CN102971274A

CN102971274A - Magnesia-based refractory material

Info

Publication number: CN102971274A
Application number: CN201180002015.6A
Authority: CN
Inventors: 土成昭弘; 小村隆之; 金谷彰文
Original assignee: Rozai Kogyo Kaisha Ltd
Current assignee: Rozai Kogyo Kaisha Ltd
Priority date: 2011-07-06
Filing date: 2011-07-06
Publication date: 2013-03-13
Also published as: WO2013005253A1

Abstract

This magnesia-based refractory material is obtained by firing a mixture comprising 60 to 90 wt.% of magnesia, 5 to 20 wt.% of zirconia and 5 to 20 wt.% of alumina, and has excellent corrosion resistance and spalling resistance and satisfactory durability. In addition, it is preferable to add at least one material selected from among 3 to 10 wt.% of titania, 0.1 to 3 wt.% of nickel oxide, 0.1 to 3 wt.% of cobalt oxide, 0.3 to 5 wt.% of manganese oxide and 0.5 to 3 wt.% of yttrium oxide to the mixture.

Description

The magnesia refractory materials

Technical field

The present invention relates to a kind of for steel-making with casting ladle, RH, VOD stove, AOD stove or the grey melting furnace, melting furnace, liquid waste incinerator and the cement burning that the burning ash that produces after the burning disposal the are carried out melting treatment refractory materials with the liner of rotary kiln etc.

Background technology

All the time, the inner lining fireproof material as using in above-mentioned various stoves etc. has used magnesia chrome brick, but magnesia chrome brick can generate sexavalent chrome after use.Described sexavalent chrome meeting harmful to human and environmental health, the refractory materials after the slag of discharging from stove and the use can cause environmental pollution, has therefore proposed very early not contain fully the demand of the so-called chromium-free brick of chromium.

A kind of as in the described chromium-free brick, the magnesia carbon brick that is composited with carbon has been proposed, yet when using this magnesia carbon brick, because the oxidation of carbon causes the brick tissue fragile, thereby exist can't life-time service shortcoming, in addition, the titanium dioxide carbon that produces owing to oxidation of coal, the global warming effect can be aggravated, therefore the brick that meets current needs can not be said.

As the chromium-free brick of eliminating these shortcomings, proposed in magnesium oxide, to add the basic refractory of titanium dioxide etc., for example in the Japanese kokai publication hei 9-20550 communique (patent documentation 1), having proposed a kind of magnesium calcium titanium is basic refractory; In Japanese kokai publication hei 11-147755 communique (patent documentation 2), a kind of typing refractory materials that adds aluminium titanates in spinel has been proposed; In addition, in TOHKEMY 2001-253765 communique (patent documentation 3), a kind of magnalium titanium matter brick has been proposed.

The prior art document

Patent documentation

Patent documentation 1: Japanese kokai publication hei 9-20550 communique

Patent documentation 2: Japanese kokai publication hei 11-147755 communique

Patent documentation 3: TOHKEMY 2001-253765 communique

Summary of the invention

Invent problem to be solved

Yet, generate magnesium titanate after magnesium oxide and the titanium dioxide reaction, and these mineral are very fine and close, broken easily, that is to say that anti-spallation is very low, therefore can't life-time service.In addition, aluminium titanates must be synthetic by titanium dioxide and aluminum oxide, has the problem for the manufacture of the cost raising of its vitrified brick.And, with regard to magnalium titanium matter brick, owing to the blending ratio of the large raw materials of magnesium oxide of the coefficient of expansion is larger, therefore still there is the inadequate problem of anti-spallation.

The present invention researchs and develops and finishes to address the above problem as problem, and its purpose is to provide erosion resistance, anti-spallation is good and magnesia refractory materials with sufficient weather resistance.

For the method for dealing with problems

Realize the method for described purpose as addressing the above problem, the present invention's exploitation has also been adopted a kind of magnesia refractory materials, it is characterized in that, form by the mixture that contains magnesium oxide 60～90 % by weight, zirconium white 5～20 % by weight, aluminum oxide 5～20 % by weight is calcined.

In addition, magnesia refractory materials provided by the present invention also can form by the mixture that contains magnesium oxide 60～90 % by weight, zircon 5～20 % by weight, aluminum oxide 5～20 % by weight is calcined.

And then, magnesia refractory materials provided by the present invention also can be in the magnesia refractory materials that consists of in the above described manner, add in titanium dioxide 3～10 % by weight, nickel oxide 0.1～3 % by weight, cobalt oxide 0.1～3 % by weight, manganese oxide 0.3～5 % by weight, yttrium oxide 0.5～3 % by weight etc. more than at least a kind and form.

The invention effect

As invent 1 described magnesia refractory materials, by at excellent corrosion resistance and add aluminum oxide in the low magnesium oxide of anti-spallation, can improve anti-spallation, and by adding zirconium white, magnesium oxide and zirconium white can form sosoloid, even thereby have minute crack, organize still and can indurate, thus excellent corrosion resistance.

As invent 2 described magnesia refractory materialss, by adding aluminum oxide at excellent corrosion resistance in the low magnesium oxide of anti-spallation, can improve anti-spallation, and by adding zircon, can realize the raising of anti-spallation and erosion resistance.

As invent 3 described magnesia refractory materialss, by adding titanium dioxide, can with slag in the calcium reaction and generate uhligite (CaOTiO ₂), this resultant forms membranaceous near reaction surface (sowing the Move face), thereby can suppress soaking into of slag afterwards.In addition, by adding nickel oxide, cobalt oxide, manganese oxide, yttrium oxide, can form sosoloid with magnesium oxide, make in the magnesian crystal grain, crystal boundary is firm, thereby erosion resistance improves.

Embodiment

Below the magnesia refractory materials of the 1st embodiment of the present invention is described.Magnesia refractory materials of the present invention is by the mixture that contains magnesium oxide 60～90 % by weight, zirconium white 5～20 % by weight, aluminum oxide 5～20 % by weight is calcined the magnesia refractory materials that forms.

Main raw material magnesium oxide has 2800 ℃ high-melting-point, although show high corrosion resistance, coefficient of thermal expansion approximately is 2 times of aluminum oxide, therefore has the shortcoming of easily broken (anti-spallation is low).As this magnesium oxide, must use the following electrically molten magnesia of 3mm, sintered magnesia etc., and to make it contain proportional be 60～90 % by weight.If this ratio is lower than 60 % by weight, then can't fully obtain the effect of high-melting-point and erosion resistance, if more than 90 % by weight, then zirconium white, aluminum oxide contain proportional minimizing, thereby can't realize required purpose.

As alumina raw material, must use Calcined polishing aluminum oxide (purity is 98% or more, below the median size 50 μ m), and to make it contain proportional be 5～20 % by weight.The purpose of adding this aluminum oxide is, by itself and magnesium oxide being reacted and calcining, generates spinel, owing to be attended by expansion this moment, thereby can produce microfracture, and and this crack can absorb thermal stresses.If addition is lower than 5 % by weight, then anti-spallation reduction, and when 20 % by weight are above, the growing amount of microfracture increases, so that strength decreased and produce detrimentally affect.

With regard to zirconium white, use that purity is 98% or more, size is the zirconium whites below the 50 μ m, but also can uses the zirconium white of median size below 1mm.More satisfactory is below 50 μ m.Add to produce microfracture after aluminum oxide generates spinel, thereby be organized in to a certain extent tender, add zirconic purpose and namely be this is remedied.In other words, add zirconic purpose and be, magnesium oxide and zirconium white form sosoloid, even there is like this microfracture, organize also to become firm, and high about 2950 ℃ of zirconic fusing point, so also show high corrosion resistance.Addition does not have effect when 5 % by weight are following.Because zirconium white is expensive, if therefore addition is more than 20%, then selling price is high, and improper.

In addition, zirconium white can use the zirconium white through calcium oxide or stabilized magnesium hydroxide, also can use not stabilized zirconium white.But, when using not stabilized zirconium white, zirconic abnormal expansion shrinks the generation that will cause microfracture, although useful for anti-spallation, if but continue to increase addition, to the microfracture of generation be increased, thereby cause strength decreased and erosion resistance to descend, so addition can not be more than 20%.

Above-mentioned zirconium white is substituted the magnesia refractory materials that namely obtains the 2nd embodiment with zircon.Adding zircon is because it can improve anti-spallation and erosion resistance.The part zircon will begin to decompose in about 1500 ℃, becomes zirconium white and silicon-dioxide.Silicon-dioxide and magnesium oxide react and form forsterite, and the fusing point of this resultant is about 1896 ℃, significantly is lower than magnesium oxide, therefore help to improve anti-spallation.On the other hand, the zirconic effect of decomposition as mentioned above.

And then, in the present invention, as the magnesia refractory materials of the 3rd embodiment, be in said mixture, add in titanium oxide 3～10 % by weight, nickel oxide 0.1～3 % by weight, cobalt oxide 0.1～3 % by weight, manganese oxide 0.3～5 % by weight, yttrium oxide 0.5～3 % by weight more than at least a kind.

That is, explained for the said mixture of magnesium oxide, zirconium white, aluminum oxide, zircon etc., in this omission, below added materials for other and describe.When adding titanium oxide 3～10 % by weight, itself and magnesium oxide react and generate magnesium titanate, become fine and close.Add nickel oxide 0.1～3 % by weight and manganese oxide 0.3～5 % by weight, can generate sosoloid with the magnesium oxide reaction, make in the magnesian crystal grain and crystal boundary firm, thereby erosion resistance improves.In addition, when adding yttrium oxide 0.5～3 % by weight, can react with magnesium oxide, generate fusing point and be approximately 2000 ℃ mineral, so excellent corrosion resistance.If each adds material below above-mentioned scope, then there is not effect, if more than above-mentioned scope, although then produce effect, price is high, therefore, even in fact want to add more than the above-mentioned scope, also can't add.

Embodiment

Press the blending ratio allotment raw material shown in the table 1, liquid (another name: spent pulping liquor with calcium lignin sulphonate, 1 part of powder adds the liquid that 2 parts of water dilutions form) carry out mixing as binding agent, utilize 300 tons friction press to carry out press molding, make standard shape (230 * 115 * 65mm).With this molding under 150 ℃ temperature dry a day, then use shuttle kiln 1730 ℃ temperature lower calcination 6 hours.This calcined body is cut into pre-sizing, the inventive example and comparative example are carried out characteristic survey.

Evaluation item

According to the JIS standard, measure apparent specific gravity, bulk specific gravity, apparent porosity.

Cut into the size of 50 * 50 * 50mm, utilize A Musilang compression testing machine (ア system スラ one presses Shrink Try test Machine) to measure compressive strength.

Anti-spallation test places the electric furnace heating 15 minutes that remains on 1200 ℃ with the test film of 40 * 80 * 20mm, then cools off in water.Repeat this operation, calculate number of times and until the number of times till the test film breakage when test film observes the crack.

The crucible erosion test, utilizing drilling machine to offer internal diameter at the test film of 115 * 50 * 65mm is that 26mm, the degree of depth are the hole of 20mm, in this hole, put into the about 15g of various etchants, seal Erosion prevention agent oxidation with mortar, under 1730 ℃ temperature, placed 6 hours, after the to be tested cooling, it is cut off, obtain the thickness that soaks into of etchant.It is fewer to soak into thickness, and the result is better in expression.

As etchant, use:

Ratio is 6: 4 steel and slag, the basicity CaO/SiO of slag ₂=3;

In the situation of copper refining slag, under 1500 ℃ * 2 hours condition, carry out;

The metal (main component is iron substantially) that produces in the ash melting furnace.

[table 1]

As shown in Table 1, when zirconium white only adds 10%, and when the addition of aluminum oxide increased, when the aluminum oxide addition increased, anti-spallation was also better, and corroding thickness also can reduce, thereby respond well, if but addition is too much, and then effect can variation.This is that microfracture increases because the spinel of aluminum oxide and magnesium oxide reaction generation is when increasing.Therefore, can release to draw a conclusion, that is, in 5～20% scope, limit the addition of aluminum oxide by making zirconic addition, can obtain good anti-spallation and erosion resistance effect.

[table 2]

As shown in Table 2, when zirconic addition up to 20% the time, compare with the situation of only adding 10% in the above-mentioned table 1, compressive strength increases.In addition, along with the addition of aluminum oxide increases, can generate spinel, so aggressiveness and anti-spallation improve all, if but add too much aluminum oxide, then the generation of microfracture increases, and makes the aggressiveness variation.Consider zirconic price, it is limited to 20% on adding.

[table 3]

Zircon can resolve into zirconium white and silicon-dioxide under about temperature more than 1500 ℃, the silicon-dioxide of decomposition and magnesium oxide reaction form forsterite.The fusing point of forsterite is 1896 ℃, than magnesian 2800 ℃ low, from magnesian angle, becomes low melting point, thereby anti-spallation raising.The addition of zircon can't obtain this effect 5% when following.In addition, the addition of zircon is 20% when above, because low melting point increases, although anti-spallation raising, opposite, erosion resistance can reduce, so addition can not be more than 20%.In addition, when the addition of aluminum oxide increased, it is large that void content will become.Thereby this is to cause the cause that expands owing to generate spinel, and therefore anti-spallation improves.When addition was too much, void content increased, and aggressiveness reduces.Therefore the addition of aluminum oxide is preferably 5～20%.

[table 4]

As shown in Table 4, by adding additive, can be observed obviously effective to aggressiveness.Titanium oxide and magnesium oxide react and generate magnesium titanate, become fine and close.The reaction of nickel oxide and manganese oxide and magnesium oxide generates sosoloid, make in the magnesian crystal grain and crystal boundary firm.Yttrium oxide and magnesium oxide reaction generate fusing point and are approximately 2000 ℃ mineral, have therefore obtained good result.

Utilizability on the industry

The present invention can be effective to as steel-making such as the casting ladle of the various refining vessels of molten steel, RH, AOD stove, VOD stoves with the secondary fine furnace, waste is directly carried out the melting furnace of melting or the burning ash of waste is carried out in grey melting furnace, liquid waste incinerator and the cement kiln etc. of melting.

Claims

1. a magnesia refractory materials is characterized in that, forms by the mixture that contains magnesium oxide 60～90 % by weight, zirconium white 5～20 % by weight, aluminum oxide 5～20 % by weight is calcined.

2. a magnesia refractory materials is characterized in that, forms by the mixture that contains magnesium oxide 60～90 % by weight, zircon 5～20 % by weight, aluminum oxide 5～20 % by weight is calcined.

3. magnesia refractory materials as claimed in claim 1 or 2, it is characterized in that, in described mixture, add in titanium dioxide 3～10 % by weight, nickel oxide 0.1～3 % by weight, cobalt oxide 0.1～3 % by weight, manganese oxide 0.3～5 % by weight, yttrium oxide 0.5～3 % by weight more than at least a kind and form.