CN115389416A - Method for detecting kiln coating hanging performance of refractory bricks for cement kiln - Google Patents

Abstract

The invention provides a method for detecting the kiln coating hanging performance of refractory bricks for a cement kiln, which comprises the following steps: cutting three refractory brick sheets with the same size from the refractory brick to be tested; sequentially stacking three refractory brick sheets along the thickness direction of the refractory brick sheets to form a refractory brick sheet bonding body, wherein the end faces of the refractory brick sheets on two sides are aligned, the refractory brick sheet in the middle protrudes for a certain distance, cement raw slurry is coated between the contact surfaces of the adjacent refractory brick sheets, a heavy object is pressed on the refractory brick sheet bonding body, and after the slurry is solidified, the refractory brick sheet bonding body and the heavy object are placed into a high-temperature furnace together for sintering; the taken-out firebrick sheet bonding body is vertically placed, supports are respectively placed on two sides of the firebrick sheet bonding body, then a vertical downward load is applied to the protruded middle firebrick sheet, the pressure F when the middle firebrick sheet is separated from the firebrick sheets on the two sides is measured, and the pressure is a quantitative index of the kiln coating hanging performance of the firebrick for the cement kiln. The method can accurately and quantitatively detect the kiln coating hanging performance of the refractory brick for the cement kiln.

Description

A performance test method for hanging refractory bricks for cement kilns

technical field

The invention relates to the technical field of evaluation of refractory materials, in particular to a method for detecting the performance of hanging kiln skins of refractory bricks used in cement kilns.

Background technique

Cement rotary kiln refractory bricks are commonly used as kiln lining materials in cement kilns. Their main function is to protect the kiln shell from damage by high-temperature gas and high-temperature materials and ensure normal production. With the improvement of cement kiln production process and mechanical properties, and the increasing output, the requirements for refractory materials are becoming more and more stringent. The area where refractory bricks are used in the firing zone is the area with the highest process temperature. During their service, they will suffer multiple damages such as clinker liquid phase erosion, alkali and salt penetration, thermal shock fluctuation damage caused by kiln skin shedding, and structural spalling.

The so-called kiln skin is a layer of sintered clinker attached to the inner surface of the rotary kiln firing belt kiln lining. This ability to form a kiln skin on the surface of the refractory kiln lining is called the hanging kiln skin performance. During the normal production process of any cement rotary kiln, a layer of uniform, stable and suitable thickness of the kiln skin needs to be adhered to the hot surface of the firing zone refractory bricks. Fluctuation damage is of great help and is essential to prolong the service life of refractory bricks and the long-term, efficient and safe operation of the rotary kiln.

In recent years, there are mainly Holderbank method, drum method, three-point flexural method and static shear method for testing refractory bricks used in cement kilns.

The Holderbank method is to place a refractory brick sample at the bottom of a gas heating furnace, and place cement raw materials on it for heat treatment, while cooling the back of the refractory brick sample. The Holderbank method can generate a suitable temperature field inside the refractory brick and the cement clinker can fully penetrate into the hot surface layer of the refractory brick, and can better simulate the condition of the floor hanging kiln skin in the actual use of the refractory brick. Expensive, and cannot quantify the kiln skin performance of refractory bricks.

The rotary drum method is to build refractory bricks in a small rotary kiln. After heating to the set temperature with a burner, the rotary kiln rotates and adds raw cement several times. After cooling, observe the thickness of the kiln cortex on the surface of the refractory bricks. Determine the kiln skin hanging performance of refractory bricks. This method is a dynamic method, which can better simulate the production state of cement rotary kiln, is more practical, and can effectively avoid the hang-up caused by too little liquid phase or too much liquid phase of cement raw material measured by the static kiln hanging skin method. The illusion that the kiln skin is stronger. However, this method cannot quantitatively detect the performance of refractory bricks hanging on the kiln skin, and the operation process is complicated, and the experimental cost is relatively large.

The three-point flexural method is a static method, and the cement clinker is sandwiched between two refractory brick samples for detection. Due to the small contact area between the cement clinker and the brick surface, the combination is not stable when the high temperature furnace is processed, and the refractory brick and the brick surface are not stable. The clinker contact surface is easy to be dislocated. In addition, due to the small bonding area between the brick surface and the clinker, the corresponding bonding force is also small. The sampling and testing process can easily destroy the bonding force between the cement and the refractory brick surface, resulting in the failure of the test and the inaccuracy of the test data. The error is large and the repeatability is poor. Although it can be quantified, it is not accurate enough.

The static shearing method is to place an appropriate amount of preheated cement raw material evenly between the two cut pieces of refractory bricks, heat them together with the support in the furnace and cool them down, then stand the bricks upright and press them vertically to the cut surface of the refractory bricks Separation, the size of the pressure is the performance of the hanging kiln skin. This detection method ignores the friction between the brick and the cement clinker, and the measured pressure value may not be able to objectively reflect the bonding strength between the brick surface and the cement clinker. , and this method is relatively difficult to prepare samples.

Therefore, there is an urgent need to improve the existing performance testing methods for hanging kiln skins.

Contents of the invention

The invention provides a method for detecting the kiln skin hanging performance of refractory bricks used in cement kilns, which can quantitatively detect the kiln skin hanging performance of refractory bricks used in cement kilns.

The invention provides a method for testing the performance of hanging kiln skin of refractory bricks used in cement kilns, which comprises the following steps:

(1) Cut out three refractory brick slices of the same size from the refractory brick to be tested, and then cut out a heavy object from the same refractory brick to be tested;

(2) Three refractory brick slices are stacked sequentially along the thickness direction to form a bonded body of refractory brick slices. The end faces of the refractory brick slices on both sides are aligned, and the middle refractory brick slice protrudes for a certain distance. Between the contact surfaces of adjacent refractory brick slices Smear cement raw material slurry between them, press the weight obtained in step (1) on the refractory brick sheet bonded body, put the refractory brick sheet bonded body and the weight into a high-temperature furnace for sintering together after the slurry is solidified;

(3) The taken-out refractory brick sheet bonded body is placed vertically, and supports are placed on both sides to fix the refractory brick sheet bonded body, and then a vertical downward load is applied to the protruding middle refractory brick sheet, and the middle refractory brick is measured. The pressure F when the flakes are separated from the refractory brick flakes on both sides, the pressure F is the quantitative index of the performance of hanging the kiln skin of the refractory bricks used in cement kilns.

It should be noted that when cutting the refractory brick slice in step (1), it can be cut from any direction of the refractory brick, so as to ensure the size of the refractory brick slice. Preferably, the refractory bricks are cut vertically along the length direction, which is easy to operate and easy to cut. The length, width, and thickness mentioned in the present invention generally refer to the length (degree) of the longest side, the thickness (degree) of the shortest side, and the width (degree) between the two. The vertical placement in step (3) means that the length direction is perpendicular to the ground.

According to the method for testing the performance of hanging kiln skin of refractory bricks used in cement kilns provided by the present invention, in step (1), the length × width × thickness of the refractory brick slice is: (114±2)mm×(65±2)mm× (10±2) mm.

According to the performance testing method of hanging refractory bricks for cement kilns provided by the present invention, in step (1), the weight of the weight is 3000-4000g, and further controlled at 3250-3600g.

According to the performance testing method of refractory brick hanging kiln skin for cement kiln provided by the present invention, in step (2), the consumption of described cement raw slurry is to meet the thickness of the bonding joint between adjacent refractory brick sheets at 2 ± 0.05mm. allow. For details, please refer to the building materials industry standard JC/T 2463-2018 (refractory materials for cement kiln hanging kiln skin performance - static test method) brick joint thickness requirements.

According to the method for detecting the performance of hanging kiln skin of refractory bricks used in cement kilns provided by the present invention, in step (2), the preparation of the cement raw material slurry includes: weighing a certain amount of cement raw material, pouring it into a mortar and grinding until all Pass through a 0.088mm standard sieve, then add the same amount of glycerin, mix and grind evenly, and set aside.

According to the method for testing the performance of hanging kiln skins of refractory bricks for cement kilns provided by the present invention, the cement raw meal is cooled cement raw meal pre-calcined at 1050° C.-1150° C. for 2-4 hours.

According to the detection method for hanging kiln skin performance of refractory bricks used in cement kilns provided by the present invention, the purity of the glycerol is chemically pure.

According to the performance testing method for hanging refractory bricks for cement kilns provided by the present invention, in step (2), the protruding distance of the middle refractory brick slices is 10-20 mm. The present invention finds that if the protrusion distance is less than 10 mm, it is not easy to observe the phenomenon of cracking and separation of the refractory brick sheet bonding body when applying a vertical downward load; if the protrusion distance is greater than 20 mm, the area of the bonding contact surface is reduced too much, It is not conducive to enlarging the hanging kiln skin force of refractory bricks, and reduces the accuracy of the determination of hanging kiln skin performance.

In a specific embodiment of the present invention, the length×width×thickness of the refractory brick sheet is 114mm×65mm×10mm, and the protruding distance of the refractory brick sheet in the middle of the bonded body of the refractory brick sheet is 14mm.

According to the detection method for hanging kiln skin performance of refractory bricks used in cement kilns provided by the present invention, in step (2), the high-temperature furnace is heated to 1450-1550 ° C, kept for 3-5 hours, and the refractory bricks are naturally cooled to room temperature. The laminate bond was removed from the high temperature furnace.

According to the method for testing the performance of hanging refractory bricks for cement kilns provided by the present invention, in step (3), a vertical downward load of 0.05±0.005MPa/s is applied to the protruding middle refractory brick slices.

The invention provides a method for testing the performance of the hanging kiln skin of refractory bricks used in cement kilns, that is, the interlayer method. Compared with the dynamic method for testing the performance of the hanging kiln skin, the interlayer method of the present invention has the advantages of quantification, simple operation, and low experimental cost. ; Compared with other static methods for testing the performance of hanging kiln skins, the interlayer method of the present invention has the advantages of stable detection data, good repeatability and better operability. In addition, the present invention increases the contact area between refractory bricks and cement raw materials to provide cohesive force, thereby better and more accurately distinguishing the performance of hanging kiln skins of different refractory bricks, and further improves the performance detection method of existing refractory materials .

Description of drawings

Fig. 1 is the schematic diagram of placement mode of refractory brick thin slice bonding body in the heating process of the present invention;

Fig. 2 is a schematic diagram of the placing method of the refractory brick sheet bonded body during the loading process of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Apparently, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Example 1

This embodiment provides a method for testing the performance of hanging refractory bricks for cement kilns, and the operation steps are as follows:

a. Cut out three refractory brick slices from the refractory brick (magnesia-iron brick) to be tested. The length × width × thickness of the refractory brick slice is: 114mm × 65mm × 10mm; objects, the weight of which is 3460g;

b. Cement raw meal preparation: Weigh a certain amount of cement raw meal (cooled cement raw meal pre-calcined at 1100°C for 2-4 hours in a high-temperature furnace), pour it into a mortar and grind until it passes through a 0.088mm standard sieve , then add an equal amount of glycerol, mix and grind evenly and set aside;

c. Take a certain amount (to control the thickness of the bonding joint within 2mm) of cement raw material slurry and evenly spread it on the plane where the length and width of the refractory brick sheet are located, and stack them sequentially along the thickness direction (that is, the direction of the side length of 10mm) to form refractory bricks Sheet bonded body, wherein the middle refractory brick sheet protrudes 14mm, press the heavy object in step a and scrape off the excess slurry, as shown in Figure 1, after the slurry is solidified, put the refractory brick sheet bonded body and the heavy object together into the high temperature furnace;

d. Heating to 1500°C in a high-temperature furnace, keeping it warm for 4 hours, and removing the bonded body from the high-temperature furnace after naturally cooling to room temperature;

e. Place the refractory brick sheet bonded body vertically, place a support on each side to fix the bonded body, and then apply a vertical downward load at 0.05±0.005MPa/s to the protruding middle refractory brick sheet, as shown in Figure 2 It shows that the pressure F when the refractory brick sheet in the middle is separated from the refractory brick sheet on both sides is measured, and this pressure is the quantitative index of the performance of the refractory brick used in cement kiln to hang the kiln skin. When the measured F value is greater than 10KN, it shows that the magnesia-iron brick has good performance of hanging the kiln skin.

Example 2

This embodiment provides a method for testing the performance of hanging refractory bricks for cement kilns, and the operation steps are as follows:

a. Cut out three refractory brick slices from the refractory brick (magnesia-aluminum brick) to be tested. The length × width × thickness of the refractory brick slice is: 114mm × 65mm × 10mm; objects, the weight of which is 3320g;

b. Cement raw meal preparation: Weigh a certain amount of cement raw meal (cooled cement raw meal pre-calcined at 1150°C for 2-4 hours in a high-temperature furnace), pour it into a mortar and grind until it passes through a 0.088mm standard sieve , then add an equal amount of glycerol, mix and grind evenly and set aside;

c. Take a certain amount (to control the thickness of the bonding joint within 2mm) of cement raw material slurry and evenly spread it on the plane where the length and width of the refractory brick sheet are located, and stack them sequentially along the thickness direction (that is, the direction of the side length of 10mm) to form refractory bricks Sheet bonded body, wherein the middle refractory brick sheet protrudes 18mm, press the heavy object in step a and scrape off the excess slurry, as shown in Figure 1, after the slurry is solidified, put the refractory brick sheet bonded body and the heavy object together into the high temperature furnace;

d. Heating in the high temperature furnace to 1550°C, keeping it warm for 3 hours, and removing the bonding body from the high temperature furnace after naturally cooling to room temperature;

e. Place the refractory brick sheet bonded body vertically, place a support on each side to fix the bonded body, and then apply a vertical downward load at 0.05±0.005MPa/s to the protruding middle refractory brick sheet, as shown in Figure 2 It shows that the pressure F when the refractory brick sheet in the middle is separated from the refractory brick sheet on both sides is measured, and this pressure is the quantitative index of the performance of the refractory brick used in cement kiln to hang the kiln skin. When the measured F value is greater than 4KN, it shows that the magnesia-alumina brick has better performance of hanging the kiln skin.

In summary, the interlayer method of the present invention is more operable than the static shearing method. The static shearing method needs a special mold to be fixed when cutting samples. The actual refractory bricks are not easy to fix firmly because of size deviation. The block is easy to slide, resulting in a large error in cutting size. In addition, compared with the static shearing method, the interlayer method of the present invention can double the cohesive force when the size is the same, which can reduce the influence of human error and equipment error in the experiment process, and can hang different refractory bricks weakly. The kiln skin force is distinguished, which is more accurate.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A cement kiln is characterized in that, comprises the following steps: (1) Cut out three refractory brick slices of the same size from the refractory brick to be tested, and then cut out a heavy object from the same refractory brick to be tested; (2) Three refractory brick slices are stacked sequentially along the thickness direction to form a bonded body of refractory brick slices. The end faces of the refractory brick slices on both sides are aligned, and the middle refractory brick slice protrudes for a certain distance. Between the contact surfaces of adjacent refractory brick slices Smear cement raw material slurry between them, press the weight obtained in step (1) on the refractory brick sheet bonded body, put the refractory brick sheet bonded body and the weight into a high-temperature furnace for sintering together after the slurry is solidified; (3) The taken-out refractory brick sheet bonded body is placed vertically, and supports are placed on both sides to fix the refractory brick sheet bonded body, and then a vertical downward load is applied to the protruding middle refractory brick sheet, and the middle refractory brick is measured. The pressure F when the flakes are separated from the refractory brick flakes on both sides, the pressure F is the quantitative index of the performance of hanging the kiln skin of the refractory bricks used in cement kilns. 2. The method for testing the performance of hanging refractory bricks for cement kilns according to claim 1, wherein in step (1), the length × width × thickness of the refractory brick sheet is (114 ± 2) mm × (65±2)mm×(10±2)mm. 3. The method for testing the performance of hanging refractory bricks for cement kilns according to claim 2, characterized in that, in step (1), the weight of the weight is 3000-4000g. 4. the refractory brick hanging kiln skin performance detection method for cement kiln according to claim 1, is characterized in that, in step (2), the consumption of described cement raw slurry satisfies the bonding between adjacent refractory brick flakes The seam thickness shall prevail at 2±0.05mm. 5. the refractory brick hanging kiln skin performance detection method for cement kiln according to claim 4, is characterized in that, in step (2), the preparation of described cement raw meal slurry comprises: take a certain amount of cement raw meal, Pour it into a mortar and grind until it passes through a 0.088mm standard sieve, then add an equal amount of glycerol, mix and grind evenly, and set aside. 6 . The method for testing the performance of hanging refractory bricks for cement kilns according to claim 5 , wherein the cement raw meal is cooled cement raw meal pre-calcined at 1050° C.-1150° C. for 2-4 hours. 7. The method for detecting the performance of hanging kiln skin with refractory bricks for cement kilns according to claim 5, characterized in that, the purity of the glycerol is chemically pure. 8. The method for testing the performance of hanging refractory bricks for cement kilns according to claim 1, characterized in that, in step (2), the protruding distance of the refractory brick sheets in the middle is 10-20mm. 9. The method for testing the performance of hanging refractory bricks for cement kilns according to claim 1, characterized in that in step (2), the high-temperature furnace is heated to 1450-1550 ° C, kept for 3-5 hours, and naturally cooled After reaching room temperature, the refractory brick sheet bonded body is removed from the high temperature furnace. 10. The method for testing the performance of hanging refractory bricks for cement kilns according to claim 1, characterized in that, in step (3), a vertical pressure of 0.05 ± 0.005MPa/s is applied to the protruding middle refractory brick slices. charge.

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