A review of Alumina: Most abundant and productive material of the mother

nature

 

KAYAALP UmayPAPOUTSOGLOU Dimitra

 January 2012

 Supervisors: AYRAL Andre; andre.ayral@iemm.univ-montp2.fr 

BACCHIN Patrice ; bacchin@chimie.ups-tlse.fr January 26, 2012

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1. Introduction

Ceramics:

‘’The art and science of making and using solid articles which have as their essential component, and are composed in large of inorganic nonmetallic materials.’’ Kingerly

‘’All high-temperature chemistry and physics of nonmetallic materials, and the techniques of forming products at high temperatures.’’ Mitchell

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1. Introduction

Aluminum is the most abundant metal in the earth's crust and the third most element in the earth's crust, after oxygen and silicon.

Aluminum is too reactive to be found pure. Bauxite (mainly aluminum oxide) is the most important ore.

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1. Introduction

The following information has been gathered:

occurrence in nature

mineralogical characteristics

mechanical, thermal, chemical and colloidal properties

alumina membranes fabrication

modules and industrial applications 

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2. Nomenclature

Figure 1: Dehydration Sequence Of Alumina Hydrates In Air

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3. Structure And Mineralogical Properties

Crystal structure is the main factor controls the properties of alumina

In general, the phases of alumina are produced by pseudomorphic dehydration

Pseudomorphosis is of considerable importance because of its effect on surface area of the intermediate phase structures, and on crystal size and size distribution

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3. Structure And Mineralogical Properties

Alumina is widely used as a catalyst or catalyst support in many heterogeneous catalytic processes owing to its high surface area, superior chemical activity and low cost.

Resistance to: softening swelling and disintegration when immersed in water or other

liquids thermal shock and corrosion

The ability to return to the original highly adsorptive from by a suitable thermal regenerative treatment

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4. Mechanical – Thermal Properties

Alumina has remarkable mechanical properties in comparison with conventional porcelains and other single oxide ceramics

The interest in mechanical – thermal properties lead to several applications such as possible substitution of alumina ceramics for refractory metal parts in air-bone equipment, or fabrication forms.

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4. Mechanical – Thermal Properties

Mechanical properties

Tensile Strength (MPa) 173 117

Bending Strenght Mpa 413 307 Modulus of Elasticity (E) X 108 MPa 26.8 21.27 Compressive Strenght Mpa 3733 1600 Modulus of Ridity(G) X 108 MPa 11.3 8.67 Hardness on the mohs scale 9 

Thermal properties

Melting point OC2051±9.7

Boiling Point OC3530

± 200 January 26, 2012

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5. Chemical Properties

Chemical reactions of alumina of general ceramic interest include the resistance to attack of sintered alumina by various reagents, particularly at high temperatures.  

Finely divided alumina is rapidly dissolved by HF, hot concentrated H2SO4, mixtures of these acids, ammonium fluoride, molten alkali bisulfates or pyrosulfates, and by concentrated HCl, especially when under pressure.

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Alumina membranes are constantly growing area. In the Figure 3, it can be seen that, the publication numbers are highly increasing parallel with the membrane research especially during recent years.

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6. Alumina Membranes

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6. Alumina Membranes

Excellent mechanical strength

Tolerance to solvents, as well as pH, oxidation,

Can be used at significantly higher temperatures

Have better structural stability

Can be backflushed

Less cost

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6. Alumina Membranes

Highly selective

Permeable / Selective ( based on pore size and dist.)

Durable

Hydrophilic to maximize flow and minimize fouling

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6. Alumina Membranes

Table 2 : Selected commercial Alumina Membranes

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6.1. Macroporous Membranes

Usage: Filtration , diffusion, dispersion rolls, inkpads for fingerprinting

Anodizing of pure aluminum most common path Anodizing well controlled process and provides

homogenous pore distribution The preparation of regular pore arrays typically

involves electrolytic polishing and multiple anodising steps or even mechanical pre-texturing.

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6.1. Macroporous Membranes

Macroporous alumina membranes also can be made from particles or discontinuous fibers by the use of a binder or by sintering .

Silica, vitreous glass and also phosphate are widely used binders in the refractory and ceramic industry

This method is generally used to produce alumina microfiltration filters, which contain larger pores and supports for ultrafiltration membranes, which contain smaller pores

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6.2. Mesoporous Membranes

Figure 4: Preparation procedure of boehmite sol

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6.2. Mesoporous Membranes

Figure 5: Schematic drawing of the rapid gelation processing, 1 - nozzle, 2 - atomizing sol and 3 -substrate.

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Mesoporous -alumina membranes are formed by dip-γcoating a porous substrate in a Boehmite ( -AlOOH) γprecursor sol, will be treated by heat and sintering steps.

The quality and properties of the membrane depend on the dispersion rheology and quality of the Boehmite sol and the dip-coating process as well

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6.2. Mesoporous Membranes

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6.3. Microporous Membranes

A conventional path to synthesis microporous membranes is slipcasting.

In the slipcasting method, a porous support is usually made first by conventional ceramic processing techniques to provide rigid structure with relatively large pore size for slip deposition.

The ability to consistently produce high quality alumina membranes on a commercial scale has been the key to wider acceptance of ceramic membranes as a separation tool.

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7. Membrane ModulesTubular mode / Multichannel / Monolithic

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Schematic side-view of membrane module consisting of multi-channel

elements [Remigy, 2007]

Cross-section of a monolithic multi-

channel membrane element [Hsieh et al.,

1998]

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Composite or anisotropic / Multilayer

Schematic representation of Polypeptide films formed inside pore walls of a thin anodic alumina membrane

[Duran H. et al., 2004]

7. Membrane Modules

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Honeycomb mode

(a) AnoporeTM alumina membrane with honeycomb pore size distribution

(b)Commercial version of honeycomb alumina membrane by Lianyungang Highborn Technology Co., Ltd

7. Membrane Modules

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Kerasep® alumina membrane module

•Alumina/Titanium oxide layers•7-84 channels•Pore size>0.8μm•Compact•d<1178mm •P>80bar•Θ>80oC•pH 0-14

Bulk fermentation / Milk and dairy products / Beverages (beer, wine, water, fruit juice)

7. Membrane Modules

8. Applications

Adsorption layer of alumina

Microfiltration – Ultrafiltration

Crossflow filtration – High Crossflow velocity

Transmembrane pressure : driving force of operation

Concentration of soluble molecules and suspended solids &

Clarification by removing suspended solids

Pretreatment process

8.1 Liquid phase separation (LPS)

1. Environmental

Ions removal from wastewater (Cr, F, Ar)

Eg. Microporous Alumina membrane for Heavy metals removal in petrochemical industry

Oil Recovery

2. Food/Beverage

Clarification of juices

Eg. Pretreatment prior ion exchange/chromatography of clarified juice

Filtration of sugar cane juice

Alcoholic beverages

3. Pharmaceutical

Fermentation broths clarification Eg. Recovery of antibiotics

Fungal cells ultrafiltration

Eg. microfiltration of biological media, such as human red blood cells

Lysozyme ultrafiltration, Penicillin recovery

ECN industry demonstration of inorganic membrane module for liquid phase separation [ecn.nl]

In a wide range of wastewaters, alumina membranes assumed to be suitable for Ar(V) and Cr (III) removal

γ-Al2O3/α-Al2O3, mesoporous alumina / Calcium doped alumina / Composite membranes

Concentration of arsenic ions decreased from 1ppm in 5ppb

Flocculation was used as a pretreatment / for the treatment of the stone cutting wastewater

Example:

Pagana et al., 2008 : Composite γ-Al2O3 membranes made by sol–gel method

Pilot system for Cr(III) and Ar(V) removal

Ar(V) 2 stages adsorption – ultrafiltration process in series

Cr(III) 1 adsorption-ultrafiltration parallel process

8.1 LPS / As (V) – Cr (III) Removal

8.1 LPS / As(V) – Cr (III) Removal

Flow diagram of the Cr (III) removal process [Pagana et al., 2008]

Conclusion: Adsorption-ultrafiltration ion process using ceramic membranes may offer a low cost effective alternative arsenic and chromium purification technology basically in terms of membrane stability, applied pressure and product flux with the additional advantage of being suitable for small local units

8.2 Gas Phase Separation (GPS)

1. Carbon Dioxide Capture

CO2/N2 separation

H2/CO2 separation

2. Hydrocarbons separation

Acetone recovery

Propane separation

Alcoholic beverages

3. Catalytic reactors

VOCs oxidation

Methane to ethane reaction

INSIDE Céram membrane by TAMI industry [tami-industries.com]

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Alumina membrane are used in combination with catalysts or used for catalyst recovery in a wide range of applications

Example: Saraco et al., 1999 / University of Saragoza Chem. Eng.Lab.

Pt/Al2O3 and perovskite-containing membranes

Using hydrogenation reactions over Pt/Al2O3 catalysts in membrane module

Purification (by catalytic combustion) of air streams containing volatile organic compounds (VOCs) in low concentrations

Membrane would be expected to give high contact efficiency in the reaction of diluted streams

Conclusion: The membrane performed very efficiently in the combustion of VOCs at low temperatures, although at the expense of a significant pressure drop.

8.2 GPS /VOCs removal

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Schematic of a multi tube membrane module for H2 and CO2 separation [Diriz

et al., 2007]

Applications of membrane reactors [Coronas et al., 1999]

8.2 GPS /VOCs removal

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Nanotechnology / Composite structures Modifications Sensitive active layers Alumina Catalysts/ Surface Adsorption Nanofiltration Gas separation Lower Cost (10 times > Polymeric, Remigy, 2004)

Lower Fragility / Fouling/ Cracking

Application of ceramic membranes in fields “traditionally” dominated by polymeric

membranes!

9. Perspectives

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Acknowledgements

We would like to express our sincere thanks to

EM3E for its support

Prof.A.Ayral, Prof.P.Bacchin and A.Julbe for their advices

EM3E GROUP FOR THIS FIRST… HARD SEMESTER!

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Goodbye France!