Spray coating has become a refrailable material used in industrial kiln lining.

Spray coatings have become one of the most important infinitive refractive materials used in many industrial kiln linings. It can be used both in cold conditions to construct and repair furnace linings and to coat them into protective layers, as well as in thermal conditions to repair furnace linings. Compared with pouring materials, high-tightness and high-strength spray coatings can be constructed by spraying

. Because during spray construction, the various particles of the mixture have a high momentum and can be continuously injected into the underlying material. Particles accumulate tightly and are firmly embedded to form a strong bond.
present, the domestic market spray coating is generally the use of dry spray construction method, dry spray materials do not need to be pre-mixed. However, the injection operation is more complex, the injection rebound loss of up to about 20%, the biggest disadvantage is that the dust produced during construction is particularly large, causing great harm to the environment. A spray coating can be constructed by wet spray. When the material is constructed, it is fully stirred with a blender and sprayed directly with the company's wet spray method. Because the sprayed material is stirred in advance, the working environment conditions for spraying construction are good and there is no dust hazard. And the adhesion of the material can also be very good. In addition, wet spray coatings also have the advantages of simple injection operation, less loss of injection rebound (only about 5%.) and so on. In this paper, the development of wet spray coating and ordinary dry spray paint comparison, analysis and comparison of the two spray coatings of the chemical and chemical properties.
1 test
1.1 sample preparation
the main raw materials used in the test are coking gemstones, bauxite, brown coarse jade, blue crystal, alumina powder, silicon powder and calcium aluminate cement. Its chemical composition can be found in Table 1.
of wet spray coatings and dry spray coatings can be found in Table 2, according to Table 2 accurately named each raw material. Specifically, the bone and powder into the mixing tank, stirring well and then adding water stirring 3min and then prepared into 160mmx40mmx40mm sample room temperature care 24h after release. After drying at l10 degrees C, the wet spray coating and the dry spray coating were tested for line change rate, volume density, fold strength and pressure resistance after different heat treatment temperatures, respectively, in 1O00 degrees C, 1300 degrees C and 1500 degrees C insulation 3h heat treatment.
1.2 performance
YB/T5200-1993 dense refracing pouring material air pore rate and volume density test method. YB/T5203-1993 dense fire-resistant pouring line change rate test method, YB/T5201-1993 dense fire-resistant pouring material normal temperature folding strength and pressure-resistant strength test method. The volume density, linear change rate, folding strength and pressure resistance strength of the burned sample were detected respectively. The shrinkage of the specimen is determined by the cursor caliper, and its linear rate of change and volume density are calculated. The anti-fold strength of the test was tested with a Japanese-made CT1000 anti-folding test machine. The test sample's pressure strength
2 results and the test results of the
dry spray coating and wet spray coating are discussed in Table 3 with the Japanese-made MS-20-S1 pressure tester. From Table 3, it can be seen that the volume density of wet spray coating after 110 degrees C drying and after 1000 degrees C, 1300 degrees C, 1500 degrees C heat treatment is greater than the volume density normal temperature folding strength and pressure resistance of dry spray coatings are also greater than dry spray coatings. Although there are studies showing that. The greater the content of calcium aluminate cement, the greater the folding strength and pressure resistance of the material, but this difference can be made up by the substrate of the material. The two spray coatings use different substation materials, wet spray coating is the use of bauxite as the substation, dry spray coating is the use of coking gemstones as the substation. The material strength of bauxite as the substring is high, so the mechanical performance of wet spray coating is better than that of dry spray coating.
wet spray coating after 110 degrees C drying and after 1000 degrees C, 1300 degrees C, 1500 degrees C heat treatment line shrinkage rate is greater than dry spray coatings, the reason is: (1) wet spray coating moisture content than dry spray coatings, resulting in samples After 110 degrees C shrinkage is greater than dry spray coating, (2) wet spray coating using bauxite as a substrate material, and the composition also contains brown corundum, the two substances in the TiO2 content is higher, at higher temperatures it and calcium aluminate cement contains CaO reaction, and the formation of a low melting point substance CaO. TiO2, which leads to the promotion of sintering, the distance between the sample particles is pulled closer, so the shrinkage of the material increases: (3) the dry spray coating contains blue crystal, the theoretical composition of al2O3. SiO2, where the blue crystal is heated to 1300 degrees C, is broken down into molybton and molten free silicon dioxide (square quartz glass), which reacts in the form of: 3 (AL2O3) SiO2) →3AL2O3.2SiO2 plus SiO2, the occurrence of this heat absorption reaction is accompanied by a large volume expansion, blue crystal due to high temperature decomposition caused by the expansion offset some of the contraction of dry spray coating.
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