Development direction of refractory technology for cement kiln

The China building materials association commission of experts ms Li Yanjing two second generation demands for refractory materials research and development and manufacture of innovative, in the fourth session of China's refractories production and application of the international conference report made clear. It points out the technical development direction of cement kiln refractory as a large user of refractories in building materials industry:

First, product innovation:

1. Low thermal conductivity and energy saving refractory

Low heat conduction can reduce the temperature of the cylinder and reduce the heat loss, thus reducing the energy consumption. (1) lightweight: the material structure is designed to achieve lightweight under the premise of ensuring necessary alkali resistance and other functions; (2) micropore technology: to study microstructure and performance controllable technology; (3) multilayer composite technology: the whole life thermal matching stability control technology of laminated refractory composite interface is studied. There are mainly: light alkali resistant castings, low heat conduction anti-stripping bricks, multi-layer composite silicon mullite bricks, multi-layer composite mullite bricks, high strength and low magnesium aluminum spinel bricks.

2. Environment-friendly refractory

No chromatization - solve the problem of chromium pollution. It is used in the high temperature belt of cement rotary kiln, and it is mainly used to study the coating property, weight softening temperature and thermal shock property of refractory. The refractory used in cement kiln is chrome free. There are mainly: magnesite - ferroalumina spinel brick, magnesia - fe - al composite spinel brick, magnesia - ca - zirconium brick, magnesia - al spinel brick, etc.

3. Long life refractory

The application of long-life refractory can reduce the consumption of mineral resources and save energy. There are mainly: toughening type castings, low thermal conductivity wear-resistant castings, anti-explosion castings, high strength, hard anti-corrosion castings, self-flow refractory castings, etc.

Kiln mouth and coal injection pipe: it is one of the most important parts in the sintering system of cement kiln, and it is also a weak link in the use of refractory. Therefore, the longevity of refractory at the kiln mouth and coal injection pipe is particularly important, and its life can be realized systematically through product optimization, structural design optimization and construction scheme optimization.

4. Coordinate the disposal of refractory for cement kiln

The coordinated disposal of cement kiln waste has obvious advantages of energy saving and environmental protection. The content of alkali chlorine sulfide in the kiln increased obviously, which caused damage to the material resistance of the kiln and the kiln tail. The corrosion resistance, atmosphere fluctuation and crust resistance of materials are studied.

The main products are: high purity magnesia aluminum spinel brick, fired magnesia aluminum spinel brick, magnesia calcium zirconium brick, new type magnesia iron aluminum composite spinel brick, etc. A new type of anti - crust pouring material for kiln tail smoke chamber and decomposition furnace.

5. Recovery and reuse of refractory after use

The post-use resistant material is also a secondary resource, which should be recognized from the perspective of resources and environmental protection. The cement kiln produces a large number of waste and old resistant materials every year for maintenance. In developed foreign countries, the recycled resistant materials amount to over 60%, while we only use about 20%.

Research emphasis: fully research, key research regeneration treatment and the special production equipment, the formation of efficient utilization, and research on the application of recycled materials and further form the economic and reasonable application solutions.

Second, technological innovation

1. Preparation process of high energy efficiency of refractory: the preparation process of refractory will change from high energy consumption to high energy efficiency. Refractory has always been considered as a high energy consumption industry, so it will be the research direction to reduce the burning consumption and reuse of waste heat. Environmental standards will become more stringent: NOX, SO2 and dust emissions will be strictly controlled, and desulfurization and denitrification will become an inevitable trend. The degree of automation in the production process will be greatly improved. The unsteady proportion will also be further increased to promote energy conservation.

2. Spraying technology: dry and wet spraying technology is more advanced

During the construction, no mould support is required, the construction speed is fast and the efficiency is high. It is suitable for the kiln door cover, grate cooler, preheater, three times air duct and waste heat boiler of cement kiln.

3. Pumping technology: the ground pump can guarantee the manual safety, the mechanical pump can achieve the effect of labor saving, the rapid energy saving time of pumping, and the controllable addition of water can improve the quality. It is suitable for kiln cover, grate cooler, pre-decomposed kiln cone and three times air duct.

4. Prefabricated parts: it is an integrated innovation of refractory products and construction technology to realize the formalization of amorphous refractory materials. Features: early quality control, high construction efficiency, good adaptability to the environment, and large improvement in performance; Effectively solve the problems of hard baking, easy to burst, and difficult to construct parts; Fundamentally solve the construction site environment and think factors on the quality of refractories. It is suitable for preheater of cement kiln, dissociation furnace, kiln mouth, coal injection pipe, kiln cover, grate cooler, third time air pipe, valve, etc.