Rumors At present, high-grade exterior wall decoration materials are mainly granite stones. Its polished surface is like a mirror surface, the texture is translucent, luxurious and elegant; the sand surface is simple and solemn. Most of the construction methods are installed on the outer wall in the form of steel keel hanging. The man-made material comparable to granite stone is microcrystalline glass microcrystalline stone, and the construction method is basically the same. The disadvantage is that the construction cost is high and the insulation performance is not provided. Therefore, it is necessary to develop a new artificial material which has the decorative effect comparable to that of granite and marble, and has the thermal insulation performance and low construction cost. In order to achieve this goal, after intensive research, the tuff is used as the basic raw material foam insulation layer, and the microcrystalline glass particles are used as the surface layer and sintered at high temperature. Tuff is abundant in Baishan City, Jilin Province, and is a kind of volcanic sedimentary rock, also known as volcanic clastic rock. At present, tuff resources are basically not exploited in Jilin Province. Tuff can be melted into a porous glass-ceramic foam at 11601200C, so foam ceramics can be developed with its relatively low melting point and low loss of ignition. It can also sinter the glass-ceramic glaze on the base foam once. After polishing, it can have the simplicity of the granite stone, such as mirror-transparent, non-polished natural matte surface, which is comparable to granite stone. The foam ceramic product has the dual functions of heat preservation and decoration, and can be used for heat preservation and decoration of interior and exterior walls of buildings, park building pieces, etc., especially for exterior wall insulation and decoration. The products studied have been expanded by the manufacturer, and the crystallized kiln of microcrystalline glass and the internal combustion coal gangue sintered brick tunnel kiln have been successfully fired. It lays a solid foundation for the future research results applied to industrial production, and opens up a new way for the rational development and utilization of tuff resources.
1 Tuff characteristics 1.1 Selection of ore points and physical characteristics Tuff resources in Baishan City and surrounding areas of Jilin Province are widely distributed and have many ore points. According to the investigation and sampling of the initial burning, the slate mine is the closest to the urban area, with convenient transportation and abundant reserves. Therefore, the project mainly uses slate ore tuff as the research object. The appearance of slate ore tuff is grayish green. After weathering, the particle diameter is below 30mm. It can be gradually pulverized after water immersion. Mohs hardness <3. 1.2 Chemical composition analysis Table 1 Tuff chemical composition analysis (mass) burnout 1.3 burning characteristics The sampling results at temperature are shown in Table 2.
The sample with a diameter of 15mm was fired in a high-temperature furnace, and softened at a different firing temperature of 1140C, and the liquid phase increased; 1601: Deng Jiaping (1955-), professor-level senior engineer; mainly engaged in glass, foam ceramics Wait for research. E-mail: dpl00126.com 200 ° C began to gradually foam, and the pores are closed by a round hole, water absorption rate is small; 2301250 ° C pores increase, there are broken holes, water absorption increased.
Table 2 Slate stone tuff mine at different temperatures firing characteristics firing temperature water absorption rate performance density foaming aperture (mm) appearance color sintering light red sintering light red micro-hole light red medium red dark red 2 tuff glaze foam ceramics overall research ideas The glaze at this temperature is determined by the study of the sintering characteristics of the slate tuff mine at different temperatures, taking into account the feasibility of the industrial production, the final determination of the optimum foaming temperature is 10501100C, the foaming aperture is 0. 82.0mm, the glaze at this temperature The layer reaches the optimum melt crystallization state and matches the foam layer properties.
The glazed layer of the anti-paving process is laid on the bottom layer, and the foam layer is laid on the glaze layer to form a blank, so that the glaze is smooth. After cutting and polishing, the mirror surface of the imitation granite is formed; the surface of the imitation granite is formed by cutting and not polishing.
3 Tuff glazed foam ceramic 3.1 foam ceramic base layer (foaming insulation layer) 3.1.1 flux for the best foaming temperature of 1 0501100C, foaming pore size of 0.82.0mm, a certain amount of flux must be added. The cosolvent is mainly waste glass, and the addition amount is 25% and 35%. As the amount of flux increases, the melting point of the batch material can be significantly reduced.
3.1.2 Foaming mechanism and the amount of foaming agent The carbonaceous compound is used as a foaming agent. The product can release CO or C2 gas above 1 000 C, so that the softened ceramic body glaze body uniformly foams inside and expands in volume. By adjusting the amount of the blowing agent, the density of the foam can be controlled. By formulating a reasonable temperature system, a uniform closed bubble with a diameter of 0.82.0 mm can be formed inside the ceramic body glass body. The amount of blowing agent is in the range of 0.2% to 2.0%. The relationship between the blowing agent and the product density is shown in Table 3.
Table 3: Relationship between foaming agent and product density Foaming agent dosage (mass) Product density (kg/m3) 3.1.3 Antioxidant mechanism and effect Considering the heating time of industrial production is longer 015h), it is necessary to introduce anti-injection into the batch. An oxidizing agent to ensure that the blowing agent contained in the batch during the heating stage is not oxidized. The antioxidant has a strong pre-melting effect and a network function, and the material is wrapped, so that the oxidation process of the foaming agent is very slow, and the oxidation failure of the foaming agent is avoided to ensure the foaming quality of the foam. The amount of antioxidant used is 1.5% 6.0%. The antioxidant and flux in the formulation must be used in proportion. The relationship between antioxidant, flux and foaming temperature is shown in Table 4.
Table 4: Antifoam and cosolvent combined with foaming temperature Flux (mass) Antioxidant (mass) Foaming temperature (C) 3.2 Basic formula and temperature system 3.2.1 Rapid foaming process Rapid foaming process Applicable conditions In order to complete from the temperature rise to the end of foaming, it should be completed within 5 hours, and the production cost of the product using the rapid foaming process is low. Temperature system: normal temperature 950C heating time is 130150min; 950C constant temperature time is 3040min; 501080C heating time is 3050min1080C constant temperature time is 5060min, and then natural cooling annealing to 5080C is released, the whole process is 2024h. The rapid foaming process formula range is shown in Table 5. Show.
3.2.2 Slow foaming process The slow foaming process is suitable for the temperature from the heating to the end of the foaming time of 915h, mainly to meet the needs of industrial production, suitable for both the glass-ceramic sintering kiln and the internal combustion coal gangue tunnel. Kiln temperature system. Temperature system: Normal temperature 1080C heating time is 915h; 080C constant temperature is 12h and then naturally cooled to 5080C, the whole process is 2440h, the pilot plant is 3540h). The slow foaming process recipe table is shown in 5.
Table 5 foam insulation layer process formula raw material name rapid foaming process formula (quality) slow foaming process formula (quality) raw material preparation process tuff waste glass tuff, waste glass, foaming agent, antioxidant according to the formula ratio of blowing agent Mixing, grinding to 250 mesh antioxidant 3.3 microcrystalline glass glaze layer) as the main crystalline phase, shrinking small, and tuff foam 3.3.1 microcrystalline glass glaze formation mechanism Microcrystalline glass is also called crystal glass, selected for this study The glass-ceramic ceramics have the best combination at high temperatures. The crystallization mechanism of the glass-ceramic particles during sintering is 'nucleation-growth'. The crystal extends from the surface to the inner layer mainly with wollastonite p-CaO Si2), which has high strength and wear resistance. Corrosion resistance, weathering resistance, non-absorption, and other excellent properties, and the crystallization of crystallized granite microcrystalline glass is completed by interfacial crystallization of silicon glass pellets. 3.2 Preparation of microcrystalline glass glaze layer by microcrystal The glass formula is required to be evenly mixed and placed in a porcelain refill, and then placed in a high-temperature furnace, melted at 1450 ° C, and quenched to 5 mm or less for use.
3.4 Formation of glass-ceramic glazed foam ceramics The glass-ceramic glazed series is divided into polished glazed and matte series. The glass-ceramic particles are placed on the bottom layer of the mold, the thickness of the material layer is 45 mm, the plastic film is laid after flattening, and the plastic film is pressed to prevent the foaming material from penetrating into the glass-ceramic layer, and the thickness of the foaming layer is laid. Flatten for 3035mm). Sintering, crystallization, foaming, cooling and drying, and then grinding and polishing, which is polished microcrystalline glaze, crystal flower formed by crystal can be compared with natural polished granite slab; non-polished is glazed Similar to granite stone slate. Changing the color ratio of the glass-ceramic particles can change a variety of crystal lattice patterns. The mold used is: a silicon carbide plate or a cordierite plate as a bottom plate, a stainless steel as a side mold, and a ceramic fiber paper having a thickness of 0.711.0 mm as a release agent. After firing, the thickness of the blank is 70100mm, and the thickness of the finished product after cutting is 5080mm. See the physical image of the polished glazed sample and the physical image of the glazed surface.
4 bubble ceramic sample main performance (see Table 6) Table 6 foam ceramic sample main technical performance index test number foaming temperature density strength water absorption coefficient thermal conductivity frost resistance compressive strength (MPa) flexural strength (MPa) strength loss quality loss The pilot test of 5 bubble ceramics was conducted in Inner Mongolia Chifeng Huafu Building Materials Industry Co., Ltd. and Jilin Province Everbright Group Jiutai Branch.
Inner Mongolia Chifeng Huafu Building Materials Industry Co., Ltd. uses a 180m3 shuttle kiln with LNG as fuel. Crystallization kiln temperature system: temperature rise to crystallization point temperature 10801100C) time is 10h; 10801100C constant temperature time is 1h; then natural cooling to 8060C kiln, the whole process is 3540h. Jilin Province Everbright Group Jiutai Branch, the company The kiln length of the 60 million standard block production line is 144.6m, and the kiln width of the 4.6m sintered coal gangue brick tunnel kiln is the internal combustion junction method. Hollow brick temperature system: the temperature of the kiln is heated to 10501080C, the heating time is 1011h, the temperature is 10h at 10501080C, and the temperature is reduced to 100C. The cooling time is 1215h, and the total firing time is 2530h. Although the temperature difference between the upper and lower tunnels is larger, However, only one test sample is placed on the uppermost layer of the tunnel kiln, and the relative temperature difference is small. Since the tunnel kiln adopts an internal combustion mode, it has a certain reducing atmosphere, which is favorable for foaming. The five density grade samples tested were ideal, especially the freeze resistance was better than that of other kiln fired samples.
6 Application test and cost comparison Natural granite, marble: its general price is 120150 yuan / m2, steel keel material and installation costs are 80100 yuan / m2, dry hanging marble labor costs is 100130 yuan / m2, the total cost is 300380 yuan / M2; steel keel construction needs to occupy 150200mm installation space, and the wall covering 100m length needs more land area of ​​1520m2; no insulation performance.
Glass-ceramic glazed foam ceramic products: It is estimated that the proposed selling price is 100130 yuan/m2, the tile adhesive is salty and ordinary 1:2. 5 cement pottery mortar) The material cost is 1020 yuan/m2, and the construction fee is 2530 yuan. /m2, the total cost is 140180 yuan / m2; construction does not need to occupy the installation space, so the wall area can save 1520m2 in the length of 100m; has a certain thermal insulation performance, if the thickness of the foam ceramic insulation layer is 50mm, according to the thermal conductivity 0. K, can increase the wall thermal resistance 0. 仄) / ¥. We used the glass-ceramic glazed foam ceramic sample for application test, and used 1.00:2.5 cement pottery mortar to paste the sample on the outer wall of our hospital. It is still intact after 8 winter tests.
7 Conclusions Tuff as the main raw material, adding flux, foaming agent and antioxidant, forming foam ceramic insulation layer density of 300600kg/m3 at 10501100°C, and baking glazed surface to form glazed foam ceramic series. The rational development and utilization of tuff resources has opened up new avenues.
The water-quenched glass-ceramic particles are placed under the foam layer, and the main process of the glass-ceramic glazed series of thermal insulation decorative materials can be made by one-time baking and foaming; the formed tuff glazed foam ceramic decorative effect can be Natural granite and marble are comparable; combined with the corresponding main wall materials can meet certain energy-saving requirements.
The tuff glazed foam ceramic has the advantages of high strength, small thermal conductivity, low water absorption, good anti-freezing performance, low construction cost and convenient and quick production.
According to the small test and the pilot test, the feasible industrial production process and the practical furnace type are determined, that is, the single-layer firing of the existing crystallized glass crystallization kiln or the internal combustion type sintered porous hollow brick brick kiln, the kiln The furnace can be sintered with a slight improvement.
(Finish)
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