The feeding sequence during the mixing process is:
First, add refractory raw materials, stir evenly, then add sawdust powder and stir evenly, and finally add water. The amount of water added is generally controlled at around 50% to maintain good fluidity of the slurry, facilitate molding, and prevent excessive moisture from affecting the curing time. During the mixing process, additives such as water reducing agents and green reinforcement agents should also be added. After the mud is mixed into a slurry, add additive A and mix evenly again. Inject the prepared mud into the model to form it, and let it stand at room temperature for curing to disperse and evaporate excess water in the mud. Generally, it can be demolded after being left to stand for about 24 hours, at which point the moisture content of the mud blank is about 35%. When the moisture content drops to 25%~30%, the drying car on the billet enters the dryer for forced drying, and the drying temperature can reach up to 110 ℃; After drying for 24-48 hours, when the moisture content of the billet is below 2%, it is fired in the kiln. The firing is carried out in a 20m3 gas shuttle kiln at a firing temperature of 1300 ℃, with insulation for 4 hours. After the fire stops, the temperature is lowered to below 200 ℃ before being discharged from the kiln. The raw material after firing is mechanically polished and processed, and after passing inspection, it is the finished product. The appearance of the product is white, and the pores are mostly micro pores of about 1mm. Compared with products using EPS particle balls as pore forming agents, the pores are smaller, more uniform, and the texture is finer.
By using sawdust alone as a pore forming agent, using the injection molding method, and adding a certain amount of additives, high-performance lightweight mullite insulation bricks can be produced. This process is simple, suitable for mass production, and does not use EPS raw materials, which saves costs and is environmentally friendly. The pure sawdust mullite lightweight insulation brick produced has a density of about 0.57g · cm-3 and a thermal conductivity of 0.16W · (m · K) -1 at 400 ℃. The thermal conductivity index of the product is better than that of common products, and the energy-saving effect is significantly improved, with good economic and social benefits.
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Email:wp@cnjingganrefractory.com/sdwenping@163.com
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