Discussion on the cause of burning through of refractory material in submerged arc furnace of mangan

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Discussion on the cause of burning through of refractory material in submerged arc furnace of manganese-silicon gold mineManganese-silicon alloy is a good deox

Discussion on the cause of burning through of refractory material in submerged arc furnace of manganese-silicon gold mine

Manganese-silicon alloy is a good deoxidizer in steelmaking industry, and it is the second most important alloy in ferroalloy production. With manganese silicon and the expansion of the gold ore heat furnace type, the emergence of the bottom of the molten iron wear accidents is also more and more, analyze the reason of the rising of the temperature in the bottom of the manganese silicon alloy furnace, furnace bottom and analyzing and burn through the cause of the accident, reduce and avoid the furnace bottom burn-out accident, to the stable production of manganese silicon alloy and the reducing of the cost

1, manganese silicon alloy has important significance to the erosion of carbon bricks

manganese silicon alloy furnace bottom density is larger because of its high density of manganese silicon alloy, and the denser alloy furnace bottom carbon block more serious scour, erosion, denser alloy slag on the osmosis of carbon blocks gap is larger, so the manganese silicon alloy furnace bottom is its also alloy furnace bottom life much shorter

(2) manganese silicon alloy easily increased carbon reaction of manganese and carbon brick can be generated and carbon Mn, c3. Mn3C , Mn2396, its 4Mn3C is also an essential intermediate gas in manganese silicon smelting.

(3) in the production of manganese silicon alloy with low basicity of slag erosion of carbon bricks manganese silicon alloy is commonly slant acid slag during smelting operations, and carbon brick of alkaline slag resistance strong, weak ability to resist acid slag, so the manganese silicon alloy in the process of smelting, slag on the erosion of carbon bricks is more serious than other alloy

2, measurement of the temperature of furnace bottom and cool

now large -arc furnace when the design is the bottom of the furnace temperature Measurement and cooling, but use manufacturer still continue operating mode, small furnace type for the measurement of the temperature of furnace bottom and cooling attention is not enough, often is the bottom of the furnace temperature is exorbitant, furnace bottom plate fever turns red to take measures to cool the furnace bottom irreversible deformation have occurred, cooling can only delay the furnace bottom, but the service life of furnace lining will be greatly reduced.

measurement of the temperature of hearth bottom

temperature can be measured at the bottom of the furnace lining embedded thermocouple, thermocouple can be buried in the three-phase electrode formation of the crucible were directly, because the temperature is one of the largest parts, furnace bottom of the conduction of the thermocouple temperature control range based on the depth of the thermocouple is buried decision, when the thermocouple inserted between the high alumina bricks and clay bricks, depth of 250 ~ 300 mm, hot thermocouple temperature control between 600-800 ℃ lower than 600 ℃ furnace bottom can stop the cooling, raise the temperature of the furnace bottom, reduce heat loss, thus improve the furnace temperature, saving energy and reducing consumption, thermocouple temperature higher than 800 c, the heat conduction to the furnace bottom plate, bottom plate, furnace bottom beams will heat deformation, which in turn will deformation and cracking furnace bottom shoot brick layer, this Should strengthen the furnace bottom cooling

The cooling of the bottom of the furnace is to use air cooling or water cooling. Because of the large investment in water cooling and the existence of great safety risks, fan cooling is more commonly used. Through the bottom of the furnace cooling can make the steel plate of furnace bottom and furnace bottom support steel at a reasonable temperature, keep the steel key degrees, according to the principle of solidification lining through the bottom of the furnace cooling can make the surface temperature of the carbon brick is lower than the solidification temperature of the molten slag, thus form a solidified on the surface of refractory layer

3, silicon manganese ore heat furnace in several problems that should be paid attention to in the design of manganese silicon alloy smelting of some unique The design of manganese-silicon furnace should be different from other ferroalloy furnace or calcium carbide furnace.

The refractory material should have enough heat preservation effect design should be done in detail thermal calculation, calculation value of the bottom steel plate temperature should not exceed 3509C, design calculation data is the basis of the furnace body material selection and masonry thickness. Generally speaking, due to the influence of refractory material quality and masonry quality, there are certain errors in calculation data, which should be fully considered in design.

There should be bottom temperature measurement and cooling scheme in the design of many manganese silicon alloy furnace is because the bottom temperature is too high, resulting in the softening of refractory brick sinking and bottom deformation sinking, furnace sinking will inevitably cause the deformation dislocation of carbon brick layer, the final result is the penetration of molten iron into the bottom. If there is no record of bottom temperature measurement, it is impossible to judge when the bottom wearing accident occurs, and it is also impossible to judge whether the bottom is worn before the bottom temperature rises, or the bottom is worn after deformation. The judgment and prevention of the cause of the accident cannot be carried out. Therefore, the temperature measurement and cooling design of the bottom of the furnace is not optional, nor can it be omitted because of the compression of investment costs. 3.3 Bottom support I-steel should have enough thermal strength. The strength of steel decreases sharply with the rise of temperature, when the temperature reaches 350℃, 500℃, 600℃:, the strength of steel is reduced by 1/3, 1/2 respectively. 1/3. When the load-bearing steel is subjected to 500℃C temperature for more than 15 minutes, it will deform and collapse. Therefore, the strength change of supporting I-steel after heating should be fully considered in the design, and the furnace bottom should be thickened or the refractory material with good heat insulation effect should be considered when necessary

4, furnace bottom masonry in qualified refractory cases, furnace masonry quality on the bottom of the furnace life influence is very big, so in the furnace is in the process of building must be in strict accordance with the design requirements and GBI211 industrial furnace lining engineering construction and acceptance specification requirements carefully all refractory masonry to ensure the qualified, general manufacturers to the demand is higher, the quality of refractory brick and carbon brick and correlation Fire soil, seam paste to examine lax, if the interaction between the degree of fire and composition of the differences, can produce crack after blowing in refractory and heat insulation materials especially magnesia materials to prevent be affected with damp be affected with damp, rainy areas of refractory materials piled up to have rain, refractory moisture is too large, the time needed for the oven will be extended. The seam of furnace body is the weakest link in the furnace body, and the lining life depends on the quality of the seam to a certain extent. When seamless masonry is built, the site should be pre-built, brick picking, and the seam finishing place should be strictly stitched and ramming. The site of masonry should be kept clean and debris should be strictly prevented from mixing.

5, oven new masonry furnace body contains a certain amount of water, if not through the oven directly feeding production at high temperature water vapor evaporation expansion will make furnace lining deformation or cracking. In addition, there is a certain gap in the ramming paste around the carbon brick, which can be melted and coking to form a dense whole and improve the life of the furnace lining. In the oven process, the carbon brick must be protected to prevent oxidation. In the oven process, the heat preservation of the refractory material at about 100℃ is conducive to the evaporation of water, and the slower temperature rise between 300-500℃ is conducive to the coking of ramming material.

6, manganese can react with carbon to generate a variety of manganese carbon compounds, if the furnace charge in the process of batching lack of carbon or local ingredients uneven will intensify the reaction of manganese and carbon brick, resulting in erosion of the furnace bottom. Operation in order to improve the si02 reactivity, average flow rate basicity control between 0.5 to 0.7, but low alkalinity can reduce slag melting point, carbon brick and slag layer between the lining is not easy to form of solidification, the slag is synchronous down on line the erosion of carbon bricks, slag on the erosion of carbon bricks intensified

7, epilogue

in the design of furnace bottom masonry material selection is not reasonable, and inadequate thickness of bottom is easy Increase the bottom temperature of the furnace.

The bottom of the furnace temperature measurement is not enough attention, no bottom cooling measures make the bottom of the furnace temperature continues to rise, the bottom of the furnace deformation and subsidence, and ultimately lead to the bottom wearing accident

refractory materials are not qualified, the bottom of the furnace, especially the brick joints at the masonry quality is not qualified, also prone to molten iron wearing accident.

The moisture of refractory material is too large, and heating up too fast is also one of the reasons for the cracking of furnace bottom.

Unreasonable treatment operation is also one of the reasons for the bottom wearing accident.