Aluminum hydroxide is produced commercially using the Bayer process, which involves dissolving bauxite in sodium hydroxide. It has a wide range of uses including as a flame retardant, in toothpaste, and as an antacid. It can also be processed into aluminum oxide, which exists in several forms and has applications as an abrasive and refractory material. Ultra-fine aluminum hydroxide specifically has properties making it suitable as a flame retardant and filler.
2. Mineral Ores containing Aluminium
Hydroxide
Found in mineral ores of gibbsites, bayertute, doyleite
and strandite.
Gibbsite, Al(OH)
Raman spectra of
bayerite (β-Al(OH)3)Doyleite Al (OH) 3
3. How is aluminium hydroxide produced
Virtually all the aluminium hydroxide
used commercially is manufactured by
the Bayer process which involves
dissolving bauxite in sodium hydroxide
at temperatures up to 270 °C (518 °F).
The waste solid, bauxite tailings, is
removed and aluminium hydroxide is
precipitated from the remaining
solution of sodium aluminate
High Investment
REQUIRED
4. Smelter Grade Alumina (SGA)
All commercial Smelter Grade
Alumina (SGA) is produced by
Calcination of Aluminium
Hydroxide in Alumina
Refineries
5. Other Methods of producing Aluminium
Hydroxide
Other processes to obtain aluminium
hydroxide are the hydrothermal technique, the
micro-emulsion or the Sol-gel. These methods
have the advantage of producing an
compound with a higher level of purity.
6. Aluminium Oxide
Aluminium oxide exists in many forms,
α, χ, η, δ, κ, θ, γ, ρ; these arise during
the heat treatment of aluminium
hydroxide or aluminium oxy
hydroxide. The most
thermodynamically stable form is
α-aluminium oxide
Basic Raw Material for
many products – moderate
investment
Following projects
(next slides ) are
based on
Aluminium oxide
9. Aluminium Hydroxide - Uses
Aluminium hydroxide has a wide
range of uses, such as flame
retardants in plastics and rubber,
paper fillers and extenders,
toothpaste filler, antacids, titania
coating and as a feedstock for the
manufacture of aluminium chemicals,
e.g. aluminium sulfate, aluminium
chlorides, poly aluminium
chloride, aluminium nitrate.
10. Low Soda
Many applications, particularly in the
electrical/electronic areas, require a
lowlevel of soda to be present in the
aluminum oxide. A low soda alumina
is generally defined as with a soda
content of <0.1% by weight. This can
bemanufactured by many different
routes including acid washing,
chlorine addition, boron addition, and
utilisation of soda adsorbing
compounds.
11. Reactive ALUMINA
“Reactive” alumina is the term normally
given to a relatively high purity and
small crystal size (<1 μm) sample which
sinters to a fully dense body at lower
temperatures than low soda, medium
soda or ordinary sodas.
These powders are normally supplied
after intensive ball milling which breaks
up the agglomerates produced after
calcination. They are utilised where
exceptional strength, wear resistance,
temperature resistance, surface finish
or chemical inertness are required.
12. Tabular
Tabular aluminum oxide is recrystallised or sintered αalumina,
so called because its morphology consists of large, 50500
μm, flat tablet shaped crystals of corundum. It is produced by pelletising, extruding,
or pressing calcined alumina into shapes and then heating these shapes to a
temperature just under their fusion point, 1700-1850 ºC in shaft kilns.
After calcination, the spheres of sintered alumina can be used as
they are for some applications, e.g. catalyst beds, or they can be
crushed, screened and ground to produce a wide range of sizes.
As the material has been sintered it has an especially low
porosity, high density, low permeability, good chemical
inertness, high refractoriness and is especially suitable for
refractory applications.
13. Fused
Fused alumina is made in electric arc
furnaces by passing a current between
vertical carbon electrodes. The heat
generated melts the alumina. The furnace
consists of a water cooled steel shell and
320 tonne batches of material are fused at
any one time. The fused alumina has a high
density, low porosity, low permeability and
high refractoriness. As a result these
characteristics, it is used in the manufacture
of abrasives and refractories.
14. High Purity
High purity aluminas are normally
classified as those with a purity of
99.99% and can be manufactured by
routes starting from Bayer hydrate using
successive activations and washings, or
via a chloride to achieve the necessary
degree of purity
Applications include the manufacture of synthetic gem
stones such as rubies and yttrium aluminium garnets
for lasers, and sapphires for instrument windows and
lasers.
15. Flame retardants used in textiles
Flame Retardant are substances that can be chemically
inserted into the polymer molecule or be physically
blended in polymers after polymerization to suppress,
reduce, delay or modify the propagation of a flame. There
are several classes of flame retardants; Halogenated
Hydrocarbons (Chlorine and Bromine containing
Compounds and reactive flame retardants), Inorganic
flame retardants ( Boron Compounds, Antimony oxides,
Aluminium Hydroxide, molybdenum Compounds, zinc and
magnesium oxides ), Phosphorous containing Compounds
(Organic Phosphate Esters, Phosphates, halogenated
phosphorus Compounds and inorganic phosphorus
containing salts).
16. Market
• The increasing demand for antacids is one of the
key factors expected to fuel the market’s demand
in the forthcoming years. Antacids are
increasingly being used to treat chronic conditions
including GERD. GERD is often caused by the
backflow of stomach contents including gastric
acid into the esophagus.
• The use of antacids including aluminum hydroxide
gel powder offers quick relief from heartburn
caused by gastroesophageal reflux disease and
indigestion, in turn, increasing its demand in the
pharmaceutical preparation
17. Ultra-fine Aluminum
Hydroxide
Ultra-fine Aluminum Hydroxide (ATH) is a kind of
aluminum hydroxide and it has many unique properties
of resistance to high temperature, wear resistance,
corrosion resistance and high thermal conductivity. It
is mainly used as flame retardants and fillers in
thermosetting plastics and liquid dispersions.
Europe is the dominate producer of Ultra Fine Aluminium
Hydroxide, the production is 190066 MT in 2015, according for
about 39.73% of the total amount, followed by China, with the
production market share of 23.27%. China has the highest
production growth rate of 6.07% from 2011 to 2015. Even
though a huge space for growth in the Chinese market exists,
the quality and technology should further improve.