy dokonano analizy kinetyki flotacji polkowickiej rudy miedzi mielonej w warunkach laboratoryjnych w obecności mielników stalowych (stal kuta), żeliwno-chromowych i nierdzewnych (stal łożyskowa) przy trzech różnych dawkach przemysłowego odczynnika zbierającego. Analizie poddano kinetykę flotacji miedzi, srebra, węgla organicznego oraz składników nieużytecznych, w oparciu o dostępne w literaturze modele kinetyczne. Otrzymane wyniki analiz pozwoliły na określenie charakteru kinetyki wzbogacania poszczególnych składników po procesie mielenia w różnych warunkach.

EN

Kinetics of laboratory flotation of copper ore from Polkowice Division of Concentrators after milling in the presence of grinding media with different chemical composition Abstract: Numerous data in the literature confirm that the kind, chemical composition and consumption of grinding media have an influence on the electrochemical properties of flotation suspension and the upgrading process effectiveness. The paper presents an analysis of kinetics of laboratory flotation tests of the copper ore milling in the presence of three different grinding media (forged, high-chrome and stainless) iron and three different doses of industrial collector. The analysis of flotation kinetics of copper, silver, organic carbon and remaining components content in concentrate was carried out basing on available in literature kinetics models. The results of analyses allowed to characterize the flotation kinetics of analyzed components of copper ore after milling under different conditions.