Fused Corundum Bricks

Graphite electrode manufacture process

Low Creep High Alumina Brick Properties

In the development of low creep high alumina bricks, a certain amount of quartz particles are generally added. There are different views on the action and effect of quartz particles. It is generally believed that the effect of adding quartz has two main aspects, namely, increasing the viscosity of the high temperature liquid phase and utilizing the expansion effect and the expansion stress effect produced by the unbalanced reaction to improve the load resistance.

The addition of quartz particles to the low creep  high alumina brick can increase the SiO2 content in the liquid phase, increase the degree of crosslinking of the silicon oxytetrahedron in the liquid phase, and increase the viscosity. At the same time, due to the presence of part of Al2O3 in the matrix, it has strong diffusion ability at high temperature, and Al3+ diffuses into the quartz particles to form an aluminosilicate layer with cristobalite as the core. Al2O3 reacts with SiO2 to form mullite, and this reaction produces an appropriate amount of expansion to increase its creep resistance.

A thin layer composed of mullite crystal phase and amorphous phase or microcrystalline phase exists along the center of the cristobalite grain to the edge of the cristobalite grain, and the content of SiO2 gradually decreases. However, the Molybdenum reaction is far from reaching equilibrium. With the extension of time, the thickness of the reaction layer is increasing, and the reaction rate is slowed down, which can ensure that this non equilibrium reaction lasts for a long time.

It is generally believed that quartz is preferably added in the form of medium particles and requires a certain particle size interval, such as. The amount of quartz added is related to the amount of corundum. When all the fine powders are corundum, the amount of quartz added is preferably left and right. Since the reaction process of corundum fine powder and quartz particles is slow, there is still residual quartz and corundum after the green body is fired. The high alumina brick will continue to react with quartz and corundum to form mullite during high temperature use. Along with volume expansion, this expansion can just offset or partially offset the shrinkage generated during high temperature use, making the hot blast furnace with low creep high alumina bricks with excellent creep resistance.

Alumina magnesia spinel ladle castable

The ladle is a container of molten steel. The commonly used refractory materials are alumina magnesia spinel ladle castable, magnesia alumina spinel brick, ladle lining brick, etc. Use of alumina magnesia spinel can provide flaking resistance of refractory materials.

 Alumina magnesia spinel castable is also called corundum or high alumina magnesia spinel refractory castable, also called composite alumina magnesia spinel refractory castable. It has excellent functions and is used in large and medium sized ladle.

Magnesia alumina spinel has excellent corrosion resistance, strong corrosion resistance, good slag resistance, anti abrasive ability, good thermal shock resistance and high temperature resistance. It is the ambition material for the high temperature belt of cement rotary kiln with magnesia alumina spinel brick, ladle lining refractory brick, ladle castable and other refractory products. Magnesia alumina spinel is widely used in refractory materials, steel exercise, cement rotary kiln and glass industrial furnaces.

1. Aluminium-magnesium spinel ladle castable is a kind of special grade bauxite, corundum, high-purity spinel as the main material, and participates in the mixing of appropriate additives and dispersants. High density and durability;

2. Ladle castables should be stored in warehouses with rainproof equipment and monotonous ventilation according to the varieties and trademarks. Beware of moisture, prevent prolonged agglomeration, chemical bond failure, and affect the application effect.

3. In the case of better storage conditions, the shelf life is half a year. After half a year, the physical and chemical function indicators need to be checked. Once the requirements are met, they can be used as usual.

Sillimanite Bricks Properties

Sillimanite Bricks Properties

1.Sillimanite bricks have good creep resistance, low creep rate in high temperature environment.

2.Sillimanite refractory bricks have good thermal shock resistance.

3.Sillimanite bricks have The load is softened and stabilized.

4.Sillimanite bricks have good resistance to gas attack.

What is a sillimanite brick? 

1.Sillimanite brick is a refractory brick that participates in some sillimanite in high alumina brick materials. It is customarily called sillimanite brick. It is a kind of silicon lined high alumina brick, which is a refractory product variety of modified high alumina refractory brick.Sillimanite brick is made of bauxite as the main refractory material, adding sillimanite powder and participating in bonding agent, after mixing and molding. Refractory bricks fired at high temperatures. Because sillimanite bricks appear in the high temperature firing process, they can be classified into mullite refractroy bricks; sillimanite bricks can be attributed to high alumina refractory bricks in terms of alumina content. Sillimanite brick has a refractoriness of 1770-1830 ℃, and the load softening starts at a temperature of 1500-1600 ° C.

Sillimanite Brick Introduction to Creep Type

According to the high alumina brick, the creep characteristics and mechanism of the sillimanite brick were deeply studied systematically. The creep curve of the 400-1500 °C sillimanite fire brick was divided into three types.

The first variety: a form that fits the general creep curve. The initial stage is the deceleration and metamorphosis stage in which the creep rate is gradually decreased, followed by the constant velocity creep stage in which the creep rate is constant, and the creep rate is continuously added. The creep curve of this type is mostly found in low creep refractory bricks of 1400~1500℃, that is, sillimanite brick are participated in the general fired high alumina bricks.

The second type: the initial stage of the creep curve is the deceleration creep stage in which the creep rate decreases. After a certain time, the creep rate is zero and the creep rate does not change with time. That is, the creep rate is equal.

The third type: the creep curve is the decelerating creep stage in which the enthalpy change rate decreases first. When the creep rate reaches the maximum, the creep rate becomes a negative value, see the gradual increase and the creep rate gradually decrease. It appears in the low creep high alumina brick of 500~1550℃, that is, refractory brick with sillimanite and corundum material is added in the general high alumina refractory brick.

where is Sillimanite Brick Found

Rongsheng refractory brick manufacturers are committed to the research, development and production of advanced special refractory materials. Now the leading products are: high alumina brick, high purity corundum products, corundum mullite products, mullite corundum products, alumina hollow sphere products, light corundum products, lightweight corundum mullite products, zircon brick products, chrome refractory brick products, 75 mullite bricks, 70 mullite bricks, 65 sillimanite bricks, 60 sillimanite bricks, rutile various shaped refractory bricks.

Perennial supply of mullite brick, sillimanite brick: aluminum content greater than 65%, iron content less than 1%, apparent porosity less than 20%, bulk density greater than 2.5, normal temperature compressive strength greater than 80, load Softening temperature is more than 1600 ℃

High Aluminum Poly Light Insulation Brick

High Aluminum Poly Light Insulation Brick Feature

1.Insulation and heat insulation: Because the aerated concrete is in the process of production, the internal pores are formed. These pores constitute an air layer in the material guessing, which greatly improves the thermal insulation effect, so that the thermal conductivity of the aerated concrete is 0.11. -0.16W/MK. The insulation effect is 5 times that of clay fire bricks and 10 times that of general concrete.

2.Light weight fire brick: Lightweight brick has a dry capacity of only 500-700Kg/m*3, which is 1/4 of general concrete, 1/3 of clay, and 1/2 of hollow block, because its bulk density is smaller than water. Commonly known as aerated concrete floating on the water, the use of this refractory product in the construction can reduce the weight of the building and greatly reduce the inductive cost of the building.

3.Earthquake resistance: The same building structure uses high alumina poly light refractory bricks to improve the seismic rating of clay fire bricks.

4. Environmental protection: production, transportation, and application process without pollution, maintenance of plowing, energy saving, which is a green refractory material.

High Alumina Poly Light Firebrick Production Process and Material Introduction

Grade III alumina clinker, Al2O3 powder and soft clay. The R2O content in the tertiary alumina is 0.5% to 2%, and the sintering temperature is between 1100 and 1400 ℃. According to the experiment, R2O in the gentleman can promote the decomposition of mullite crystal phase. 1% R2O can constitute 10% glass phase and corundum. When the R2O content is close to 2%, the mullite crystal phase tends to disappear. The formation of more corundum and glass phase is due to the decomposition effect of R2O on mullite, which leads to the collapse of the network structure in which the mullite needle like crystals cross each other in the bauxite. The mullite refractory brick is present in the glass phase in the form of an island, which causes the load softening temperature to decrease and the thermal stability to deteriorate. Therefore, the R2O content in the quality guess is particularly constrained, and the grouting process using sodium rosin as a foaming agent is particularly strict.

TiO2 is also one of the higher impurities in bauxite. In the third grade bauxite, TiO2 enters the glass phase more, lowering the viscosity of the liquid phase, which is beneficial to sintering, but is not conducive to the high temperature function of the lightweight high alumina brick.

R2O has a large solid melting degree in the main crystal phase mullite and corundum of bauxite clinker. Fe2O3 is solid-melted to mullite at 1200 °C and solidified by 10% to 12% at 1300 °C. In corundum brick 1200 ° C is about 12% solidified, and at 1400 ° C is about 18% solid solution. In a restorative atmosphere, the solid solubility decreases and it is easy to melt off into the glass phase. When lightweight alumina bricks are used in a rejuvenating atmosphere, the Fe2O3 is also strictly restrained.

Refractory Brick for Converter Furnace Lining

The converter furnace is a high temperature metallurgical equipment and must be stacked with refractory materials. In particular, the inner lining of the converter is subject to the chemical corrosion of high temperature molten steel and slag, as well as the scouring effect of molten steel, slag, furnace gas and the mechanical resistance of waste indium. which is more demanding on refractory materials. The function of the refractory material is not only related to the life of the lining, but also affects the quality of the steel.

The converter refractory brick lining consists of a working layer, a filling layer and a permanent layer. The working layer is directly touched by molten steel, slag and furnace gas, which is constantly subjected to physical, mechanical and chemical corrosion effects, the filling layer is interposed between the working layer and the permanent layer, generally using tar magnesia or tar dolomite. The effect is to reduce the extrusion of the furnace shell when the refractory brick lining expands to prevent damage to the permanent layer, and to remove the residual bricks in the working layer, the permanent layer is used to maintain the furnace shell, which can be used to burn magnesia brick, tar combined with magnesium, refers to the construction of refractory bricks. Generally do not replace when repairing the furnace.

The damage mechanism of the converter lining is very complicated. In general, the oxygen converter lining under the effect of physical, chemical and thermal stress, the phenomenon of mechanical wear, erosion and heat loss occurs, which eventually leads to the damage of the lining. Because the working conditions of the various parts of the converter lining are very different, the damage of the various parts of the converter lining is different, so the function of the refractory bricks for each part of the converter lining is very demanding.

The mouth of the furnace and the part of the furnace hat: firstly, it is washed by the high the attachment is finished, it is mechanically hit, the two furnaces are subjected to intense exercise during the exercise. The influence of thermal shock requires that the refractory material of the masonry has high thermal shock resistance and slag resistance, slag resistance and high temperature furnace gas scouring, which is not easy to stick steel, even if the steel is easy to be finished. Therefore, the high strength magnesium charcoal fire bricks are often used in this part.

The charging side of the lining: in addition to the corrosion of molten steel and slag, it is also subjected to the intense impact of scrap steel and the intense erosion of molten iron during charging, this effect is very severe. Therefore, the refractory material required for masonry on the converter charging side has high temperature strength, good thermal shock resistance, high slag resistance. Therefore, most of the areas used are high corrosion resistant and high thermal resistant magnesia carbon bricks.

The tapping side of the lining: less affected by thermal shock, but due to the hot scouring effect of the molten steel, the same grade of refractory material as the charging side can be used, and the thickness can be slightly thinner.

The trunnion parts on both sides: in addition to the corrosion of molten steel and slag during the blowing process, and also subjected to the erosion and oxidation of the airflow, the surface of the lining is not covered by the slag layer, so the carbon in the lining refractory brick is easily oxidized, and further damaged, It is not very good to repair, so the erosion is severe. The masonry brick with high oxidation resistance and slightly higher carbon content should be used for masonry.

Slag line: Long term contact with slag is a severe part of corrosion caused by slag. The tapping side slag line changes with the time of tapping, and the damage is not significant; but the slag side, because of the intense slag corrosion effect, plus other effects suffered by the converter belly during the blowing process, the corrosion is more severe. Therefore, high corrosion resistant magnesium carbon bricks should be used.

The molten pool part: although it is affected by the erosion effect of molten steel in the blowing process, compared with other parts, the damage is lighter, and the operation of the slag splashing protection of the converter tends to increase the bottom of the converter, so the molten pool part of the converter can be used. General magnesium charcoal bricks.

The tapping part: the tapping port is affected by the corrosion and erosion of high temperature molten steel and slag, the sudden change of temperature, the damage is more severe, so the masonry fire brick with good erosion resistance and high oxidation resistance should be built. Use all the magnesia carbon bricks, or combination of magnesia carbon bricks, and repair or replace them after using them for a certain number of times.

Refractory Brick for Converter Furnace Construction

1.Shake the converter to zero position, find the center line of the bottom of the furnace, check the air holes on the gas supply casing and the steel structure, and ensure that all the pipes and air holes are unblocked, the three layers of magnesia bricks are laid on the bottom of the furnace floor and are laid to the ventilation place. The hole is close to the furnace shell and is required to be flush with the refractory brick. The third layer of magnesia fire brick is placed on the lower edge of the flange, the gap between the fire brick and the flange is filled with refractory material.

2.The working layer of the bottom of the furnace is set up with magnesia carbon bricks. Firstly, find the center of the bottom of the furnace, and pre-assemble the masonry center firebricks. The degree of partial pain should meet the requirements. The surrounding bricks should be built according to the planned bricks, and the wrong teeth should be handled. When laying permeable bricks, the thickness of the fire bricks around the ventilated bricks is not more than 1mm. The venting pipes should be twisted according to the orientation of the venting ducts. After the venting bricks are positioned, the materials are used to cut the holes under the venting firebricks.

1) When laying the briquetting bricks, use the ramming refractory material to control the height of the briquetting bricks to ensure the flatness of the outer side of the briquetting bricks, use the alcohol resin to select the air hammer between the briquetting brick and the permanent layer.

2) The permanent layer of the furnace body is built, the cone part of the converter pool, the straight part of the furnace body, the permanent layer of the cone part of the furnace cap are made of magnesia refractory brick, with the furnace shell as the guide surface, close to the furnace shell, and the conditioning fire brick door, control the level of each ring, fill the firebrick joint with fine magnesia powder.

3).The cone part of the converter pool, the straight part of the furnace body, the cone part of the furnace cap are made of magnesia carbon brick, with the furnace shell as the guide surface, the working layer is close to the permanent layer, the expansion layer is pressed as required, and the working layer brick. The gap between the fire bricks and the permanent layer bricks is filled with materials to ensure the level of each ring; each door is closed at a door, the orientation of the door bricks is arranged between 15℃ and 30℃ of the center line of the interval tapholes. The door bricks should be staggered by at least 2~3 bricks, the processing of the door bricks should not exceed two-thirds of the original brick width.

1) When the tapping hole is built, the orientation and viewpoint of the tapping port should meet the planning requirements. The center line of the tapping port should be consistent with the center line of the furnace. Use the brine magma mud to wet the firebrick, between the refractory brick and the pipe. The lining and the furnace shell are filled with refractory materials, and the seam is not clamped within 1m of the tapping area. The fire brick joint is not more than 1mm.

2) Reserve about 100mm between the topmost brick of the furnace hat and the furnace door, weld the anchor on the furnace shell, and beat it with the ramming material.