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Low thermal conductivity mullite brick

Low thermal conductivity mullite brick is our company according to the existing cement kiln preheating decomposition zone with refractory materials with serious alkali erosion, frequent thermal shock, material wear and other characteristics.

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Refractory materials for cement industry

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Product Introduction

Low thermal conductivity mullite brick is a new energy-saving and environmental protection product developed by our company according to the characteristics of serious alkali erosion, frequent thermal shock and large material wear of refractory materials used in cement kiln preheating decomposition zone, combined with more than 40 years of research and development experience in the production of refractory materials for cement kiln. The product uses high-quality light alkali-resistant mullite as the main raw material, and introduces special additives in the production process, so that a large number of mullite mineral phases are formed in the sintering process, and the internal pores are distributed in a spherical discontinuous state. In the process of use, the brick surface can form a glass body, effectively preventing the erosion of alkali salts in the material to the product, improving the alkali resistance, wear resistance and thermal shock stability of the product, while reducing the thermal conductivity and bulk density of the product. The product has the characteristics of low thermal conductivity, high strength, wear resistance, high load softening temperature, excellent thermal shock stability, etc., and is an ideal alternative product for the rear of the transition zone, the preheating decomposition zone and the tertiary air pipe on the large cement rotary kiln.

1. Performance advantages

1) Energy saving and consumption reduction. A. energy saving and consumption reduction: low thermal conductivity mullite brick has low thermal conductivity (at 1000 ℃, low thermal conductivity mullite brick is only 1.1-1.2w/m k; Silica brick is 1.7-2.0w/m k; Anti-spalling high alumina brick is 1.4-1.5w/m k), with good heat insulation effect (when used at 35-73m of 4.8 × 74M cement kiln, the temperature of the cylinder is 60-80 ℃ lower than that of silica brick, it is 30-40 ℃ lower than anti-peeling high alumina bricks), reducing heat loss, increasing heat utilization rate, and saving energy consumption. (The coal consumption per ton of clinker can be reduced by 0.5Kg, 900 tons of coal can be saved every year, and the capital can be saved by about 900000 yuan.) B. Emission reduction: it can save about 900 tons of coal every year, reduce about 2400 tons of carbon dioxide emissions, about 10 tons of sulfur dioxide, about 7 tons of nitrogen oxides, about 10 tons of soot and other harmful substances, which will help cement enterprises to meet the "double carbon" policy and achieve the goals of environmental protection, energy conservation and consumption reduction.

2) The volume density is small, which can not only reduce the load of the cylinder, but also ensure the safe operation of the thermal equipment of the cement kiln, and the cost performance is high. Taking 4.8 × 74M cement kiln as an example, the preheating decomposition zone adopts mullite brick with low thermal conductivity of 35 meters. Compared with silica brick, the weight of refractory lining can be reduced by about 60 tons, the purchase cost can be reduced by about 300000 yuan, and the economic benefit is remarkable.

3) Strong flexibility, excellent thermal shock stability, and strong adaptability to temperature fluctuations.

4) High strength, wear resistance, not easy to peel off, and strong adaptability to stress concentration.

5) The internal pores of the product are evenly distributed in a fine spherical shape, and the low-aluminum mullite mineral phase formed by a special process makes the product have high resistance to alkali erosion and long service life.

6) The construction is convenient and the use results are remarkable. The product uses a special process, which not only effectively solves the problem of difficult construction of multi-layer composite energy-saving materials, but also solves the problem of easy fracture of the composite part and improves the service life.

2. Physical and chemical indexes

Project	HWDDR-A	HWDDR-B
Al₂O₃ (%)	58-63	35-45
Fe₂O₃(%)≤	1.5	2
Bulk density g/cm³≥	2.55	2.2
Percent porosity (%)≤	16	18
Normal temperature compressive strength (MPa)≥	90	60
0.2 MPa load softening temperature (T0.6 ℃)≥	1500	1350
Thermal shock stability (1100 ℃ water cooling) times ≥	15	10
Thermal conductivity (1000 ℃)W/M · K ≤	1.3	1.2