JPS5844633B2 - Low temperature curing monolithic refractories - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a metal melting/scouring furnace, a ladle, a tundish, and a metal melting/scouring furnace.
The present invention relates to a novel, low-temperature hardening monolithic refractory with great industrial applicability, which is mainly used for lining molten metal containers such as cupola forehearths and gutters.

As is well known, conventional lining refractories have a content of 3 to 10% by weight (hereinafter, % by weight is simply referred to as %).

) of water and other liquids, it is necessary to heat and dry at a high temperature before actual operation, which requires a large amount of thermal energy and a long time, and also There is a very serious problem in that heating and drying operations tend to cause fatal damage such as cracks and peeling to the lining structure, so it is important to reduce costs, extend the operating time of the construction target, and extend the service life of the lining structure. Therefore, the establishment of fundamental improvement measures in this area has been a long-standing concern in this field.

The purpose of the present invention is to solve these concerns all at once, and thereby immediately respond to the fierce demands of today's Japanese industry, especially the steel industry.

Next, the configuration of the present invention will be specifically explained.

The deficient refractory of the present invention is made by adding aluminum powder or silicon powder as a sintering material to ordinary refractory raw materials by 0.5% of the total.
-5% and 0.5 to 3% of the total phosphate glass as a sintering and hardening material, and used in dry powder form, as well as ordinary refractory raw materials, Aluminum powder or silicon powder is used as a sintering material in a proportion of 0.5
5% of the total, 0.5 to 3% of phosphate glass powder as a sintering and hardening agent, and 0.5% of pinch powder as a low temperature hardening agent.
It is formulated to be used in dry powder form by blending 1 to 6%.

Metal powders such as aluminum and silicon, which are the sintered materials constituting the refractories of the present invention, are used as crosslinked sintered materials, but they react extremely sensitively to the sintering temperature.
For example, in the case of silicon powder, there is a significant difference in physical properties such as strength between the part that has been heated to 600°C and the part that has not, and cracks that can lead to structural failure occur at this boundary. In order to suppress the adverse effects caused by a sensitive reaction, it is necessary to set the upper limit of the content in the refractory of the present invention to 5%.

On the other hand, if the amount of the aluminum powder or silicon powder is less than 0.5%, it will no longer function as a cross-linked sintered material. %.

Next, the phosphate glass powder, which is the sintering and hardening material constituting the refractory of the present invention, exhibits a crosslinking and sintering effect as is well known, but furthermore, the glass composition melts at a low temperature of 250 to 300°C. hardening effect.

In this case, phosphate glass is present in the refractory of the present invention.
% or more, firstly, the liquid phase produced by glass melting remains inside the structure and does not volatilize, which attracts aggregate and causes so-called liquid phase contraction, which not only causes cracks but also reduces the fire resistance. This causes harmful effects such as lowering the temperature and increasing chemical reactivity with molten metal or slag.
In addition, it becomes difficult to effectively utilize the characteristic that the crosslinking reaction as a sintering effect in phosphate glass powder is slower with respect to temperature than the sintering reaction with aluminum powder or silicon powder described above. .

In other words, when a large amount of phosphate glass is used, exceeding 3%, differences in physical properties such as differences in structural strength due to differences in reaction temperature suddenly become significant, causing stress concentration near the boundaries of differences in physical properties within the structure. This causes cracks and collapse inside the structure.

For the above two reasons, especially the first reason, the amount of phosphate glass blended is 3% or less.

On the other hand, if the blending amount of phosphate glass is 0.5% or less,
Not only cannot a crosslinking sintering effect be obtained, but also almost no hardening effect can be obtained.

This is why the amount of phosphate glass powder added is limited to 0.5 to 3%.

In the present invention, as mentioned above, by blending 0.5 to 3% by weight of phosphate glass powder, which serves as a sintering material and hardening material, not only a sintering effect but also a hardening effect is obtained. Furthermore, 0.1 to 6% of pitch powder is added as a low temperature curing agent.
When blended, the effect of low-temperature curing becomes even more powerful.

That is, the refractory of the present invention utilizes the property of softening → hardening (carbonization) due to heating of pitch powder,
During construction, the refractory of the present invention in the form of dry powder loaded into the site to be constructed is supported by formwork or retaining plates and heated, softening and melting the blended pitch powder, causing the aggregate to be attracted (captured). After that, the pitch is further hardened by heating to harden the adhesive between the refractory aggregates.

In this case, the pitch powder is 6% in the refractory of the present invention.
If the above is blended, plastic deformation of the lining structure due to the above-mentioned softening, collapse due to its own weight, environmental disturbance due to gas generated in the process of pitch softening → melting → hardening, and drying of the water-containing refractory will occur. In addition, even after the pitch has hardened (carbonized), it remains easily flammable due to the presence of a large amount of pitch inside the lining structure, and depending on the conditions of use of the lining, it may reduce wettability with molten metal. This leads to drawbacks such as a negative factor such as a decrease in structural strength due to combustion rather than a positive factor.

On the other hand, if the blending amount of pitch is 0.1% or less, it will not function as a low temperature curing material.

This is why the amount of pitch powder blended is limited to 0.1 to 6%.

It goes without saying that the amount of pitch powder not added can be adjusted by adjusting the amount of the phosphate glass powder mentioned above.

In short, the refractory of the present invention is constructed in such a way that it can be used in dry powder form, with or without pitch powder, and there is no need to mix water or other liquids. It is something that

According to the inventor's experiments, the refractory of the present invention having the above structure enables easy volatilization of volatile substances contained in the mixed raw materials, and can be supplied to the work site in the form of dry powder. In such cases, filling satisfies the need for a particle size structure that provides close packing while retaining structural strength, which is also known as self-retaining ability as a structure, and furthermore, it satisfies the need for a particle size structure that is densely packed in relation to hardened materials and sintered materials. In order to obtain the desired hardenability and sinterability, and to achieve a preferable balance between matrix, cous and aggregate in terms of refractory physical properties, the overall particle size composition must be 1X or more.
~70%, 1~0-088 12~22%, o, oss
It has become clear that it is preferable to set the value below z to 20 to 30%.

The refractory of the present invention having the above structure is used in dry powder form and does not require the addition of water or other liquids, so it does not have to be kneaded with water or other liquids, which is a problem with conventional monolithic refractories. Because the construction is carried out at high temperature, high temperature heating and drying is required before actual operation, which not only requires a large amount of thermal energy and long work hours, but also causes cracks and cracks in the lining structure due to the heating and drying operation. This method fundamentally eliminates the serious drawback of the drum, which is its tendency to cause fatal damage such as peeling, and has great industrial applicability in this respect.

In addition, since the refractory of the present invention uses materials such as the hardened material and sintered material that are compatible with a wide range of refractory raw materials, any one of commonly used refractory raw materials can be used as appropriate. Desired refractory raw materials can be selected and used,
In this respect as well, it has particular practicality.

Next, examples of the present invention will be described.

Example 1 (1) Combination

Claims (1)

[Claims] 1. Into ordinary refractory raw materials, 0.5 to 5% by weight of aluminum powder or silicon powder as a sintering material and (15% by weight of phosphate glass powder as a sintering and hardening material) ~3
A low-temperature curing monolithic refractory, which is composed of % by weight and used in dry powder form. 2. Into ordinary refractory raw materials, 0.5 to 5% by weight of aluminum powder or silicon powder as a sintering material, 0.5 to 3% by weight of phosphate glass powder as a sintering material/hardening agent, and Use pitch powder as a low-temperature curing agent in a total amount of 0.1~
A low-temperature curing monolithic refractory which is composed of 6% and used in dry powder form.