Brief Description of the Use and Construction of Alkali-resistant Castables

Alkali-resistant castables are mainly used as refractory and alkali-resistant linings in certain parts of kilns exposed to alkali erosion. For example, the cement kiln preheater system, piping system, and the end of the dry rotary kiln barrel. It can also be used as various kiln linings without alkali attack. High-quality products can also be used in parts with high strength and wear resistance requirements.

Storage of alkali-resistant castables: This product must be stored in a dry warehouse.

A brief description of the construction of alkali-resistant castables

1. Water must be clean drinking water.

The pH value is between 6 and 8. Mixing water should be accurately weighed.

The water consumption is as follows: 7% to 8% of the total material amount for high-quality products and 9% to 10% for first-class products.

2. Mixing

It is recommended to use a 200~375 forced mixer. All mixing tools must be clean. Mix until the ingredients are uniform.

3. Construction Overview

3.1 The pouring surface of all molds used should be coated with engine oil.

3.2 All embedded metal parts should be coated with a layer of green paint before pouring.

3.3 The castables should be used within 0.5 hours after mixing. When the pouring thickness is within 250mm, it is advisable to pour to the specified thickness at one time and vibrate until it is completely dense.

3.4 The curing humidity should be 100%, and the curing temperature should be between 10 and 30°C. Demold 24 hours after pouring. The total curing time is 3 to 7 days.

3.5 This material shall not be mixed with other fresh concrete or used in direct contact.

4. Drying system

Linings or structures made of alkali-resistant castables must undergo appropriate heat treatment before use.

4.1 Dry at around 150℃ to remove the attached water. The time depends on the thickness.

4.2 Raise the temperature to about 500℃ at a rate of 25℃/h (depending on different parts and actual possibilities).

4.3 Keep the temperature at about 500℃ for 2 days.

4.4 From about 500℃, heat up to the operating temperature at 30~50℃/h.

4.5 According to the needs and possibilities of different parts, keep the temperature constant for more than 2 days at the operating temperature.

The above is the construction summary of alkali-resistant castables. During use, we must use it according to the construction’s water requirements and construction requirements to prevent cracking and non-solidification caused by improper operation.