High alumina refractory Presented by - Manish Tiwari Mayank Kumar Mayank Dubey

REFRACTORY MATERIAL A refractory material is a material that retains its strength at high temperatures. ASTM defines refractories as "...non-metallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above 1,000 °F (811 K; 538 °C).“ Refractory materials are used in for furnaces, kilns and incinerators. They are also used to make crucibles and moulds for casting glass and metals.

Classification Classification of refractory materials Based on chemical composition 1 Acidic refractory eg.Silica 2 Neutral refractory eg.Chromites, Alumina 3 Basic refractory eg.Magnesite,Dolomite Based on method of manufacture 1 Shaped 2 Unshaped (monolithic refractory)

High Alumina Refractory Alumina refractories containing more than 45% alumina are generally termed as high alumina materials. The alumina concentration ranges from 45 to 95%. Commonly used refractory are sillimanite (61%), mullite (70 –85%) and corundum (99%).

Chemical Composition Alumina:80% Silica:10% Kaolin:10%

METHODOLOGY 1.40g of Al203 is taken and mixed with 5g of SiO2 and 5g of Kaolin.The mixture are mixed thoroughly for 1 hour . 2.Ball milling of the mixture is done for 15 minute.It makes the particles finer. 3.Sieving is done to reduce the particle size to 75 micron 4.Prepare Binder (PVA) by taking 95ml of Water and 5g of P.V.A. and put them on a magnetic styler with a magnetic bit in a beaker maintaining the temperature around 60 degree Celsius..

CONTINUE……… 5. The mixture is mixed with 4-5 drops of PVA and mixed thoroughly for 30 minute. 6. Now the pellete is prepared by taking some mixture and compressed under Hydraulic press for 3 minutes. 7. Three samples are prepared in the same way. 8.The pellete is kept for drying for 2-3 days . 9.Now the pellete is fired in the furnace maintaining temperature starting from room temperature and increasing by 5 degree per celsius till 1450 degree celsius 

CONTINUE……….. 10.The pellete is allowed to stand for about an hour on the same temperature 11. Now the temperature of furnace is reduced to 500 degree and allowed to cool.

Equipments Hydraulic Press:

CONTINUE……… Furnace:

Pellete

Mechanical Properties Physical Properties Mechanical Properties Thermal Properties

Physical Properties 1.Density: Alumina has a specific gravity of 3.96 and silica, in its various forms, ranges in specific gravity from 2.26 to 2.65. 2.Apparent Porosity: The apparent porosity or open porosity (oPo) is the volume of the open pores, into which a liquid can penetrate, as a percentage of the total volume of the refractory.It is 22%for our sample. 3.Bulk Density:Bulk Density is the ratio of weight (or mass) to volume and it is expressed in pounds per cubic foot (lb/ft2) or kilograms per cubic meter (g/cm3). It is2.33g/cm3 for our sample.

Mechanical Properties 1.Cold crushing strength: The Cold Crushing Strength (CCS) represents the ability of a product to resist failure under compressive load at room temperature. It has an indirect relevance to refractory performance, and is used as one of the indicators of abrasion resistance. It is greater than 45 MPa. 2.MOR: Flexural strength, also known as modulus of rupture, or bend strength, or transverse rupture strength is a material property, defined as the stress in a material just before it yields in a flexure test.it is 120 to 160kg/cm2 at room temperature.

Thermal Properties 1.Thermal conductivity: Alumina has high heat resistance and corrosion resistance compared to other ceramics such as silica or mullite. However, for its application to refractory bricks, its high thermal conductivity must be reduced. ... At room temperature, the thermal conductivity was about 0.12 W/mK .But High Alumina refractory brick has 4.1w/m degree kelvin. 2.PLC: Permanent Linear Change (PLC) is a factor used to judge the suitability of refractories in ranges of temperature limits. It is 0.1 to 0.4 for high alumina refractory brick.

CONTINUE……… 3.Refractoriness under load : Refractoriness under load (RUL) is a measure of the deformation behavior of refractory ceramic products subjected to a constant load and increasing temperature.it is 1520 degree celsius in 0.2MPa. 4.Refractoriness: It is resistence of a refractory material to change properties with change in temperature.It is measured in pyrometric cone value.for High alumina refractory brick refracoriness is 1790 degree celsius.

XRD

High Alumina Refractory Brick Suppliers Imperial World Trade Private Limited in Rajkot United Industries in Ahemdabad Steelage Refractories Private Limited in Mandi Gobindgarh Ess Ess Ceratech in Faridabad

THANK YOU