JPH01147023A - Manufacture of sintered ore - Google Patents

Abstract

PURPOSE:To economize the cost for the manufacture of sintered ores by sintering lime stone powder contg. specific amounts of powder coke as the top layer on a pallet of a sintering machine and using the generated raw lime stone powder as a binder for sintering. CONSTITUTION:A hopper 19 for lime stone is equipped between a hopper 4 for supplying ores and an ignition apparatus 15 and lime stone powder 9 to which 5-20% powder coke 18 is mixed is poured into the material 2 from the hopper 19 to laminate. Ignition is executed by an ignition apparatus 15 to convert the lime stone powder 9 into raw lime stone. The raw lime stone is absorbed by a blower 25 in a hood 21 and a scraper 22 in front of an ores discharging part 26 and is stored via a cyclone 24 into a hopper 20. Said raw lime stone is charged to a hopper 16 for a binder in a compounding cell 27 and is mixed together with other new material, lime stone powder 9, returning ores 11 and powder coke 18 by a mixer 8; the mixture is charged to the hopper 4 for supplying ores and is supplied to the floor paving ores on a pallet 1. In this way, a by-produced binder for sintering is manufactured at low cost in the sintering process and the permeability is improved by recovering it, thereby reducing the unit of coke.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing sintered ore, and more specifically, to reduce the cost of producing sintered ore by producing a sintering binder at low cost in the sintering process. This invention relates to a manufacturing method that can be manufactured at low cost.

[Prior Art] A schematic diagram of a sintering operation is shown in FIG. Raw material 2 cut out from an ore feed hopper 4 is stacked and supplied on bedding ore cut out from a bedding hopper 3 onto a pallet l. The raw material 2 is ignited by the igniter 15, the coke in the raw material is combusted by ventilation from the main blower 14, and the raw material 2 is sintered to become sintered ore. The sintered ore is crushed by a crusher 5, cooled by a cooler 6, and then classified by a sieve 7. The product on the sieve with a particle size of 8 to 16 mm is returned to the bedding hopper 3 as bedding ore 1O, and the remainder is transported to the blast furnace as product 13. Classified particles with a particle size of -5 mm or less are treated as return ore 11 and are transferred to mixer 8 to produce new raw material 12.
After being mixed with ore, it is returned to the feed hopper 4. Generally, as a means to improve the air permeability of the raw material 2 on a pallet, a binder may be mixed into the raw material. Quicklime (Cab) is commonly used as a binder.

As a method of producing and utilizing this CaO at low cost, Japanese Patent Application Laid-Open No. 58-133331 discloses that lime (Cab) 9 is cut out using a lime hopper I9, stacked on top of the raw material 2, and heated by the ignition device 15. Quicklime powder (Cab)
), a method has been proposed in which the returned ore is recovered together with the return ore 11 through a sieve 7 and used as a binder.

However, in this method, ■ Separation of product 13 and return ore 11 in sieve 7 is not complete (
Binder is mixed into the product 13.

(2) Due to ventilation cooling in the cooler 6, a part of the manufactured binder is scattered.

(2) The igniter 15 alone does not completely decompose CaO, and the conversion rate to CaO as a binder is insufficient.

There are other problems.

[Problems to be Solved by the Invention] As described above, the conventional methods have problems such as low binder recovery yield, low conversion rate to CaO, and contamination of the binder into the product. If a binder is mixed into the product, the chemical components of the sintered ore, including 0% Ca, will deviate from the target value, and the dispersion will increase, resulting in a major quality problem.

The present invention was proposed to solve the above-mentioned problems.

■It is completely separated from the product sintered ore and does not affect the chemical composition of the product.

■High conversion rate to CaO as a binder.

■High binder recovery yield.

It is an object of the present invention to provide a method for producing sintered ore that produces the above-mentioned binder as a by-product.

[Means for Solving the Problems] The present invention solves the above-mentioned problems, and consists of charging coke and limestone powder to the top layer on the sintering machine pallet and sintering the produced limestone. It was applied to a method for producing sintered ore in which powder is supplied as a sintering binder, and the following technical measures were adopted. That is, this is a method in which 5% to 20% of coke is mixed in limestone powder and sintered, and after collecting quicklime powder in the surface layer near the ore discharge section by suction, it is supplied to a sintering raw material supply hopper.

[Function] The present invention utilizes not only the ignition device but also the combustion heat of coke, so the conversion rate to CaO is high, and the generated binder is palletized using a scraper, blower, etc. by utilizing its specific gravity. Since the binder is recovered at the top, the recovery yield of the binder is greatly improved compared to the method of classifying with a sieve, and the cost of producing sintered ore can be reduced.

Figure 2 shows the relationship between the coke content in limestone powder and the CaO conversion rate determined by a pot test. According to FIG. 2, the conversion rate is 97% at a blending ratio of 5%, and even if the blending ratio is increased further, the conversion rate hardly changes. However, if it exceeds 20%, it becomes excessive and causes residual combustion, which increases costs, so the upper limit is 20%. On the other hand, if the blending ratio is less than 5%, the blended raw materials under the lime layer will not ignite. Therefore, the optimal coke powder blending ratio is 5% to 20%.

[Example 1] FIG. 1 shows that the present invention can be suitably implemented. An explanatory diagram of a sintered ore manufacturing apparatus is shown. A limestone hopper 19 is installed between the ore feed hopper 4 and the igniter 15. Limestone hopper 1
Limestone powder 9 and coke 18 are mixed and charged into a limestone hopper 19, stacked on top of the raw material 2, and cut out. It is ignited by the igniter 15, the coke is combusted, and the limestone powder is thermally decomposed to become quicklime (Cab).

A hood 21 and a scraper 22 are installed in front of the ore discharge section 26. The scraper 22 scrapes up the upper part of the raw material 2, and the blower 25 sucks the quicklime. The sucked quicklime powder is collected by the cyclone 24 and stored in the hopper 20. In this case, the burned coke is also sucked in at the same time, but there is no problem in terms of operation.

After being collected in the hopper 20, the binder hopper 16 in the blending tank 27 is charged with other new raw materials, limestone powder 9, return ore 11.
The mixed coke 18 is mixed with the raw material cut out from each tank in the mixer 8, charged into the feed hopper 4, and supplied onto the pallet l.

Note that limestone powder 9 and a portion of coke powder 18 are charged into the limestone hopper 19 by a mixer 28 and supplied to the uppermost layer of the raw materials 2 on the pallet.

Reference numeral 3 denotes a bedding hopper which receives sintered ore of a predetermined particle size and supplies it to the bottom layer of the pallet as bedding ore.

FIG. 3 is an explanatory diagram of the stacking situation of the raw material 2 on the pallet 1, in which limestone powder 9 and coke powder 18 are placed on the mixed raw material 29.
It shows how they are mixed and layered.

Sinter production 6700~6900 (dry-t/da
y), new raw material consumption (excluding coke bed ore and return ore)
) 7200~7500 (dry-t/day)
In the DL type sintering machine, the CaO blending ratio for the binder was 1.
0% (relative to new raw material), blending ratio of coke powder in limestone powder5.
Under the production premise of CaO% of 5% and sintered ore target CaO% of 9.5%, operations were carried out for one month each in the case of no binder, the conventional method with the addition of a binder, and the method of the present invention. The operating status is shown in Table 1.

By manufacturing and adding a binder, the air permeability of the raw material layer on the pallet can be improved and the layer thickness can be increased. As a result, the sensible heat of the exhaust gas was utilized more effectively, and the coke consumption per unit of sintered ore could be reduced. In the present invention, the layer thickness was increased by 30 mm compared to the conventional method, and the coke consumption rate was reduced by 5 (kg/1 sinter).

Table 2 also shows a comparison of the manufacturing status of by-product binders.

In the conventional method (Japanese Unexamined Patent Publication No. 58-133331), the binder is scattered by the tar or mixed into the product, so the yield of the binder relative to the raw lime powder is low at about 81%. In contrast, in the present invention, the yield was improved to 98% and most of the binder could be recovered. Furthermore, Ca0% in the binder was 85% in the conventional method, but was significantly improved to 97% in the present invention. As described above, the manufacturing conditions of the binder in the process of the present invention are superior in both quality and quantity compared to the conventional example, and the effect of improving air permeability in the sintering operation is also greatly improved.

Table 1 Table 2 In addition, Ca in sintered ore, which was the biggest problem with the conventional method,
The transition of Y to the deviation from the target value of 0% (9.5%) is the fifth
In FIG. 6, the changes in the daily fluctuation oX are shown in a graph in comparison with the present invention.

In the conventional method of binder production and ignition operation, which involves classification using a sieve, the deviations and fluctuations mentioned above increase, but since the method of the present invention uses a suction method, it is possible to utilize the difference in specific gravity between ore with a high specific gravity and limestone powder with a low specific gravity. Therefore, the collection efficiency is good, and the control accuracy is almost the same as in normal operation without using a binder.

[Effects of the Invention] As explained above, according to the present invention, the by-product binder (Cab) for sintering is produced at a low cost in the sintering process and recovered and used, thereby improving air permeability and reducing the coke consumption rate. It became possible to lower the amount by 5 (kg/1 sinter).

Furthermore, the control accuracy of CaO% during sintering, which had been a problem in the production of conventional by-product binders, has been greatly improved and is now on the same level as when no binder is used. The present invention has an excellent effect on reducing the cost of producing sintered ore as a raw material for blast furnaces.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the manufacturing process of sintered ore in which the present invention can be suitably used; Fig. 2 is an explanatory diagram of the principle of the present invention;
The figure is an explanatory diagram of the stacking state of raw materials, etc. of the present invention, and Figures 4 and 5 are graphs showing comparison with the conventional example.
a0% deviation, Figure 5 shows daily variation. FIG. 6 is an explanatory diagram of a conventional sintered ore manufacturing process. l...Pallet 2...Raw material 3...Bedding hopper 4...Ore feed hopper 5...Crusher
6... Cooler 7... Sieve 8... Mixer 9... Limestone powder 10... Bedding ore 11.
... Return ore 12 ... New raw materials 13 ... Products
14... Prower 15... Ignition device 1
6... Binder hopper 18... Coke powder 1
9... Limestone hopper 20... Hopper 21
... Hood 22 ... Scraper 24 ... Cyclone 25 ... Blower 26 ... Ore discharge section 27
... Mixing tank 28 ... Mixer 29 ... Mixed raw materials

Claims (1)

[Claims] 1. A method for producing sintered ore, in which coke powder and limestone powder are charged into the uppermost layer on a sintering machine pallet, sintered, and the generated limestone powder is supplied as a sintering binder. , the coke powder is mixed in limestone powder at 5% to 20% and sintered, and after suctioning and recovering the quicklime powder on the surface layer near the ore discharge section, this is supplied to the sintering raw material supply hopper. A method for producing sintered ore.