Construction method for digging and repairing kiln refractory bricks after brick falling

Abstract

The invention relates to a construction method for digging and repairing after brick falling of kiln refractory bricks. The method comprises the following steps: step 1, determining positions of collapse, collapse and brick falling of the refractory bricks built in a kiln and a range in which the refractory bricks need to be repaired; 2, residual refractory bricks at local falling brick and loose and collapsed positions of the refractory bricks of the furnace kiln are cleaned, normal masonry door closing construction can be adopted for local masonry and replacement of new refractory bricks until door closing refractory brick construction cannot be conducted, and notch positions are reserved, and 3, stainless steel anchoring parts are welded to the steel cylinder of the furnace kiln in the notch positions; 4, a high-temperature-resistant fiber blanket is placed at the position, close to the inner surface of the steel cylinder, in the notch for heat insulation; 5, adding water and steel fibers into the high-strength castable, stirring for 5-8 minutes, ramming the castable in the notch position, and compacting; and 6, after the castable is poured, maintenance is conducted for 11-13 hours, and the special supporting piece is dismantled. And 7, kiln drying is carried out to recover production.

Description

Technical Field

[0001] The invention relates to the field of furnace refractory brick masonry construction, and mainly relates to a construction method for repairing refractory bricks of horizontal furnaces such as hot blast furnaces and rotary kilns after local brick falling occurs. Background Art

[0002] Hot blast furnaces and rotary kilns are key equipment for processing and manufacturing in cement, building materials, steel and other industries. The appearance of the furnace body is generally a horizontal cylinder shape. The inner lining of the furnace is generally made of an inner ring of refractory bricks. The refractory bricks are wedge-shaped refractory bricks (one end is large and the other end is small) and are laid in rings. When each ring is laid to the last 2-3 refractory bricks, the "door closing" construction is carried out. The last refractory brick is called the door closing brick. The door closing brick is knocked in from the side to make the entire ring of refractory bricks compact, and then the next ring of refractory bricks is laid.

[0003] In daily furnace production, refractory bricks are inevitably broken and dropped due to the scouring of furnace airflow, friction of sintering materials, alternating changes in temperature stress (kiln shutdown), and quality problems of the refractory bricks themselves or masonry quality. Compared with local broken bricks, local brick dropping is a more serious fault and needs to be repaired immediately; otherwise, after brick dropping, due to the lack of support from the front and rear refractory bricks, the entire ring of refractory bricks will loosen, fall off and move, and then gradually develop into "loosening and collapsing" of refractory bricks, forcing the furnace to be stopped for emergency repairs and maintenance.

[0004] Generally, there is a problem of "falling bricks" in some parts of the refractory bricks in the kiln. During the repair, since there is no way to carry out the closing construction of a single refractory brick by conventional methods, it is basically necessary to remove the refractory bricks from the damaged position to the head or tail of the kiln, and then rebuild the refractory bricks; if the refractory bricks fall in the middle of the kiln, then the entire demolition and reconstruction project will be relatively large, the maintenance time will be long, the material consumption cost will be high, and the impact on the production of the kiln will also be great. Summary of the invention

[0005] The present invention provides a construction method for excavating and repairing refractory bricks after they fall off in a furnace, mainly solving the technical problem that after the refractory bricks in the furnace are partially rotated, large-scale demolition and re-laying are generally required. The present invention provides a construction method for excavating and repairing refractory bricks in the furnace after they are partially rotated, instead of adopting the conventional large-scale re-laying method, a method for excavating and repairing refractory bricks is adopted using special tools, anchors and high-strength castables.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A construction method for excavating and repairing refractory bricks after bricks fall off during kiln masonry construction, the method comprising the following steps

[0008] Step 1: Determine the location where the refractory bricks in the kiln are loose, collapsed, or falling, and the range of refractory bricks that need to be repaired; use two or more special support tools with adjustment functions to support the refractory bricks outside the range that needs local repair, see the schematic for details Figure 1 , to ensure that the normal refractory bricks outside the repair range (no need to repair) will not loosen or move. Other technical characteristics require that the support force applied by the special tool should be about 2 times the yield strength of the refractory bricks according to the physical and chemical indicators of the refractory bricks.

[0009] Step 2: Clean the remaining refractory bricks in the local fallen bricks and loose positions of the furnace refractory bricks. Normal masonry and door closing construction can be used to carry out local masonry and replace new refractory bricks until the door closing refractory brick construction cannot be carried out, leaving the gap position. For details, see Figure 2 The technical characteristics require that the size of the gap should be within the size range of a whole brick. If it does not meet the requirements, other refractory bricks that have been laid should be cut. The size requirements of the refractory bricks to be cut should be in accordance with the requirements of GB50211-2014 "Construction and Acceptance Specifications for Industrial Furnace Masonry Projects" and GB50309-2007 "Quality Acceptance Specifications for Industrial Furnace Masonry Projects". At the same time, other technical characteristics require that the cut bricks are not constructed in Notch location Front and back parts.

[0010] Step 3: Weld the stainless steel anchor to the steel cylinder of the furnace in the notch. The technical characteristics require that the stainless steel anchor should be a "branch" type, and the length of the anchor should be 2 / 3 the length (depth) of the refractory brick. For details, see Figure 2 .

[0011] Step 4: Place a high-temperature resistant fiber blanket near the inner surface of the steel cylinder in the notch for heat insulation; the technical characteristics require that the high-temperature resistant fiber blanket be 10-20mm thick to reduce heat conduction and heat dissipation.

[0012] Step 5: Add water and steel fiber to the high-strength castable and stir for 5-8 minutes. Ram the castable in the notch and make it dense. The technical characteristics require that the high-strength castable is a corundum wear-resistant castable. For details, see Figure 2 , corundum wear-resistant castable, the composition is as follows:

[0013] name <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> CaO MgO <![CDATA[K2O]]> <![CDATA[Na2O]]> White Corundum 99.54 0.12 0 0 0.06 0.28

[0014] Step 6: After pouring the castable, cure it for 12 hours and remove the special supports.

[0015] Step 7: Dry the kiln and resume production.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] A construction method for "digging and repairing" refractory bricks after they are turned around in the kiln masonry. Instead of removing most of the refractory bricks and rebuilding them in the conventional way, special tools, anchors and high-strength castables are used for digging and repairing, which solves the problem of large-scale removal of refractory bricks and achieves the characteristics of short time consumption and low material consumption. Compared with conventional refractory brick masonry repair construction, it has obvious advantages:

[0018] (1) There is no need to remove the damaged refractory bricks on a large scale and then rebuild them. The present invention can reduce the original construction workload by 90%;

[0019] (2) Conventional repair construction in the past also required a certain amount of new refractory bricks for construction, while the present invention only requires a very small amount of high-strength wear-resistant corundum castable, which is only the amount of castable in the shape of a door brick;

[0020] (3) With the "excavation and repair" construction method of the present invention, the construction time plus the curing time of the castable generally only takes about 16 hours (including the curing time of the castable), which is 5-6 days less than the conventional demolition and re-bricking process which takes 6-7 days.

[0021] The "digging and repairing" construction method of the present invention can greatly reduce material consumption and repair time, and directly reduce maintenance costs and production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the construction structure for excavating and repairing a furnace after partial brick loss according to the present invention;

[0023] Figure 2 Schematic diagram of the excavation and repair construction method of the present invention.

[0024] In the figure: 1- high-strength castable, 2- stainless steel anchor, 3- refractory brick, 4- special support. DETAILED DESCRIPTION

[0025] Embodiment 1: A construction method for excavating and repairing refractory bricks after bricks fall off during kiln masonry construction, the method comprising the following steps

[0026] Step 1: Determine the location where the refractory bricks in the kiln are loose, collapsed, or falling, and the range of refractory bricks that need to be repaired; use two or more special support tools with adjustment functions to support the refractory bricks outside the range that needs local repair, see the schematic for details Figure 1 , to ensure that the normal refractory bricks outside the repair range (no need to repair) will not loosen or move. Other technical characteristics require that the support force applied by the special tool should be about 2 times the yield strength of the refractory bricks according to the physical and chemical indicators of the refractory bricks.

[0027] Step 2: Clean the remaining refractory bricks in the local fallen bricks and loose positions of the furnace refractory bricks. Normal masonry and door closing construction can be used to carry out local masonry and replace new refractory bricks until the door closing refractory brick construction cannot be carried out, leaving the gap position. For details, see Figure 2 The technical characteristics require that the size of the gap should be within the size range of a whole brick. If it does not meet the requirements, other refractory bricks that have been laid should be cut. The size requirements of the refractory bricks to be cut should be in accordance with the requirements of GB50211-2014 "Construction and Acceptance Specifications for Industrial Furnace Masonry Projects" and GB50309-2007 "Quality Acceptance Specifications for Industrial Furnace Masonry Projects". At the same time, other technical characteristics require that the cut bricks are not constructed in Notch location Front and back parts.

[0028] Step 3: Weld the stainless steel anchor to the steel cylinder of the furnace in the notch. The technical characteristics require that the stainless steel anchor should be a "branch" type, and the length of the anchor should be 2 / 3 the length (depth) of the refractory brick. For details, see Figure 2 .

[0029] Step 4: Place a high-temperature resistant fiber blanket near the inner surface of the steel cylinder in the notch for heat insulation; the technical characteristics require that the high-temperature resistant fiber blanket be 10-20mm thick to reduce heat conduction and heat dissipation.

[0030] Step 5: Add water and steel fiber to the high-strength castable and stir for 5-8 minutes. Ram the castable in the notch and make it dense. The technical characteristics require that the high-strength castable is a corundum wear-resistant castable. For details, see Figure 2 , corundum wear-resistant castable, the composition is as follows:

[0031] name <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> CaO MgO <![CDATA[K2O]]> <![CDATA[Na2O]]> White Corundum 99.54 0.12 0 0 0.06 0.28

[0032] Step 6: After pouring the castable, cure it for 12 hours and remove the special supports.

[0033] Step 7: Dry the kiln and resume production.

[0034] Example 2: Reference Figure 1 and Figure 2 Taking the local excavation and repair of refractory bricks of Ф1700mm rotary kiln as an example, the specific implementation process is as follows:

[0035] (1) First, use two or more special support tools 4 with adjustment functions to support the refractory bricks outside the area that needs to be repaired locally, as shown in the schematic diagram. Figure 1 ;

[0036] (2) Clean the refractory bricks that are partially loose inside the rotary kiln and the remaining refractory bricks around the fallen bricks, lay wedge-shaped refractory bricks 3 in the allowed construction space, and leave a refractory brick space by processing the refractory bricks;

[0037] (3) Welding a stainless steel anchor 1 to the furnace steel cylinder at the notch position, and the material of the stainless steel anchor 1 is 1Cr13;

[0038] (4) Place a 10-20 mm thick high temperature resistant fiber blanket near the inner surface of the steel cylinder for heat insulation;

[0039] (5) Ramming the corundum wear-resistant castable 2 in the notch and vibrating it to make it compact;

[0040] (6) Casting the corundum wear-resistant castable 2, curing for 12 hours, and removing the special support 4;

[0041] (7) After curing, clean the local construction area and dry the kiln to resume production.

[0042] It should be noted that the above embodiments are not intended to limit the protection scope of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions all fall within the protection scope of the claims of the present invention.

Claims

1. A construction method for excavating and repairing refractory bricks in a furnace after bricks have fallen off, characterized in that: The method comprises the following steps: Step 1: Determine the location where the refractory bricks in the kiln are loose, collapsed, or falling, and the scope of the refractory bricks that need to be repaired; Step 2: Clean the remaining refractory bricks in the local fallen bricks and loose positions of the kiln refractory bricks. Normal masonry and door closing construction can be used to carry out local masonry and replace new refractory bricks until the door closing refractory brick construction cannot be carried out, leaving the gap position. Step 3: Weld the stainless steel anchors to the steel cylinder of the furnace in the notch. The stainless steel anchors are "branch" type and the length of the anchors is 2 / 3 of the length of the refractory bricks. Step 4: Place a high temperature resistant fiber blanket near the inner surface of the steel cylinder in the notch for heat insulation; Step 5: Add water and steel fiber to the high-strength castable and stir for 5-8 minutes. Ram the castable in the notch and make it dense. The high-strength castable is a corundum wear-resistant castable. Step 6: After pouring the castable, cure for 11-13 hours and remove the special support. Step 7: Dry the kiln and resume production.

2. The construction method for excavating and repairing furnace refractory bricks after bricks fall off according to claim 1, characterized in that: In step 3, a stainless steel anchor (2) is welded to the furnace steel cylinder at the notch position, and the material of the stainless steel anchor (2) is 1Cr13.

3. The construction method for excavating and repairing furnace refractory bricks after bricks fall off according to claim 2, characterized in that: The corundum wear-resistant castable in step 5 has the following composition in terms of mass percentage: 。 4. The construction method for excavating and repairing furnace refractory bricks after bricks fall off according to claim 3, characterized in that: The high temperature resistant fiber blanket is 10-20mm thick to reduce heat conduction and heat dissipation.

5. The construction method for excavating and repairing furnace refractory bricks after bricks fall off according to claim 2, characterized in that: Follow step 6 for 12 hours.

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