Vietnam is aiming to develop its domestic
refractories industry to serve its burgeoning
aluminium and steel sectors
Vietnam hosts abundant mineral resources, including barytes,
bauxite, and clays. In addition, the country has significant
resources of industrial minerals suitable for use in the
foundries and refractories markets, which are discussed
The results of geological
investigation and exploration within Vietnam found many mineral
resources suitable for use in the metallurgical industry. Some
of these can be used directly in the process of steel
production, while others are used to manufacture the
In order to meet the developmental
requirement of Vietnams aluminium and steel industries in
the coming years, the investment to strengthen the exploitation
of refractory minerals and production of a refractory base is
more pressing than ever.
In this article, we wish to deal
with the main mineral resource groups discovered in recent
times as well as the strategic aim of refractory industrial
development in Vietnam out to 2020.
Silica refractory group
Mineral resources that have the chemical formula RO2
such as silica (SiO2) and zirconia
(ZrO2), are used for manufacturing acid-based
refractories that are consumed by acid slag furnaces. Bricks
manufactured from quartzite come under this group and require
large amounts, around 8.5 kg per tonne of steel.
Diatomite, a mineral essentially
composed of the siliceous remains of marine phytoplankton
(diatoms), is also used for this purpose (its melting point is
Zirconium is very much preferred in
the manufacture of crucibles, fire bricks and sparking plugs.
The crucibles that contain zirconium can withstand a
temperature of over 2,500oC.
Many quartzite deposits have been discovered in North Vietnam,
of which the Don Vang in Phu Tho province is the best quality
(97-98% SiO2) used for production of refractory
bricks at Thai Nguyen Iron and Steel Co.s plant since the
The Xuan Hong quartzite in Ha Tinh
province has a melting point of 1,730oC and is
suitable for production of bricks and ceramics. Especially in
Tinh Gai and Dong Son districts (Thanh Hoa province) there are
some quartzite (sandstone) occurrences with 90-95%
SiO2, occurring in the form of large boulders on the
land surface, that may be mined and directly used.
Up to now, there have been 24
quartzite deposits evaluated with a total reserve of 272m
tonnes. There are some large deposits such as the Lang Lai of
131.5m tonnes, the Don Vang at 31m tonnes and the Xuan Hong at
15m tonnes which will be important material sources,
highlighted to supply the steel complexes being constructed in
Ha Tinh and Lao Cai provinces.
In Vietnam, 33 deposits of ilmenite and zircon have been
identified with total reserves of 30.919m tonnes, of which
zircon is 1.030m tonnes. Some coastal placers of high zirconium
content are the Ky Khang, Ha Tinh province (65,500 tonnes) with
zirconium content of 18-18.5 kg/m3; the Quang Ngan,
Thua Thien - Hue province (48,700 tonnes) with zirconium
content of 12.2-13. 44 kg m3; the Cat Khanh, Binh
Dinh province (32,055 tonnes) and the Ham Tan, Binh Thuan
province (442,200 tonnes) with zirconium content of 2.0-56.7
The exploitation of zirconium ores
is concentrated mainly in Ha Tinh, Thua Thien - Hue and Binh
Dinh provinces, with production from 10-20,000 tpa.
Some state-ranked projects carried out in 1990s have clearly
outlined the distribution and potential of diatomite deposits
in the Phu Yen, Kon Tum and Lam Dong provinces in South Central
and Highlands (Tay Nguyen) of Vietnam.
The diatomite deposits in Tuy An
disctict, Phu Yen province (South Central) distribute in four
areas, namely Hoa Loc, Tuy Duong, Trung Luong and Tra Rang with
total reserve of about 90m tonnes, of which the Hoa Loc is the
largest with a reserve of 61m.m3 (about 50m
Mined ores are milled to a grain
size of <0.2 mm and heated at a temperature range of
800-1,000oC. The resulting product has a chemical
composition of 73.8% SiO2, 13.02%
Al2O3, 1.10% Fe2O3,
and 0.04% TiO2, and is used to manufacture products
for heat insulation, light aggregates, hydraulic cement, and
fire bricks; as well as filters, absorbents, rubber additives,
soaps and insecticides etc.
Alumina refractory group
The alumina materials group consists of fire clay, fire kaolin
and high alumina refractories. They are used for the
manufacture of chamottes brick, which are stable for all acid
and basic slags and are the most used materials in
In the Tuyen Quang and Hai Duong provinces, the fire clay
deposits can be used to produce refractory bricks of A and B
grade chamottes. The Tuyen Quang clay deposit in Tuyen Quang
province, with a melting point at 1,690-1,730oC, has
been mined since the 1930s by the French.
The Truc Thon in Hai Duong
province, with a reserve of 9.4m tonnes, has been exploited for
many years - supplying raw materials for the production of
refractory bricks and ceramics. The three main clay types are:
1) fire clay soil, grading ³26%
Al2O3; 2) white clay soil, grading
³17-26% Al2O3, with plasticity of
14-19 and whiteness of 45.5%; and 3) chamottes to make
different refractory grades, including grade I (³30%
Fe2O3, melting point of
1,650oC) and grade II (³28%
Fe2O3) with moisture absorption for both
grades at ²8%.
Along left side of the Red River, from Lao Cai to Son Tay
(about 220 km), there are many kaolin deposits of good quality
that could be used for the manufacture of high grade porcelain,
electric porcelain, refractory materials and fillers. These
have been prospected in detail and mined.
Kaolin in the Dinh Trung (Vinh Phuc
province), with reserve of 1.2m tonnes, is the product of
weathering from fine grained granite which exhibits a high
degree of plasticity and is especially suitable for manufacture
of chamottes brick.
The Tan Mai pyrophyllite-kaolin
deposit in Quang Ninh province, discovered in 1977 consisting
of many bodies formed by hydrothermal alteration of acidic
eruptive rocks, has very important economic significance.
The quality of the kaolin is rather
stable, has a high alumina content (averaging 38.5%), and has a
low level of impurities present. This kaolin has a
refractoriness of 1,770oC, equivalent to same kind
of kaolin found in China and the Czech Republic, to completely
satisfy the requirement for manufacture of the A grade
chamottes brick. The deposit has a reserve of 45.14m tonnes;
approximately 20% of Vietnams total kaolin reserves.
Pyrophyllite can be divided into
three types, the best of these being of fine-grained and
massive texture; soft, opalescent, greenish and bluish colour.
The content of pyrophyllite mineral can reach 90%, with a
chemical composition of 63.3-68% SiO2, 25.1-28.5%
Fe2O3, 0.4-0.9% TiO2 and a LOI
of 4.8-7.3%. Test results showed that refractory bricks
produced from the Tan Mai pyrophyllite had a quality equivalent
to that of Japan, with applications in the metallurgical and
In the Central region, the A Luoi
kaolin deposit located in the west side of Thua Thien - Hue
province, consists of 19 ore bodies with total reserve of 5.2m
tonnes. It has been mined and the site is home to a kaolin
processing factory which is considered to be the best in
Vietnam. After processing, two kaolin grades are produced -
grade I (Al2O3 content of 32.03%) and
grade II (21.15% Al2O3) with recovery
In the Highland region (Tay
Nguyen), the Ia Knop deposit in Dac Lac province is an
important refractory material source. The kaolins
chemical composition ranges 22.2-34.2%
Fe2O3, with a plastic index of 9-13 and a
refractoriness of 1,700¡C. The reserve of this deposit is
about 3m tonnes.
High alumina refractories
The silimanite group of alumino-silicate minerals, consisting
of silimanite, andalusite, and kyanite (with dumortierite and
mullite being similar in structure), are used in high-alumina
refractories of over 1,800oC. Kyanite is usually
finely ground and mixed with fire clays to increase the
refractoriness of the brick. Kyanite, together with andalusite,
may be used for making spark plugs for internal combustion
In North Vietnam, kyanite has been
found in Thanh Son district, Phu Tho province and in Quy Hop
district, Nghe An province. The Thanh Son kyanite comprises
(after gravity and magnetic beneficiation) 53.52%
Al2O3, 40.65% SiO2, 2.23%
Fe2O3, 1.12% CaO, and 0.20% MgO. The
deposit has a reserve of 60,000 tonnes.
Material from this deposit was
successfully tested in the manufacture of high-alumina
refractory bricks from the Tan Mai kaolin (Quang Ninh province)
mixed with Thanh Son kyanite.
In South Vietnam, the Hung Nhuong
silimanite occurrences in Son Tinh district, Quang Ngai
province lie in four bodies in association with graphite. The
average content is 27-29% Al2O3,
1.03-3.38% Fe2O3, and with total reserves
of 105,500 tonnes.
The magnesia material group is used for making alkaline
refractories, applied in the basic slag heating zone of kilns.
The minerals have formula of RO, largely represented through
magnesia (MgO) which is sourced primarily from magnesite
Other alkaline bricks are
manufactured from similar mineral resources such as dolomite,
serpentine, chromite and so on. The demand for alkaline
refractories in industrial sectors is not as large as other
compositions, but the high refractoriness of 2,800oC
makes these products irreplaceable in certain applications -
such as the heating zone of cement rotary kilns and basic steel
Magnesite ore was discovered recently in the Ban Phung, Son La
province in 1995 and in the Kon Queng, Gia Lai province in
2005. Although the deposits do not have large reserves, they
can meet the requirements of alkaline refractories and aid the
development of Vietnams steel industry.
Ban Phung deposit: Preliminary exploration of a 4
km2 area has highlighted a probable reserve of more
than 1.2m tonnes magnesite. The ore belongs to the
metasomatic-genetic type from ultramafic rocks, with the main
minerals being magnesite-quartz accompanied by
From processed ores, the refractory
plant of Thai Nguyen Iron and Steel Co. has successfully
manufactured magnesia bricks grading 89.87% MgO, 3.51% CaO,
1.65% SiO2, 0.5% Al2O3, and
By using suitable technology, Ban
Phung magnesite can be used to manufacture magnesia bricks of a
quality equivalent to imported Russian bricks (GOST -
Kon Queng deposit: The Kon Queng magnesite deposit was
discovered in 2005 in Kon Chro district, Gia Lai province
(Highlands). The total reserve is estimated at 14.782m tonnes,
of which proven reserves are 6.1m tonnes.
The ore belongs to
hydrothermal-metasomatic type from dolomite, seen as the most
promising magnesite type in the world. An average content of
the ores is 42.12-43.04% MgO, 0.95-1.90% CaO, 1.74-2.74%
SiO2, 3.8% Fe2O3, and 0.01%
Good quality ore can be
beneficiated and used for refractory materials, and also may be
used for making monolithics for linings in steel and cement
Dolomite deposits occur in many locations in north-east,
north-west Bac Bo, Central Vietnam (Trung Bo) and in some areas
of the Highlands (Tay Nguyen). In Vietnam, 17 deposits have
been evaluated with total reserves more than 1.8bn tonnes, of
which the biggest is the Ban Chanh in Hoa Binh province with
The two main deposits being
exploited by Thai Nguyen Iron and Steel Co. are Ngoc Long,
Thanh Hoa province and La Giang, Thai Nguyen province, with
current production at about 50,000 tpa. The refractoriness of
Ngoc Long dolomite is 1,780oC and La Giang is
During 1970-1980, when Vietnam was
not exploiting magnesia raw materials, the Gia Sang steel
laminating plant of Thai Nguyen Steel, successfully developed
alkaline refractories based on dolomite and coke oil. These
products were used in the lining of two furnaces at the plant
and for welding and repairing the wall of another
Five serpentine deposits that have been explored are Bai Ang
(Thanh Hoa province), Xom Quyt (Hanoi), Suoi Can (Son La
province), Thuong Hoa (Yen Bai province) in North Vietnam and
Lang Hoi (Quang Nam province) in South Vietnam with total
reserves of 41.3m tonnes, but up to now only the Bai Ang has
The chemical composition of Bai Ang
serpentine is 32.42-35.54% MgO, 38.96-40.82% SiO2,
1.25-1.37% Al2O3, 7.41-7.46%
Fe2O3, 0.4-1.07% Ni.
The Bai Ang serpentine deposit has
a reserve of 15m tonnes and 25-30,000 tpa is exploited for
thermo-phosphate fertiliser plants. Test production of
periclase-forsterite brick from Bai Ang serpentine has also
obtained very good results.
In Vietnam, chromite was first found in Co Dinh, Thanh Hoa
province in 1927 and exploitation started in 1930 by the
French. Rather than being in lump form, the ore occurs in
sandy, granular (placer) grades. The majority of the chromite
grain size falls between 0.07-0.7mm, which is very favourable
for refractory production.
Test results have shown that the
chrome-magnesia bricks manufactured from the Co Dinh chromite
ore always meet quality standards, and correspond to some brick
grades of Austria, the Czech Republic and Russia.
The Co Dinh chromite deposit has a
total reserve of 21.5m tonnes, accompanied by 3m tonnes of
nickel (Ni) and 281,000 tonnes of cobalt (Co). Vietnam stands
in the top ten chromite resources of the world.
Vietnams refractory industry to
In the 1960-70s, the refractory plant of Thai Nguyen Steel used
Don Vang (Phu Tho province) quartzites for manufacturing bricks
(SiO2 ³93%) for repairing the coke refining
furnaces, with output totaling about 3,000 tpa.
In 1980-90s, the chamottes brick
and mortar occupied up to 80% of Vietnams refractory
production; mainly from the Cau Duong plant (Hanoi), the Tam
Tang plant (Bac Giang province) and the refractory plant of
Thai Nguyen Steel.
Now, in Vietnam, there are three
foundations of refractory production: the Thai Nguyen
refractory joint stock company, Cau Duong refractory company
and Tu Son alkaline refractory factory.
The Thai Nguyen refractory joint
stock company is the leading producer with an output of
60-65,000 tpa fire brick and mortar. The products of A and B
grade chamottes brick, high-alumina brick with
Al2O3 content from 45-80% and
magnesia-carbon brick supply many sectors such as metallurgy,
cement, chemicals, ceramics and glass etc. The products also
have been exported to some Asian countries such as South Korea,
Taiwan, Japan and Indonesia.
The Cau Duong refractory joint
stock company in Dong Anh district, Hanoi, was established in
1959 and has a capacity of 20,500 tpa of A and B grade
chamottes brick; 6,000 tpa of high-alumina brick with
Al2O3 content from 48-85% and 2,500 tpa
of heat insulation spongy brick, fireproof mortar and chamottes
grids. The companys products have been approved by the
Vietnam standard TCVN 4710 - 98 and European standards.
The Tu Son alkaline refractory
plant in Bac Ninh province, built in 2001, produces the
magnesia-spinel and magnesia-carbon bricks, tamping material,
stone powder and fireproof mortar attaining international
standards (alkaline refractory material).
The plant output reached 7,250
tonnes in 2007, of which the brick used for cement rotary kilns
was 6,376 tonnes, 378 tonnes for steel blast furnaces, and 495
tonnes for tamping material.
The total output of Vietnamese
refractory materials in recent years has ranged in 95-100,000
tpa, consisting of three main products: chamottes,
high-alumina, and alkaline bricks.
The development of Vietnams
iron and steel industry to 2020 and vision to 2025 will see the
exploitation of the iron deposits at Tien Bo (Thai Nguyen
province) with a total reserve of 24.2m tonnes. In addition,
iron deposits will be developed at Quy Xa (Lao Cai province)
with 116.2m tonnes of reserves, and Thach Khe (Ha Tinh
province) with a total reserve of 544m tonnes and an average
content of 58.04% Fe (this project envisages an initial
production of 5m tpa iron ore).
Iron ore from Thach Khe deposit
will be supplied for the Ha Tinh Steel Complex with a capacity
of 4.5m tpa.
The development aim of
Vietnams steel industry to 2025 is as following:
- To 2020: production
attaining 8-9m tonnes pig iron;
- To 2025: production reaching
10-12m tonnes pig iron.
To meet the demand for refractories
within metallurgical sector and others, the target to 2020 is
as follows: chamottes production growing from 560,000 to
630,000 tpa; silica-based bricks production growing from 68,000
to 76,500 tpa; and alkaline refractories production climbing
from 148,000 to 156,500 tpa.
The target aims for total
refractories production to grow from 776,000 to 854,000
In order to guarantee sufficient
supplies of refractories to Vietnams steel complexes in
Ha Tinh province and Lao Cai province, and expanded to the Thai
Nguyen Steel complex in Thai Nguyen province, we request
foreign investors to strengthen the domestic refractories
industry; focusing mainly in the alumina and alkaline groups,
the raw materials of which exist abundantly in Vietnam.
The deposits that show most promise
for development include the Tan Mai pyrophyllite-kaolin in
Quang Ninh province, the Son Man kaolin in Lao Cai province,
the Thuong Hoa serpentine in Yen Bai, the Ban Chanh dolomite in
Hoa Binh province, the Co Dinh chromite in Thanh Hoa, the Xuan
Hong quartzite in Ha Tinh province, and the Kon Queng magnesite
in Gia Lai province.
The mineral resources that can be
used for refractories production are abundant in Vietnam, and
more refractory materials will be needed over the coming years.
With a new, amended mineral law that came into effect on 1 July
2011, more favourable conditions exist for foreign
Contributor: Dr Tran Kim Phuong, Vietnam Institute of
Geosciences and Mineral resources (VIGMR), Thanh Xuan, Hanoi,
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4, pp.195-206, Vietnam Institute of Geosciences and Mineral
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Tri. 1983. Mineral resources of Vietnams north
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Ngo Van Minh. 2005. Geological
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