SEPARATION TECHNOLOGY(CKD 20103)MINI PROJECT

“THE BAYER PROCESS” By,

GANESH S/O RAVICHANDRAN (55101112079)MUHAMMAD SYAMIM BIN MOHD SUKRI (55101112016)MUHAMMAD ZULHELMI BIN SAHAT (55101211055)MOHAMAD KHAIDIR BIN HAMZAH (55101210076)

ABSTRACTThe Bayer Process, history of Bayer process, chemical use in Bayer process, schematic diagram of Bayer process

Bayer process is a process of producing pure alumina from bauxite.

Bauxite is a sedimentary rock that is the main ore of aluminium

Grinding of bauxite, Digestion of bauxite, Settling and washing residue, Crystallization of hydrate Calcination of hydrate.

INTRODUCTIONWhat is Bayer Process? The production of alumina from the bauxite ores, there are frequent disturbances and a large number of interacting processes which incorporate considerable dead time.

Bayer process simulation and process control are two important tools.

HISTORY OF BAYER PROCESSWas invented in 1887 by Carl Josef Bayer

A few years earlier, Henri Étienne Sainte-Claire Deville in France developed a method for making alumina by heating bauxite in sodium carbonate, Na2CO3

CHEMICAL USEDWhat it use?Bauxite sedimentary rock that is the main ore of aluminium.

also contain amounts of iron, clay, silt and silica.

also used in the manufacture of abrasives.

Bauxite Rock

Abrasives

CONTENTSThe Bayer Process

The Bayer Process Description

Alumina refining.

Main five descriptions - Grinding of bauxite, Digestion of bauxite, Settling and washing residue, Crystallization of hydrate and Calcination of hydrate.

Bauxite Extraction Precipitation

Calcination Alum ina

The Process Flow

Grinding of

Bauxite

• Milling and Crushing• The bauxite-liquor mixture is a red suspension (or slurry)

Digestion of

Bauxite

• Gibbsite, Böhmite and Diaspore are selectively extracted

• form a sodium aluminate supersaturated solution or “pregnant liquor”.

Settling /

Clarification

• Residue and the liquor that make up the slurry are separated by settling

• The floating liquor is filtered then sent to be precipitated.

Crystallization of Hydrate

• The liquor is cooled, diluted with the water

• The alumina hydrate slowly precipitates from tank to tank as the temperature decreases

Calcination of Hydrate

• Wet hydrate is calcinated in rotary kilns

• Calcinated alumina is produced as particles of white powder.

SEPARATION TECHNIQUESDigestion of Bauxite

 1.

 Mixture of separation

 Heterogeneous mixture (Solid - Liquid) Solid - Bauxite slurryLiquid - Sodium

Hydroxide (NaOH)

 2.

 General method

 Chemical Separation

 3.

 Separation technique

 Leaching or Solid extraction

 4.

 Separated product( Wanted )

 Sodium aluminate supersaturated solution

Settling / Clarification 1.

 Mixture of separation

 Heterogeneous mixture (Solid - Liquid) Solid - The residue

after extractionLiquid - The liquor

containing sodium aluminate

 2.

 General method

 Mechanical Separation

 3.

 Separation technique

 Settling / Gravitational Settling

 4.

 Separated product( Wanted )

 The liquor containing sodium aluminate

Filtration 1.

 Mixture of separation

 Heterogeneous mixture (Solid - Liquid) Solid - Impurities

and wet hydrate

Liquid - The liquor 2.

 General method

 Mechanical Separation

 3.

 Separation technique

 Filtration

 4.

 Separated product( Wanted )

 1) The liquor containing sodium aluminate

2) Both solid & liquid.

Crystallization / Precipitation 1.

 Mixture of separation

 Homogeneous mixture (Liquid - Liquid) Liquid - Alumina hydrate Liquid - The liquor

 2.

 General method

 Chemical Separation

 3.

 Separation technique

 Crystallization (temperature decreased)

 4.

 Separated product( Wanted )

 Wet alumina hydrate, Al(OH)3

Evaporation 1.

 Mixture of separation

 Homogeneous mixture (Liquid - Liquid) Liquid - waterLiquid - The liquor

 2.

 General method

 Chemical Separation

 3.

 Separation technique

 Evaporation

 4.

 Separated product( Wanted )

 The concentrated liquor.

ADVANTAGESSaving of raw material and particularly electrical energy.

Avoiding the environmental problems in the extraction of aluminium from the bauxite.

The unwanted aluminium can be recycled.Aluminium has a low density which is useful.

Aluminium is strong when alloyed.Aluminium is a good conductor of electricity and resist corrosion.

DISADVANTAGESHigh cost of the process because of huge amounts of electricity uses.

Loss of landscape due to mining, processing and transporting the bauxite.

Noise and air pollution involved in the operations

Atmospheric pollution from the various stage of extraction.

Pollution cause by power generation.Disposal of red mud into unsightly lagoons.

CONCLUSIONAs a conclusion, the Bayer process is a producing pure alumina from bauxite. It is also used in applications such as industrial and medical ceramics, sandpapers, pigments, cosmetics and pharmaceuticals. The Bayer Process involves many separation techniques in its processing. It is the most economic means of obtaining alumina from bauxite.

REFERENCES Noranda Alum inium Holding Corporation, (2007). Overview & The Bayer Process.

(Online) 28th November 2013 Available from W orld W ide W eb: http://www.norandaalum inum.com/bayer-process.php

The International Alum inium Institute, (2012). Aluminium M ining & Refining Process (Online) 28th November 2013 Available from W orld W ide W eb: http://bauxite.world-alum inium.org/refining/process.html

Alteo (A New W orld Of Alumina), (2012).Alum ina Refining (Online) 29th October 2013 Available from W orld W ide W eb: http://alteo-alum ina.com/en/alum ina-refining

Robert John Lancashire, (2008) The Chem istry & Processing of Bauxite. (Online) 29th November 2013 Available from W orld W ide W eb: http://wwwchem.uwimona.edu.jm/lectures/bauxite.html

The National Academ ies Press (Open Book), (2013). Separation Technologies for the Industries of the Future (1998) / 2. Chemical Industries (Online) 29th November 2013 Available from W orld W ide W eb: http://www.nap.edu/openbook.php?record_id=6388&page=16