Fireproof industry is used high pure the agglomeration of raw material and hi-tech oxide are refractory products is firing finish in kiln of superhigh temperature furnace. The pit of superhigh temperature furnace that uses as a result of fireproof industry is a lot of more phyletic, introduce impossibly one by one, below only high pure the case that the superhigh temperature shaft furnace of magnesia agglomeration and hi-tech oxide tie the kiln of superhigh temperature channel with refractory firing products to use fireproof data makes some of simple specification.
1, superhigh temperature perpendicular kiln uses fireproof data
Magnesia of tall purity, low porosity, thick grain is magnesium of manufacturing special type the raw material of simple fireproof stuff. To promote Fang Mei stone grain is brought up, use previously add a few (the oxide of the Cr203 that is less than 0.5%) , Fe203, Zr02 and Ti, V, Mn, Al, Cu and rare-earth element and salt kind method. Although these material promote MgO compact the mechanism that changes He Jing bead to be brought up is not same, but they are to use the method that diffuses quickly to come true. Be this kind of reason, they also reduced the thermochemistry stability of material, form in crystal boundary fuse-element when action especially on (wait like Fe203) when more such. This explains, if do not want to reduce the thermochemistry stability of magnesian simple fireproof stuff, ought to avoid to add other and foreign material to its interior.
Below the condition that does not add foreign material, its technology measure is to use oxyhydrogen of 5000 ℃ pretreatment to change magnesium or magnesite of 900 ℃ pretreatment, handle active MgO stock next (fine grind) , be in ball / pressure piece before add a person to perhaps do not add inert MgO any crystalline substance kind, control a ball via high pressure again / control base, hind the agglomeration in kiln of furnace of Yu Chao high temperature, make take special type magnesia.
Afore-mentioned these technical measure can reduce the porosity that prevents crystallization action, improve send density, below the condition that does not have agglomeration accelerant, can bring about grain of square magnesian stone to be brought up likewise.
If be burned to death,undertake inside rotary kiln, so even if reachs upper limit temperature (1900-2000 ℃ ) , and be lengthened inside time, in order to increase calcination strength, if does not have special measure, also can obtain grain diameter to be the magnesia of 50-120um about only. If need to obtain the magnesia with bigger grain, that uses perpendicular kiln to regard as with respect to need make the dead kiln heat that takes magnesia of big grain agglomeration (if pursue,7-1 place is shown) . Those who set upright kiln is dead burn temperature falling to also can achieve 2100~2300 ℃ without oxygen boosting condition, this can make the diameter of grain of mean square magnesian stone of magnesia of low iron agglomeration achieves 200um above.
Apparent, the superhigh temperature that produces afore-mentioned magnesia sets upright kiln agglomeration to take the fireproof material of liner to should satisfy:
(1) is right free from contamination of tall purity magnesia;
(2) can get used to the operation condition of 2100-2300 ℃ .
Accordingly, should choose to exceed build by laying bricks or stones of high pure special type magnesia brick to build firing belt. The thick grain magnesia that this kind of magnesia brick chooses purity to not be less than 3.40g/cm3 for density of the MgO of 99% , bulk normally is raw material production, its function index is 98%~99% for MgO, bulk density is less than for the Pa of 3.0g/cm3 be equal to 17% , t0 is more than be equal to 1800 ℃ . Other position (warm-up belt and cooling zone) what choose MgO content to be 97.5%~98% is high pure magnesia brick build by laying bricks or stones is built.
2, kiln of superhigh temperature channel is firing take with fireproof material
Firing high quality alkalescent oxide fastens refractory products, be like high pure brick of Mg0-Cr203 of electric frit recombine, Si02 is less than the direct union of 1% MgO-Cr2O3 special type is high pure magnesia brick when, need to be in superhigh temperature (1800-2000 ℃ ) finish inside channel kiln. Flourish Cheng Naicai provides high quality fireproof data for you.
Integrated build by laying bricks or stones builds the fireproof product that liner of kiln of channel of this kind of superhigh temperature needs to use a variety of distinct categories and social estate. The temperature demand that brings as a result of each paragraphs is different, the physics that uses fireproof product so, chemical index has very big difference. For example some company year the fireproof product that the pit of superhigh temperature channel that manufacturing 10000tMgO-Cr203 brick uses introduces 18 kinds of different types and different grade. Watch 7-1 listed this channel kiln builds line the technical index of refractory products. The high fever of afore-mentioned channel kiln is 1900 ℃ into temperature, so firing take vault job line to use brick of electric frit corundum (recombine, b.D=3.41g/cm3) , line of kiln wall job uses Nucon80MgO-Cr203 brick, back-to-back and warm-up belt, firing with cooling zone kiln the top uses Nucon60Mg0-Cr203 brick one paragraph of the belt to build line (the line of kiln wall job that includes correspondence) . Flourish Cheng Naicai is firing take double deck arch to maintain a wall to be built with build by laying bricks or stones of Mo Laishi brick, the tall aluminous brick that other position uses different type respectively according to working requirement, clay brick and adiabatic brick build by laying bricks or stones are built.
Our country is firing the superhigh temperature of high quality alkalescent brick (1800-2000 ℃ ) channel kiln is firing take liner vault to use electric frit commonly brick of half recombine MgO-Cr2O3 and high pure magnesia brick is built by zebra structure build by laying bricks or stones. As a result of former in 1800 ℃ PLC=+0.1%~+0.3%(of the heavy change that burn a line expands) , and 1800 ℃ burn latter again line change PLC=-0.1%~-0.3%(is contractive) , when using these two kinds of bricks to be built by zebra structure build by laying bricks or stones, can learn from others's strong points to offset his weakness, adjust surplus and deficiency each other, raise vault build by laying bricks or stones to build the bulk stability of body.
Nevertheless, afore-mentioned freeboard channel kiln are firing the brick of half recombine MgO-Cr203 that takes vault build by laying bricks or stones to build, because Cr2O3 is in overheating for a long time to operate a condition to fall, produce oxidation - reductive reaction, bring about bricky body to expand, and the matter that becomes vault attaint. To solve afore-mentioned problems, technical personnel once suggested, use low chromium build by laying bricks or stones of brick of half recombine MgO-Cr203 constructs pit of superhigh temperature channel firing take whole vault, prolonged service life thereby, obtain better economic result.
This shows, high quality oxidation is refractory products is firing heat of uses superhigh temperature kiln is firing the area is main use corundum qualitative refractory products, high pure MgO-Cr2O3 brick (recombine, half recombine and direct union) and high pure magnesia brick build by laying bricks or stones is built, and other each paragraphs of belt, the fireproof material that chooses a variety of types and grade according to temperature condition undertakes building line integratedly.
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