How to Install refractory lining

Refractory lining play an important role in steelmaking. Learn how to use refractory lining and find out additional information about Refractory lining. This article describes in detail how to install Refractory lining and informs about other related knowledge about Refractory lining, read this article to have a detailed understanding of Refractory lining.

Installing the Refractory Lining. After consulting with the refractory technician, industrial refractory installation is conducted.

Curing the Refractory Lining. 

Refractory Installation Temperature Control. 

Water Removal of Refractory Installation. 

Drying Out Process.

A refractory lining usually comprises a safety or backup layer behind the working lining in contact with the furnace contents. The whole body is encased in a metal shell. The temperature gradients in the system and the properties of all materials must be considered.

Process of Refractory Lining Installation

1. INSTALLING THE REFRACTORY LINING

After consulting with the refractory factory, industrial refractory installation is conducted. 

This process is the mixing of a certain amount of water with a fixed amount of refractory castable.

If not, the incorrect amount of water can spoil the refractory lining. Among these are lower strength, longer time to set, and more water to remove during the dry out process.

Hence, the technician must use the right amount and type of water. Refer to the refractory material datasheet for the utmost accuracy.

2. CURING THE REFRACTORY LINING

The castable refractory curing procedure is the process where the water reacts with the refractory cement. It is completed when the refractory material has hardened to its final form.

However, it is an intricate process. This is because the temperature of surroundings and castable can impact curing success.

Thus, curing needs a precise temperature range for it to work. Lower temperatures can weaken the curing. This will lead to lower permeability and longer curing time.

Comparably, higher temperatures will set the refractory product too quickly. Hence, it will affect the densification, making the refractory lining unfit for application.

3. REFRACTORY INSTALLATION TEMPERATURE CONTROL

Temperature is a major part when installing refractory. So store all refractory materials and equipment under a controlled setting.

If they are cold, you will lose precious time waiting for them to reach the desired temperature. Thus, refractory contractors put heaters surrounding the curing process depending on the ambiance.

Additionally, uncontrolled storage and mixing temperatures will disrupt further steps to refractory installation methods. Hence, causing severe spalling to the refractory lining

4. WATER REMOVAL OF REFRACTORY INSTALLATION

After installing and setting the refractory monolithic, the next step is water removal. To do this, apply heat to remove both physical water and chemical water.

Then, the water will evaporate at certain temperatures. However, the steam will cause volume expansion which can increase the internal pressure.

By applying the correct methods, the refractory lining is stronger with no risk of spalls.

5. DRYING OUT PROCESS

Lastly, conduct the drying out process for the refractory castable lining.

The dry-out process requires expertise from the right refractory engineering factory. If done improperly, the refractory lining will crack and weaken quickly. Also, the steam explosion might happen, risking the workers and the refractory project.

Therefore, discuss with your refractory technician for a dry-out plan of your plant.

Changxing Refractory Material

Types of Refractory Lining Materials

Refractories can be classified based on various different parameters in multiple ways as listed below:

Based on Chemical composition:

Acidic refractories (Silica refractories, Zirconia refractories, Aluminosilicate refractories);

Basic refractories (Magnesite refractories, Dolomite refractories, Magnesia-chrome refractories);

Neutral refractories (Carbon graphite refractories, Alumina refractories, Chromite refractories)

Method of manufacture: Dry press process, Hand molded, Fused cast, Formed, Unformed.

Fusion temperature: Normal refractories, High refractories, Super refractories.

Refractoriness: Super duty, High duty, Intermediate duty, Low duty.

Thermal conductivity:

Heat-resistant (temperatures≤ 1100 °C),

Refractory (temperatures≤ 1400 °C),

High refractory (temperatures≤ 1700 °C),

Ultra-high refractory (temperatures ≤ 2000 °C).

Purpose of Refractory Lining

Refractory lining is widely used in very high-temperature services.

Serve as a thermal barrier between the pipe/equipment wall and hot medium.

Withstand physical stresses.

Protect against corrosion and erosion.

Provide thermal insulation

Refractory Lining Materials 

The common materials that are used as refractory lining materials are:

Alumina or Aluminum oxide (High Alumina bricks)

Silicon oxide

Magnesium oxide

Calcium oxide

Fire clays (Clay bricks)

Zirconia

Silicon carbide

Tungsten carbide

Boron nitride

Hafnium carbide

Molybdenum disilicide

Tantalum hafnium carbide

Corundum bricks

Plastic refractory

Refractory lining material consists of refractory aggregate, admixture, powder, binder, water, or other liquid, made of amorphous refractory products or fixed refractory products.

Induction Furnace Refractory Products

The refractory tamping process for induction furnaces is a critical step that must be performed carefully to ensure the longevity and efficiency of the furnace. Here is a step-by-step guide for tamping induction furnace refractory wall material:

Filling the floor with refractory: First step is to fill refractory carefully on the furnace floor and then leveling it. Pay attention to grounding cables.

Using bottom (floor) ramming machine: Place bottom rammer into the furnace and then start vibration with the desired duration depending on furnace size. Check leveling then remove machine after bottom refractory is tight enough.

Placing the former for wall ramming: Place the steel former into the middle of furnace. Use some tools to fix it into the position and make sure it won't move while the vibration.

Filling the refractory material into the wall: Fill refractory material space between former and furnace wall. De-air with fork tool into the layers while filling completely.

Ramming the wall refractory material: Wall rammer are placed into the former, and a level close to the bottom floor. Vibration starts and wall ramming machine starts rotating while making hits into the steel former. These hits create vibration and impact in granular refractory lining material. Wall ramming machine raised up step by step until to the surface while working and hitting.

Curing: Once the refractory material has been rammed, it must be allowed to cure. The curing time can vary depending on the specific refractory material used and furnace size.

By following these steps carefully, it is possible to create a durable and long-lasting refractory lining for an induction furnace. It is important to use high-quality refractory materials and equipment to ensure optimal results.