TWI408238B - Method for increasing throughput of sintering process - Google Patents

Abstract

A method for increasing throughput of a sintering process including the following steps is described. A sintering mixture is divided into a first portion and a second portion. A calcined lime and the first portion are mixed to make a calcined lime-doped sintering mixture. The calcined lime-doped sintering mixture is applied on a sintering carrier to form a first sintering sub-bed on the sintering carrier. The second portion is applied on the first sintering sub-bed to form a second sintering sub-bed on the first sintering sub-bed. A sintering step is performed on a sintering bed composed of the first sintering sub-bed and the second sintering sub-bed in a stack.

Description

Method of increasing the yield of a sintering process

This invention relates to a sintering process and, more particularly, to a method of increasing the yield of a sintering process.

The sintering raw materials for producing the sinter of the blast furnace are mainly CaO-containing raw materials such as iron ore powder, limestone or dolomite having an average particle diameter of about 1.0 mm to 5.0 mm, and coke, smokeless medium and the like. When the sintered ore is produced, the sintering raw material is first charged into a mixing drum machine, and an appropriate amount of water is added to carry out mixing, humidity conditioning and granulation to form a granulated sintering having an average particle diameter of about 3.0 mm to 6.0 mm. raw material. Next, the granulated and sintered raw material is clothed on a mobile sintering machine trolley by a drum feeder to form a charging layer (also referred to as a sintering bed) having a thickness of about 600 mm to 800 mm. Subsequently, the carbon material charged into the layer is ignited by an ignition furnace disposed above the loading layer. Then, the bellows disposed under the trolley of the mobile sintering machine is sucked downward to sequentially burn the carbon materials in the layer. At this time, it is possible to use the combustion heat generated by the combustion to burn and melt the charged granulated and sintered raw material, thereby performing sintering.

In the sintering reaction, in order to reduce the pumping resistance of the sintered layer to accelerate the progress of the sintering reaction, lime can be used instead of limestone as a binder. The use of quicklime instead of limestone can enhance the granulation of the sintered raw material, and can increase the gas permeability of the sintered layer, thereby increasing the sintering yield. When this technology is implemented, it is usually a method in which dry raw lime is mixed with a sintered raw material and then water is added for granulation, or a method in which wet lime is pre-digested and then mixed and granulated by wet mixing. In both of these modes of operation, all the sintered raw materials are mixed with the quicklime, and then the cloth is sintered.

For example, An Yuanbangfu et al. proposed a sintering technique in an article in the "Iron and Steel" journal published in the "Iron and Steel Addition Sintering Productivity Review" published in 1998. This sintering technique combines the sintered raw materials with all the quicklime and then granulates, thereby improving the granulation property and the sintering gas permeability of the raw materials, thereby achieving the purpose of increasing production. However, since this sintering technique mixes all the sintering raw materials with quicklime, it is necessary to use a large amount of quicklime, which not only causes an increase in raw material cost, but also makes it easy to completely digest the quicklime and increase the discharge amount of the sintered dust.

An article by Seng Zeng et al., published in the "Sintered Pellet" journal published in 2006, "Study and Improvement of Shougang Sintering to Improve Lime Ratio", and published in the "Sintered Pellet" Journal published by Zhang Zhanlei and others in 2004. The technique of "increasing the gas permeability of the sintered layer" also proposes a technique for sintering using quicklime. These sintering techniques pre-digest the quicklime and then mix it with all the sintered raw materials for sintering, thereby avoiding the problem of incomplete digestion of the quicklime. Although such a technique can solve the problem of incomplete digestion of quicklime, since the operation mode of the raw material is still mixed, the problem that the amount of quicklime is large and the raw material cost due to the increase is not improved.

A sintering technique is also proposed in the Republic of China Patent Publication No. I327169. The sintering technology divides the sintering raw materials into two groups, one of which is added with quicklime, and the two groups are separately granulated, mixed, dried, and then subjected to sintering and sintering treatment, thereby achieving the goal of increasing production. However, the process of this sintering technique is quite complicated, and although the initial quicklime is only added to half of the raw materials, in the end, the raw material is mixed completely, and the effect of reducing the amount of quicklime cannot be achieved.

In summary, the technology of replacing limestone with quicklime can increase the sintering yield. However, the above-mentioned operation method of mixing the sintered raw materials and then performing the sintering treatment will greatly increase the amount of quicklime, which not only leads to an increase in the cost of the sintering raw materials, but is more likely to increase the cost of the sintering raw materials. Increase the emission of sinter exhaust dust.

Therefore, there is a need for a sintering technique that not only effectively increases the yield of the sintering process, but also avoids the problem of a large increase in sintering raw materials and an increase in the emission of sintering exhaust dust.

Therefore, an aspect of the present invention is to provide a method for increasing the yield of a sintering process by adopting a double-layer fabric method and mixing the quicklime in the lower half of the material of the sintered layer, so that not only The gas permeability of the lower part of the sinter layer can be improved, and the effect of increasing the sintering yield can be achieved, and the use amount of the quicklime can be effectively reduced, and the cost of the sintering raw material can be reduced.

In accordance with the above objects of the present invention, a method of increasing the yield of a sintering process is proposed, comprising the following steps. A sintered mixture is divided into a first portion and a second portion. The raw lime is mixed with the aforementioned first portion to form a mixed lime-sintering mixture. The ash-sintering mixture is disposed on a sintering stage to form a first sub-sinter bed on the sintering stage. The second portion is disposed on the first sub-sinter bed, and a second sub-sinter bed is formed on the first sub-sinter bed. Performing a sintering step on one of the sintering beds in which the first sub-sinter bed and the second sub-sinter bed are stacked

According to an embodiment of the present invention, in the combination of the above sintered mixture and quicklime, the proportion of quicklime ranges from 1% by weight to 3% by weight.

According to another embodiment of the present invention, in the combination of the above sintered mixture and quicklime, the proportion of quicklime ranges from 2 wt% to 6 wt%.

According to still another embodiment of the present invention, the thickness ratio of the second sub-sinter bed to the first sub-sinter bed is 7:3.

According to still another embodiment of the present invention, the thickness ratio of the second sub-sinter bed to the first sub-sinter bed is 6:4.

According to still another embodiment of the present invention, the thickness ratio of the second sub-sinter bed to the first sub-sinter bed is 5:5.

According to still another embodiment of the present invention, in the above combination of the sintered mixture and the quicklime, the ratio of the combination of the first portion and the quicklime ranges from 30% by weight to 70% by weight.

Please refer to FIG. 1 , which is a bar graph showing the yield of sinter obtained without adding quicklime, adding 1 wt% quicklime and completely mixing with the sintering raw material, and adding 1 wt% quicklime to 40% of the upper portion of the sintering raw material. In the same sintered raw material configuration, the yield of the sintered raw material without adding quicklime, adding 1 wt% of quicklime and completely mixing with the sintered raw material, and adding 1 wt% of quicklime to the upper portion of the sintered raw material at 40% was measured. From Fig. 1, the inventors have found that in the same sintered raw material configuration, 1 wt% of quicklime is added to all of the sintered raw materials, and the sintering yield can be better than that of the sintered raw material to which no quicklime is added. However, if only 1% by weight of quicklime is mixed on the upper part of the sintered raw material, that is, 40% of the upper portion of the sintered raw material, the sintering yield is equivalent to the sintering yield of the sintered raw material to which no quicklime is added under the same raw material arrangement ratio. There is no effect of increasing the sintering yield.

According to the above test results, the inventors speculated that the gas permeability of the lower portion of the sintered raw material layer is the main factor affecting the sintering reaction rate, and it is considered that by increasing the gas permeability of the lower portion of the sintered raw material layer, the yield of the sintering process should be effectively improved. It is speculated that the inventors conducted another test in which the sintered raw material was not added with quicklime, 1 wt% of quicklime was added and completely mixed with the sintered raw material, and 1 wt% of quicklime was added to the sintered raw material under the same sintering raw material configuration. The yield of the lower 40% medium case. The test results are shown in Figure 2. It can be seen from Fig. 2 that, in the same sintering raw material, whether 1 wt% quicklime is added to all the sintering raw materials, or 1 wt% quicklime is added to 40% of the lower portion of the sintering raw material, the sintering yield is better than that of the unadded quicklime. Sintering yield of the sintered raw material. Moreover, as can be seen from Fig. 2, the sintering yield of adding 40% of the raw lime to the lower portion of the sintered raw material is slightly better than the sintering yield of all the sintered raw materials.

Since the quicklime is added to the sintering raw material, the granulation can be enhanced, and the effect of increasing the particle size of the pseudo-particles can be achieved. Therefore, the inventors believe that the above-mentioned 40% incorporation of 1% by weight of quicklime under the sintered raw material can increase the sintering yield because the addition of quicklime can increase the particle size of the raw material in the lower part of the sintered raw material, thereby improving the gas permeability of the sintered raw material layer. Sex. Moreover, by adding a small amount of quicklime to the lower portion of the sintered raw material, the yield of the sintering process can be greatly improved.

In view of this, the inventors hereby propose an implementation method which can increase the yield of the sintering process. Please refer to FIG. 3 , which is a schematic flow chart of a sintering process according to an embodiment of the invention. In this embodiment, the sintered mixture 100 of the sinter for the blast furnace is first provided. In one embodiment, the sintered mixture 100 of the sinter used in the blast furnace may, for example, comprise iron ore, fine coke, a flux, and the like. Next, the sintering mixture 100 is conveyed by a conveying device 102 such as a conveyor belt. Next, these sintered mixes 100 are divided into a first portion and a second portion. The ratio of the first portion to the second portion of the sinter mixture 100 can be adjusted according to the type of iron ore used. The quicklime can be added by dry addition or by pre-digested wet mixing. The first portion of the sinter mix 100 can be conveyed into the mixing drum 106 and the second portion can be transported to another mixing drum 108 to effect mixing and granulation of the sinter mix in the mixing drums 106 and 108, respectively. In the present embodiment, before the first portion of the sinter mixture 100 is placed in the mixing drum 106, the quicklime stored in the quicklime silo 104 is first added to the first portion of the sinter mixture 100, and then fed to the mixing drum. 106 is mixed to form a sinter-sintered mixture.

The proportion of quicklime incorporated into the sinter mix 100 can be adjusted in addition to the type of iron ore used, and can be adjusted depending on the stimulation target and cost required by the operator. In one embodiment, the combination of the first portion of the sintered mix 100 and the incorporated quicklime may range, for example, from 30 wt% to 70 wt% in the combination of the sintered mix 100 and the sow incorporated. In other embodiments, the proportion of quicklime may range, for example, from 2 wt% to 6 wt%, in the combination of the blended quicklime and the total sintered mix 100. In a preferred embodiment, the proportion of quicklime may range, for example, from 1 wt% to 3 wt%, in combination with the blend of quicklime and all of the sintered mix 100.

Next, the second portion of the sinter-sintered mixture and the sinter mixture 100 can be transferred from the mixing drums 106 and 108 to the silos 110 and 112, respectively. In the present invention, the cloth material of the sintered raw material is a double-layer cloth. In the present embodiment, the silo 110 is a lower silo, and the silo 112 is an upper silo. Next, the cloth is used by the silos 110 and 112. In one embodiment, the silo 110 is disposed behind the silo 112 relative to the direction of travel 122 of the sintering deck 114 of the mobile sintering machine trolley. Therefore, the silt-sintering mixture is first laid on the sintering stage 114 by the silo 110, and the first sub-sinter bed 116 composed of the mixed lime-sintered mixture is formed on the sintering stage 114. Then, when the sintering sub-stage 114 carries the first sub-sinter bed 116 in the traveling direction 122, the second portion of the sintering mixture 100 is disposed on the first sub-sinter bed 116 above the sintering stage 114 by the front silo 112. The second sub-sinter bed 118 is formed on the first sub-sinter bed 116. The first sub-sinter bed 116 and the second sub-sinter bed 118 are stacked to form a sintering bed 120.

In the present embodiment, the thickness ratio of the first sub-sinter bed 116 to the second sub-sinter bed 118 of the sintering bed 120 can be adjusted according to the granulation property of the sintering raw material used and the performance of the sintering machine, so as to be achievable In the case of improving the gas permeability effect of the sintered raw material layer, the amount of quicklime used is reduced, and the cost of the sintering raw material is further reduced. In an embodiment, the thickness ratio of the second sub-sinter bed 118 to the first sub-sinter bed 116 may be 7:3. In another embodiment, the thickness ratio of the second sub-sinter bed 118 to the first sub-sinter bed 116 may be 6:4. In still another embodiment, the thickness ratio of the second sub-sinter bed 118 to the first sub-sinter bed 116 may be 5:5.

Next, the charcoal material in the combustion bed 120 is introduced by an ignition furnace 124 disposed above the sintering bed 120 on the sintering stage 114. In some embodiments, the bellows may be disposed under the mobile sintering machine trolley, and while the combustion junction bed 120 is being drawn, the carbon material in the sintering bed 120 is sequentially burned by the downward suction of the bellows. The combustion heat generated when the carbon material is burned, the molten sintering bed 120 can be burned to perform sintering of the sintering bed 120.

In the sintering process, since the first sub-sinter bed 116 composed of the sinter-mixed lime-mixed mixture is located below the sintering bed 120, the gas permeability of the sintering bed 120 can be improved, and the pumping resistance can be lowered, thereby accelerating the sintering reaction. , to achieve the effect of the production process of the sintering process.

It can be seen from the above embodiments of the present invention that one of the advantages of the present invention is that the method of the present invention is a method of adopting a double-layer fabric, and the quicklime is mixed in the raw material of the lower half of the sintered layer, thereby not only improving the sintering. The gas permeability in the lower part of the material layer can achieve the effect of increasing the sintering yield, and can effectively reduce the amount of quicklime used and reduce the cost of the sintering raw material.

According to the embodiment of the present invention, another advantage of the present invention is that the method of the present invention can be implemented only by adding a mixing drum and a cloth bin to the original sintering process equipment, so that the method of the present invention is simple. And easy to implement.

While the present invention has been described above by way of example, it is not intended to be construed as a limitation of the scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100. . . Sintered mixture

102. . . Conveyor

104. . . Raw lime silo

106. . . Mixing roller

108. . . Mixing roller

110. . . Silo

112. . . Silo

114. . . Sintering carrier

116. . . First sub-sinter bed

118. . . Second sub-sinter bed

120. . . Sinter bed

122. . . Direction of travel

124. . . Ignition furnace

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood.

Fig. 1 is a bar graph showing the yield of sinter obtained without adding quicklime, adding 1 wt% of quicklime and completely mixing with the sintered raw material, and adding 1 wt% of quicklime to 40% of the upper portion of the sintered raw material.

Fig. 2 is a bar graph showing the yield of sinter obtained without adding quicklime, adding 1 wt% of quicklime and completely mixing with the sintered raw material, and adding 1 wt% of quicklime to 40% of the lower portion of the sintered raw material.

3 is a schematic flow chart showing a sintering process according to an embodiment of the present invention.

100. . . Sintered mixture

102. . . Conveyor

104. . . Raw lime silo

106. . . Mixing roller

108. . . Mixing roller

110. . . Silo

112. . . Silo

114. . . Sintering carrier

116. . . First sub-sinter bed

118. . . Second sub-sinter bed

120. . . Sinter bed

122. . . Direction of travel

124. . . Ignition furnace

Claims (9)

A method for increasing the yield of a sintering process, comprising: dividing a sintering mixture into a first portion and a second portion; mixing a raw lime with the first portion to form a mixed lime-sintering mixture; and sintering the mixed lime mixture Disposed on a sintering stage to form a first sub-sinter bed on the sintering stage; the second part is disposed on the first sub-sinter bed, and a second sub-sinter is formed on the first sub-sinter bed a sintering bed; and a sintering step of sintering the one of the first sub-sinter bed and the second sub-sinter bed. A method of increasing the yield of a sintering process as recited in claim 1, wherein the sintered mixture comprises iron ore, fine coke, and a flux. A method of increasing the yield of a sintering process as recited in claim 1, wherein mixing the quicklime with the first portion comprises placing the quicklime and the first portion in a mixing drum. A method of increasing the yield of a sintering process as recited in claim 1, wherein the ratio of the quicklime ranges from 1% by weight to 3% by weight in the combination of the sintered mixture and the quicklime. A method of increasing the yield of a sintering process as recited in claim 1, wherein the ratio of the quicklime ranges from 2 wt% to 6 wt% in the combination of the sintered mix and the quicklime. A method of increasing the yield of a sintering process according to claim 1, wherein a thickness ratio of the second sub-sinter bed to the first sub-sinter bed is 7:3. A method of increasing the yield of a sintering process according to claim 1, wherein a thickness ratio of the second sub-sinter bed to the first sub-sinter bed is 6:4. A method of increasing the yield of a sintering process as described in claim 1, wherein a thickness ratio of the second sub-sinter bed to the first sub-sinter bed is 5:5. The method of claim 1, wherein the combination of the first portion and the quicklime comprises a ratio ranging from 30 wt% to 70 wt%.