1. Plasticity of refractory materials.

Plasticity refers to the performance of refractory materials mixed with adhesives and diluents to a specified consistency, rubbed into shape, and subjected to external forces to change shape without cracking. Generally speaking, refractory materials with mixed adhesives have a certain degree of plasticity. Refractory plastics, crushed materials, clay, or materials mixed with adhesives have obvious plasticity, but the plasticity of mechanically pressed semi dry formed products is poor. Metallurgical furnace layer materials

2. Adhesion of refractory materials.

Refractory brick masonry requires materials with certain adhesion at room and high temperatures, so refractory slurry is usually used. Silicon, clay, high aluminum, and magnesium refractory slurries achieve adhesion between refractory products through intermolecular forces at room temperature. In high-temperature environments, ceramic bonding can be achieved through sintering. In order to achieve ceramic bonding at lower temperatures, some additives can be added to the slurry to promote sintering.

3. Elasticity of refractory materials.

The elasticity of refractory materials is specific to sprayed materials. During the spraying construction process, due to the elastic scattering of aggregate particles, it often leads to the waste of refractory spraying materials and the unreasonable grading of spraying particles, resulting in a decrease in bulk density and affecting the service life of the lining.

4. Consistency and grouting of refractory materials.

(1) Consistency is used to indicate the flowability of refractory materials. The concept of consistency is widely used in the construction of refractory slurries, castables, plasticity, and some wet spraying materials. Immerse the specified metal cone into the flowing material. The settlement depth value is the consistency of the material, measured in 0.1 millimeters.

The adjustment of consistency is mainly achieved by adjusting the particle size grade of the material and the combination of binders and diluents. Adding an appropriate amount of water reducing agent can also adjust the consistency index.

(2) Flooding refers to the formation of a layer of slurry on the surface of materials during the construction process of refractory concrete due to vibration and compaction. This is mainly caused by the continuous sinking of aggregate particles.

When constructing multi-layer refractory castable materials with large volume or thickness, after the layer material is vibrated, the bleeding layer should be scratched and a second layer of material should be added. Due to the shiny surface of the slurry layer, it is easy to cause thickness stratification.

5. Hardening time of refractory materials.

Hardening refers to the mechanical strength of the structure formed by physical and chemical changes in refractory materials and binders under certain external environmental conditions.

Various amorphous refractory materials do not require high-temperature sintering under the action of binders. As long as they meet their specific requirements, they can achieve chemical or physical bonding, achieving the hardening and high strength of refractory materials. For example, various types of refractory cement, after being mixed with refractory aggregates, powders, and water, undergo a period of maintenance and hardening, and their strength continues to improve. High temperature fired refractory materials or thermal sprayed refractory materials. During the cooling process, the original liquid phase undergoes vitrification or crystal activity decreases, achieving a hardening process.

Six major properties of refractory materials

The performance of refractory materials refers to their performance when used at high temperatures. This includes fire resistance, load softening temperature, rate of change in reburning line, heat shock resistance, slag resistance, vacuum resistance, etc.

1. Fire resistance performance.

Fire resistance refers to the property of refractory materials that resist high temperatures without melting under no load, and is used to indicate the resistance of refractory materials to high temperatures. Fire resistance is the basis for determining whether a material can be used as a refractory material. According to the International Organization for Standardization, inorganic non-metallic materials with a fire resistance of over 1500 ℃ are refractory materials. The meaning of fire resistance is different from the melting point, and fire resistance cannot be used as the temperature of use for refractory materials.

2. Load softening temperature.

The load softening temperature is the temperature at which refractory materials undergo specific compression deformation under the combined action of a certain load and thermal load. It is an important indicator of the high-temperature mechanical properties of refractory materials, indicating the ability of refractory materials to maintain stability under the combined action of load and high-temperature thermal load. The high-temperature load deformation temperature of refractory materials is an important quality indicator, which to some extent represents the structural strength of the product under the same conditions as its use. The main factor determining the load softening temperature is the chemical mineral composition of the product, which is also directly related to the production technology of the product.

Triple firing line change rate (high-temperature volume stability)

The high-temperature volume stability of refractory materials refers to the stability of the product's external volume or linearity without deformation during long-term use at high temperatures. For sintered products, it is generally measured by the rate of change in sintering volume or sintering line of the product under no heavy load. The change in sintering volume is also known as residual volume deformation, and the change in sintering line is also known as residual line deformation. The re burning deformation of refractory products is of great significance for determining the high-temperature volume stability of the product, ensuring the stability of the masonry, reducing the gap of the masonry, improving its sealing and corrosion resistance, and preventing the damage of the overall structure of the masonry.

4. Thermal shock resistance.

Heat-resistant shock, also known as resistance to rapid cooling and heating, refers to the ability of refractory products to withstand rapid temperature changes without damage.

In practical work, refractory materials often suffer from rapid changes in temperature, resulting in significant changes in working temperature in a short period of time. This rapid change in temperature is called thermal shock. Thermal shock can cause cracking, peeling, and collapse of refractory materials. Therefore, when the working temperature of refractory materials changes sharply during use, its thermal shock resistance must be checked.

In order to improve the thermal shock resistance of materials and avoid material cracking, it is necessary to increase the strength of the material, especially the tensile strength and shear strength, to improve the crack resistance, while reducing the elastic modulus and Poisson's ratio of the material, thereby reducing the potential thermal stress.

Three slag resistance properties.

Slag resistance performance refers to the resistance of refractory materials to erosion and erosion of slag at high temperatures. Here, the concept of slag broadly refers to metallurgical slag, fuel ash, fly ash, various materials, and gaseous substances.

2. Vacuum resistance.

Generally speaking, refractory materials have low steam pressure at room temperature and can be considered very stable and non volatile. However, when working under high temperature and reduced pressure, volatility can become an issue that cannot be ignored, causing losses and accelerating damage due to reduced volatility. Vacuum resistance has become one of the important characteristics of refractory materials that are different from those used at high temperature, room temperature, and atmospheric pressure in this situation.

Classification of amorphous refractory materials

Amorphous refractory materials are unformed and fired refractory materials composed of reasonably graded particles, powder materials, and binders. They do not have a fixed shape and can be made into slurries, slurries, and loose forms, hence they are also known as loose refractory materials. This material can form a seamless overall structure, also known as monolithic refractory materials. The classification method is as follows:

According to the construction method, it is divided into pouring materials, ramming materials, plastic materials, self flowing materials, and spraying coatings;

According to the hardening method, it can be divided into water hardening, gas hardening, and thermal hardening;

c. According to the classification of binders, water includes cement bonding, phosphate bonding, water glass bonding, and micro powder (without cement at all);

According to materials, it is divided into high aluminum, corundum, mullite, silicon carbide, clay, magnesium, etc;

e. According to performance, it is divided into wear-resistant, acid resistant, and alkali resistant;