Wear-Resistant and Corrosion-Resistant Mullite Refractory Castable for Hazardous Waste Rotary Kiln

For hazardous waste treatment rotary kilns, the composition of hazardous waste is complex and diverse. Among them, medical hazardous waste includes glass slides, infusion bottles, injection tubes, surgical residues, animal testing waste, etc. Therefore, the complexity of the chemical composition of hazardous waste is determined. Hazardous waste is generally burned in a rotary kiln at a temperature of 700 to 1000°C. Moreover, the main component of the gas after calcining hazardous waste is acidic.

mullite castable for hazardous waste rotary kiln

Working Conditions for Refractory Castable Lining of Hazardous Waste Rotary Kiln

Among refractory materials, refractory bricks, and castables have good stability against acidic gases such as sulfuric acid gas and hydrogen chloride gas. However, when the operation is stopped and the temperature in the rotary kiln drops below the dew point, the corrosion caused by the acid needs to be considered. Among them, when the chlorine concentration exceeds 5000ppm (i.e. 0.5%), it is necessary to use bricks and castables with good corrosion resistance of AL2O3-SiO2. Moreover, products with the lowest possible Fe2O3 content or no Fe2O3 content in refractory materials should be selected. The FeCL3 generated by the reaction of Fe2O3 and chlorine is in the gas phase and will volatilize and cause the brick to lose balance. Therefore, it is generally not recommended to use the corrosion-resistant and environmentally friendly product commonly used in cement rotary kilns - mafic spinel bricks. Similarly, because of chlorine problems, low-cement castables should also be used for feed and discharge ports. Because CaO in cement will react with chlorine to generate liquid CaCl2, which will reduce the heat resistance of the castable. In addition, hazardous waste incineration rotary kilns generally adopt a downstream incineration process. That is to say, the fuel primary air and hazardous waste enter from one direction, and the length of the kiln is short (the length-to-diameter ratio is generally only 3 to 5m). The single reaction in the kiln is a combustion and oxidation reaction, so its refractory material configuration can be relatively simple. Based on the above factors, it is recommended that refractory materials with wear resistance, good thermal shock stability, and good corrosion resistance should be used in hazardous waste rotary kilns. Among the current mainstream products, silica mullite bricks are a more suitable product, and the castables can be made of mullite.

Application of Refractory Castables in Hazardous Waste Incineration Rotary Kiln Lining

The chemical composition of hazardous wastes when incinerated in rotary kilns is complex, and the temperature is between 700-1000°C. Mainly due to severe erosion. The main component of the gas after calcining hazardous waste is acidic, and there are also uncertain factors, including acid and alkali components. Therefore, lining with refractory castable is the worst choice.

Refractory castables have good corrosion resistance to acidic gases, but refractory castables corresponding to the matrix are produced according to actual conditions in the atmosphere of different kiln linings. When the temperature of the lining of the hazardous waste rotary kiln drops, the corrosion caused by the acid liquid must be considered. When chlorine exceeds 0.5%, high-aluminum silicon carbide castables need to be considered to resist corrosion.

Due to the problem of chlorine gas, low-cement refractory castables should be used as castables for the feed and discharge ports. Because CaO in cement will react with oxygen, the resulting liquid phase will reduce the heat resistance of refractory castables. Low cement castables have less cement added and low calcium content.

In the entire hazardous waste rotary kiln lining, in addition to the hazardous waste rotary kiln body itself, the secondary combustion chamber is also very important. Secondly, the room temperature is above 1100℃. The use of refractory castables requires high soft-loading temperatures, better corrosion resistance, and good thermal shock stability. Therefore, mullite castable is a good choice. Of course, low-cement mullite castable is also required.

To purchase high-quality wear-resistant and corrosion-resistant mullite castables for hazardous waste rotary kilns, please choose Rongsheng Refractory Materials Manufacturer. We can not only provide high-quality refractory castable products but also provide practical refractory lining solutions. Contact us to get free samples and quotes.