|LED lighting is
expected to be an area of growth which will increase
demand for high purity alumina. According to LED
Lighting’s Global Outlook, demand is
expected to reach 4.1bn lamps in 2025, from 864m lamps in
High purity alumina (HPA), or aluminium oxide with a minimum
purity of 99.99% (4N) Al2O3, is a high
value speciality product with a broad range of uses. The
material is most commonly turned into synthetic sapphire for
use in LEDs, semiconductors, phosphors and lithium-ion (Li-ion)
batteries, among other markets.
HPA is produced on an industrial scale via the Bayer refining
or Hall-Heroult smelting techniques used to turn bauxite into
alumina, followed by hydrolysis of aluminium alkoxide.
Alternative methods are thermal decomposition and the water
Australia’s Altech Chemicals Ltd is attempting
to shake up the HPA industry by producing the material directly
from kaolin clay and is hoping to start commercial production
Total HPA demand, according to Altech, was around 19,040
tonnes in 2014 – a figure which the company expects to
Altech estimates that continued expansion in the Li-ion
battery market could see HPA consumption in this sector alone
rise from around 1,000 tpa today to around 15,000 tpa by 2025.
This forecast hinges on a recent bullish scenario prediction by
Deutsche Bank that Li-ion battery usage will rise from 70
GWh/year in 2015 to 535GWh/year by 2025.
The major application of HPA in Li-ion batteries is as a
coating on the ceramic separator sheet that divides the cathode
and anode electrodes within the battery (see Figure 1).
|Figure 1: Structure of a Li-ion
HPA-coated separators improve battery safety by withstanding
unusually high temperature incursions and reducing flammability
during thermal runaway events. They also increase a
battery’s discharge rate, lower self-discharge and
lengthen battery life cycles. These advantages have prompted an
increasing number of manufactures to use HPA in their
But while the Li-ion batteries show significant growth
potential, it is the LED market which currently accounts for
the largest share of HPA demand and this too is expected to
require higher volumes in the near future.
If Altech’s demand estimates are correct, then
the LED industry currently consumes just under 11,000 tpa HPA.
Around 90% of LEDs use an HPA substrate, so higher LED usage
will quickly boost HPA consumption. However, in this sector,
HPA faces competition from silicon carbide and silicon metal
substrates, which may reduce the pace of volume growth.
According to a 2017 Goldman Sachs report, entitled "The New
Energy Landscape", LED technology’s share of the
global lighting market is expanding and is slated to reach 43%
this year, potentially rising to around 75% by 2020.
The HPA market opportunity
|HPA end markets (%),
Orbite Technologies believes it has a
system which can recycle red
mud, the waste product from
traditional alumina production using the Bayer
process. Red mud has increasingly become both an
environmental and economic liability. it is also a
highly caustic substance which contains
"considerable" amounts of alumina, titanium and rare
earths. According to Orbite, around 3bn tonnes of red
mud are stored in ponds around the world with no
viable alternative to re-use the material and 120m
tpa is produced globally. In 2010 the collapse of
MAL’s red mud tailings reservoir at the
Ajka plant in Veszprem (pictured) left nine people
dead. (Source: MAL).
In November 2016, Altech signed a 20-year lease agreement
for a proposed HPA plant construction site in Johor, Malaysia
where the company can take advantage of a corporate tax rate of
just 25% to reduce its operating costs. The facility will
produce around 4,000 tpa of 4N (see table) HPA – a
product Altech expects to sell for around $23,000/tonne
– from kaolin sourced from the company’s
Meckering deposit in Western Australia.
Meckering, which holds 1.22m tonnes of reserves and a
further 11.5m tonnes in resources, only needs to be mined at a
relatively slow rate according to Altech – around
42,055 tpa – owing to the alumia-rich nature of the
ore, which averages 29.5% Al2O3 in the
minus 300 micron kaolin fraction.
At the beginning of December last year, Altech submitted a
proposal and a mine closure plan for Meckering which, if
approved, will enable the company to start building the mine
later this year.
It expects to produce finished HPA at an all-in cash cost of
approximately $8,140/tonne, yielding a gross cash margin of
$14,860/tonne. At present, most HPA producers purchase
aluminium sulphate or aluminium metal from which to produce HPA
for around $3,000/tonne, before incurring their own processing
These economics, according to Altech, give the company a
vertically integrated cost advantage on top of having a cheaper
Using kaolin as an alternative alumina source to bauxite is
not a new idea – there was significant research into
this area in the US during the 1940s, spurred by the sinking of
ships carrying bauxite imports during World War Two.
One particularly well-known paper was published in 1946.
Entitled the "Development of a Hydrochloric Acid Process for
the Production of Alumina from Clay", it details the steps
needed to extract alumina from kaolin, as well as the kaolin
properties required for the mineral to be used as an alumina
Since every kaolin deposit is unique and
Altech’s HPA production process has tailored the
principles laid down in the 1946 paper to suit the Meckering
ore. Meckering kaolin is first calcined at 600o C in an
indirect rotary kiln, which converts the clay structure into a
more reactive form. The material is then cooled, ball milled
and screened to a particle size of less than 300
The kaolin is leached with hydrochloric acid, converting all
oxide components, with the exception of silica, to soluble
chlorides. The resulting slurry is sent to a series of reactors
where it is heated and condensed hydrochloric acid vapours are
The leached slurry undergoes a series of filtration steps
before it is crystallised and processed into a filter cake. The
purified cake is then heated in stages to remove impurities,
including any residual acid. The remaining product is a highly
pure alpha-alumina, or HPA.
Altech’s proposed HPA chemical process
Once cooled, the HPA is fed into a grinding mill before
being bagged, stored and dispatched. Altech’s
modernised process allows the company to recapture and recycle
the hydrochloric acid used to leach kaolin, bringing costs down
compared to the original method.
The company’s modernised version of the standard
alumina extraction process is shown in Figure 2.
Because the process of making HPA is well-known, Altech
admits that there is a risk their production method will be
copied, but has reassured its shareholders that it is "probably
5-6 years ahead" of any copycat competition.
Although Altech is confident that it has a head start on
anyone wishing to imitate its HPA process, there are other
businesses that have been independently working on their own
HPA projects for a number of years who could challenge Altech
for new market share.
Orbite Technologies Inc. is a Canadian cleantech company
which has developed a proprietary low-cost process to produce
HPA from a variety of feedstocks, including aluminous clay,
kaolin, nepheline, bauxite, red mud, fly ash and serpentine
residues from chrysotile processing.
Orbite’s kaolin will be sourced from its
Grande-Vallée aluminous clay deposit in Quebec, which
contains an indicated mineral resource of 1.04bn tonnes with an
average alumina concentration of 23.13%. The deposit also
contains rare earths, which Orbite hopes to extract as
The company is looking to produce consistent quality 5N+ (see
table) HPA at a rate of 3tpd from its plant in Cap Chat,
Quebec, this year before ramping up to 5tpd.
Orbite’s HPA processing method has been under
development since 2004 and consists of five stages: feedstock
preparation; leaching; selective extraction of alumina;
calcination; and acid recovery.
Feedstock is prepared by grinding the material into small
particles, before hydrochloric acid is used to leach it at high
temperatures, dissolving all the constituent metals except
Alumina and iron dissolve to form aluminum chloride
(AlCl3) and other metals like ferric chloride
(FeCl3). To extract the alumina, the resulting
leachate undergoes precipitation to remove AlCl3 as
aluminium chloride hexahydrate (ACH), which is then calcined to
The leachate can be further processed to remove hematite,
magnesium, gallium, scandium and rare earths. In January 2016,
Orbite announced that it had conducted preliminary research
indicating that gold recovery from fly ash using its processing
methods is potentially feasible.
Among the advantages Orbite claims for its process are the
ability to recycle red mud, a waste product of commercial
alumina production, although the company will only be able to
put this strategy into practise once its HPA facility is fully
up and running.
HPA can be subdivided into various categories (see table).
HPA in the 5N-6N bracket is commonly used in the liquid crystal
display (LCD) and semiconductor industries in sputtering and
thin film applications, while 4N purities are commonly found in
LEDs, energy storage capacitors and Li-ion batteries, as well
as in decorative and bright-finish applications.
According to Norsk Hydro, a Norway-based producer of high
purity aluminium, 4N8-5N purities are also in demand for Li-ion
battery applications. Norsk Hydro produces HPA via the
traditional bauxite refining process and currently sells its
4N8-5N products into the medical and cosmetic industries.
Orbite has stated that the premium HPA market requires 4N-5N
purities, however Altech believes that the bulk of high-value
demand is in the 4N category and is therefore concentrating on
In 2015, Orbite shipped samples of its 4N8 HPA to customers
for testing and reported positive feedback, but subsequently
upgraded some of its processing methods to achieve 5N5 purity
– samples of which it also sent to customers.
In November last year, it successfully produced ACH, the
precursor to HPA, at a purity of 5N8.
|Figure 3: Global HPA market volume
|Source: Persistence Market Research,
The race is on between Orbite and Altech to lock in
customers for their respective HPA products. In September 2015,
Altech signed a sales agreement with Japan’s
Mitsubishi Corp. for exclusive distribution in the Japanese
market, while Orbite has commenced a number of supplier
If the HPA market grows to the extent these companies
predict, then there should be more than enough demand to
support both operations. Furthermore, successful proof of
concept at a large commercial scale could create a significant
new demand channel for kaolin and, in Orbite’s
case, a way of dealing with the problem of growing stockpiles
of toxic red mud.
HPA Sonics is a third company attempting to break into the
HPA industry with a new patented processing technology. Dr
Frank Ferrer, HPA Sonics owner, contacted IM with details on
"What my process has been able to do is to inhibit
passivation," he said. Ferrer explains that aluminium in a
metallic state has a high affinity to oxidisation, whereby it
loses its "shining metallic reflection" by forming a layer of
aluminium oxide on the meterial’s surface. This
thin layer of Al2O3 inhibits the natural
tendency to be oxidised, and is known as
Ferrer told IM that "the disruption of
passivation" is undertaken by "pitting of the protective film
of Al2O3 […] thus accelerating
and allowing a reaction that normally does not occur to move
"The force used is that of ultrasonics which creates micro
bubbles which form and then collapse (called Cavitation). This
reaction is exothermic in nature thus requiring minimal amounts
of energy to complete the reaction.
"Plus it generates an energy-carrying-hydrogen at a faster
rate than that of electrolysis (one kilo of pure hydrogen in 30
min at a 2Kw energetic expense).
Ferrer goes on to explain why his technique can compete on
price, "as you add three atoms of oxygen to the metallic
aluminium you almost double the total weight of the HPA
produced, thus cutting in half the cost of your aluminium stock
needed to generate one kilo of HPA."
Ferrer also disputes the pricing his competitors use,
claiming that "the Chinese market […] has lowered the
market value of HPA Down to $10/Kg", whereas according to
Altech, pricing is around the $23-25/Kg.
HPA Sonics hopes to commercialise their technique in
|Orbite has produced
HPA from its CapChat plant in Canada. (Source: Orbite