JPS6028889B2 - Pre-treatment method of lignite ore for sintering - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for pre-treating lignite-containing ore for sintering.

Limonite-containing ore is widely used as a raw material for sintering, but since limonite is inherently easily meltable, it has been difficult to incorporate it in large quantities.

That is, the limonite ore easily melts, especially in the lower layer of the dawn formation, forming a large amount of brittle glassy slag. As a result, the ventilation of the sintered layer decreases, resulting in a decrease in production rate and deterioration in the quality of the sintered ore. Therefore, the actual situation is that the amount of limonite-containing ore used has traditionally been limited in dawning operations. The present invention has been made in order to solve such problems and to enable a large amount of limonite-containing ore to be blended without deteriorating the production rate and the quality of the crystallized ore. 0 to limonite-containing ore containing 2% or more of
．． Contains 80% or more of particles on the 25 side or below and 1% or less of crystal water,
By pre-granulating fine ore of Felo% or less in a range of fine ore weight/limonite ore weight = 20/80 to 60/40 and coating the fine ore on the surface of the fine iron ore particles. , which is characterized by suppressing overmelting of iron ore containing skirting.

It is well known that limonite-containing ores have good reactivity and are easily melted, and this tendency is remarkable in limonite-containing ores containing 2% or more of crystallization water. Therefore, in the present invention,
Average particle size 1.5~ which is usually used as raw material for brining
The target is lignite-containing ore that has about 4 sides and contains 2% or more of water of crystallization. In general, the lower layer of the sintered bed is heated and has a higher bell than the upper layer, so overmelting of lignite ore is noticeable in the lower layer of the sintered bed. Therefore, if a large amount of limonite-containing ore is used, the ventilation will drop sharply in the latter half of the dawn feed. As a result of various studies on suppressing overmelting of limonite-containing ore, it was found that covering limonite-containing ore with a low-reactivity pulverulent ore before use is extremely effective in suppressing overmelting. Coating with fine ore is achieved by adding a bottle amount of fine ore to limonite-containing ore and granulating it using a granulator such as a drum or disk. Limonite-containing ore has a highly uneven surface and is easily wetted, so it easily incorporates powdery ore onto the surface to form a powdery adhesion layer.

In other words, a mini-vellet is formed with limonite-containing ore as the core and grain ore as the adhesion layer. The powdery ore easily adheres to the surface of the lignite-containing particles. The grain size of powdery ore is 0.
．． If it exceeds the 25 side, the adhesion will decrease, so it is desirable that the particle size of the grain ore is 0.25 grain or less, and a grain ore containing at least 80% of particles of 0.25 grain or less should be used. is necessary to ensure smooth formation of the adhesion layer. In addition, the limonite-containing ore is present on the surface of the limonite-containing ore and has the function of suppressing the reaction of the limonite with the flux, so it is required to have as low reactivity as possible. Therefore, brown iron-based or magnetic iron-based ores are not preferable as grain-bearing ores, and red iron-based ores with low reactivity are preferable. From this point of view, the composition of the mineral ore is less than 1% crystal water, Fe
It is desirable that it be 0.010% or less. There is an appropriate range for the amount of fine ore that should be added to limonite-bearing ore.

When the weight ratio of powdery ore P and limonite-containing ore N is expressed as P/N, if P/N is less than 20/8, the original purpose of suppressing overmelting of limonite-containing ore will not be achieved; When P/N exceeds 60/40, the fine ore does not adhere to the surface of the limonite-containing ore, and good mini-vellets are not formed, resulting in a decrease in aeration of the cohesive layer and a deterioration in production rate and quality of the coagulate. Therefore, the P/N needs to be adjusted within the range of 20/80 to 60/40. If P/N is within this range, mini-vellets can be smoothly manufactured without particularly adding a semi-occupant. The size of the mini pellets depends on the particle size of the lignite-containing ore, but it is usually within the pseudo particle size range of the sintered feedstock used,
In other words, it is best to have most of them be 1 to 1 enemy.

Mini pellets with a grain size of 1 grain are undesirable for ensuring bed ventilation, and mini pellets with a grain size of more than 1 grain remain in the sintered ore as unmelted source ore and cause a decrease in strength. Undesirable.

By pre-granulating the limonite-containing ore under the above conditions and using it as a continuous raw material, overmelting of the limonite-containing ore can be significantly suppressed.

If lignite-containing ore containing 2% or more of crystal water is used after the above-mentioned preliminary treatment, smooth bran bonding operations can be ensured without deteriorating production rate and quality. As shown in Example Table 1, Comparative Example-1 in which limonite ore A was blended at 25%, Comparative Example-2 in which hematite B ore was blended at the same time as A ore, and both A and B ores were blended. A comparative test was conducted on Comparative Example-3 in which a binder was added to the raw material to strengthen granulation, and 4 Examples of the present invention in which only the A and B ores were pre-granulated and mixed with other raw materials. Ta.

(Table 2, Table 3) For preliminary granulation, granulation was carried out for 2 minutes using a 1m◇ drum.

No binder was added. In the case of Examples, in addition to other ores in the pre-granulated mini pellets (1 to 7 pellets), and in the case of Comparative Examples 11, -2, and 13, all the ores were added to each liter.
After putting it in the m0 drum and mixing for 1 minute, the moisture content of the blended raw materials is 6.
Granulation was continued for an additional 3 minutes while adding water so that the resulting amount was 30%.

In the case of Comparative Example-3, granulation was performed by adding 1% quicklime as a binder. The blended raw materials after granulation have a layer thickness of 40 mm and an inner diameter of 2
It was charged into a 66-rib tying pot, and tying was carried out at a negative pressure of 150 and a slope ratio of 0.

By adding a binder, the aeration of the raw material layer is improved, so the dawning time is shortened. The overmelting of limonite still remains unimproved, and the product's cracking strength and falling strength are at low levels. On the other hand, in the example, overmelting of limonite in the lower layer of the bed was suppressed, and as shown in FIG. 1, the ventilation was significantly improved in the latter half of solidification.

As a result, the productivity and quality of sintered ore have been significantly improved as shown in Figure 2. Table 1 Table 1 2 Table 3

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the change in the wind speed passing through the dawning bed during the dawning process, and FIG. 2 is a diagram showing the results of the sunrise pot test. Figure 1 Figure 2

Claims (1)

[Claims] 1. 0.25
Fine ore containing 80% or more of particles of 1 mm or less, crystal water of 1% or less, and FeO of 10% or less is added in a range of fine ore weight/limonite-containing ore weight = 20/80 to 60/40 for pre-granulation. A method for pre-processing lignite-bearing ore, characterized in that it is turned into mini-pellets and used as a raw material for post-sintering.