Refractory materials' ability to withstand the erosion caused by hot molten slag without destroying it is known as slag resistance.
The term "slag" is used to refer to the metallurgical process of slag, fly ash, fuel ash, different metal melts, furnace charges as well as various gaseous substances etc. which are in contact with refractory materials at very high temperatures. The slag erosion process involves mostly the process of dissolution of materials that are refractory in slag, and an process of intrusion (penetration) procedure of the slag to the inside of the refractory materials. Of them, the most rapid intrusion is via the stomata.
Thus increasing densities of products as well as reduction in the porosity of product is a good way to increase its resistance to slag.
The slag resistance of refractory material is typically tested with the crucible method, as well as using the method of rotary. The latter is the static slag resistance test method.
It could be a reflection of the chemical reaction between refractory and slag materials when heated to high temperatures. Through the examination of samples following slag corrosion as well as the analysis of the composition of metamorphic and slag-corrosion layers, it can help to study the process of erosion of refractory material by melting slag and adjust the chemical and mineral composition of refractory materials.
Testing and performance of Refractory materials
It is important in order to increase its resistance to erosion of slag. It is an active slag resistance test method. The molten slag as well as the Refractory material are both in motion. The temperature difference between the surface of work and the back of the material that is refractory. Slag is frequently replaced and is in line with the usage of the material used for refractory. It is comparatively close to be used to measure how much erosion, and penetration of the slag into refractory materials and can be useful in comparison of the slag resistance of Refractory materials.
1.) Method of resistance to slag in the Crucible
Crucible testing is the most commonly employed test method for evaluating the resistance to corrosion of slag in Refractory materials. It is easy and straightforward to apply and the slag corrosion results are quite easy to comprehend. But, due to the minimal quantity of slag incorporated into the crucible structure of the chemical composition shifts rapidly and can easily reach saturation when the amount of erosion in the refractory material increases throughout the testing. Additionally, the whole material remains in a non-isothermal static state and there isn't any temperature gradient in the material that is used to make the refractory. Furthermore, the slag exhibits no erosion and flow effect that is incompatible with actual applications and makes it difficult to assess the resistance to slag in Refractory materials.
The crucible of the shape-fitting refractory material could be removed from the material or created using a specific test mold machine. Crucible samples of unformed refractory materials should be pounded or poured to form a shape.
The crucible test block made of the material that can be cast is made by self-flow casting or vibration casting. The common crucible shape is illustrated in figure 6-8. After molding and casting it has been dried for 110degC for 24 hours. 110g of slag having particles smaller than 1mm was added to the. After the slag was burned at 1600degC for 3 hrs, the crucible evenly cut in two halves. The erosion and the penetration of the slag along the cross-section of the crucible were observed and compared. A quantitative conclusion could be drawn. The results of. When you measure, first trace a straight line across the central axis of section of the crucible that is parallel to the central axis with a distance of 10mm. Next, draw four straight lines that are symmetrical and determine the extent of slag erosion and penetration depth for every straight line location and then take the average.
2) Rotary anti-slag method
The rotary slag method is a fairly reliable test method to determine the Slag resistance of refractory materials and can be used for a variety of possible applications. The main advantages of this method include: 1. The device is quite simple to build and is much easy to build and take down the furnace. 2 The tests for slag resistance of several materials is possible to conduct simultaneously. 3. A layer may be created between the shell of the furnace with the material samples of the refractory, it is possible to build a layer of Insulation material thus an equivalent temperature gradient to that of the furnace could be created within the refractory material. 4 When refractory material samples that contain various chemical compositions and materials are produced simultaneously in a rotary furnace the adjacent samples will impact one another; 5 By control of heating, it causes fast cooling, and speedy heating for the sample. The thermal shock resistance and slag resistivity of the materials can be measured simultaneously.
When testing is conducted, the refractory samples are utilized to make an elongated hexagonal (usually hexagonal) test panel that serves as the lining for the rotary cylindrical furnace. The form and the assembly diagram of the specimen are depicted on Figure 6-10. The sample is heated to testing temperature using the help of a gas flame that is liquefied. The furnace is rotates experiencing the erosion and eroding of the slag chosen. The slag can be changed at the set time. Check the thickness of the sample prior to and after the test to determine the slag resistance of the sample.
3) Slag dissolution rate method
The resistance to slag of refractory materials employed in blast furnaces are typically measured by the rate of slag corrosion. The sample is submerged in blast furnace slag for 1490 degrees +10degC with nitrogen protection. After about 40 minutes of operation the sample is removed and cooled in water and then dried. slag that has adhered to the surfaces is removed and the test is weighted. Based on what the mass of your specimen determine the rate of corrosion by using the following formula.
R=100x(W1-W2)/W1
In the formula W1-weight of the sample prior to testing in G
The W2-weight (W2) of the specimen, after testing G
R erosion rate
Alongside indicating the thickness variation of one sample and every sample group after tests, form as well as the composition of slag as well as the total volume of the sample must be clearly identified, as should the appearance typical of each sample following the test should be described in detail in detail, including what the layer of reaction looks like, adhesion layer thickness and erosion characteristics, among others.
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