A kind of corundum-mullite composite material and preparation method
Technical field
The invention belongs to fire resisting material field, particularly a kind of corundum-mullite composite material.
Background technology
Because mullite has good high-temperature mechanics, high temperature thermal property, makes the mullite synthesizing goods have higher density and purity, lower heat-conduction coefficient and thermal expansivity, thermal structure intensity height, high temperature creep rate is low, and heat-shock resistance and chemical corrosion are strong, the fusing point advantages of higher; And the corundum good springiness, the fusing point height at high temperature has good wear-resisting, chemical resistance of concrete and volume stability, and hardness is big, the refractoriness height; Mullite crystal is generally column or prism-shaped in addition, the corundum body is generally granular, so the preparation corundum-mullite composite material will compile the two-fold advantage of corundum crystal and mullite crystal, thereby make this material all be better than single-phase mullite material or corundum material in every respect.If but synthesize with pure raw material then seriously improved the production cost of material, especially as refractory materials.Therefore, adopt natural matter can reduce the production cost of material undoubtedly significantly.
China's bauxitic clay reserves are very abundant, and the place of production is from the Shanxi to the north of the Yellow River, Hebei and Shandong, pass the Henan and the Guangxi at middle part, Guizhou and Yunnan up to southwest, the main place of production that produces the bauxitic clay grog at present in Shanxi, Henan and Guizhou.Bauxitic clay is formed by mineral weathering such as feldspar, mica, and his essential mineral type is gibbsite, diasporite and boehmite, in addition because the condition difference that forms also may contain impurity such as kaolinite, quartz, calcite.Diaspore in China's bauxitic clay-kaolinite type (DK) and boehmite-kaolinite type (BK) is most widely used, and DK type bauxitic clay grog is pressed Al
2O
3Content atmosphere top grade, I etc., IIA etc., IIB etc., III etc., its main chemical compositions sees Table 1 and table 2
All kinds of BK type of table 1 alumine calcining back chemical ingredients (wt%)
|
Al
2O
3 |
SiO
2 |
Fe
2O
3 |
TiO
2 |
Na
2O
|
K
2O
|
I.L |
Henan, Guizhou |
59.80 62.44 |
23.52 20.68 |
0.51 0.64 |
1.08 1.82 |
0.07 0.03 |
0.02 0.11 |
14.66 14.12 |
All kinds of DK type of table 2 alumine calcining back chemical ingredients (wt%)
Rank |
Al
2O
3 |
SiO
2 |
Fe
2O
3 |
TiO
2 |
CaO |
MgO |
K
2O
|
Na
2O
|
S I I IIA IIA IIA IIB IIB III |
86.20 82.40 79.80 76.03 72.20 69.80 67.50 60.50 54.10 |
7.60 11.55 14.50 19.40 22.00 25.70 27.40 33.70 40.50 |
1.76 1.52 1.64 1.46 1.78 1.71 1.54 1.92 1.72 |
4.02 3.64 3.17 2.87 2.64 2.44 2.82 2.94 3.00 |
- - - - - - - - - |
0.25 0.28 0.30 0.15 0.18 0.17 0.11 0.18 0.17 |
0.14 0.13 0.10 0.10 0.15 0.12 0.16 0.16 0.14 |
0.06 0.06 0.05 0.10 0.05 0.06 0.20 0.10 0.05 |
Coal gangue is the byproduct that produces in coal mining and washing process, is one of industrial residue of China's quantity discharged maximum.Coal gangue output is pressed 15% of raw coal output and is calculated, annual coal gangue increases more than 1~200,000,000 ton at least, about 2,000,000,000 tons of the coal gangue of storing up over the years, take up an area of nearly 100,000 mu, and, just risen to hundred million tons of 3.l, and not only taken a large amount of farmlands and soil in 2000 still in continuous increase, and serious environment pollution, how to administer and fully utilize the attention that coal gangue is also obtaining people.Shanxi is the big province of producing coal, so also there is a large amount of coal gangues to pile up simultaneously, its main chemical compositions is SiO
2Content about 50%, Al
2O
3Content also contains a spot of CaO, MgO, TiO simultaneously about 20%
2, Na
2O, K
2The C of O and different content, its exploitation prospect is very optimistic.
Summary of the invention:
The object of the invention purpose is making full use of and promote the solid waste resource recovery regeneration in conjunction with China's existing resource, selected a kind of natural matter and solid waste to come synthetic fire resistive material to make corundum-mullite composite material, not only made full use of existing resource, simultaneously also reduced the pollution that solid waste is brought, reduced production costs greatly.
A kind of corundum-mullite composite material, the main raw material that it is characterized in that synthetic corundum-mullite composite material are bauxitic clay and coal gangue, and the weight percent content of coal gangue is 5~25%, and the weight percent content of bauxitic clay is 75~95%, Al in the bauxitic clay
2O
3Content requirement is greater than 75%.Optimum material proportion: the weight percent content of coal gangue is 10~20%, and the weight percent content of bauxitic clay is 80~90%.
Its making method is: raw material is done medium with dehydrated alcohol, is incubated 12 hours through ball milling after 6 hours in baking oven, takes out the back mechanical pressing, 1350 ℃~1450 ℃ insulations 3~6 hours, synthesizes under the air atmosphere.Through test, and the composition of matrix material that utilized XRD analysis, test-results shows: the synthetic corundum-mullite composite material is very pure, can find out that from the analysis of SEM fracture apperance crystal morphology is typical long column shape crystalline substance, the intensive growth of mutually staggered, its length-to-diameter ratio are greatly about 8: 1 even bigger, and the crystal grain cross-sectional dimension is near nano level, fracture mode is a transgranular fracture, and this can significantly improve the various aspects of performance of material.
Because the main raw material of synthetic corundum-mullite is bauxitic clay and coal gangue, abundant raw material is cheap, and the synthetic corundum-mullite composite material has very high added value, so be another new way of preparation high-temperature refractory.
Description of drawings:
Fig. 1: corundum-mullite composite material synthesis technique figure
Fig. 2: corundum-mullite composite material XRD figure (10wt% coal gangue)
Fig. 3: corundum-mullite composite material XRD figure (20wt% coal gangue)
Fig. 4: corundum-mullite composite material SEM schemes (10wt% coal gangue)
Fig. 5: corundum-mullite composite material SEM schemes (20wt% coal gangue)
Embodiment:
1. raw material is chosen
1. the chemical analysis results of bauxitic clay
2. the chemical analysis results of coal gangue
2. raw material is synthetic
5,10, the bauxitic clay of 20wt.% coal gangue and 95,90,80wt.% proportioning raw materials is respectively:
3. synthesis step: see Fig. 1
From XRD figure, see very clearly in the mark and under this test conditions, synthesized very pure corundum-mullite composite material.
Can find out that from the analysis of SEM fracture apperance crystal morphology is typical long column shape crystalline substance, the intensive growth of mutually staggered, its length-to-diameter ratio are greatly about 8: 1 even bigger, and the crystal grain cross-sectional dimension is near nano level, fracture mode is a transgranular fracture, and this can significantly improve the various aspects of performance of material.