Refractories For Glass Furnace

The main thermal equipment of glass production, such as fusing density, couple groove, feeding channel and annealing density, are mainly made of refractory materials the service efficiency and service life of the equipment and the quality of the glass largely depend on the type and quality of the refractories used the progress of production technology depends on the improvement of refractory manufacturing technology and quality to a great extent. Therefore, it is necessary to reasonably choose and make it is very important to use refractories in the design and daily operation of glass thermal equipment the second is the service conditions and corrosion mechanism of various parts of thermal equipment fire materials refer to inorganic nonmetallic materials or products with fire resistance not less than 1500 ℃ (1580 ℃ in China and the former Soviet Union) it can be natural raw materials, also can be man-made products and materials, refractories in addition to a certain degree of fire resistance, but also need to have the ability to

Main technical performance of the system:

① In order to meet the requirements of high temperature operation, it should not soften and melt at high enough temperature;

② It can bear the load of the furnace and the stress in the process of operation, and bear a certain negative pressure at high temperature;

There is no loss of structural strength, deformation and failure;

③ High temperature volume stability can not produce too much shadow or shrinkage, dense furnace masonry or pouring body will not shrink due to volume expansion existing cracks or cracks;

④ The thermal shock resistance does not break under certain temperature variation and thermal shock;

⑤ The anti invasion performance can withstand the long-term action of gas, liquid and solid corrosive medium without rapid erosion, and can withstand the corrosion oxidation reduction at high temperature it can withstand the potential of high temperature and high speed flow flame and smoke, the erosion of liquid metal and slag, as well as the pressure drop impact grinding of metals and other materials;

② The thermal evaluation of thermal resistance and structural residual property refers to the crack and test drop of brick body caused by temperature change. Structure.

Falling refers to the fact that the melt of refractories will sneak into the brick along its pores and crack channels, and interact with it to form the same structure as the original one.

When the temperature changes dramatically, the metamorphic layer with different brick structure and properties will crack and fall.

The glass industry is unique in that the eroded part of the glass dense sulfur body will remain in the liquid glass if it can be completely dissolved.

In glass, the composition of glass is only affected to a small extent, which is not harmful to one glass, but not to some special glass.

Xu: if it cannot be completely dissolved, a series of glass defects such as stones, nodules and bubbles will be formed, resulting in waste products. The other side.

At present, the service life of China’s large-scale float glass has reached 50 years.

More than 8 years, but there is still a big gap compared with countries with relatively developed glass industry. Therefore, the quality of refractory is the key to the quality of glass.

Key factors of industrial development

Characteristics of refractories for glass furnace

Refractories are a group of multiphase and multicomponent complex systems, which are composed of a variety of different chemical compositions and minerals with different structures

Plastid. The properties of refractories are closely related to their chemical composition, phase composition, bonding morphology and distribution, as well as the characteristics of each phase.

chemical composition

The chemical composition of refractories is one of the basic factors that determine the properties of refractories.The chemical composition of refractories can be divided into two parts according to the composition and function: the main component which accounts for an absolute large amount and plays a decisive role in its performance, and the minor component which accounts for a small amount is called the secondary component. The secondary component includes the impurity component accompanying the raw material and the additive component specially added to achieve a certain purpose.

(1) Principal component principal component is the composition of time fire matrix in refractories, which is usually one or several kinds of high melting ignition oxides or non oxides formed by composite minerals. Its performance and quantity directly determine the properties of time fire materials. Time fire materials can be divided into acid, alkaline and neutral according to their chemical properties.

(2) The impurity component refers to the refractory material which is brought in or mixed in the production process due to the use of natural mineral raw materials

Generally speaking, Ko, Nao, FeO and FeO are time fire materials

The harmful impurities in the product. In addition, the acid oxide (ro2) and acid oxide in the basic pyrotechnic material (RO is the main component) are also increased

The oxides in pyrotechnic materials are regarded as harmful components, which have strong solvation at high temperature. The effect is not obvious

Only the formation temperature of eutectic liquid phase decreases and the amount of liquid phase increases, and with the increase of temperature, the amount of liquid phase decreases

The increasing speed is accelerated, which seriously affects the high temperature performance of refractory products. Therefore, it is necessary to control the impurity composition as low as possible

For example, the main component of silica brick is SiO, and the harmful components include Ao, to and alkali metal oxides. American Standard

It is required that the total content of impurities in special grade silicon breaker is less than 0.5%, and the content of Ao in British standard silicon breaker is 0.3%

There are two kinds of fluxing effects of impurities in refractories with the content of a1o less than 0.6%

(1) Due to chemical reaction, low melting liquid phase is formed; (2) The liquid phase formed at the same temperature is not necessarily low melting large quantity.

(3) In order to improve the physical performance, production performance and workability of refractory, the addition of chemical composition in the production or use of refractory.

A small amount of additives that can be added to improve the performance of the product is called additive. The dosage of additives varies with their properties and functions, and is generally low.

It is a few ten thousandths to a few percent of the total composition of pyrotechnic materials. Additives can be divided into the following categories according to their purposes and functions:

（1）Time fire material aggregate binding performance class: binder, also known as cementing agent or standing agent； （2） adjust the setting and hardening rate class: including accelerating agent, polar agent and so on； （3）change the rheological properties: including water reducer, plasticizer, gelling agent and degumming agent, etc; （4）Adjust internal organization Structure class: including foaming agent, defoamer, shrinkable agent, swelling agent, etc.; （5）improving durability class: including inhibitor, preservative, anti swelling agent, etc Cryoprotectants, etc; Improve performance, including sintering aid, mineralizer, fast drying agent, stabilizer, etc. Hydration resistance；Antioxidant, anti reducing agent, etc.

There are many kinds of additives, which are the key research objects in the fire material industry

Less: 2. It can obviously change some functions or characteristics of refractory products; 3. It has no serious influence on the main properties of the products, such as the production of silica bricks.

The addition of lime milk and iron is mineralizer to facilitate the formation of quartz; Cao added to the product is a stabilizer to make the product stable.

The results show that the cubic ZrO 2 formed at high temperature is stable at low temperature: MgO and other additives in high purity Al 2O ceramics are sintering aids high density sinter can be obtained at low temperature.