JP7572621B2 - Foaming calming material and foaming calming method using same - Google Patents

Description

The present invention relates to a foaming suppression material for suppressing foaming of slag discharged from a converter into a slag ladle, and a foaming suppression method using the same.

During or after the refining process of molten iron, the slag foams due to CO bubbles that are generated at the interface between the molten iron and steelmaking slag (hereinafter referred to as slag) when the C in the molten iron reacts with the FeO (iron oxide) in the slag, or due to CO bubbles that are generated inside the slag itself when the FeO in the slag reacts with the C in the iron particles contained in the slag. If this foaming of the slag is severe, the 1300-1500°C slag may overflow from the refining equipment or the transport vessel, and if the refining equipment or transport vessel is damaged, a great deal of time and effort will be required to restore them. If the FeO concentration in the slag is high, a large amount of CO bubbles will be generated, so slag with a high FeO concentration has strong foaming properties (it expands rapidly and easily overflows).

To calm the foaming of the slag, it is necessary to destroy the layer in which the CO bubbles remain (hereafter referred to as the foam layer) and shrink the slag. A commonly known method for this purpose is to add a mass of material (calming material) that gasifies inside the slag to the slag, and to use the volume expansion energy generated when the mass gasifies through pyrolysis to destroy the foam layer.

Here, as one of the smelting processes of molten iron, a multi-function converter process is generally known in which after dephosphorization in a converter, a part of the slag is discharged (intermediate discharge) into a slag ladle outside the furnace, and the decarburization process is continued in the same converter. In this multi-function converter process, if the foaming of the slag becomes so severe during the dephosphorization blow that the slag is about to overflow from the throat of the converter, the dephosphorization blow must be interrupted, and the progress of the dephosphorization reaction becomes insufficient. Therefore, in order to increase the dephosphorization rate in the next decarburization blow, it is necessary to add extra CaO to the converter, which leads to an increase in refining costs and an increase in the amount of slag generated. In addition, when slag foaming progresses in the slag ladle that receives the slag during intermediate slag removal, if the slag is about to overflow from the slag ladle, intermediate slag removal must be interrupted, and as a result, the weight of P ₂ O ₅ in the slag remaining in the converter increases, and rephosphorization occurs during decarburization blowing, so extra CaO must be added to the converter. Furthermore, in decarburization blowing, if slag foaming progresses too rapidly, there is a concern that the slag will flow out of the converter throat when the converter is tilted during tapping. For these reasons, it is necessary to add a silencing material to the converter during dephosphorization and decarburization, and to the slag ladle during intermediate slag removal. Usually, such agglomerates that have a destructive effect are called silencing materials, and examples of such silencing materials are disclosed in Patent Documents 1 to 8.

Japanese Unexamined Patent Publication No. 54-32116 Japanese Patent Application Publication No. 4-180507 Japanese Patent Application Publication No. 5-287347 Japanese Patent Application Publication No. 7-145417 Japanese Patent Application Publication No. 11-50124 JP 2008-255446 A JP 2009-270178 A JP 2009-287050 A

On the other hand, in recent years, in order to improve the production capacity of converters, high-speed slag disposal operations have been carried out in which the intermediate slag disposal time has been shortened to less than four minutes, which is three-quarters of the conventional time. Under such operating conditions, slag containing a large amount of iron granules falls into the slag ladle, and the carbon in the iron granules reacts with the FeO in the slag, generating CO gas and promoting slag foaming. Therefore, the conventional silencing materials described in the above Patent Documents 1 to 8 cannot sufficiently suppress the outflow of foaming slag from the slag ladle. Furthermore, in order to suppress slag foaming under such operations, a large amount of silencing material needs to be added continuously, which increases the cost of the silencing material.

In consideration of the above-mentioned problems, the present invention aims to provide a foaming calming material that efficiently, quickly, and inexpensively calms the foaming of slag discharged from a converter into a slag ladle, and a foaming calming method using the same.

In order to solve the above problems, the inventors have investigated important factors for quenching slag foaming. As a result, they have found that the foaming quenching effect obtained by adding a quenching material is related to the gas generation volume ( ^Nm3 /kg) of the quenching material at high temperatures and the apparent density (kg/ ^m3 ) of the quenching material, and that slag foaming can be quickly quenched by designing the gas generation volume and the apparent density of the quenching material to be controlled to predetermined conditions.

In order to control the gas generation volume to an appropriate condition, it is important that the quenching agent contains an organic compound, and in order to increase the apparent density, it is important that the quenching agent contains an inorganic material.The inventors have therefore conducted extensive research and have found that if a quenching agent consisting of a mixture of an organic compound and an inorganic material is added to the foamed slag, the foamed slag can be quenched efficiently, quickly, and inexpensively, and the quenching agent has a gas generation volume of 0.4 ^Nm3 /kg or more and less than 2.0 ^Nm3 /kg when completely combusted, and an apparent density of 1300 kg/m3 or ^more .

Here, the gas generation volume is the volume of gas (Nm ³ /kg) generated per 1 kg of the quenching material when the quenching material comes into contact with the foamed slag and is completely combusted. For example, it can be measured by a method in which a sample is heated in an oxygen-containing atmosphere and the generated gas is collected in a bag. The gas generation volume can also be calculated using the components and composition of the quenching material. In addition, the apparent density is the density of the molded product including the volume of the pores contained inside the molded product when the quenching material is solid. In the case where the foamed quenching material is made of multiple solids made of different materials, the apparent densities are averaged using the apparent densities and ratios of each solid, and the average apparent density may be used as the apparent density of the foamed slag. In addition, in the present invention, since there is almost no difference between the apparent density and the bulk density, the apparent density may be used as the bulk density. The apparent density can be measured, for example, by the method described in JIS Z8807:2012.

The present invention has been made based on the above findings, and the gist of the present invention is as follows.
(1)
A foaming calming material for calming foaming of slag discharged into a slag ladle, comprising:
A foaming sedative material characterized in that, when the gas generation volume _VgT is the volume of gas generated when the mixture is completely combusted , the gas generation volume ^VgT calculated by the following formulas (1) and (2) _is ^{0.4 Nm3} /kg or more and less than 2.0 ^Nm3 /kg, and the apparent density is 2000 kg/m3 or ^more .
V _g ^T =V _g ^O +V _g ^I ₁ +V _g ^I ₂ +V _g ^I ₃ +...+V _g ^I _n ...(1)
V _g ^O =22.4・W _O /100・(a+0.5・b)/(12・a+b+16・c)
... (2)
Here, VgO _represents the gas generation volume (Nm3/kg) generated when the organic compound in the mixture is completely combusted, and VgI1, VgI2, VgI3, ... VgIn represent the gas generation volume (Nm3/kg) ^{generated when} _hydrogen contained in each ^inorganic _{material is} completely combusted _when n _types ^{of inorganic} _materials ^are contained in the mixture . Also, WO represents the ratio (mass%) of the organic compound in the foaming calming material, a represents the total number of carbon atoms in the chemical formula C aHbOc of the composition representative of the organic compound, b represents _{the total} ^number of _{hydrogen atoms in} the _chemical formula C aHbOc of the composition representative of the organic compound , _and c _represents the _total number of oxygen _atoms in the chemical formula _C aHbOc of the organic _compound .

(2)
The foaming calming material according to (1) above, characterized in that the inorganic material includes one or more of slag, dust, refractory material, and concrete.

(3)
A foaming calming method, comprising adding the foaming calming material according to (1) or (2) above to foaming slag discharged in a slag ladle.

The present invention provides a foaming calming material that efficiently and quickly calms the foaming of slag that occurs during slag discharge, and a foaming calming method using the same.

The foaming calming material according to the present invention is a mixture of an organic compound and at least one inorganic material, and is characterized in that the volume ^VgT ( ^Nm3 /kg) of gas generated upon complete combustion is 0.4 or more and less than 2.0, and the apparent density of the mixture is 1300 kg/ ^m3 or more.

As mentioned above, it is known that the calming material destroys the foam layer by utilizing the volume expansion energy generated during gasification in the foaming slag. Therefore, it is considered that the larger the gas generation volume of the calming material, the larger the volume expansion energy, and the easier it is to destroy the foam layer of the foaming slag. On the other hand, the inventors have confirmed that when suppressing foaming of slag discharged from a converter to a slag pan, a substance with an excessively large gas generation volume has a small apparent density, cannot settle in the foaming slag, and reacts on the surface of the foaming slag, so no clear calming effect can be obtained. In addition, even if the apparent density is increased and the substance is allowed to settle in the foaming slag, it may cause re-foaming of the slag, leading to an extension of the slag discharge time. In other words, it has been found that when suppressing foaming of slag discharged from a converter to a slag pan, it is necessary to control the gas generation volume of the calming material within an appropriate range.

However, the method for accurately calculating the actual gas generation volume when the sedative gas is gasified is unclear, and it has been difficult to design a sedative with the appropriate composition. One of the reasons for this is that it is not clear under what conditions the gas generated by the sedative gas in the foaming slag is generated. This is because the foaming slag into which the sedative gas is added is a slag that contains inert CO gas, and the gas generation volume from the sedative gas added to such an inert gas atmosphere changes continuously depending on the progress of the decomposition reaction of the gas generated from the sedative gas, making it difficult to identify.

The inventors therefore conducted extensive research into methods to clarify the volume of gas generated from the quenching agent added to foaming slag. As a result, taking into account the oxygen supplied from foaming slag, they determined the volume of gas generated when the hydrogen, carbon, etc. in the quenching agent are completely combusted by this oxygen, and confirmed that there is a statistically high correlation between the volume of gas generated in the case of complete combustion and the slag quenching effect of the quenching agent.

The perspective of considering the supply of oxygen from the foaming slag is extremely important when searching for materials with a high gas generation volume. The gas generated by the thermal decomposition of the tranquilizer supplied into the foaming slag comes into contact with the molten slag over a wide area, and oxygen is instantly shared by the lower oxides contained in the molten slag, such as FeO and MnO.

Here, a method for calculating the gas generation volume will be described. The foaming calming material according to this embodiment is a mixture of an organic compound and one or more inorganic materials. Here, the gas generation volume from the calming material is mainly the volume of gas from the organic compound, but the inorganic material may also contain a gas generation component. The gas generation component contained in the inorganic material is typically hydrogen, and is contained in water, hydrates, hydroxides, etc. These also effectively act on the slag calming effect. Therefore, in this embodiment, when the calming material contains n types of inorganic materials, the gas generation volume (Nm3/kg) in the case of complete combustion in the calming material can be calculated by adding up the gas generation volumes from each of the inorganic materials when the hydrogen contained in each of ^them is completely combusted.

In other words, if the gas generation volume from an organic compound when it is completely combusted is V _g ^O (Nm ³ /kg) and the gas generation volumes when the hydrogen contained in each of n types of inorganic materials is completely combusted are V _g ^I ₁ , V _g ^I ₂ , V _g ^I ₃ , ... V _g ^In (Nm ³ /kg), the gas generation _volume V _g ^T (Nm ³ /kg) from the sedative can be calculated using the following equation (1).
V _g ^T =V _g ^O +V _g ^I ₁ +V _g ^I ₂ +V _g ^I ₃ +...+V _g ^I _n )...(1)

Furthermore, when the chemical _formula of an organic compound is _CaHbOc (the formula is in parentheses for polymeric compounds), the volume of gas generated from the organic compound when it _is completely combusted, _Vg0 ^, can be calculated from the following formula (2).
V _g ^O =22.4・W _O /100・(a+0.5・b)/(12・a+b+16・c)
... (2)

Here, _W0 represents the proportion (mass%) of organic compounds in the sedative. In addition, a represents the total number of carbon atoms in the chemical formula of the organic compounds, b represents the total number of hydrogen atoms in the chemical formula of the organic compounds, and c represents the total number of oxygen atoms in the chemical formula of the organic compounds. In the case of an organic compound that does not contain oxygen, c=0. For example, in a sedative containing 50% by mass of cellulose ( _{C6H10O5 ) n} as an organic compound, the gas generation volume _Vg0 from ^cellulose in the case of complete combustion can be calculated to be 0.8 ^Nm3 _/ kg.

In addition, when a sedative contains multiple organic compounds, it may be difficult to identify, quantify, or estimate the type and composition of all the organic compounds. Therefore, the gas generation volume _VgO from the organic compounds is calculated by using the chemical formula of one representative organic compound contained in the sedative, and further using the total ratio of the multiple organic compounds in the sedative as _Wo . Here, as a criterion for defining a representative organic compound, for example, an organic compound that has the highest ratio (mass% ⁾ and accounts for 25 mass% or more of the total of the multiple organic compounds is considered to be a representative organic compound. On the other hand, when a sedative contains multiple organic compounds and each organic compound can be identified, the gas generation volume from each organic compound may be calculated using formula (1) for each organic compound, and the sum of ^the gas generation volumes _VgO from the organic compounds contained in the sedative may be calculated.

In addition, when the main composition of the organic compound is unknown, the chemical formula C _a H _b O _c may be estimated by the following procedure to obtain a, b, and c. For example, in a combustion tube, a sample of the organic compound is burned together with an oxidizing agent CuO that promotes complete combustion, and then, in two subsequent U-shaped tubes, a calcium chloride tube is used to absorb H ₂ O, and a soda lime tube is used to absorb CO ₂ , and the masses of absorbed H ₂ O and CO ₂ are obtained. In this case, instead of directly quantifying O alone, the masses of all elements other than O are subtracted from the mass of the sample, and the molar ratio of each element is obtained by dividing the mass [g] of each element by the atomic weight of each element. Since the ratio of the substance amounts of each element represents the ratio of the number of atoms, the simplest integer ratio is obtained to obtain the composition formula representing the organic compound, and a, b, and c in the chemical formula can be obtained. In addition, the chemical formula may be obtained by analyzing spectral data obtained by physical techniques such as nuclear magnetic resonance, mass spectrometry, infrared spectroscopy, and ultraviolet-visible spectroscopy.

On the other hand, the gas volume generated when hydrogen contained in an inorganic material is completely burned can be measured by the temperature programming method or the thermal conductivity method. If the contained substance is water or a hydrate, it can be measured by the Karl Fischer method, etc., as specified in JIS K 0068: 2001.

Next, the organic compounds and inorganic materials contained in the foaming calming material according to this embodiment will be described. As described above, in this embodiment, based on the gas generation volume calculated using formula (2), an organic compound is selected such that the gas generation volume V _g ^T from the calming material when completely burned is 0.4 Nm ³ /kg or more and less than 2.0. As can be seen from formula (2), in the chemical formula, it is preferable to have more hydrogen, and the less oxygen, the more likely the gas generation volume is to be large. In addition, from the viewpoint of producing the calming material inexpensively, it is preferable to use recyclable waste such as PET bottles and discarded plastics.

In addition, the inorganic material contained in the quenching agent according to the present embodiment is mainly non-combustible, and is not particularly limited to the type as long as it can be mixed so that the apparent density of the quenching agent is 1300 kg/ ^m3 or more. However, from the viewpoint of inexpensively producing the quenching agent, it is preferable that the quenching agent is a waste or by-product that can be obtained inexpensively in a steelworks, such as slag, dust, concrete, or refractory material. Here, the refractory material is a composite inorganic material waste such as bricks generated in various processes such as pig iron making, steel making, and rolling processes, and concrete is a composite inorganic material waste generated during demolition work, etc. In addition, the slag is a by-product of a composite inorganic material containing various oxides generated in the pig iron making or steel making process, and the dust is a by-product of a composite inorganic material containing various substances attached to a filter, etc.

Although some of these wastes or by-products can be recycled within the plant or used as roadbed materials, the demand is small compared to the amount generated, and most of the remaining waste is disposed of in landfills at great expense. Therefore, if these can be used as foaming sedation materials, raw material costs and disposal costs can be reduced. For example, refractories can be easily obtained by collecting refractories dismantled due to deterioration or wear and tear, and then crushing and magnetically separating them. In addition, concrete generated during construction work within the plant is often difficult to reuse, but it has been confirmed that it can be reused by mixing it with this sedation material. These have a relatively high density and are effective in increasing the apparent density. In addition, they can be used regardless of their composition. This is because the density does not depend much on the composition. In addition, not only one type of inorganic material but two or more types may be mixed.

Next, the conditions of the foaming calming material made of the mixture of the organic compound and the inorganic material will be described. As described above, in order to obtain the foaming calming effect, the calming material is a mixture of the organic compound and the inorganic material, and the volume _VgT of the gas generated during complete combustion must be 0.4 ^Nm3 /kg or more and less than 2.0 ^Nm3 /kg. If the volume ^VgT of the gas generated during complete combustion is less than 0.4 ^Nm3 /kg, the volume expansion energy is insufficient and the foam layer of the foaming slag cannot be sufficiently destroyed. In addition, if the volume _VgT of the gas generated during complete ^combustion is ^2.0 _Nm3 /kg or more, the volume expansion energy is large, and although the foaming slag calms down once, ^re -foaming occurs quickly thereafter, which results in an extension of the intermediate slag discharge time. This is believed to be because the molten iron discharged together with the slag into the slag ladle, the iron nuggets contained in the slag, and the slag in the slag ladle are vigorously stirred by the large amount of gas generated, causing the carbon in the molten iron and the iron nuggets to react with the FeO and MnO components in the slag, increasing the rate of CO gas generation. Preferably, V _g ^T is less than 1.0 Nm ³ /kg.

However, the inventors have found that even if the gas generation volume of the tranquilizer is appropriately controlled, if its apparent density is low, sufficient tranquilization effect cannot be obtained. In other words, it is necessary to set the gas generation volume of the tranquilizer to 0.4 ^Nm3 /kg or more and less than 2.0 ^Nm3 /kg, and to increase the apparent density to a certain value or more. This is because when the foamed slag that has become hot in the converter is discharged into the slag ladle at room temperature, the foamed slag is cooled and a solidified high-density slag layer covers the surface of the foamed slag, and the viscosity of the foamed slag increases due to cooling, so that it is necessary to increase the apparent density in order to increase the settling speed of the tranquilizer.

In this embodiment, the apparent density of the settling material is set to 1300 kg/ ^m3 or more, so that the foaming slag in the slag ladle can be quickly settled during intermediate slag removal. The apparent density is preferably 1800 kg/ ^m3 or more, more preferably 2000 kg/m3 or ^more . In general, the density of organic compounds that are burned and gasified is low, so the apparent density of the settling material tends to decrease as the proportion of organic compounds increases. Therefore, it is preferable that the inorganic material to be mixed with the organic compounds has a relatively high apparent density.

In addition, regarding the particle size of the tranquilizer, if the tranquilizer is added directly to the foamed slag without being placed in a container such as a burlap bag or a plastic bag, it is preferable that the proportion of particles with a particle size of 5 mm or more is 50% by mass or more. By making the proportion of particles with a particle size of 5 mm or more 50% by mass, scattering of the tranquilizer due to gases, etc. ejected from the foamed slag is suppressed, and the proportion of particles that can reach deeper into the slag is increased, resulting in a higher tranquilizing effect. More preferably, the proportion of particles with a particle size of 5 mm or more is 60% by mass or more. Also, if the proportion of particles with a large particle size is too large, the time required for the tranquilizer to react in the foamed slag increases, and the foamed slag cannot be efficiently tranquilized, so it is preferable to make the proportion of particles with a particle size of 60 mm or less 50% by mass or more, and more preferably, to make it 60% by mass or more.

In addition, when the sedative is added in a container such as a burlap bag or a plastic bag, since there is a small risk of the sedative scattering before it reaches the foaming slag, it is acceptable for the sedative to contain particles of fine particle size, but it is preferable that the proportion of particles with a particle size of 1 mm or more is 50 mass% or more. In addition, it is preferable that the proportion of particles with a particle size of 60 mm or less is 50 mass% or more, and more preferably 60 mass% or more. Here, the above-mentioned particle size and its distribution can be measured, for example, using a sieve such as JIS Z 8801.

As described above, in order to make the volume V _g ^T of gas generated during complete combustion 0.4 Nm ³ /kg or more and less than 2.0 Nm ³ /kg, and to make the apparent density 1300 kg/m ³ or more, by mixing 20 to 95 mass% of slag, dust, refractory material or concrete with the organic compound, the foaming calming effect can be maintained at a high level. It is preferable that the organic compound and inorganic material are mixed in a bonded state, and in this case, there are a method of bonding them with a binder such as cement, a method of compressing powdered materials, a method of fusing the materials together, and the like. The organic compound and other inorganic materials may also be used as a calming agent in a container.

Next, the foaming and settling method for slag using the above-mentioned settling material will be described in detail. In this embodiment, foaming slag in a slag ladle during intermediate slag removal operation will be described as an example, but the method can also be applied to operations in other refining vessels. In addition, there is no limitation on the temperature of the slag.

The slag ladle is added, for example, via a hopper installed near the slag ladle. This hopper is connected to a bunker that stores the slag, and any amount of slag can be added as set by the operator. The timing for adding the slag is preferably when the slag formed in the slag ladle reaches a height of about 4/5 of the height of the refining furnace, and the slag material described below is added. The slag height may be determined by video observation or visual inspection of the slag ladle. When adding the slag to the converter, for example, there are methods for measuring the lance vibration information, using μ-waves, and predicting the sound level inside the furnace.

The calming agent may be added when the slag height is less than 4/5 of the height of the slag ladle, but if the slag is not sufficiently foamed, the calming effect of the calming agent may decrease and a larger amount of calming agent may be required. On the other hand, if the slag height reaches 4/5 or more of the height of the refining furnace, the slag may flow out of the slag ladle due to foaming. The effect of the calming agent is also achieved when it is added after the slag has flowed out of the slag ladle due to foaming.

The above describes preferred embodiments of the present invention, but the present invention is not limited to these examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

Next, an embodiment of the present invention will be described. However, the conditions in the embodiment are merely an example of conditions adopted to confirm the feasibility and effects of the present invention, and the present invention is not limited to this example of conditions. Various conditions may be adopted in the present invention as long as they do not deviate from the gist of the present invention and achieve the object of the present invention.

250t of molten iron was charged into a 300t converter, and after adding auxiliary materials and carrying out dephosphorization treatment, the converter was tilted and about 10t of foaming slag in the converter was discharged into a slag ladle outside the furnace. The slag temperature at this time was 1300-1450°C, and the slag composition was CaO = 30-40 mass%, _SiO2 = 20-35 mass%, T.Fe = 10-20 mass%, MgO = 5-10 mass%, MnO ₌ 5-10 mass% _{, P2O5} = 2-5 mass%, and _Al2O3 = 0-5 mass%.

In this study, the calming agent, a mixture of organic compounds and inorganic materials, was added to the foaming slag in the slag ladle at a rate of 20 kg/min under the conditions shown in Table 1 after the start of slag discharge, and the slag discharge time from the converter to the end of slag discharge was investigated. Here, the slag discharge time refers to the time from when the converter starts tilting for intermediate slag discharge to when the converter is restarted after slag discharge is completed. If the foaming calming is insufficient, the slag discharge from the converter is temporarily stopped to prevent the slag from flowing out, and the slag discharge time is longer accordingly. In other words, the shorter the slag discharge time, the greater the calming effect of foaming in the slag ladle. The calming agent was added by an operator who manually threw the bagged calming agent directly into the center of the foaming slag in the slag ladle.

Here, each sample was prepared by mixing the organic compound and inorganic material in Table 1 in a given ratio and placing the mixture in a 5 kg bag in a vinyl container. Molded PET bottles, polyethylene resin, and soap were used as the organic compounds in Table 1. Representative organic compounds contained in these were polyethylene terephthalate, polyethylene, and soap, respectively, and the gas generation volume _VgO was calculated using the chemical ^formulas of the representative organic compounds.

In addition, slag, refractory material, dust, and concrete were used as inorganic materials, and the moisture content of each was measured to calculate gas generation volumes V _g ^I ₁ to V _g ^I _4. V _g ^T in Table 1 is the sum of the gas generation volumes of each sample. The apparent density was measured by the method described in JIS Z8807:2012.

The molten iron temperature measured after the completion of dephosphorization blowing was 1,330 to 1,380°C, and the slag composition was CaO = 30 to 40 mass%, _SiO2 = 20 to 35 mass%, T.Fe = 10 to 20 mass%, MgO = 5 to 10 mass%, MnO = 5 to 10 mass% _{, P2O5} = 2 to 5 mass%, and _Al2O3 = 0 to ₅ mass%.

The slag in Table 1 was steel slag generated in the converter process, and the refractory material was a mixture of refractory powder and slag powder generated from equipment such as tundishes, blast furnace runners, converter furnace bodies, KR (Kanbara Reactor) impellers, and RH-type vacuum degassing equipment. The dust was collected dust generated in the sintering, blast furnace, and steelmaking processes, and the concrete was concrete rubble generated as construction waste. The particle size of these inorganic materials and organic compounds was 50% by mass with a particle size of 5 mm or more. The calming material O in No. 15 is a paper waste molding, which is a mixture of 50% by mass of paper waste and 50% by mass of steel slag, and is formed into a cylindrical mass with a diameter of about 50 mm and a height of about 50 mm. In addition, No. The calming material P 16 is made by bagging waste paper and steel slag in ratios of 10% by weight waste paper and 90% by weight steel slag.

As shown in Table 1, the gas generation volumes V _g ^T of Nos. 1 to 12 were 0.4 Nm ³ /kg or more and less than 2.0 Nm ³ /kg, and the apparent densities were 1300 kg/m ³ or more. The apparent densities of Nos. 13 and 15 were less than 1300 kg/m ³ , the gas generation volumes V _g ^T of No. 14 were 2.0 Nm ³ /kg or more, and the gas generation volumes V _g ^T of No. 16 were less than 0.4 Nm ³ /kg.

In Table 1, No. 2, No. 3, No. 6 to No. 8, and No. 12, which are invention examples, had a shorter slag drainage time and a higher slag sedation effect than No. 13 to No. 16, which are comparative examples. This is because the gas generation ^volume _VgT of No. 2, No. 3, No. 6 to No. 8, and No. 12 was 0.4 ^Nm3 /kg or more and less than 2.0 ^Nm3 /kg, and the apparent density was 2000 kg/m3 or ^more , and the sedation material settled in the foaming slag and did not cause slag reforming. This is thought to be because the sedation material reacted quickly and efficiently by controlling the gas generation volume _VgT to an appropriate ^level . Also, inventive examples No. 2, No. 3, No. 6 to No. 8 , and No. The draining time of Example 12 was shorter than that of Reference Examples 1, 4, 5, and 9 to 11. This is thought to be because the apparent density of Examples 2 , 3, 6 to 8 , and 12 was 2000 kg/ ^m3 or more, and therefore the foamed slag settled to a deeper part and reacted.

Claims (3)

A foaming calming material for calming foaming of slag discharged into a slag ladle, comprising:
A foaming sedative material characterized in that, when the gas generation volume _VgT is the volume of gas generated when the mixture is completely combusted , the gas generation volume ^VgT calculated by the following formulas (1) and (2) _is ^{0.4 Nm3} /kg or more and less than 2.0 ^Nm3 /kg, and the apparent density is 2000 kg/m3 or ^more .
V _g ^T =V _g ^O +V _g ^I ₁ +V _g ^I ₂ +V _g ^I ₃ +...+V _g ^I _n ...(1)
V _g ^O =22.4・W _O /100・(a+0.5・b)/(12・a+b+16・c)
... (2)
Here, VgO _represents the gas generation volume (Nm3/kg) generated when the organic compound in the mixture is completely combusted, and VgI1, VgI2, VgI3, ... VgIn represent the gas generation volume (Nm3/kg) ^{generated when} _hydrogen contained in each ^inorganic _{material is} completely combusted _when n _types ^{of inorganic} _materials ^are contained in the mixture . Also, WO represents the ratio (mass%) of the organic compound in the foaming calming material, a represents the total number of carbon atoms in the chemical formula C aHbOc of the composition representative of the organic compound, b represents _{the total} ^number of _{hydrogen atoms in} the _chemical formula C aHbOc of the composition representative of the organic compound , _and c _represents the _total number of oxygen _atoms in the chemical formula _C aHbOc of the organic _compound . 2. The foaming calming material of claim 1 , wherein the inorganic material comprises one or more of slag, dust, refractory, and concrete. A foaming calming method, comprising adding the foaming calming material according to claim 1 or 2 to foaming slag discharged in a slag ladle.