The abrasives industry is an
important consumer of industrial minerals; however, they
compete with a variety of other inorganic and organic abrasive
There is a wide choice of these
abrasive materials and their selection is based on the end use
application combined with the hardness, chemistry, particle
size, and grain shape of the abrasive material.
For example, pumice blasted at a
ships rusted hull just would not do the job, while steel
shot sprayed on denim garments would render them denim ribbons
very quickly. Switch around the abrasives, and then one will
find that they are ideally suited for the respective
applications. It is often a case of horses for courses.
Close-up of VV Mineral beach sand sourced
garnet, Tamil Nadu, India, which is exported
worldwide as a blasting abrasive.
In this article it is blasting abrasives which are the focus.
This is one of the key abrasive market sectors, and one which
uses relatively coarse particle sizes (12/20 and 30/60 mesh
sizes) and loose abrasive grains. Other loose grain abrasive
markets include the more precision-based polishing and lapping
sectors, which use much finer particle sizes, and the growing
use of waterjet cutting.
The other key abrasive market
sectors are bonded abrasives (a mixture of abrasive grains,
fillers, and bonding materials, eg. grinding wheels), coated
abrasives (abrasive grain bonded to a backing material, eg.
sandpaper), and superabrasives (grinding, polishing, or
dressing tools manufactured using diamond or carbon boron
According to a report published by
Market Technology Publications (MTP) in 2009, The Abrasives
Industry in Europe and North America, the total market for
loose, bonded, coated, and superabrasive products in the
European Union in 2008 was valued at about 3.4bn. Germany
is the largest market in the EU, with about 27% of the
The report considers that the
overall total market is expected to shrink to around
2.9bn. in 2010 and then resume slow growth.
Another report, World
Abrasives, published earlier this year by The Freedonia
Group Inc., forecasts that global demand for abrasive products
is to climb 5.9% annually through 2013 to $38.2bn.
Advances in developing parts of
Asia, the Africa/Middle East region, Eastern Europe and Latin
America are expected to considerably outperform demand in the
USA, Western Europe, and Japan.
China, India, and Russia are
anticipated to post some of the biggest sales gains. China,
which has surpassed the USA as the largest national market for
abrasives, will account for two-thirds of all additional
product demand through 2013.
Anne Williams, marketing manager of
leading silicon carbide and fused alumina producer Washington
Mills Electro Minerals Corp., USA, told IM:
The market was down in 2009 but is recovering in 2010. We
expect the market to continue to improve. The industry of
pressure blasting is largely dependent on the strength of the
manufacturing sector in general, such as in automotives and
V. Subramanian, managing director,
of Indias largest garnet supplier, VV Minerals Ltd
explained to IM: The sand blasting
market is doing well for us. Though the US market is showing a
very slow recovery, the Middle East is still strong in sand
blasting abrasive consumption. This is mainly due to many of
the oil companies starting to revive projects which were on
hold during the recession.
One of VV Minerals classification plants at its
Tamil Nadu, India beach sand operation.
The company sells some 70-75,000 tpa of
blasting grade garnet.
The blasting market
According to MTP, blast cleaning and related abrasive material
use in the EU is in excess of 850,000 tpa, worth approximately
285m. However, this figure also includes about 175,000
tpa of steel and cast iron abrasives.
This shows the relative
competitiveness of alternative materials to abrasive industrial
minerals. The accompanying table outlines the main industrial
minerals used in blasting, and also the metallic and other
Although the end use and physical
and chemical properties of abrasives are key to their
selection, cost, efficiency, and availability are also
There are very few commercial
sources of garnet worldwide - Australian, Indian, and US
garnets are the major ones that trade globally (see US
garnet panel) - while there are even fewer for emery,
olivine, and staurolite.
Synthetic industrial mineral
abrasives such as fused alumina and silicon carbide are much
more expensive than natural abrasive minerals (broadly
speaking, natural mineral abrasives up to $200/tonne, while
synthetic grades are >$700/tonne).
Therefore, alternative media such
as coal slag, copper slag, iron grit, steel shot, and crushed
glass, which are cheaper, much more readily available, and some
of which tick the green box of potential recyclability as
abrasives, can be more attractive to end users.
Another issue has been the move to
using more silica free abrasives. However, the adherence to
silica bans and reduction of use of certain slags owing to
environmental concerns is less strictly enforced in certain
Commenting on alternative
materials, V. Subramanian, said: Copper slag, though it
is banned in many places, is still being used in most dry
docks, due to the large volumes and very low price that
manufacturers are dumping in the market. Coal slag is also a
popular abrasive, mainly in Europe, but it tends to leave a
coating/residue on the surface compromising the quality of the
Raymond Ding, managing director, of
Chinese garnet producer Wuxi Ding Long Co. Ltd, commented to
IM: For China, the domestic sandblasting
market is very limited. The existing market has been dominated
by copper slag due to its very cheap price and there being no
strict government regulation on pollution control. The main
competitive abrasive media is still slag such as copper slag
and nickel slag. Of other natural minerals, maybe olivine sand
is a potential one in the future.
The upshot is that metallic slags
and coal slag have a market only because of their very low
price when compared to garnet. Garnet is still claimed by
producers as the only natural eco-friendly abrasive which is
inert and safe for the environment.
We do see steel slag as a new
entrant and we are yet to see how the market responds to this
material. added Subramanian.
Blasting abrasive applications
|End use sector
|Shipbuilding and maintenance
||shipyards for blasting coatings and stubborn mill
scale and rust. Navy contracts very significant, eg.
vertical launch systems, superstructures, fibreglass
hulls, hangar decks, tank work and aluminium
|Industry, infrastructure cleaning
||various industrial structures like tanks, and
superstructures such as bridges, also stone and concrete
|Oil & gas industry
||rigs, platforms, pipes
|Specialist industrial tasks
||more precise blasting required in blasting rooms and
for heavy equipment cleaning (eg. construction, military
vehicles); abrasive usually recycled; often utilising
non-ferrous abrasives where aluminium surfaces, sensitive
substrates, or installed electromagnetic components
preclude the use of metallic abrasives.
||use of soft abrasives to achieve desired
The silica issue
For many years, one of the primary blasting abrasives was
silica sand. However, owing to its threat as a health hazard in
causing silicosis its use has declined dramatically in recent
Today, most blasting abrasives need
to demonstrate a free crystalline silica content of <1-1.5%
SiO2. Thus the term sand blasting refers
to sand in the sense of the particle size of the
material rather than silica sand itself.
However, there are parts of the
world where silica sand remains the top abrasive of choice.
This is the case in India where silica sand sourced from
alluvial deposits is widely used in the treatment of garments,
such as stonewashing denim jeans.
Indian media reports claim there
are some 100 factories using silica sand in this application,
with medium sized operations consuming 2,200 cu ft of river
sand each month.
Previously, this Indian market had
been outsourced to Turkey, but that country banned silica sand
in this application in March 2009.
Some Indian garment companies are
now using alumina abrasives instead of silica, but the
investment in protective clothing and other measures is a major
Clearly, the overall phase out of
silica sand as a blasting abrasive has created market
opportunities for other mineral abrasives and also alternative
Abrasives are used in an enormous variety of blast cleaning
applications, from architectural restoration to marine hull
cleaning. Each application favours a particular abrasive
material for its cost efficiency and desired end result of the
The latter will be influenced by
the abrasive particle size, shape, and hardness. The
accompanying table illustrates some of the main applications
for blasting abrasives.
The driver behind the blasting
abrasives market is the essential requirement for proper
surface preparation prior to any repainting or coating of
industrial (and domestic) surfaces. In general, premature
failure of a protective coating system is caused by improper or
sub-standard surface preparation. One of the most effective
methods of surface preparation is abrasive blast cleaning.
For large, industrial scale
cleaning uses, where high iron content abrasives can be
accepted, then much of the metallic abrasive media such as the
slags and shot are used.
But if non-ferrous media is
required, and also there is some care to be taken over avoiding
damage to the structures substrate, then some of the
industrial mineral abrasives will be favoured.
For more sophisticated blasting
applications, eg. for specific components or small surface
areas requiring very hard abrasives, then more expensive
synthetic mineral abrasives like fused alumina and silicon
carbide are applied in special blasting rooms where spent
abrasive material is recycled.
Although brown fused alumina is
>$700/tonne FOB (and white fused alumina around double), it
is one of the hardest abrasives on the market (only silicon
carbide is harder), it is relatively light, and can be recycled
Fused alumina is used in specific
industrial uses such as cleaning engine heads, valves, pistons
and turbine blades in the aircraft industry, to lettering in
monument and marker inscriptions. It is also commonly used for
The hardest mineral abrasive is
silicon carbide, and can cost >1,500/tonne CIF UK.
Silicon carbide has a very fast cutting speed and can be
recycled and reused many more times than other abrasives. The
hardness of silicon carbide allows for much shorter blast times
relative to softer blast media.
Silicon carbide grit is the ideal
media for use on glass and stone in both suction or siphon and
direct pressure blast systems.
Washington Mills Electro Minerals
Corp. is the largest manufacturer and supplier of silicon
carbide and fused alumina (both white and brown) to the
abrasive blasting industry in North America.
Anne Williams, marketing manager
Washington Mills told IM: Brown
aluminium oxides high
durability means that it can be used on multiple passes through
the pressure blasting machine, thus increasing its efficiency
as a blasting material. White fused aluminium oxide is higher
purity than brown and the grains are more friable. It is used
in applications where surface contamination is unacceptable
such as cleaning medical devices or electrical circuit
At the other end of the scale is
corn cob, an organic biodegradable blast media that will not
etch or warp the surface being blasted. Corn cob is suited for
applications such as wood surfaces, eg. in log homes, and thin
metals and plastics.
||Mohs hardness (1, talc -10, diamond)
||naturally occurring corundum (alumina) with
||almandine and andradite varieties used
||used more in waterjet cutting
||stonewashing clothes use
||byproduct of minsand operations
|Brown/white fused alumina
|synthetic; specialist use in blast rooms;
||synthetic; specialist use in blast rooms;
||aluminosilicate waste from coal fired power
||ferrosilicate; fast cleaning rates
||made from alloy-free iron scrap; recycled
||high density, high productivity
||very durable, low friability
|used as absorbent and abrasive; soft abrasive
||no detectable silica
|made from recycled glass
|eg. polyester, melamine; non-aggressive; used where
underlying substrate cannot be damaged
|common soft abrasive
Garnet, which can be sourced from hard rock deposits (more
angular) or alluvial deposits (more rounded), is one of the
most popular natural mineral abrasives used in blasting
applications. Particle sizes used are mostly the mesh sizes
12/20, 20/40, and 30/60, ranging 250-1,700 microns.
Compared with fused mineral
abrasives, garnet is far cheaper, eg. Chinese blasting grades
(hard rock) are $185-195/tonne FOB Chinese main port; and those
from India (alluvial) are 12/20 mesh, 270/tonne, 20/40
mesh, 220/tonne, and 30/60 mesh, 165-190/tonne all
FOB Tuticorin. Generally, Indian coarse grades are more
expensive owing to their tight availability.
Advantages in using garnet include:
a wide range of grades and composition available for different
uses and profiles; garnet grains create a uniform profile
virtually free of embedment, providing an excellent surface for
coating adhesion; cost-effective, highly effective with low
consumption; non-toxic; inert; non-porous, will not draw
moisture; recyclable up to five times; and low dust levels.
The mineral also has important
markets in water filtration and waterjet cutting.
Although there are relatively few
commercially developed garnet sources, garnet is traded
worldwide, and certain players, such as Opta Minerals Inc.,
Canada, and GMA Garnet Group, Australia, have been very active
in establishing processing and distribution plants in North
America and Europe for their imported material.
This year was a significant one for GMA Garnet. The
groups Chinese subsidiary, GMA Garnet (China) Ltd
commenced production at Rizhao, Shandong, where it operates a
mine and 24,000 tpa garnet processing plant. The plant produces
standard sand blast and waterjet grades, and will also produce
a 20/40 mesh grade product for particularly thick sand blasting
In Italy, GMA opened its upgraded
Garnet Reprocessing & Recycling Plant on a new site in
Aulla, Pallerone, the plant was previously located in Follo, La
The Italian plant, operated by GMA
Garnet (Europe) GmbH, will reprocess 15,000 tpa of used garnet
from blasting and waterjet applications and has the capacity to
upgrade production in line with demand.
In the USA, GMA Garnet Group opened
a loose bulk handling and packaging facility in Fairless Hills,
Pennsylvania, as a vital staging ground in the groups
distribution network for North America.
The facility receives approximately
10,000 tpa loose bulk shipments of GMA garnet shipped directly
from Geraldton, Australia, which after processing, is
distributed to waterjet and sandblast customers in the East
Coast, Upper Mid West and Eastern Canada regions.
Elsewhere in the USA, GMA has
established warehouses in Los Angeles, San Francisco, Phoenix,
US garnet market 2009 (tonnes)
|Sold by producers:
|Imports for consumption:
||Emerald Creek Garnet Ltd., Idaho (WGI Heavy Minerals
||Barton Mines Co. LLC, New York
||NYCO Minerals Inc., New York
||Ruby Valley Garnet LLC, Montana
||Opta Minerals Inc. (Canada/USA locations)
||GMA Garnet Group, Perth, Australia (US
Sinogarnet pursues Japan
In China, Wuxi Ding Long Co. Ltd, which produces 6-7,000 tpa of
various blasting grades at Wuxi, Jiangsu, is seeing its 20/40
mesh grade perform well in export markets, especially in Japan,
owing to its relatively large grain size range and lower price
compared to Indian and Australian alluvial garnet.
After so many years mining,
the Indian and Australian alluvial garnets are short of coarse
grades said Raymond Ding, managing director, Wuxi Ding
Long Co. Ltd.
VVM eyes Middle East
Indias leading garnet supplier is VV Mineral (VVM), which
has mine and plant operations in the Tirunelveli district in
Tamil Nadu, India.
VVM, and sister company Transworld
Garnet India, sell about 70-75,000 tpa of blasting abrasives of
which 25,000 tpa goes to the UAE, 10,000 tpa to Saudi Arabia,
20,000 tpa to the USA, 15,000 tpa to Malaysia/Singapore, and
5,000 tpa to Europe.
VVM is witnessing strong demand
from the revived oil industry in the Middle East. V.
Subramanian, managing director, VV Minerals Ltd told
IM: We foresee the demand will grow
further in the coming months and we are already in the process
of planning our next expansion ready to cater the growing
Some of our Australian Garnet competitors are running
short of coarse grades required for the sand blasting industry,
which automatically puts the Indian manufacturers in a much
stronger position. Subramanian added.
US import sources 2005-08
(2009 imports 41,100 tonnes)
US consuming markets 2009
Annual world production in 2009
(rounded total 1.4m. tonnes)
Source: adapated from data from USGS.