Steel industry

Since 1980s, the domestic steel industry in order to further reduce the production costs of steel, improve the quality of steel, after years of research and practice, vigorously develop the processing technology of molten steel in steelmaking, refining the molten steel processing technology is becoming more and more perfect. At the same time, refining molten steel not only extend the transportation time, increase the molten steel processing operations, but also greatly increased the molten steel temperature drop of molten steel, the decrease of temperature will directly affect the continuous casting and other process smoothly. The modern steelmaking technology requires that the ladle is no longer a simple transport container, which requires the use of more modern refractory materials to meet the stringent requirements of the process.

The steel ladle permanent layer of steelmaking plant is made of castable refractory or refractory brick. However, these refractory material thermal conductivity, shell wall temperature field measurement of an average of 250 to 330 DEG C, caused by heat loss, high heat deformation and damage of ladle shell, and a working layer, a permanent layer service liner is not high, to ensure uniform temperature of molten steel is not up to the requirements. Therefore, how to improve the insulation effect, reduce the ladle refractory for ladle lining thickness, increase the effective volume, improve the steel quantity and packing steel ladle ladle increased headroom, is an important topic for steelmaking.

Nano porous insulation materials developed in recent years, the body with high energy to replace the traditional lining lining work, for iron and steel industry to reduce energy consumption, ladle lining material thickness, increase the effective volume, increase the amount of steel, steel ladle packaging to reduce and eliminate a positive effect node package of accidents.

1. Brief introduction of nano microporous insulation material

Nano porous thermal insulation board is a new type of high efficient thermal insulation material based on nano pore theory. The material is mainly composed of silica 7 to 12 nm, the formation of numerous nano micropore inside, and contains high infrared reflection components, the maximum inhibition of heat conduction, convection and radiation, its thermal conductivity is lower than the static air. The thermal insulation performance of the material is 3 to 6 times of the traditional material, so far it is one of the most high temperature resistant insulation materials. Products commonly used in the form of flat type, roller type. Flat type can be used for flat furnace wall or radian of the furnace wall is too much, shutter type is mainly used for piping systems.

Fig. 1 MT-1000 nanoporous insulation materials in different packaging forms

2. The main characteristics of nano porous insulation materials

Low thermal conductivity:
The thermal insulation performance is 3-4 times of the traditional material (Figure 2), can reduce the energy consumption of the equipment, reduce the required insulation thickness / weight, or provide a larger equipment capacity.
Good thermal performance:
The utility model has the advantages of small specific heat, low heat storage capacity and thermal shock resistance, and can be used for a long time without being damaged by external force.
Green:
Does not contain harmful fiber components, in line with domestic and international environmental standards.
Easy installation:
The use of adhesive tape or refractory mud and ladle in ladle.
Non combustibility:
This product is non combustible material.

Fig. 2 Comparison of thermal conductivity of different thermal insulation materials

3. The main role of nano porous insulation materials in the iron and steel industry

Reduce heat loss, reduce energy consumption, improve the working environment of the factory, extend the life of the equipment, reduce the thickness of the insulation layer, increase the internal volume or reduce the volume of the equipment, reduce the heat accumulation of the insulation layer, and increase the heating rate.

4. Application Introduction

4.1  Ladle

The method is used to clean the inner wall of the ladle, and a layer of glue is coated on the wall of the ladle, and then the HT-1000 is pasted, and then the permanent layer is arranged in turn.

Fig. 3 installation of HT-1000 in ladle

Use effect

1) reduce the heat loss of ladle shell,
2) reduce the tapping temperature of converter
3) reduce the amount of heat required for ladle baking
4 reduce the ladle shell temperature, increase ladle life and safety
5) replace the thick insulation brick
6) reduce the cold and hot temperature of refractory bricks
7) the material consumption of the permanent layer is decreased, the weight of the ladle is lightened, the load of the hanging crane is reduced, and the safety factor is increased.

Fig. 4  When using HT-1000 to increase the volume of ladle

It is worth mentioning that in the current domestic iron and steel manufacturers, but also the use of a kind of composite nano reflective insulation material. This material has largely played the function of heat insulation and thermal insulation materials, but the nanopore is still a certain room for improvement, especially in the thermal conductivity, thermal shrinkage and specific gravity (heat capacity) aspects. Here we list the difference between the two materials for customer reference.

Table 1 Comparison of nano porous thermal insulation material and composite reflective insulation board

4.2 Tundish

Using the method in the package inside wall, avoid the bag on the wall of steel nails, a layer of flat HT-1000 insulation board (5 ~ 10mm), and then install the castable. (Figure 5)
The results show that the heat loss in the continuous casting process is reduced, the temperature of molten steel is reduced and the quality of continuous casting is improved.