Vitreous frit kiln is a kind of hot project facilities that comprises by fireproof material. The use efficiency of vitreous frit kiln and service life depend on greatly the breed of fireproof material and quality. The development of vitreous production technology depends on greatly the improvement of fireproof material production technology. Accordingly, the logical choice of fireproof material and using is the very serious content in design of vitreous frit kiln. Want to accomplish this, we should master the following at 2 o'clock, it is the characteristic that picks fireproof material and applicable place, 2 it is the use condition of each place mixes vitreous frit kiln corrode a mechanism.
Brick of electric frit corundum is fused in electric arc furnace alumina, in casting the model that appoints appearance next, through anneal and heat preservation, acquire wants product through treatment next. Average production technology is high pure to calcine alumina (95% above) with a few additive. Burden throws electric arc heat, cast after high temperature of 2300 ℃ above is fused to prefab cast, take out after heat preservation anneal. The cold working with the blank careful course that takes out, be assembled beforehand and examine, make the finished product that accords with a requirement.
According to alumina crystallization configuration differ and amount, cent of brick of electric frit corundum is 3 kinds of types: One kind is α - Al2O3 is said to give priority to brick of corundum of brilliant photograph α ; 2 be with α - Al2O3 and β - Al2O3 brilliant photograph is given priority to, content is roughly identical, call brick of α β corundum; 3 kinds of β - Al2O3 brilliant photograph is given priority to, call β corundum brick. The brick of commonly used electric frit corundum in kiln of frit of float law glass is 2 kinds mix 3 kinds, namely brick of corundum of β of α of brick of electric frit corundum and β corundum brick. The manage of brick of the corundum in brick of corundum of β of α of frit of report of article general introduction and kiln of frit of glass of β float law turns function and application.
The function of brick of corundum of 1. report frit analyses brick of corundum of β of α of frit of report of brick of corundum of β of α of 1.1 report frit to make α by 50% corundum bricks of the left and right sides - Al2O3 and β - comprise by Al2O3, crisscross of two kinds of crystallization forms very compact organization structure, have exceedingly good alkali aggressivity. Compare with photograph of brick of electric frit AZS, high temperature (1350 ℃ above) corrosion resistance is differred slightly, but under 1350 ℃ , its are able to bear or endure the corrosion resistance of frit glass is equivalent to brick of electric frit AZS. Because it does not contain the impure material such as Fe2O3, TiO2, matrix glass photograph is very few, the foreign body such as the bleb when be being contacted with melt glass is less, do not pollute matrix glass. Brick of corundum of β of electric frit α is crystal and compact, have exceedingly good corrosion resistance to vitreous fluid below in 1350 ℃ , after wide application is reached at pool of job of vitreous frit kiln place, use at brick of launder, lip, brake brick to wait normally.
Brick of corundum of β of frit of report of brick of corundum of β of 1.2 report frit comprises β by the corundum brick of nearly 100% - Al2O3 comprises β by chunk flat - the crisscross of crystallization organization crystallization of Al2O3 is coarse, in electric frit the hole in fireproof material is led big, intensity is low. But on the other hand, it is had fight goodly flake quality, have taller corrosion resistance to alkali vapour especially, because this is used at the upside structure of vitreous frit kiln. However, when alkali content heats in low atmosphere, contact late unripe reaction with SiO2, β - Al2O3 decomposes bulk systole easily to produce crackle and crackle, the position that is used at be far from vitreous raw material to fly to come loose accordingly. Electric frit α - the chemical composition of β and β corundum brick basically is Al2O3, its basically are distinguished in Yu Jing photograph composition differs, the difference of micromechanism causes the difference of the physico-chemical function such as intensity of bulk density, hot coefficient of expansion, compression.
Brick of corundum of 2. report frit uses pool bottom and pool wall mediumly in vitreous frit kiln is the part that contacts directly with vitreous liquid. To component of liquid of glass of all and direct contact, the function with fireproof main material is corrosion resistance, there is chemical reaction between fireproof material and vitreous liquid namely. From analysis of 3 yuan of phasor, do not have inside working temperature limits in all melting point, the bound facing between fireproof material and vitreous liquid is relatively stable, namely although fireproof material is in erode condition, but the surface still complete, won't fall off in vitreous liquid, produce the limitation such as stone. In recent years, in the electric frit that evaluates as direct as vitreous fluid contact when the quality index of fireproof material, besides physico-chemical index and chemical composition, mineral composition, still must evaluate the following 3 index: Fight glass to erode index, bleb precipitation index and crystal precipitation index.
The scope of application of electric frit brick is wider, taller to glassy capacity demand, frit kiln productivity is bigger. The electric frit brick with vitreous frit commonly used kiln is AZS department (Al2O3-Zro2-SiO2) . When AZS brick exceeds 1350 ℃ , its corrosion resistance is α β - 2~5 the Al2O3 brick of times. The corundum brick that brick of corundum of β of electric frit α arranges by close together crisscross comprises α - alumina (53%) and β - by alumina (45%) granule composition, contain a few glass photographs (make an appointment with 2%) , the hole between fill crystallization, purity is tall, can use as the brick end store of nogging of cooling ministry pool, cooling department, lid seams a brick to wait. Brick of corundum of β of electric frit α is mineral contain a few glass photographs only, when using won't oozy with contaminative glass liquid, corrosion resistance is good under 1350 ℃ , high temperature wearability is good. It is vitreous frit kiln the ideal and fireproof material of launder of kiln of frit of glass of law of bottom of wall of cooling ministry pool, pool, float. In project of kiln of frit of float law glass, brick of corundum of β of electric frit α uses as the pool nogging of ministry of refrigeration of vitreous frit kiln. In addition, the road face brick of cooling ministry and lid seam a brick to also use brick of corundum of β of Yu Dianrong α .
Brick of corundum of electric frit β is by β - the white product that by Al2O3 thick any crystalline substance comprises, contain Al2O392%~95% , vitreous photograph has 1% only the following, because crystal lattice is loose, structural intensity is low, the rate that show hole is less than 15% . Because Al2O3 itself is in 2000 ℃ above by sodium saturation, extraordinary to the action of alkaline steam stability falls in high temperature, its thermal stability is very good also. But when should be being contacted with SiO2, β - the Na2O that contains in Al2O3 is decomposed react with SiO2 happening, β - Al2O3 is very easy α of translate into Al2O3 - the volume with Al2O3 larger generation is contractive, cause crackle and damage. Accordingly, it is applied to only be far from the upside structure that contains SiO2 dust, if vitreous frit kiln works,the nozzle with the upside structure of the pool, fused hind belt, parapet around, port makes the same score arch to wait. Because it and oxide of volatile alkali metal do not have reaction, melt content won't from bricky surface oozy, pollute glass. In kiln of frit of float law glass, as a result of cooling ministry flow path the entrance closes suddenly narrow, alkalescent vapour is here easily condensation, the brick of electric frit β that because this flow path makes the same score arch,uses vapour of alkali resistance sex to erode.
3. epilogue is based on brick of electric frit corundum fighting glass to erode, fight the epispastic, superior performance that fights the side such as stone, especially its unique crystallization structure, do not have pollution almost to vitreous liquid. Accordingly, its fused belt in kiln of frit of float law glass is hind, clear the place such as belt, cooling zone, flow path, port got important applying.
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