JPH0551654A - Pretreatment and granulating method for raw material to be sintered - Google Patents

Abstract

PURPOSE:To improve air permeability in a sintering machine, to promote the burning velocity and to enhance productivity by obtaining granular material having 6-8 mm granule diameter in the case of constituting a raw material introduced into the sintering machine of iron ore and an auxiliary raw material or the like, mixing and granulating the raw material. CONSTITUTION:A powdery raw material to be sintered is constituted of iron ore, an auxiliary raw material, a miscellaneous raw material and fuel. Before this powdery raw material is mixed by a mixer and granulated, the saturated moisture value of the respective raw materials to be granulated is previously calculated. The weighted mean of the saturated moisture value of the raw materials is calculated from both the saturated moisture value of the respective raw materials and the blending rate. Water is incorporated into the raw material to be granulated so that the moisture value of the respective raw materials is regulated to 50-70% of the obtained weighted mean saturated moisture value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the production of iron ore, scale,
Before mixing and granulating auxiliary raw materials such as serpentine, silica sand, limestone, etc., and powdery sintering raw materials consisting of fuel, iron ore or this and auxiliary raw materials (hereinafter simply referred to as granulating raw materials) The present invention relates to a pretreatment method for adjusting the water content of the above and a granulation method for a sintering raw material containing the granulation raw material treated by the method.

[0002]

2. Description of the Related Art Conventionally, in order to produce a sinter of iron ore for charging a blast furnace, powdered iron ores of various brands are mixed with an appropriate amount of auxiliary raw materials, miscellaneous raw materials and fuel in a drum mixer, and water is added thereto. Is added, mixed and granulated, then loaded into a sintering machine, and fired in an ignition furnace. In the production technology of sinter, it is important how to produce high-quality sinter with high productivity. The particle size of the granulated product has a great influence on the quality and productivity of sinter. It is known. That is, in order to increase the productivity of the sintered ore, it is necessary to increase the particle size of the granulated product to improve the air permeability in the sintering machine and increase the firing rate, but if the particle size is too large, It is not possible to burn the inside by normal firing. Granule size is generally considered to have a good effect on sinter productivity +5 mm
The particle size of 10 mm or less that can be calcined to the inside by normal baking is the proper particle size, and the particle size of 6 to 8 mm is the optimum particle size.

The particle size of the granulated product is greatly affected by the water content during granulation, but the water added during granulation is conventionally 6-8.
The amount of granules of mm was added as the production target, which was empirically considered appropriate. In such a conventional method, when the brand used or the mixing ratio is changed, the quality and production rate of the sintered ore vary. In order to deal with this problem, in JP-A-61-48536, the saturated water content value of each sintering raw material used in the sintering raw material granulation step is obtained in advance, and the saturated water content value and each raw material are blended. A method is proposed in which the weighted average of the saturated water content of the sintering raw material is calculated from the ratio and 50% ± 2% of the calculated weighted average saturated water content is added to the sintering raw material for granulation. Has been done.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a powdery sintering raw material composed of iron ore, an auxiliary raw material, a miscellaneous raw material and a fuel is mixed with a mixer and granulated in advance in a predetermined amount with respect to the granulation raw material. The pretreatment method of the granulation raw material and the granulation treated by this pretreatment method, which is adjusted so as to contain the water It is an object of the present invention to provide a method for granulating a sintering raw material containing the raw material.

[0005]

The pretreatment method for a granulating raw material according to the present invention is such that the saturated moisture value of the iron ore used or a granulating raw material consisting of the iron ore and the auxiliary raw material is obtained in advance and the saturated moisture value is The granulation raw material is made to contain water so that the water content is 50 to 70%. The saturated water content value of the granulation raw material is the saturated water content value when the granulation raw material is pure iron ore, and in other cases, it is obtained by weighted averaging from the saturated water content value and the blending ratio of each raw material.

In the latter case, therefore, the saturated water content value of each granulation raw material is obtained in advance, and the weighted average of the saturated water content value of the granulation raw material is calculated from the saturated water content value and the blending ratio of each raw material. , 50 to 70% of the obtained weighted average saturated moisture value
The granulation raw material is made to contain water so that the moisture value becomes. The sintering raw material is composed of particles having a particle size of 10 mm or less. However, since the particle size distribution and the surface shape are different for each granulation raw material, the present inventors The following tests were conducted to find out the difference.

Six types of granulating raw materials (A to F) with different brands
Using as a sample material, a pan type mixer with a diameter of 2 mΦ was used to add water with a rotation speed of 16 rpm (Froude number of 14.5 × 10 ^-3 ), a pan angle of 55 °, a pan height of 38 cm, and a raw material supply amount of 1 T / H. The amount was changed. Fig. 1 shows that the granules thus obtained are sieved with a mesh of 10 mm, 5 mm and 2 mm,
This is the average particle size. As seen in Figure 1,
It can be seen that the optimum granulated water value at which the average particle size of the granulated product is 6 to 8 mm differs greatly depending on the granulation raw material. For this reason, in the present invention, a parameter called saturated moisture value was used as an index for objectively determining the optimum granulated moisture value for each granulation raw material. This saturated water content value is measured, for example, after putting the raw material powder into a funnel, pouring water from the top, and after a time such that water no longer drops downward, that is, after the powder is kept saturated with water. Can be determined by measuring the water content (%) per unit weight of the powder.

FIG. 2 shows that the average particle size of each granulating material is 6-8.
It is a figure which shows the ratio of the optimal granulation water value which becomes mm with respect to a saturated water value. As can be seen from FIG. 2, the optimum amount of water added to the granulation raw material is considered to be 50 to 70%. The granulation raw material obtained by the above method is then charged into a drum-type or pan-type mixer together with a miscellaneous raw material such as quick lime and a fuel to be mixed and granulated. The operating conditions for obtaining the granulated product are 8.1-14.
5 × 10 ⁻³ , granulating raw material other than fine powder type, 11.1 to 1
It has been found that 4.5 × 10 ⁻³ is optimal.

Therefore, the granulating method according to the present invention is characterized in that the granulating raw material obtained by the above method is charged into a mixer together with a miscellaneous raw material and a fuel, and granulated at the following Froude number. Fine powder system 8.1 to 14.5 × 10 ⁻³ Other than fine powder system 11.1 to 14.5 × 10 ^{−3 In} the case of a pan mixer, the limit throughput is 2.5 T / H at 2 mΦ, It was 0.2 T / H at 1 mΦ.

[0010]

[Example 1] The saturated water content of a granulation raw material used in advance was measured, water was added to the granulation raw material so that a water content of 50 to 70% of the value was added, and then the mixer was mixed with quicklime and fuel. And mixed and granulated. A pan type mixer with a diameter of 2 mΦ is used as the mixer, and the rotation speed is 16 r.
pm (Froude number 14.5 × 10 ^-3 ), pan angle 55
°, bread height 38cm, raw material supply 9.2-2.5T / H
Operated in. As a result, the average particle size after granulation is 6 to 8 which is the optimum particle size even if the brand of the granulation raw material is changed or the composition is changed.
It could be maintained at mm, and stable granulation could be performed.

[0011]

[Example 2] The same as Example 1 except that a bread mixer having a diameter of 1 mΦ was used, the rotation speed was 22.6 rpm, the bread height was 19 cm, and the raw material supply amount was 0.1 to 0.22 T / H. Mixed granulation was performed under the same conditions. As a result, the average granulation after granulation could be maintained at the optimum granulation size of 6 to 8 mm even if the brand of the granulation raw material was changed or the composition was changed, and stable granulation could be performed.

[0012]

EFFECTS OF THE INVENTION According to the method of the present invention, it is possible to obtain a granulated product having a target granulation of 6 to 8 mm regardless of whether the brand is changed or the composition is changed. The productivity is improved and the firing rate can be increased, so that the productivity is improved.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the water content during granulation of a granulation raw material and the average particle size after granulation.

FIG. 2 is a diagram showing, for each of the granulating raw materials, a ratio of a moisture value of the granulating raw material having a particle size of 6 to 8 mm after granulation to a saturated moisture value.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takenori Yamamoto 11-1 Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd. Kure Steel Works

Claims (3)

[Claims] 1. Before charging a sintering raw material composed of iron ore, an auxiliary raw material, a miscellaneous raw material, a fuel and the like into a mixer for mixing and granulating,
A pretreatment method for a sintering raw material, characterized in that a saturated water content of a granulation raw material used in advance is obtained, and the granulation raw material is contained so as to have a water content of 50 to 70% of the saturated moisture content. 2. Before charging a sintering raw material composed of iron ore, an auxiliary raw material, a miscellaneous raw material, a fuel and the like into a mixer and mixing and granulating,
The saturated water content value of each granulation raw material is obtained in advance, and the weighted average of the saturated water content value of the granulation raw material is calculated from the saturated water content value of each raw material and the blending ratio, and the calculated weighted average saturated water content value of 50 is calculated. A pretreatment method for a sintering raw material, characterized in that water is added to the granulation raw material so that the water content is about 70%. 3. A granulating raw material obtained by the method according to any one of claims 1 and 2 is charged into a mixer together with a miscellaneous raw material and a fuel to granulate at the following Froude number. Characterizing granulation method. Fine powder system 8.1-14.5 × 10 ^-3 Other than fine powder system 11.14.5 × 10 ^-3