REV.CHIM.(Bucharest) 69No. 8 2018 http:www.revistadechimie.ro 2177Establishing the Optimum Composition of Superaluminous [623829]

REV.CHIM.(Bucharest) ♦69♦No. 8 ♦2018 http://www.revistadechimie.ro 2177Establishing the Optimum Composition of Superaluminous
Refractory Products, Used for Steel Ladle Bubbling
NICOLAE CONSTANTIN1, ILIE BUTNARIU1*, RADU BUZDUGA1, CRISTIAN DOBRESCU1 , MIRON BUZDUGA2
1University Politehnica of Bucharest, Romania, 313 Spl. Independentei, 060042, Bucharest, Romania
2Research and Development Institute for Refractories and Ceramic Products-CCPPR Alba Iulia, 23 Al. I. Cuza, 510193 Alba Iulia,
Romania
It is widely acknowledged by all specialists in the field of ferrous metallurgy that the porous peg of the kit for
injecting inert gases into the steel casting ladle is the weakness of the entire assembly. This is the most
prompted piece due to the thermal shocks that occur when injecting cold gas and the wear and tear and
corrosion caused by disturbances in the steel during the injection process. The porous structure of the peg
considerably weakens the physical properties and widens the surface of metal – refractory material contact
thus enabling the destructive chemical action. In addition, the process of injecting oxygen for cleaning the
metal peg also contributes to the destructive action and the substantial decline in its endurance. All these
considered, it has been decided that the material for producing these items should contain at least 95%
Al2O3 which means using only tabular alumina. As far as the binder is concerned, it has been established that
a liquid chemical binder made of colloidal alumina should be used since this does not considerably diminish
the Al2O3 content of the end product. It is the aim of this paper to bring forward the author’s research
regarding the production of the porous plug using high-alumina refractory materials.
Keywords: ferrous metallurgy ; steel ladle; porous plug ; injecting inert gases; tabular alumina
. Increasing requirements more stringent quality steel
and need for further clues as large eject led to the
expansion of continuous casting technology which, in turn,resulted in an increase in the role and importance of gas
blowing into the pot. [1, 2]. Instilling and gas bubbling into
molten steel pot has the following essential functions thathave changed the role of simple pot of transport equipment
into a true metallurgical complex aggregate:-
Homogenizing the molten metal and the steel bathtemperature equalization over the entire height of the pot,
especially the high-capacity pots;
– Uniform and speedy dissolution of alloying elements in
steel table;
– Mixing with fillers steel desulfurization and
dephosphorisation;
– Purification by improving settlement steel non-metallic
inclusions;
– Decarburization and dezoxidation more advanced [3].With the use of a reduced energy equation and the
Green–Naghdi dissipation inequality, the entropy function
is determined in terms of the Helmholtz free energy andother functions that are known or can be determined for
certain classes of materials with temperature-rate and
strain-rate dependent thermomechanical constitutiveresponse functions [4]. The bubbling of gas in the ladle of
steel is practiced using the system lance or permeable
refractory stopper mounted in the lining of the pot.Regardless of the injection system used, the inert gases
used are argon, nitrogen and to a lesser extent. The blowing
lance the advantage possibility of directing the gas jet inless sensitive areas of the bottom of the pot or sparing
zone enclosures drawer and the possibility of alloying
elements, desulfurization and / or dephosphorisation massmetal bath, but has the great disadvantage that advanced
local causes wear liner pot in the impact zone of gas or
dust that require restoration of the
lining dense, sometimes leading even to its perforation
[5, 6] .For this reason, in the case of a stream of inert gas is
preferred refractory stopper system is mounted in the
bottom of the tundish or, more frequently at the bottom of
the side wall [7].
The main part of the ensemble is, of course, plug porous,
permeable through which the dissemination of the bubble
blowing and causing bubbling bath of liquid steel from theladle. Porous plug – may have different shapes, the most
common being frusta-conical shape and the rectangular
shape of the last with the same size of the refractory bricksconstituting the lining of the ladle to be easily classified
into the masonry. Passing the gas through the permeable
plug is made by several different ways, namely: -Uncontrolled high porosity but refractor; – Porosity directed
(oriented) take the form of channels arranged in different
ways, made by special technology; – Practiced full heightslots stopper; – Gaps between the refractory stopper and
the surrounding wall.
The choice depends on the purpose of the system, the
volume of gas that is injected, the injection, the desired
form of gas bubbles, their size and their desired movement
of the print. Thus, the use of porous plugs uncontrolled gasbubble diameter is smaller and the porous structure of the
material, in all its mass, leading to a sharp decline in
mechanical strength, advanced corrosion due to a largecontact surface steel / refractory slag- and the increased
possibilities of infiltration of steel shutter stopper gas
access routes. The use of plugs with directed porosityallows to obtain high speeds of injection of the beneficial
effects of bubbling or by homogenization, especially in the
case of casting ladles of large capacity. It also plugs withdirected porosity have a better behavior peeling, corrosion
and penetration of liquid steel in the pores. A model
explaining non-monotonic behavior of the overall thermalconductivity (TC) and monotonic behavior of the thermal
expansion coefficient (CTE) at high volume fraction of
diamond particles [8]. To ensure adequate quality, blastingcaps are manufactured from raw materials of high purity
* email: iliebut@yahoo.com

http://www.revistadechimie.ro REV.CHIM.(Bucharest) ♦69♦No. 8 ♦2018 2178oxide refractory. The most used plugs are manufactured
from aluminum trioxide (Al2O3), magnesium oxide (MgO)
or chromium trioxide (Cr2O3) with hydraulic or chemical
bond. Shaping apply to their special technology for
achieving channels.
The corrosion resistance to the penetration of the steel
as the injection of the gas is adjustable pore size. The
diameter of the channels typically directed to porous plugs
is 0.3-1.0 mm, these dimensions to avoid infiltration of steelsurface tension thereof. It should be noted that a
support
best refractory material and a reduction in the tendency tocracking due to thermal shock to which they are subjectedpermeable plugs are caught in a steel shell which allows
attaching the nozzle to jet gas. This guarantee both full gas
passing through the porous plug into the mass of liquidsteel.
Manufacturing assembly for injecting inert gas into the
steel ladle began with the expansion of continuous steelcasting technology which imposed severe conditions
refractory material used. And whilst the injection method
with refractory plug leaky has expanded and hasaccumulated experience in this field were many new
variants of the plug instilling in particular with a view to
improving its quality in order to achieve sustainability biggeroperation. Meanwhile disappeared parts of protective cap
(bushing and plate sealing) today assemblies modern
consisting only of two parts: plug porous and support him,remained necessary for the embedding of masonry bottom
of the pot and to protect his safety. It is interesting that
during appearance a new type of plugs was not limited toolder versions, which are today used in parallel depending
on the objective of the insufflations gases and the working
conditions existing steelworks. Factors determining thechoice of permeable plug are multiples depending on the
effect desired bubbling but especially in the technical
conditions for the production and treatment of steel. It may
include many factors that influences the choice of more or
less permeable plug that:
– Aggressiveness (composition) of steel and slag;
– The temperature of the casting or steel processing;
– Residence time of the steel ladle, ladle factor directly
related to the volume;
– The primary effect desired to obtain (mixing, dissolution
of the alloying elements in the steel inclusions is decanted,the temperature equalization, etc);
– Nature of the gas used (argon, nitrogen, oxygen);
– During the injection of the gas;- Ladle capacity, etc.
Given the multitude of factors that influences both user
and sustainability stopper insufflations gas ladle steelfactors which differ (sometimes essential) from a steel
producer to another, it can be seen from the start that
worldwide manufacturers of refractory materials is thatthey have focused on the preferences of their intended
beneficiaries in finding solutions to technical and
constructive optimal, whether occurring in parallel a widerrange of parts that we recommend to use depending on
specific conditions in the steel mill beneficiary. Plugs with
directed porosity (channels, segments, etc.) have a superiorbehavior peeling, corrosion and penetration steel (followed
by finishing) against uncontrolled porous plugs [9, 10].
Although demonstrated superior strength plugs porositydirected the plug porous steered not disappeared it is
preferred steelworks conditions staple work (one batch
per day or to interrupt work on weekend) because itpresents a greater capacity insufflation and has a small
cost [11]. Regarding refractories used for manufacturing
stoppers for blowing gas permeable ladle, I can make thefollowing findings:
-having the multitude of factors influencing both the
use and sustainability injection assembly
– bubbling factor which sometimes differ significantly
from a steel producer to another, it can be seen from the
start that worldwide manufacturer of refractory materialswhether they turned on preference main beneficiaries,
either in parallel to produce a wider range of parts that we
recommend to use depending on the specific beneficiarysteelworks.
Thus, every company that offers products for all blowing
gas into the steel ladle recommends that its products arebased on different raw materials from sint alumina, tabular
alumina, corundum, magnesite, chromite, etc. In recent
years, with the assimilation of a new technology formanufacturing refractory cast with a chemical binder was
passed to a new stage in the manufacturing of products
for assembly injection of inert gases in the ladle treatmentof steel [12].
New technology has enabled first assembly
manufacturing parts in one piece eliminating thedisadvantage posed by joining multiple joints. At the same
time it successfully is achieving superior characteristics
compared to the normal baseline. It is considered that animprovement in physical and mechanical characteristics
of these products will obtain higher reliability of gas
injection assembly approaching it sensitive to sustainability
which currently presents products manufactured by
renowned European companies.
Experimental part
a)- Raw material
To obtain products that contain over 85% Al2O3, it has
been established to use high purity alumina raw material
that can be purchased from our country. Therefore, thechosen feedstock is the high-alumina burned fire-clay
SA68 A) made by S.C CCPPR S.A from Alba Iulia and (N.T.I.
278/82) tabular alumina produced by S.C ‘Cemtrade S.Afrom Oradea. The characteristics of the raw materials are
presented in table 1.
As far as the granulation is concerned, the following
granulations were used in the form offered by the
producers:
-For fire clay SA 68A – the granulation is < 3.2 mm and
for fine fire clay granulation is < 0.06 mm
-For tabular alumina: fraction between 3.36 and 1.19
mm, fraction < 1.19 mm and a fine < 0.06 mm.
-The materials purchased this way were subjected to a
granulometric analysis on site and as a result the following
data was obtained.
Table 1
PHYSICO-CHEMICAL CARACTERISTICS OF
THE FEEDSTOCK

REV.CHIM.(Bucharest) ♦69♦No. 8 ♦2018 http://www.revistadechimie.ro 2179When establishing the gratings, we took into account
the chemical composition in order to produce items with
a minimum of 85% Al2O3 as well as the grading in order to
obtain maximum output of the end product. Besides this
main feedstock, chemical and hydraulic binders were used
having in view that the method of moulding was employed.Alumina cement type ALICEM 2 – produced by SC ‘CCPPR’
SA from Alba Iulia was used as hydraulic binder as well as
a chemical binder made of colloidal alumina produced bySC ‘CCPPR’ SA from Alba Iulia. The main characteristics of
alumina cement which was used are mentioned in table
2.
b)-Method of preparing the casting paste
The casting pastes were prepared in the laboratory in a
propeller agitator having the following characteristics: the
recipient volume -10 L, agitating engine – 220 V; 1000 W ,
number of rotations 950 rot/min, two – pedal agitator. Theorder in which the materials were introduced into the
agitator was as it follows: globular grease remover, fine
grease remover, hydraulic binder (alumina binder). W aterwas added after a 2-3 minute – mixture and it was stirred
for 5 more minutes. As far as the formula with chemical
binder is concerned, the order in which the materials wereintroduced was the following: globular grease remover,
fine grease remover; they were mixed for 2-3 min, water
was added, then the chemical binder and after mixing for2-3 min the intensifier was added. After one minute’s
stirring it was cast in moulds. When the cycle of
homogenization was over the past was cast in cubicmoulds of 80 mm each side, by filling. A batch containing
5 kg of material was made for each formula. This was
necessary for obtaining 3-4 samples (cubes) whose maincharacteristics were then determined.
c)- Molding, drying and burning the samples
Molding the cubic samples was made by casting the
paste prepared as previously described. After the samples
became stiff, they were taken out and allowed to dry for48 hours in open air. Then they were introduced in a drying
room and kept for 24 h at a temperature of 393.15 – 413.15K
(120-140
0C). After drying, the samples were subjected to
a process of burning in a continuous furnace at 1773.15 –
1823.15K (1500-15500C) for 16-20 h at burning point.
After burning, the cubes were subjected to physical andchemical testing in order to characterize the corresponding
formulas.d)- Establishing the testing to describe the formulas
As previously shown, this is the treatment to which the
products that make up the assembly for injecting inert gasinto the steel casting ladle were subjected: Cold or hot
pressure resistance; Resistance to steel and scum
corrosion; Resistance to shocks caused by melted steeland cold gas injection; Resistance to wear; Refractoriness
or the temperature that guarantees the usage of the
refractory material under the working conditions of thesteel foundry (casting temperature and residence time of
the liquid steel in the casting ladle). Although there are
standardized assessment methods for this stress, thesetake too long, involve high costs or require a high number
of samples. Under these circumstances, it has been
established that it is sufficient to undertake simpler andfaster means to assess the samples to ensure a
comparative description. As a result, it has been decided
to use only the following laboratory means of assessmentto define the samples: -Establishing cold pressure
resistance; -Establishing the porosity of the samples and
determining the characteristics that are related to this(water absorption and apparent density). These
characteristics are sufficient to appreciate the comparative
quality of the products obtained when the chemicalcomposition is similar.
The main technical characteristics recommended by
the producer consist just in indicating the values of thesesimple assessments, as shown in table 3.
To obtain optimum values of these important
characteristics, special attention has been paid to realizing
the proper granulometric composition because this
represents, along with the chemical composition, theessential factor in realizing high quality final products.
e)- Realizing products that contain over 95% Al2O3As far as the granulation of the of the grease remover is
concerned, having in view that the pegs will have guided
porosity (gas injection canal), one should use a granulationthat allows a compact structure of the material, like the
grids which have reached optimum results in the attempts
made to obtain products that contain 85% Al
2O3. The
experience gained in the first part of the laboratory research
was used in this way and therefore, only few attempts
were necessary. Thus, many 5 gratings were realized inthe laboratory under similar technological conditions to
those in which the first series of attempts were realized:
The same paste preparation equipment was used; Thecasting was made using the same method (by filling); 3-4
Table 2
CARACTERISTICS OF
ALICEM 2 ALUMINA
CEMENT
Table 3
THE MAIN TECHNICAL CHARACTERISTICS
REQUIRED FOR REFRACTORY PRODUCTS
WHICH MAKE UP THE KIT FOR INJECTING
INERT GASES INTO STEEL CASTING LADLE

http://www.revistadechimie.ro REV.CHIM.(Bucharest) ♦69♦No. 8 ♦2018 2180cubes were obtained in order to make the established
laboratory determinations; -After the 2-3-h hardening time,
the cubes were left for 48 h in the air after which they weredried for 24 h in a dryer at a temperature of 393.15 – 413.15K
(120-140
0C); Their burning was made in the continuous
furnace for 16-20 h at 1773.15 – 1823.15K (1500-15500C);
As mentioned before, a chemical binder was used. This
contained a self-intensifier composed of:
– Alcohol solution prepared by using chlorine hydride and
aluminum powder. The solution had a density of 1.240
(recorded with the immersion densimeter) which was
diluted to a density of approximately 1.040 – 13.5% of thisbinder was added to each formula (reported to dry
material). The solid magnesia intensifier was added in
proportion of 0.15%. Under these conditions and using thefabrication order described in point 1.3, the hardening time
of the paste in moulds was of approximately 2 h (with
slight variations according to the granulometric formulathat was employed), after which the cubes were taken
out of the moulds and subjected to drying and burning
processes. Table 3 includes the 5 formulas that wererealized and the chemical and physical mechanical
characteristics established on the cubes that resulted from
each formula.
An analysis of the data that resulted at laboratory stage
for obtaining products that contain over 95% Al
2O3,
necessary for making the porous peg for injecting inertgas in the casting ladle, points out the following important
aspects:
– Apart from grid no. 1 and 3, the other laboratory trials
meet the conditions required by internal regulations and
offered by foreign companies;
– It is mentioned that, as far as pressure resistance and
apparent porosity are concerned, the parameters
mentioned in the offers made by foreign companies are
higher although the apparent density of the products
included in the research meet the bounds in the offers.
This can be explained by the fact that the raw material
that was used was different and by a weaker compaction
of the products included in the research. Of all 5 formulas
used in the trials, formula no 4 is the one with the bestresults, respectively: apparent density- 2.79g/cm
3, water
absorption – 8.10%, apparent porosity -23.0%. Having in view
the results that were obtained during the laboratory trials,it is recommended that the products should have lower
porosity and higher-pressure resistance, corresponding to
the values in the foreign companies offers.Results and discussions
a) -Establishing optimum granulation for realizing products
that contain more than 85% Al2O3It is known that in a monodispersed system of spherical
particles the porosity does not depend on the diameter of
the spheres but on the way, they are arranged. To a greatextent, the rule also applies in the case of nonshperical
granules, the way they appear in industrial practice. In this
case, the realized porosity is approximately 40%. In thecase of a mixture of two different granulometric fractions
(a coarse one and a fine one), the fine fraction takes up the
empty spaces between the big granules and therefore aporosity of 16% in volume can be obtained. A minimum
porosity is obtained in a ratio of fractions when all the
spaces between the granules of the fraction are occupiedby fine fraction. This can be realized at approximately 30%
fine fraction and 70% coarse fraction. In a binary system of
two grain size fractions, a porosity of min 25 % can beobtained. To obtain lower porosity, it is necessary to use
more granulometric fractions. Thus, in a ternary system
(coarse fraction-medium fraction-fine fraction) porositycan be as low as 22%.
Theoretically, the porosity can be even more reduced by
using four or more fractions, but this cannot be taken intoaccount in practice. In practice, however, the problem is
much more complicated since the grain size fractions
obtained by the process of size reduction are continuous(even within certain bounds) and on the other hand the
shape of the granules obtained in different size reduction
equipment is different and it influences their arrangement,respectively the tightness of the obtained product and
therefore its porosity. For this reason, there are authors who
have suggested introducing two distinct notions tocharacterize the granules of a mixture granulometry, the
notion related to the size of the granules and which can be
expresses either as the medium diameter of the granules
or as the fraction percentage that remains or passes
through a bolter with a particular mesh [14, 15]. Granularity,notion related to the shape of the granules and which can
be expressed as a factor that is in the different granulation
calculation formulas and which mirrors the shape deviationcompared to the ideal spherical one. Besides these, it must
be mentioned that the determinations made in order to
shape these systems were realized on dry mixtures orsemidry systems with a reduced binder quantity and a
proper humidity for the spinning technology which is
generally used when producing refractory items.
Table 4
EXPERIMENTAL FORMULAS FOR PRODUCTS THAT CONTAIN OVER 95% Al2O3 AND THE RESULTS OF THE DETERMINATIONS

REV.CHIM.(Bucharest) ♦69♦No. 8 ♦2018 http://www.revistadechimie.ro 2181These conditions have decisively influenced the gliding
of one granule over another, their mutual arrangement and
therefore the shape of the obtained cubes but especiallythe value of the determined parameters. As far as the
injection moulding technology is concerned, where the
mobility of the granules in the fluid mixture is much higher,it is expected to obtain different values and even different
shape of the curves, respectively of the optimum value
zones. Having in view the reasons mentioned above andthe fact that the raw materials which are used are of a
different nature (alumina fire clay and tabular alumina), it
has been established to use a series of formulas withvarious granulations which can comprise a larger area of a
coarse-medium-fine ternary system, provided that the
realization of the set chemical composition for the endproduct allows it.
The determinations made on these mixtures will
indicate the optimum granulometric composition forrealizing a proper quality product or will at least mark off
the zone within the ternary granulometric system in which
will be placed the formulas for producing the productswhich are necessary for the assembly for injecting inert
gases into the steel casting ladle. In all the cases we found
granulometric compositions within the bounds indicatedbelow, according to the size of the granules being
considered coarse, medium and fine and according to their
shape: – coarse granules 30-50% ;- medium granules 15-25% ;- fine granules 35-55%. Since, as it has been shown,
casting provides special conditions for the arrangement of
the granules, it has been decided that the trial area in theternary system should be extended to the following ratios:
coarse granules 30-50%; medium granules 5-25%; fine
granules 25-60 %. It has been decided to take into accountthe following granulometric fractions according to the
indicated granulations and the raw materials that wereused: Coarse fraction: between 3.2-1.25 mm; Medium
fraction: between 1.25-0.5 mm; Fine fraction: less than
0.5 mm. According to this division, the raw materials that
were used have the grain-size distribution presented intable 4.
In order to obtain a chemical composition of
approximately 85-90% Al
2O3 which is necessary to inject
the inert gases and realize the protection bushings from
the injection assembly, it has been concluded that the
following composition is necessary: 35% fire clay SA68A×68% Al
2O3=23.8% Al2O3, 65% tabular alumina×99%
Al2O3= 64.4% Al2O3. 10% alumina cement was added in
all cases as binder with fine fraction (<0.06 mm). Usingthe technology previously described 13 different
granulometric formulas were realized, 3-4 cubic samples
being cast and on which the established determinationswere made after the drying and burning processes. In all
cases the pastes were prepared with 11-13% mixing water
(reportable to the weight of the solid material) to presentproper casting characteristics. The formulas that were
used, as well as the results of the laboratory determinations
are presented in table 5.
Conclusions
Refractory porous plug in running must match the
reliability, steel ladle liner and must have a durability in
service at least equal to the entire refractory linings
durability. A premature deterioration of the supportnecessity of a change in the ladle during use, causing an
interruption of casting steel for a period of time to rebuild
the entire assembly bubbling refractory linings. Therefore,besides the use of high quality refractory materials requires
respect of fabrication technologies to ensure superior
product quality characteristics.
Table 5
EXPERIMENTAL FORMULAS FOR PRODUCTS WITH 85% Al2O3 AND THE RESULTS OF LABORATORY DETERMINATIONS

http://www.revistadechimie.ro REV.CHIM.(Bucharest) ♦69♦No. 8 ♦2018 2182By analyzing the data obtained during the laboratory
work, the following can be concluded:
The formulas used during the trial (apart from formulas
2-5,7,9,10 and 13) meet and sometimes exceed the
requirements for the chemical and physical mechanical
characteristics (apparent density, apparent porosity,pressure resistance). The calculated CaO content exceeds
the recommended limit and the one offered by foreign
companies, which might lead to a slight decrease in therefractoriness characteristic (usage temperature) and
respectively in the corrosion resistance of the products to
the steel and scum action. Of all the trials, formulas no. 6and 8 have shown the best values of the characteristics,
respectively: apparent density – 2.65-2.85 g/cm³, apparent
porosity – 17.5-20.9%, pressure resistance -56.0-58.5 N/mm². These characteristics are better than those imposed
by internal standards and meet the requirements of import
products.
Considering these results, it is recommended that, for
the production of the batches which will be tried at the
beneficiary, a formula similar to no 6 or 8, respectivelycontaining 25% fire clay AS 68 A and 65% tabular alumina
(with 10% additional alumina cement ALICEM 2), with
granulations comprised between: 45-47% large granulesbetween 3.2-1.25 mm, 7-15% medium granules between
1.25-0.5 mm, 40-46 % fine material < 0.06mm.
References
1. COMSA A.M., BUZDUGA M., CONSTANTIN N., GOLEANU A.,
BUZDUGA R., Research and Development Institute for Refractoriesand Ceramic Products – CCPPR, Alba Iulia, Romania, Metalurgia
International, nr.3, 2008, p.71-75.
2. ITTU C., CONSTANTIN N., MICULESCU F., DOBRESCU C. , Insulatingpowder used in iron and steel industry , Metalurgia International , nr.
4, 2009, p.25-29.
3. BUZDUGA R., CONSTANTIN N., GOLEANU A., Research on the
synthesis of cordierite in refractory masses, U.P .B. Sci. Bull., Series
B, Vol. 78, no. 1, 2016, p. 229-236.4. SOCALICI A, POPA E., PUTAN V . s.a., Researches on the reduction
of steel hydrogen content by its secondary treatment inside the
ladle, TECHNICAL GAZETTE V ol. 23, no.5, 2016, p. 1381-1387.
5. PASCU L., STOICA D.M., SOCALICI A., Determining the cooling
affected volume by adding microcoolers in the steel,
Conference: International Conference of Numerical Analysis andApplied Mathematics (ICNAAM) , Kos, Greece, sept. 19-25, 2012.
6. COCINDAU S., DINU R., ZORLESCU D, COTOARA G., Dop poros cu
durabilitate superioara utilizat la barbotarea oțelului lichid în oala deturnare, Metalurgia , nr. 10, 2000, p.24-27.
7. VDOVIN, K. N., MAROCHKIN, O. A., TOCHILKIN, V . V ., Creating a
stream simulator to improve the wear resistance of refractories duringthe casting of steel on continuous section casters, March, 2014, p.435-
437.
8. GOLEANU A., BUZDUGA M., CONSTANTIN N., COMSA A., BUTU M.,Effects of Additives on the Sintering Process of Al
2O3-based Ceramic
Materials 2 th International Congress on Ceramics, Verona, 29 iun-4
iul 20089. COMSA A., NICOLAE M. – Applications of refractory concretes with
low hydraulic binder content, Metalurgia International, nr.8 , 2008, p.
5-7.10. COMSA A., AVRAM N., DIMA A., Refractory linings realized from
refractory concretes with low hydraulic binder content, Metalurgia
International, nr.9 , 2008, p. 9-14 .11. COMSA A., BUZDUGA M., CONSTANTIN N., GOLEANU A., BUZDUGA
R., Monolithic refractory for metallurgy, Metalurgia International,
Special issue nr.3 , 2008, p.71-72.12. BUZDUGA R., COMSA A. – Mase monolitice cu conținut redus de
liant hydraulic, Scientific Bulletin of the Politehnica University of
Timișoara, Tom 52(66), 2007,Catalog ALCAN 200713. GAILIUS A., ŽUKAUSKAS D., Optimisation of the Aggregates
Composition in Concrete, Materials Science (MEDZIAGOTYRA).,Vol.
12, no. 1, 2006, Lithuania .14. ZHARMENOV , A. A., SATBAEV , B. N., K AZHIKENOVA, S. SH.,
Development of refractory materials prepared by SHS technology,
Refractories and Industrial Ceramics, nov. 2011, p.94-302 .
15. GOYAL P ., S. V . JOSHI S.V ., WANG J., Porous Plug Gas Injection in
Anode Refining Furnaces, JOURNAL OF METALS, 1983, p. 52-56.
Manuscript received: 17.01.2018