Blast furnace is a kind of melting equipment that stays in high temperature for a long time continuously. In the long-term operation, the inside lining can be eroded, peeled off or damaged easily, which affects the normal operation of furnace deeply. In order to achieve great longevity and high efficiency for furnace, prolonging the life of furnace has been a great concern for melting engineers. Furnace’s longevity is one of the indicators for melting technology. Currently, in China, people widely use remote control hot spraying to repair lining, that is, repairing the lining during the blowing down period while the furnace is still working.
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dry spraying |
At present domestic has begun generally adopted remote control hot spraying fill blast furnace lining, is made on the premise of furnace using blast time on the inner spray to mend。[More]
Disadvantage 1:Spraying coating without water-reducing agent;
Disadvantage 2:Water added large and uncertain, uneven;
Disadvantage 3:Massive bounce, fine material enrichment, cement enrichment;
Disadvantage 4:Samples and physical discrepant;
Disadvantage 5:Ingredients of fine granularity is slants thin;
Disadvantage 6:Explosion-proof fiber is difficult to add; |
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wet spraying |
This technical implementation is can be made lining operating life reach 18 to 24 months，with the energy conservation, environmental protection, low carbon effect.[More]
Advantage1:With enough mixing time, water saving dispersant can be made the best use;
Advantage2:Less water added, the strength and abrasive resistance would improve;
Advantage3:Water and related materials would not be separated and the spraying coating would be more well-distributed and intense;
Advantage4:Rebound degree would be reduced obviously and rebounding of large particles will not exist and particle size would remain as designed.（Only about 5%）;
Advantage5:No dust when spraying; |
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A six-step decryption - “Remote control wet spraying technique for making lining for furnace ”advantage |
Use
RGP-M1 wet spraying castables--- used on the upper and middle part of furnace’s stack during hot spraying repair.RGP-A1 wet spraying castables --- used on the under- part of furnace’s stack during hot spraying repair.…[More]
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Technique characteristic
Wet spraying coating compared to dry spraying coating:With long mixing time：water saving dispersant can be made the best use. Less water added：Wet spraying technique water added for 6-8%，dry spraying coating water added for 12-15%；High strength ：Water and related materials would not be separated and the spraying coating would be more well-distributed and intense, abrasive resistance would improve.Rebound degree would be reduced obviously （particle size would remain as designed.）：Wet spraying resilient degree < 5%, dry spray resilient degree> 15 percent.Environmental pollution reducing ：No dust when spraying…[More]
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Preparation for spraying
Preparation : Relevant personnels and equipments enter into the field one day in advance. Safety personnel from Party A conduct safety education and make it clear how to identify hazards. Technological personnel from Part A pass on technological details and make sure the equipments installed and run properly.Banked fire：Party A is responsible to drop burden surface （dropped to under tuyere）， sealed by certain thickness（100-300mm） along the water residue, so that the temperature in the furnace is lower than 300℃.Meanwhile furnace gas quantity control in 50ppm.…[More]
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execution of works
cleaning with high pressure water：Our company clean the chamber wall and cooling wall with 400kg high pressure water from up to down. In order to remove dirt, float ash and slag, tumors already loose parts.Spraying：Start the equipment, pour the materials into the continuous mixer connected with spraying machine , add water mixing continuously; Put the materials mixed into the spraying maching which is carried into the remote rotating spray gun. Adjust the metering pump of accelerating agent appropriately so that the castables sprayed would not spread out excessively after repairing. Adjust the rotation speed and rotation direction of remote spray manipulator to make the thickness of spraying coating well-proportioned and appropriate. Through telecontrolling four electric hoists, spray evenly from bottom relying on positioning rule until the repair is over. …[More]
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baker
After coating spray, rake out the residue through tuyere cooler. Reinstall the tuyere.By alternately open radiation tube as close monitoring after baking 36 hours , In order to ensure the furnace running smooth.Without baking, the coating would be peeled off and that would affect the its life and proper operation of furnace greatly.…[More]
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Equiblasting and starting furnace
The wind is carried on through tap hole with a wind pipe that is connected with the blast pipe from the air heating furnace (as shows in Diagram 1). This can ensure good connection between tap hole and tuyere, which helps keep the melten iorn and slag liquid at the tap hole. That would help the furnace work properly. Equiblasting operating process is as follows: Cut a hole on tap hole part with a drill. The hole cut must match the blast pipe. Connect the main branch hot air pipe above, which sends the hot air into tap hole(not tuyere). Keep the section valves in the furnace closed and all tuyeres open; Keep blowing through tap hole for eight hours, open the section valves sending the hot air into furnace, after that, take out all hot air pipes from tap hole. That is all for the euiblasting and starting furnace process. …[More]
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