The number and scope of applications of lightweight high-aluminum refractory castables are gradually expanding, from permanent layers, insulation layers to working layers, from medium and low temperature parts to medium and high temperature parts, and from low-load environments to high-load environments. At present, the technical performance of lightweight high-aluminum castables used in the working layers of medium and low temperature (<1200℃) and high temperature (>1500℃) parts has been basically mature, but the performance of lightweight castables used in the medium and high temperature range (1200～1500℃) needs to be improved to meet the new requirements for the use of lightweight high-aluminum castables. Based on this, this work carried out the research and development of high-performance lightweight high-aluminum castables. The raw material configuration of traditional lightweight high-aluminum castables mainly uses lightweight aggregates and heavy fine powders.
The pore diameter of the lightweight aggregate used is large and the strength is low. Therefore, the thermal conductivity of the lightweight castable is high. At the same time, the overall strength of the lightweight castable is affected by the low strength of the aggregate, which limits its use at higher temperatures. Therefore, microporous aggregates and high-strength aggregates are used in this experiment. The raw materials used for lightweight high-alumina refractory castables mainly include microporous lightweight mullite, composite hollow spheres, high-alumina bauxite, floating beads, kyanite, silica powder, alumina powder, pure calcium aluminate cement, raw bauxite powder, andalusite, pore former D, pore former C, etc. The chemical composition of the main raw materials is shown in Table 1. The wall thickness of the composite hollow sphere is 0.3-0.5 mm, the particle size is 3-7 mm, and its bulk density is 0.60 g/cm3. The bulk density of microporous mullite is 0.80 g/cm3.
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Project |
Lightweight high performance refractory castable |
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Corundum |
Corundum Mullite |
High Aluminum |
Clay |
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HX-90 |
HX-70 |
HX-60 |
HX-40 |
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AL2O3 % |
≧90 |
≧70 |
≧60 |
≧40 |
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Refractoriness ℃ |
≧1790 |
≧1790 |
≧1750 |
≧1700 |
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Bulk density g/cm3 |
0.8-1.8 |
0.8-1.6 |
0.6-1.4 |
0.6-1.4 |
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Compressive strength Mpa |
110℃×24h |
5-15 |
5-15 |
3-13 |
3-13 |
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1500℃×3h |
8~20 |
8~20 |
6~16 |
6~16 |
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Flexural strength Mpa |
110℃×24h |
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1500℃×3h |
0.4-0.6 |
0.4-0.6 |
0.3-0.5 |
0.3-0.5 |
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Thermal Conductivity w.(m.k)(300℃+_25℃) |
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Line change rate after burning |
110℃×24h |
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1500℃×3h |
+_0.6 |
+_0.6 |
1450℃×3h+_0.6 |
1300℃×3h+_0.6 |
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Maximum operating temperature ℃ |
1700 |
1650 |
1450 |
1350 |
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Instructions for use |
It is used for the lining of various industrial kilns operated in neutral or oxidizing atmosphere. It has good thermal insulation performance and can achieve ideal energy saving purpose. |
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