How To Improve The Glass Phase Of Fused Cast AZS Block

Changxing Refractory Material

The segregation of fused cast AZS is also caused by the glass phase. in theory, Al2O3, ZrO2 and SiO2 do not exist in the glass phase. When the alkali metal oxides(Na2O or K2O) are introduced, most SiO2 will enter the glass phase. Na2O constitutes the key components of refractory fiber felt glass phase with SiO2 and Al2O3. With the decreasing of Na2O, the glass phase decreases. But increasing the Na2O can reduce the viscosity of glass phase.

Iron, titanium, calcium, magnesium and other impurities should be avoided. The impurities can increase the glass phase but reduce the the viscosity of glass phase and pollute the glass melt.

SiO2 and Na2O are the main components tundish well block of the glass phase of fused cast AZS blocks. The content of SiO2 and Na2O is related to the amount of glass phase. Controlling the content of SiO2 and Na2O strictly is the key to ensure the performance of glass phase.

The main composition of Clay, High Alumina insulating bricks fused cast AZS block includes baddeleyite, corundum, a small amount of mullite, glass phase and pores. In order to reduce and eliminate the residual thermal stress, the glass phase is essential for fused cast AZS to act as a buffer for the thermal stress.

However, too much glass phase zirconium sizing nozzle will weaken the corrosion resistance. In the process of corrosion, the glass phase exudes first and be replaced with the high temperature glass melt, which will accelerate the corrosion. Accompanying the exudation of glass phase, bubbles give off, which will contaminate the glass melt.

Henan Xinmi Changxing Refractory Material Co., Ltd. Located in Henan Province,China.ChangXing's product portfolio covers shaped products such as refractory materials,refractory brick, refractory castable,refractory nozzle, ceramic fiber, slide gate, etc; unshaped products including repair, construction and casting mixes and mortars.exported to more than 20 countries, such as Thailand, Indonesia, Pakistan, Saudi Arabia, South Africa, Turkey, Iran, Iraq and so on.

4 Ways for Fused Cast AZS Casting

Changxing Refractory Material

There are 4 ways of fused cast AZS casting, including normal casting(PT), Tilt casting(QX), Reinforced casting(ZWS) and Void-free casting(WS).
PT-Normal casting
It adopts general casting coil grout risers and the riser will be removed in the hot state. The shrinkage cavity in refractories brick is located under the casting scar, due to volume shrinkage from liquid-solid transform and rapid solidification of a casting. The feasible limits of cavity can be evaluated and indicated by the volume-weight testing of blocks in-situ according to the technical specifications.
PT fused cast AZS block nozzle refractory is always cheap and used in the areas with no serious corrosion such as top crown, superstructure and feeder channel. The surface with scars should not be used as the working surface.
QX-Tilt casting
In this method, the mold is inclined at an angle. The shrinkage cavity in brick disperses at one end of the brick and a completely dense zone forms at another end. The feasible limits of cavity can be evaluated and indicated by the volume-weight testing of blocks in-situ according to the technical specifications. Meanwhile, blocks which height less than 900mm are not suitable to be manufactured by this process.
QX fused cast AZS block dry vibration mix is generally used in the sidewall of glass furnaces.
ZWS-Reinforced casting
Similar to WS, merely a few shrinkage voids remain in upper part of the body. A little part of the cavity will be remained at the end of the block after the header cutting. Block evaluation in-situ begins from the determination for the feasible size and deepness of cavity remainder at first and then to the volume-weight testing of blocks according to the technical specifications.
ZWS fused cast AZS block is always used in the sidewall of glass furnaces.
WS-Void-free casting
Additional liquid from the header fills sufficiently into a casting and the header is then cut off, so no shrinkage cavity exists in brick body. Block evaluation in-situ includes the refractory fiber felt acceptance or rejection for somewhat trace of cavity remainder which perhaps appeared and the volume-weight testing of blocks according to technical specifications.
WS fused cast AZS block has a wide application in the glass furnaces such as sidewall, tank bottom, feeder channel, doghouse, throat, dam wall, electrode wall and corner wall.

Casting is a manufacturing process by which the melt is poured into a mold to be solidified. Although the process is short, it is a complex process and every step is related to the quality of the final products.

Henan Xinmi Changxing Refractory Material Co., Ltd. Located in Henan Province,China.ChangXing's product portfolio covers shaped products such as refractory materials,refractory brick, refractory castable,refractory nozzle, ceramic fiber, slide gate, etc; unshaped products including repair, construction and casting mixes and mortars.exported to more than 20 countries, such as Thailand, Indonesia, Pakistan, Saudi Arabia, South Africa, Turkey, Iran, Iraq and so on.

Abvantages Of Corundum Brick in Changxing refractory company

The products are produced by corundum and chromium oxide as main materials, formed from casting, after being treated under high temperature, it has high hot strength and good wear resistance, suitable for making the slide rail part of heating furnace.

Corundum brick is made of corundum as the main raw material. It contains more than 90% Al2O3. Due to its good stability, good corrosion resistance and excellent wear resistance, it is widely used in the petrochemical industry, metallurgical industry and the lining of coal gasifier, residual oil gasifier, pulp waste gasifier, the carbon black reactor and other industrial furnaces.

The bulk density is related to the particle size, particle distribution and particle shape. Generally, magnesia carbon brick with coarse particles have lower bulk density than those with fine particles. The smaller the gap between the particles, the greater the bulk density of the bricks. Bricks with mixed particles have higher bulk density than those with single particles. The bulk density of corundum brick increases with the density of particles.

Corundum brick has high cold compressive strength , which will directly affect the quality of the bricks. It has high Al2O3 content. The higher the Al2O3 content, the better the refractories performance of the bricks. It has high softening temperature and good high temperature performance. It has good chemical properties and excellent resistance to acid and alkali. It has good thermal shock resistance and high strength.It has wide applications.

refractory company Henan Xinmi Changxing Refractory Material Co., Ltd. Located in Henan Province,China.ChangXing's product portfolio covers shaped products such as refractory materials,refractory brick, refractory castable,refractory nozzle, ceramic fiber, slide gate, etc; unshaped products including repair, construction and casting mixes and mortars.exported to more than 20 countries, such as Thailand, Indonesia, Pakistan, Saudi Arabia, South Africa, Turkey, Iran, Iraq and so on.

our refractory product list:
http://www.yilongrefractory.com/ProductServlet?id=1

The Development of Fused Cast refractories

In 1927, Corhart was founded. It is a refractory company producing fused cast refractories. Raw materials are melted in an electric arc furnace and then casted in a mold, just like metal casting. The lining of the electric arc furnace is made of the same materials. The temperature is up to the requirements of refractory products, generally 1800-2500℃.

The first fused cast refractory is fused cast mullite refractory. It has been widely used in the sidewall of glass furnaces. Later zircon is added to the raw materials. The melting temperature is reduced and the slag resistance of the products is improved.

In 1952, fused cast magnesia carbon bricks manufacturers, a new fused cast product, was developed by Corhart. It is mainly used in the steel industry.

When producing fused cast refractories, the melt is casted into a mold with a large cap. The wall of the mold is made of refractory materials. When casting is finished, the mold wall is removed. Then the mold is put into insulation materials to reduce thermal shock to obtain crystals with uniform sizes and minimum gaps.

Fused cast refractory is larger than the standard bricks, so it is difficult to cast. Currently, fused cast products for sale are always cut from big blocks.

Henan Xinmi Changxing Refractory Material Co., Ltd. Located in Henan Province,China.ChangXing's product portfolio covers shaped products such as refractory materials,refractory brick,high insulating brick , refractory castable,refractory nozzle, ceramic fiber, slide gate, etc; unshaped products including repair, construction and casting mixes and mortars.exported to more than 20 countries, such as Thailand, Indonesia, Pakistan, Saudi Arabia, South Africa, Turkey, Iran, Iraq and so on.

Our product list:
http://www.yilongrefractory.com/AllProductServlet?id=4&number=20

Application of magnesia-chrome brick for arc furnace

Magnesia Carbon Brick is mainly used for electric furnace lining, which enjoys advantages including high temperature resistance strength, corrosion and spalling resistance. According to the smelting conditions and the kind of smelting steel, different brands magnesia carbon bricks are available. 

Furnace cover electrode triangle due to the more demanding working conditions, generally uses the corundum, magnesia carbon brick chromium corundum and quality of corundum-spinel castables and precast, simplifies construction, improve the service life of the furnace cover. According to the electric arc furnace slag from smelting magnesia carbon bricks properties characteristics, thermal regime, and the nature of almost all basic refractories for furnace wall.

Electric arc furnace cover mainly silica fire brick masonry in the past, but because of its high refractoriness, poor thermal shock resistance, metal and slag corrosion spalling damage occurred, short life. Later widespread use of excellent performance of high-alumina brick and high-alumina refractory unshaped refractories, 2-3 times more life MGO brick manufacturers than silica mortar.
As super high power electric of development, due to steelmaking rhythm accelerated, arc furnace cover work conditions more bad, have development out has various combines agent preparation of not burn high aluminum brick, or in ingredients in the introduced Silicon line stone family mineral raw materials, added micro-powder, and tip spar, and SIC,, improve brick of anti-slag performance, and high temperature volume stability and the hot earthquake stability, to meet super high power electric development of needs.


Henan Xinmi Changxing Refractory material Co., Ltd. our product portfolio covers shaped products such as refractory material, refractory brick, refractory castable, refractory nozzle, ceramic fiber,slide gate, etc;

our product list:
http://www.yilongrefractory.com/AllProductServlet?id=3&number=20

Magnesia Brick in the process used for industry furnace

Magnesia-carbon bricks are resin bonded bricks containing high-purity fused and or sintered magnesia and flake graphite as their main ingredients.

Magnesia Brick in the process:
magnesia carbon brick hearth furnace is mainly used for basic open-hearth steelmaking, electric stove and oven walls, permanent lining oxygen converter and nonferrous metal smelting furnace, high temperature tunnel kiln, rotary kiln calcination silica mortar and cement lined furnace walls, glass furnace regenerator checker bricks and so on. I magnesia carbon brick for sale sintered magnesia as main raw material, reasonable gradation, high pressure forming, refractories high-temperature sintering. The product has a strong resistance to slag erosion ability.

Henan Xinmi Changxing Refractory material Co., Ltd. our product portfolio covers shaped products such as refractory material, refractory brick, refractory castable, refractory nozzle, ceramic fiber,slide gate, etc;

New Types of Refractory For The Glass Furnace

Low cement castable can be widely used for those industrial furnace's working lining, permanent lining( working temperature under 1400c), such as little refining Ladle cover, Ladle & Tundish permanent layer, heating furnace working wall, top and bottom. Blast furnace body, Hot metal ladle permanent layer.

Fused cast AZS block has been successfully used in the crown for many years. It can be used at 1600℃ or 1650℃ and can withstand the cycle of cooling and heating well. Compared to fused cast AZS, fused cast alumina block refractories can be used at 1700℃ and has better mechanical strength and thermal stability.

In the past, high chromium brick was mainly used for the production of reinforced glass and sometimes in the insulation castable refractory material glass furnace. Now it is increasingly used in some soda-lime glass furnaces. It has much better corrosion resistance to glass and can prolong the service life of throat. Besides the throat, it is also used in the end wall, the angle brick of the feeder port. However, clay insulating bricks the chromium may color the glass liquid, thus it can not be used in the white glass furnace. It was primarily used in the colored glass furnace, but now it has been successfully used in the transparent container glass furnace.

Low glass phase fused cast AZS block has been successfully used in the superstructure. The development of the oxygen-fuel combustion technology makes it find wider application in the superstructure. Since it contains a low amount of glass phase, it has better creep refractory fiber board resistance and the amount of exuded glass phase has been reduced to a very low level.
Fused cast high zirconia block is a new type of refractory, mainly used in the glass contact areas in high quality glass furnace. It has a low potential of causing stones, knots and bubbles and can effectively reduce glass defects. It is also in some low alkali glass or hard borosilicate glass furnaces.

The need of the glass manufacturers to maintain and improve the quality of glass and expand the service life of the glass furnace and the impact and influence of the oxygen-fuel combustion technology, promote the improvement of refractories and development of the new insulating castable refractories.
Fused cast alumina block has been widely used in the crown of the oxygen-fuel furnace, especially when manufacturing high quality glass. Before the application of the oxygen-fuel combustion technology, only β alumina block is used in the superstructure of the melting furnace. Now both β fused cast alumina block and α-β fused cast alumina block can be used in the crown of the oxygen-fuel furnace for producing TV glass, float glass and borosilicate glass.

Henan Xinmi Changxing Refractory Material Co., Ltd. Located in Henan Province,China.ChangXing's product portfolio covers shaped products such as refractory materials,refractory brick, refractory castable,refractory nozzle, ceramic fiber, slide gate, etc; unshaped products including repair, construction and casting mixes and mortars.exported to more than 20 countries, such as Thailand, Indonesia, Pakistan, Saudi Arabia, South Africa, Turkey, Iran, Iraq and so on.

product list:
http://www.yilongrefractory.com/AllProductServlet?id=2&number=20

Suggestions On The Proper Use Of Fused Cast AZS

The products are produced by corundum and chromium oxide as main materials, formed from casting, after being treated under high temperature, it has high hot strength and good wear resistance, suitable for making the slide rail part of heating furnace.

For structures constructed with fused cast AZS and silica brick (such as the front wall of the feeder pool),each material should have its own structure, because they have different volume changes at high temperature. For the superstructure that is less than 8m, there is no need to leave expansion joints. For the superstructure ceramic fiber felt that is longer than 8m, it is recommended to divide it into several parts by expansion joints(4-6mm).
There are masonry joints between the sidewall block and the bottom block. When the refractory materials are heated, 4-5mm volume expansion per meter will be expanded into the masonry joints.
Fused cast AZS block has a higher thermal conductivity. When used in the sidewall, it parts near the liquid ladle castable level require bigger cooling air flow.

Based on the campaign life of the glass furnace, the indicators of the furnace operation and the physical and chemical properties and performance of fused cast AZS block, some reasonable suggestions high insulating brick are made on the proper use of the fused cast AZS.
Fused cast AZS is characterized with stable and dense structure and good corrosion resistance to glass. During 900-1200℃, it will have a abnormal volume expansion due to its crystal phase transition.

Henan Xinmi Changxing Refractory Material Co., Ltd. Located in Henan Province,China.ChangXing's product portfolio covers shaped products such as refractory materials,refractories brick, refractory castable,refractory nozzle, ceramic fiber, slide gate, etc; unshaped products including repair, construction and casting mixes and mortars.exported to more than 20 countries, such as Thailand, Indonesia, Pakistan, Saudi Arabia, South Africa, Turkey, Iran, Iraq and so on.

product list:
http://www.yilongrefractory.com/AllProductServlet?id=4&number=20