Wyniki wyszukiwania - BazTech

1

Selected mineral materials grinding rate and its effect on product granulometric composition

Olejnik T. P.

Physicochemical Problems of Mineral Processing

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2013

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Vol. 49, iss. 2

407--418

EN

The article presents investigation on the grinding rate constant. A selection function was measured for different raw materials using a ball mill, and effects of the grinding ball diameter and feed particle sizes on the materials grinding rate constant were investigated. The study was conducted for the mill on a semi-technical scale. The process was carried out periodically using several sets of grinding media. Relations for all investigated materials were expressed by the modified Snow equation. Additionally, the descriptions of the grinding rate was examined. The tendency in the variation of the grinding rate constant with the particle size was similar for all materials used, and was independent of the ball diameter. The author used two selection functions derived theoretically by Tanaka.

2

Grinding kinetics of granite considering morphology and physical properties of grains

Olejnik T. P.

Physicochemical Problems of Mineral Processing

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2012

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Vol. 48, iss. 1

149-158

EN

The article presents the results of studies on the kinetics of grinding of granite taking into consideration the morphology and mechanical properties of particular size fractions of the feed. The study was conducted in a mill on a semi-technical scale. Milling was carried out periodically using several sets of grinding media. The output fraction of the ground material was of size 3-5 mm. The granulometric analysis of the raw material was carried out in a multiple manner. The granulometric composition of milling product was analyzed every 30 minutes. Simultaneously, ground material was subjected to an analysis of the shape of grains and microscopic analysis of morphology and chemical composition. Strength tests of grains were performed applying selected fractions of particle size ranges. The change of particle breakage rate function Si, for selected particles size ranges, was described with the Austin-Gardner expression. The influence of destructive force on kinetics of grinding was defined.

3

Analysis of the breakage rate function for selected process parameters in quartzite milling

Olejnik T. P.

Chemical and Process Engineering

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2012

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Vol. 33, nr 1

117-129

EN

The paper presents the results of studies on quartzite milling in a ball mill. The milling was conducted in a batch system, for diversified compositions of balls. The milling product was subjected to granulometrical, morphological and strength analyses. On the basis of the developed Reid's theory and using the Austin-Gardner equation, a form of the function circumscribing the specific rate of comminution of selected size fractions was determined. The values of the breakage rate function bi, for the mill's apparatus conditions were determined. The impact was investigated for a variable number of grinding media contact points on the values of specific rate S and the values of the breakage rate function bij. Furthermore, the values of coefficients occurring in the equations circumscribing the specific rate of milling S and breakage parameter bij were determined.

4

Milling kinetics of chosen rock materials under dry conditions considering strength and statistical properties of bed

Olejnik T. P.

Physicochemical Problems of Mineral Processing

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2011

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Vol. 46

145-154

EN

The article presents the results of investigations concerning the analysis of milling kinetics of chosen rock materials taking into consideration their strength properties. Investigations were carried out for a mill operating on a semi-industrial scale. Milling was conducted in a periodical mode using grinding media differing in diameters. Mineral raw materials differing in terms of crystallographic structure were subjected to grinding. The process of milling was carried out for quartzite, granite and greywacke. Input fraction of ground material was of size 5 - 8 mm. Grain strength from particular size fractions and its influence on the process kinetics were determined. Grinding rate of particular size fractions and basic parameters used in the theory of statistical moments were calculated.

PL

Artykuł przedstawia rezultaty badań kinetyki mielenia, wybranych materiałów skalnych, z uwzględnieniem ich własności wytrzymałościowych. Badania prowadzono dla półprzemysłowego młyna kulowego. Przemiał realizowano w trybie okresowym, używając mielników o zróżnicowanych wymiarach. Materiał skalny różnił się budową krystalograficzną. Mielenie przeprowadzono dla kwarcytu, granitu oraz szarogłazu. Nadawa charakteryzowała się początkową frakcją rozmiarową z przedziału 5 - 8 mm. Zbadano wytrzymałość ziarn, należących do poszczególnych frakcji rozmiarowych, oraz jej wpływ na kinetykę procesu. Obliczono szybkość przemiału poszczególnych frakcji rozmiarowych oraz rozkłady wielkości matematycznych, wykorzystywanych w teorii momentów statystycznych.

5

Kinetics of grinding ceramic bulk considering grinding media contact points

Olejnik T. P.

Physicochemical Problems of Mineral Processing

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2010

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Vol. 44

187-194

EN

Results of experiments carried out in a pilot-plant ball mill are discussed in the paper. The objective of the experiments was to determine the effect of the number of contact points between grinding media on the rate of grinding. The experimental material was ceramic body used in the production of floor and wall tiles. Main component of the feed was a mixture of feldspar and clay with antiemulsifiers. The feed was subjected to wet grinding. During grinding the rate of comminution of particular size fractions was determined. Changes in particle size distribution of ground material in time were analysed and the effect of ball size, mill filling with the feed and the number of grinding media on the process rate was described. Main objective of the study was to define the effect of changes in the number of grinding media contact points on the grinding rate. Additionally, the effect of mill filling with the feed on changing specific rate of grinding of particle fractions was determined. The change in time of the particle size composition enabled to calculate the grinding rate of particular fractions. In the calculations Gardner and Austin differential equation was used for discrete values of fractions.

PL

W artykule omówiono wyniki badań przeprowadzonych w półprzemysłowym młynie kulowym. Celem badań było określenie wpływu liczby punktów kontaktu, pomiędzy mielnikami a nadawą, na szybkość przemiału. Do eksperymentu użyto kul materiałów skalnych wykorzystywanych w produkcji ceramiki budowlanej. Rozdrabniany materiał składał się z mieszaniny skaleni oraz glinki z dodatkiem antyemulgatorów. Przemiał wykonano na mokro. W trakcie przemiału określano skład granulometryczny mielonego surowca. Zmiany wymiarów ziarna średniego w czasie, poddano analizie ze względu na wpływ wielkości mielników, wypełnienia młyna oraz liczby mielników, określając szybkość procesu rozdrabniania. Główny cel badań dotyczył określenia wpływu zmiany liczby punktów kontaktu mielników na szybkość właściwą rozdrabniania nadawy. Zmiana w czasie rozmiaru ziarn pozwoliła na określenie szybkości procesu dla poszczególnych klas rozmiarowych. Do obliczeń wykorzystano równanie Gardnera i Austina w formie dyskretnej.