Development of high alumina insulation brick

Lightweight high-alumina brick is one of the ideal heat-insulating refractory materials at present. It has the characteristics of high compressive strength, low thermal conductivity, good heat preservation performance and low price. It is widely used in ceramic tunnel kilns, rod kilns and shuttle kilns. , wall kiln, various heating furnaces, coke ovens and other thermal equipment, heat treatment pipelines in the steel industry Short, rave reviews.

1. Raw material requirements

a Clinker: crushed by a wheel defect machine and a vibrating ball mill, passed through a 4-mesh sieve (coarse particle), 2, 0-mesh sieve (medium particle), and an 80-mesh sieve (fine particle), and then stored in the warehouse for future use. Coarse particles: medium particles: fine particles = 5:2:3 match.

b Kaolin: The chemical composition is Al2O3>34%; SiO2<49%; Fe203<0.5; CaO+MgO<1.5; K20+Na20<0.5.

c Industrial alumina: the chemical composition is: Al from > 99%; Fe from <0.05%; Si02<0.1 0%.

2. Preparation of Foaming Agent

The materials used to prepare the foaming agent are: caustic alkali, rosin and bone glue. First, the caustic alkali and water are heated in a water bath in proportion to be completely dissolved, and the rosin powder (not larger than 3 mm) is slowly added to the caustic alkali and water solution. After all the reactions are galvanized, bone glue (expanded glue block soaked in water) is added. Under vigorous stirring (about 80' t of product), make it fully blended into a viscous concentrate (preventive agent, dried and broken, with a pore size range of 161 holes/cm20.

3. Ingredients

Weigh the ingredients according to the formula, first add the raw material, industrial alumina, and Suzhou soil into the mixing tank to dry for two minutes, then add (foaming agent and binding agent into it, stir while adding, and after stirring, the material can be used for 24 hours. .

4. Forming and drying

Using high-frequency vibration pressure forming, first add raw materials, and control the weight. When forming, the key is to adjust the applied pressure and time, otherwise the extruded bricks will still be layered, and the foaming agent will be concentrated on the upper layer, which is prone to surface defects after burning. The formed semi-finished products are transported to the drying room, 40°C for 24 hours, and 60't: for 24 hours.

5. Firing

The brick embryos are fired in a domestic 24-meter gravity center tunnel kiln, the temperature is controlled at 1420-1470't:, and the firing cycle is 24 hours.

Appearance quality inspection and physical and chemical performance tests were carried out on the finished high alumina insulation brick, and the results are shown in the table. It can be seen from Table 2 that compared with the national standard of physical and chemical indicators of foam light bricks in the refractory manual, except for the formula, the physical and chemical properties of the bricks produced by the other formulas have reached or exceeded the national standard. After the appearance quality inspection of 5 formula bricks, the color is white, the edges and corners are clear, the size is more accurate, and it meets the user's requirements.

There are mainly two forming methods for the production of light-weight high-alumina bricks at home and abroad. One is casting forming, which has long cycle time, low production efficiency and high cost. process, the cost is higher and the cycle is longer. The light-weight high-alumina bricks I developed are formed by high-frequency vibration and pressure forming, with more than 50% clinker, low cost, and short cycle. It is a new process worthy of mass promotion.

6 Conclusion

In the production of high alumina insulation brick, a large amount of clinker is introduced, and a new process of high-frequency vibration pressure forming is adopted. The appearance quality and physical and chemical indicators of the finished products meet or exceed the national standards of similar products in the 1990s, and are well received by users. A new process method worthy of extensive promotion.