JP6228149B2 - Manufacturing method of carbon material interior ore - Google Patents

Description

  The present invention relates to a method for producing a carbonaceous interior ore used as an ironmaking raw material in a blast furnace.

  In recent years, for the purpose of reducing the ratio of reducing material in blast furnace operation, carbon material interior ore formed by mixing carbon material and iron oxide-containing raw material has been used.

  Carbonaceous interior ore has a great feature that it is more reducible than sintered ore or pellets, but when used as a raw material for blast furnace, it is pulverized when transported to blast furnace and charged into blast furnace. Therefore, it is necessary to ensure a predetermined cold crushing strength.

  Therefore, cold crushing strength is improved by mixing and forming iron-containing raw materials such as sintered dust and fine powdered iron ore, powdered carbon materials such as powdered coke and coke dust, and hydraulic binders such as cement. A method for producing an improved non-fired carbon-containing agglomerated mineral is known (for example, see Patent Document 1).

  Further, there is known a method for producing a metal oxide agglomerate by adding hydrochloric acid or lignin, which are acidic substances, to metal smelting dust containing 0.7% by mass or more of an alkali metal element (for example, Patent Document 2). reference.).

JP 2009-161791 A Japanese Patent No. 3944378

  However, in the structure of the above-mentioned patent document 1, since it takes much time and expense for the primary curing and secondary curing after molding, and the drying treatment after curing, there may be a problem that it cannot be efficiently manufactured. .

Further, in order to use the hydraulic binder of the high content cement such as CaO and SiO ₂ as a binder, slag content in the carbonaceous material decorated ore is increased, there is a possibility that the reducing agent ratio in blast furnace is increased .

  In the configuration of Patent Document 2 described above, since a large amount of hydraulic binder such as cement is not used, the amount of slag can be kept low, but it is assumed to be used in a rotary hearth furnace that requires significantly less strength than a blast furnace. Specifically, its strength is about 0.1 kN / p, which is too low as a raw material for a blast furnace.

  In addition, in the method of Patent Document 2, the conditions for obtaining the strength required as a blast furnace raw material are unknown, and the strength can be improved when a raw material having an alkali metal element content of less than 0.7 mass% is used. It is not clear whether or not.

  Therefore, there has been a demand for a method capable of efficiently producing carbonaceous interior ore and ensuring a good crushing strength as a blast furnace raw material.

  This invention is made | formed in view of such a point, and it aims at providing the manufacturing method of the carbonaceous material interior ore which can be manufactured efficiently and can ensure favorable crushing strength as a raw material for blast furnaces.

The method for producing a carbon material-containing ore according to claim 1 comprises adding an organic binder to a powdered iron oxide-containing raw material and a powdered carbon material, adjusting the moisture, mixing and granulating the carbon material-containing ore. The total addition amount of the organic binder is 2% by mass or more and 10% by mass or less in terms of external number with respect to all raw materials not containing the organic binder in terms of solid content, and iron oxide in 50 ml of water. When the pH is 9.5 or more when 1 g of the starting material is added and stirred for 1 minute , at least two kinds of organic binders are added so that the absolute value of the zeta potential is 20 mV or more.

  The method for producing a carbon material interior ore according to claim 2 is the method for producing a carbon material interior ore according to claim 1, wherein the organic binder is at least one of pulp waste liquor, molasses, fermentation liquor and acrylic polymer. It is something.

According to the present invention, the iron oxide-containing raw material has a pH of 9 . In the case of 5 or more, since at least two kinds of organic binders are added so that the absolute value of the zeta potential is 20 mV or more, it is possible to ensure a good crushing strength as a raw material for blast furnaces and to efficiently manufacture without firing. .

It is a graph which shows the relationship between the crushing strength at the time of using a South American iron ore as an iron oxide containing raw material, and the amount of organic binders. It is a graph which shows the relationship between the crushing strength at the time of using steel mill dust as an iron oxide containing raw material, and the amount of organic binders. It is a graph which shows the relationship between the crushing strength of a carbon material interior ore, and the pH of an iron oxide containing raw material. It is a graph which shows the crushing strength by the difference in the addition state of an organic binder. It is a graph which shows the zeta potential by the difference in the addition state of an organic binder.

  Hereinafter, the configuration of an embodiment of the present invention will be described in detail with reference to the drawings.

  When producing carbonaceous material ore used as a raw material for iron making in a blast furnace, an organic binder is added to the powdered iron oxide-containing raw material and the powdered carbonaceous material, the water content is adjusted, mixed and granulated .

  As the iron oxide-containing raw material, for example, iron ore for pellets or sintered ore, dust or dust scale generated in a steel mill, mixed powder of dust scale, or the like is appropriately used.

  As the carbon material, for example, powder coke, steam coal, anthracite, coke dust, blast furnace primary ash, and the like are appropriately used.

  As the organic binder, lignin sulfite, pulp waste liquid containing lignin sulfite and having a dispersion effect, molasses, fermentation broth, starch, acrylic polymer, and the like are appropriately used.

  Further, as the binder, for example, an inorganic binder such as quick lime or bentonite may be added to the organic binder as long as the amount of slag in the raw material does not increase.

  When granulating, a briquette machine (roll-type compression granulator) with a pair of forming rolls is used to produce a pillow-type briquette or almond-type briquette, or a pelletizer (pan-type granulator) is used to form a spherical shape. A rolling granulation method or the like that is formed into a shape can be applied as appropriate.

  In addition, it is necessary to ensure the predetermined intensity | strength in order for the non-baking carbonaceous material interior ore immediately after shaping | molding to prevent the powdering of the transport to a blast furnace, and the powdering at the time of blast furnace charging. Therefore, it is preferable that the raw carbon material interior ore after the molding is dried for the purpose of improving the strength. The conditions for this drying treatment can be determined as appropriate, but it is preferable to carry out the drying so that the moisture content is 3% or less with hot air at 100 to 300 ° C., for example.

  Here, it is important to select an appropriate organic binder in accordance with the pH of the iron oxide-containing raw material in order to increase the strength of the carbonaceous interior ore that does not require curing and has a low slag amount.

  Therefore, in order to clarify the conditions under which the crushing strength can be improved, each iron oxide-containing raw material shown in Table 1 and each organic binder shown in Table 2 are used to produce a carbonaceous interior ore, The difference in crushing strength due to the organic binder was confirmed. In addition, mixed powder is the raw material which mixed ingot, gas ash, etc. which generate | occur | produce in an ironworks.

  FIG. 1 shows the relationship between the crushing strength and the amount of organic binder when South American iron ore A is used as the iron oxide-containing raw material, and FIG. 2 shows the case where steel mill dust is used as the iron oxide-containing raw material. The relationship between crushing strength and the amount of organic binders is shown.

  In FIG. 1 and FIG. 2, powdered coke was used as the carbon material, and pulp waste liquid and molasses were used as the organic binder. Moreover, the addition amount of an organic binder is a value with respect to all the raw materials in solid content conversion.

  The carbonaceous material interior ore was kneaded while adding moisture to the raw material, and then compression molded using a briquette machine. The produced raw briquette has an almond shape of W: 25 mm × D: 18 mm × H: 10 mm. Such raw briquettes were dried at 105 ° C. for 2 hours or more, and then subjected to a crushing strength test based on JIS M 8718.

  That is, in the crushing strength measurement, when the raw briquette is loaded at a constant pressure plate speed of 10 mm / min and the load becomes 50% or less of the maximum load value in the test, or the gap between the upper and lower compression is the raw briquette. When the load was applied until 50% of the average particle size, the pressing operation was terminated. And the maximum value of the compressive load obtained by pressurization operation was made into crushing strength.

  In addition, it is preferable that the crushing strength as a carbon material interior ore which is a raw material for blast furnaces is 0.8 kN / p or more.

  As shown in FIG. 1, when the South American iron ore A is used as the iron oxide-containing raw material, the crushing strength increases as the amount of the organic binder increases, regardless of whether the pulp waste liquid or molasses is used as the organic binder. By setting the binder amount to 2% or more, the crushing strength is 0.8 kN / p or more required as a blast furnace raw material.

  On the other hand, when steel mill dust is used as the iron oxide-containing raw material, the increase in the crushing strength accompanying the increase in the amount of organic binder is small regardless of whether the pulp waste liquid or molasses is used as the organic binder, and 0 required as a raw material for blast furnaces. A crushing strength of 8 kN / p or more cannot be obtained.

  Therefore, the cause of the difference in the increase in crushing strength when an organic binder was added depending on the type of iron oxide-containing raw material was confirmed by focusing on the pH of the iron oxide-containing raw material.

  FIG. 3 shows the relationship between the crushing strength of the carbon material-containing ore and the pH of the iron oxide-containing raw material. In addition, the powdery coke was used as a carbon material, and 3% of pulp waste liquid was added to the organic binder. Further, the pH of the iron oxide-containing raw material was measured after adding 1 g of the raw material (particle size 0.125 mm or less) to 50 ml of water and stirring for 1 minute.

  As shown in FIG. 3, when iron ore having a pH of about 8.0 to 8.5 is used as an iron oxide-containing raw material, a high crushing strength exceeding 0.8 kN / p is obtained by adding only pulp waste liquid as an organic binder. can get.

  It is considered that the crushing strength changes in a shaded region in FIG. 3 due to the influence of pH. The width of the crushing strength is affected by other factors such as the raw material particle size.

  And in the case of pH9.5 or more, there exists a possibility that the crushing strength of 0.8 kN / p or more which is the standard as a blast furnace raw material cannot be obtained.

  Here, even when an iron oxide-containing raw material having a high pH is used, two or more kinds of organic binders are added, and the absolute value of the zeta potential is set to 20 mV or more, thereby improving the crushing strength and improving the blast furnace. The crushing strength required as a raw material can be obtained.

  FIG. 4 shows the crushing strength when iron mill dust is used as the iron oxide-containing raw material, powdered coke is used as the carbonaceous material, and pulp waste liquid and molasses are used as the organic binder. In addition, as an object to be compared, the crushing strength when an organic binder is not used and when a pulp waste liquid or molasses is added alone as an organic binder is also shown.

  As shown in FIG. 4, when the pulp waste liquid or molasses is added alone as the organic binder, the crushing strength does not increase much compared to the case where the organic binder is not added, and the required strength as a blast furnace raw material. Cannot be secured.

  On the other hand, when the pulp waste liquid and molasses are added in combination as an organic binder, the crushing strength is improved and the strength required as a raw material for a blast furnace can be ensured as compared with the case where no organic binder is added.

  FIG. 5 shows the measurement result of the zeta potential under the conditions shown in FIG. The zeta potential was measured using ultrasonic spectroscopy in a state where particles were dispersed after adding 1.5 g of the kneaded material (particle size: 0.125 mm or less) to 48.5 g of distilled water and stirring.

  As shown in FIG. 5, when the pulp waste liquor and molasses are added alone, the absolute value of the zeta potential is small, whereas when the pulp waste liquor and molasses are added in combination, the absolute value of the zeta potential increases. .

  Here, the zeta potential is an index representing the dispersion behavior of the particles, and it is said that the larger the absolute value of the zeta potential, the better the dispersibility of the particles. An organic binder, for example, pulp waste liquid, is mainly composed of lignin sulfonic acid having a dispersing effect, and has an effect of improving crushing strength by dispersing fine particles in the raw material.

  A raw material having a low pH has a large absolute value of the zeta potential even if only one kind of organic binder is used, and a high crushing strength can be ensured by the dispersing effect of the binder.

  On the other hand, in an iron oxide-containing raw material having a high pH, if only one organic binder is added, the absolute value of the zeta potential is small, so that the dispersion effect is difficult to achieve and the crushing strength is low. By adding the organic binder, the absolute value of the zeta potential is increased, so that a high crushing strength can be ensured by the dispersion effect of the organic binder.

  Although the detailed reason why the absolute value of the zeta potential increases by adding an organic binder in combination is not clear, the use of a plurality of organic binders makes it easier for the organic binder to be adsorbed on the particle surface. It is thought that the absolute value of becomes larger.

  Therefore, when the pH of the iron oxide-containing raw material is less than 9.5, at least one organic binder is added. When the pH of the iron oxide-containing raw material is 9.5 or higher, the absolute value of the zeta potential is 20 mV or higher. Thus, at least two kinds of organic binders were added in combination.

In addition, when the addition amount of the organic binder is less than 2% by mass with respect to the total raw materials not containing the organic binder in terms of solid content, there is a possibility that the crushing strength necessary as the raw material for the blast furnace cannot be ensured. On the other hand, when the addition amount of the organic binder exceeds 10% by mass with respect to all raw materials not containing the organic binder in terms of solid content, the action for improving the crushing strength may be saturated, resulting in an increase in cost. Therefore, the total addition amount of the organic binder is 2% by mass or more and 10% by mass or less with respect to all raw materials not containing the organic binder in terms of solid content.

  Next, the operation and effect of the one embodiment will be described.

  According to the one embodiment, when the pH of the iron oxide-containing raw material is less than 9.5, at least one organic binder is added, and when the pH of the iron oxide-containing raw material is 9.5 or more, zeta Since at least two kinds of organic binders are added so that the absolute value of the potential becomes 20 mV or more, the dispersion effect by the organic binder can be secured and the crushing strength can be improved. Therefore, even if it is not baked, it can be efficiently produced without spending much time and cost for curing and drying treatment as in the above-mentioned Patent Document 1, etc., and 0.8 kN / p or more as a raw material for a blast furnace Good crushing strength can be secured.

The addition amount of the organic binder is 2% by mass or more and 10% by mass or less with respect to all raw materials not containing the organic binder in terms of solid content. It is possible to prevent an increase in cost due to saturation of the improving action.

  Since the carbonaceous interior ore can be improved in strength by granulating, for example, with hot air at 100 to 300 ° C. after granulation so that the water content is 3% or less, pulverization and transportation during transportation to the blast furnace are possible. Powdering during charging into the blast furnace can be prevented.

  Hereinafter, this example and a comparative example will be described.

  The iron oxide-containing raw material, the carbonaceous material and the organic binder were kneaded while adding moisture in the formulation shown in Table 3, and compression molded using a briquette machine and granulated. The addition amount of the organic binder is indicated by an external number.

  The granulated raw briquette has an almond shape of W: 25 mm × D: 18 mm × H: 10 mm.

  After this raw briquette was dried at 105 ° C. for 2 hours or more, it was subjected to crushing strength measurement based on JIS M 8718.

  In the crushing strength measurement, when the raw briquette is loaded at a constant pressure plate speed of 10 mm / min and the load becomes 50% or less of the maximum load value in the test, or the upper and lower compression gaps are the average of the raw briquette When a load was applied until the particle size reached 50%, the pressing operation was terminated. And the maximum value of the compressive load obtained by pressurization operation was made into crushing strength.

  No. in which the pH of the iron oxide-containing raw material is less than 9.5. 1 to No. In No. 4, any one of pulp waste liquid, molasses, and acrylic polymer was added alone as an organic binder.

  Moreover, No. whose pH of an iron oxide containing raw material is 9.5 or more. 5 to No. No. 8 was a composite addition of pulp waste liquid and molasses as an organic binder, or a composite addition of pulp waste liquid and fermentation liquor. In addition, these No. 5 to No. 8 also measured the zeta potential.

  Table 3 shows the test conditions and test results for each of the examples and comparative examples.

As shown in Table 3, No. 1 which is a reference example in which the pH of the iron oxide-containing raw material is less than 9.5 and one organic binder is added. 1 to No. For No. 4, a high crushing strength of 0.8 kN / p or more, which is a standard for blast furnace raw materials, was obtained.

  Further, in this example, the pH of the iron oxide-containing raw material is 9.5 or more and two kinds of organic binders are added. 5 to No. For compound No. 8, the absolute value of the zeta potential was 20 or more by adding an organic binder in combination, and a high crushing strength of 0.8 kN / p or more, which is the standard for blast furnace raw materials, was obtained.

  On the other hand, a comparative example No. No. 9 had a crushing strength lower than 0.8 kN / p, which is the standard for blast furnace raw materials, because the amount of organic binder was less than 2%.

  Further, No. 1 which is a comparative example in which the pH of the iron oxide-containing raw material is 9.5 or more and only one organic binder is added alone. 10 and no. No. 11 had an absolute value of zeta potential smaller than 20 and a crushing strength lower than 0.8 kN / p, which is the standard for blast furnace raw materials.

  From the above results, by selecting an organic binder according to the pH of the iron oxide-containing raw material, it is possible to produce an interior ore with excellent crushing strength as a raw material for a blast furnace even if it is not fired.

Claims (2)

An organic binder is added to a powdered iron oxide-containing raw material and a powdered carbon material, the moisture is adjusted, mixed and granulated, and a method for producing a carbonaceous interior ore,
The total addition amount of the organic binder is 2% by mass or more and 10% by mass or less in terms of external number with respect to all raw materials not containing the organic binder in terms of solid content,
Add 1g of iron oxide-containing raw material to 50ml of water, and if the pH is 9.5 or more after stirring for 1 minute , add at least two organic binders so that the absolute value of zeta potential is 20mV or more A method for producing a carbonaceous interior mine characterized by: The method for producing a carbonaceous interior mine according to claim 1, wherein the organic binder is at least one of pulp waste liquid, molasses, fermentation liquid, and acrylic polymer.

Images