JP6849280B2 - Desulfurizer addition equipment - Google Patents

Description

The present invention relates to a desulfurizing agent addition facility, and relates to a facility for adding a desulfurizing agent used for a desulfurization treatment in ferronickel smelting to a desulfurization apparatus.

Ferronickel is an alloy of iron and nickel and is used as a raw material for stainless steel and special steel. As a method for producing ferronickel, that is, a method for smelting ferronickel, nickel oxide ore is used as a raw material, and a (preliminary) drying step, a firing and partial reduction step, a reduction melting step, a desulfurization step, and a casting step are used. A dry smelting method having the above can be mentioned.

Specifically, first, in the (preliminary) drying step, the raw material ore is mixed so as to have a predetermined mixing ratio, and then the raw material ore is dried using a rotary kiln (rotary dryer). 35% by mass to 45% by mass) is removed. For example, the adhering water content in the raw material ore is set to a ratio of about 25% by mass to 35% by mass. The ore obtained in this drying process is called "dry ore".

Next, in the calcination and partial reduction steps, a carbonaceous reducing agent (coal) and, if necessary, a melting agent are added to the obtained dry ore, and the ore is charged into a rotary kiln and calcinated at about 800 ° C. to 900 ° C. By firing at a temperature, the remaining moisture (adhered water, crystalline moisture) contained in the dried ore is completely removed, and a partially reduced calcined ore (calcination) is generated.

Next, in the reduction melting step, the obtained burnt ore is reduced and melted in a reduction furnace such as an electric furnace or a blast furnace to generate crude ferronickel (metal) and slag. The crude ferronickel produced in this reduction furnace contains iron as a main component, contains nickel having a grade of about 16% by mass to 25% by weight depending on the set amount of the carbonaceous reducing agent, and sulfur derived from fuel. It contains many impurities such as. In addition, slag produced separately from crude ferronickel contains most of iron oxide in the raw material ore, silicon dioxide and magnesium oxide, and is used as a magnesia filler for component adjustment in the steel sintering process and concrete. Used as fine aggregate, materials for civil engineering work, etc.

The crude ferronickel (crude ferronickel melt) obtained in the reduction melting step was subsequently transferred to the desulfurization step when desulfurization treatment was required according to the product specifications, and a ladle or the like was used. Desulfurization is performed by a mechanical stirrer or an electrically inductive stirrer.

Specifically, in the desulfurization step, a desulfurizing agent such as calcium carbide is added to the crude ferronickel melt and stirred using a mechanical stirrer or an electrically inductive stirrer in the crude ferronickel melt. Sulfur is fixed in slag (hereinafter, also referred to as "purified slag") as calcium sulfide (CaS) and separated and removed to obtain a purified ferronickel melt.

Then, in the casting process, the obtained purified ferronickel melt is poured into a mold or coarse-grained through a rotating disk-shaped medium, and then cooled to ingot or flake-shaped ferronickel (product). To get.

By the way, in the smelting of ferronickel, in the desulfurization treatment (desulfurization step) for crude ferronickel obtained through the reduction melting step, as described above, a mechanical stirrer using a radle or the like, an electric induction stirrer or the like A predetermined desulfurization device is used. The desulfurization equipment is equipped with equipment for adding the desulfurizing agent used for the desulfurization treatment, and the crude ferronickel melt in the desulfurization equipment is charged from the equipment for adding the desulfurizing agent, and the desulfurizing agent is added into the ladle. It is processed.

Conventionally, in a desulfurizing agent adding facility in which a desulfurizing agent is added into a desulfurizing apparatus, the desulfurizing agent and a solvent are directly put into the hopper, and the desulfurizing agent naturally falls from the hopper outlet in an hourglass manner, so that the desulfurizing apparatus is used. A desulfurizing agent was supplied to the crude ferronickel melt contained in the radle.

However, such a method has a problem that the mixing ratio of the desulfurizing agent and the solvent per hour when contacting the crude ferronickel melt is not constant.

For example, Patent Document 1 discloses a technique relating to a mixing and cutting device for different kinds of powder, but does not disclose an adjusting mechanism for maintaining a constant mixing ratio after cutting.

Japanese Unexamined Patent Publication No. 6-055527

The present invention has been proposed in view of such circumstances, and in performing desulfurization treatment on a crude ferronickel melt in ferronickel smelting, a desulfurizing agent and a solvent are used on the crude ferronickel melt. It is an object of the present invention to provide equipment capable of uniformly supplying.

The present inventors have made extensive studies to solve the above-mentioned problems. As a result, the desulfurizing agent is placed by the desulfurizing agent feeder so as to spread over a range of 50% or more in the belt width direction of the belt conveyor, and the solvent is placed in the substantially center of the desulfurizing agent placed on the belt conveyor by the solvent feeder. By adding the desulfurizing agent and the solvent conveyed by the belt conveyor to the desulfurization apparatus, the desulfurizing agent and the solvent can be uniformly supplied, and the present invention has been completed. It was.

(1) The first invention of the present invention is a facility for adding a desulfurizing agent used for a desulfurization treatment in ferronickel smelting to a desulfurization apparatus that executes the desulfurization treatment, and is a desulfurizing agent that supplies the desulfurizing agent. A feeder, a solvent feeder for supplying a solvent, a desulfurizing agent supplied from the desulfurizing agent feeder, and a belt conveyor for carrying the solvent supplied from the solvent feeder are provided. The desulfurizing agent feeder and the solvent feeder are provided in order from the upstream side of the belt conveyor, and the desulfurizing agent feeder is spread over a range of 50% or more in the belt width direction of the belt conveyor. It has an outlet on which the desulfurizing agent can be placed, and the solvent feeder is fixed to a moving device that can move in the belt width direction, and is substantially the center of the desulfurizing agent placed on the belt conveyor. This is a desulfurization agent addition facility on which the solvent is placed.

(2) In the second invention of the present invention, in the first invention, a chute provided with a hopper is provided on the downstream side of the belt conveyor, and the inside of the hopper is divided by a partition plate. Desulfurization agent addition equipment with multiple storage chambers.

According to the present invention, when performing a desulfurization treatment on a crude ferronickel melt in ferronickel smelting, an equipment capable of uniformly supplying a desulfurizing agent and a solvent to the crude ferronickel melt is provided. be able to.

It is a schematic diagram which shows the structure of the desulfurizing agent addition equipment. It is a figure which shows the relationship of the desulfurization reaction efficiency with respect to the desulfurization amount index by a desulfurization treatment.

Hereinafter, a specific embodiment of the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention.

<1. Desulfurizer addition equipment ＞
The desulfurizing agent addition equipment according to the present embodiment is equipment for adding a desulfurizing agent used for desulfurization treatment of crude ferronickel in ferronickel smelting to a desulfurization apparatus that executes the desulfurization treatment.

FIG. 1 is a schematic view showing the configuration of a desulfurizing agent addition facility. FIG. 1 shows a desulfurizing agent adding facility 1 and a desulfurizing device 2 to which a desulfurizing agent is supplied from the desulfurizing agent adding facility 1. As will be described in detail later, in the desulfurization agent addition equipment 1, the desulfurization agent and the medium solvent supplied from the feeders (11, 12) are carried to a chute 14 provided on the upper part of the desulfurization apparatus 2, and the chute 14 is used to carry the desulfurization agent and the solvent. Then add the desulfurization agent and the medium solvent.

Here, the chute 14 is provided with a hopper 15, and the desulfurizing agent and the medium solvent temporarily stored in the hopper 15 are added to the desulfurization apparatus 2 via the chute 14. The inside of the hopper 15 is divided into a plurality of storage chambers, and the desulfurizing agent and the medium solvent are stored in each storage chamber, and then the desulfurizing agent and the medium solvent are stored in each storage chamber via the chute 14. Is added. Therefore, it is important that the desulfurizing agent and the medium solvent are evenly charged into each storage chamber.

Hereinafter, the configuration of the desulfurizing agent addition equipment 1 will be described more specifically.

As shown in FIG. 1, the desulfurizing agent addition equipment 1 includes a desulfurizing agent feeder 11 for supplying a desulfurizing agent, a solvent feeder 12 for supplying a solvent, and a belt conveyor 13 for conveying the desulfurizing agent. Further, in the desulfurization agent addition equipment 1, chute 14 is continuously provided on the downstream side of the belt conveyor 13, and the crude ferronickel molten metal charged from the chute 14 into the ladle in the desulfurization apparatus 2. A desulfurization agent is added to the. As shown in FIG. 1, in the desulfurization agent addition equipment 1, the desulfurization agent feeder 11 and the solvent feeder 12 are provided in order from the upstream side with respect to the belt conveyor.

(Desulfurizer feeder)
The desulfurizing agent feeder 11 is a device for supplying the desulfurizing agent used for the desulfurization treatment, and supplies and places a predetermined amount of the desulfurizing agent stored in the hopper 16 on the belt conveyor 13.

The desulfurizing agent used in the desulfurization treatment is not particularly limited as long as it can fix sulfur in the crude ferronickel melt as calcium sulfide (CaS). For example, calcium carbide, lime, and mixtures thereof and the like can be mentioned. Among them, it is preferable that the wettability with the crude ferronickel melt is good, and in particular, it is preferable to use a desulfurization agent containing calcium carbide as a main component, which can obtain high desulfurization efficiency. The shape and purity of the desulfurizing agent are not particularly limited, and commercially available industrial chemicals such as granules or granules can be used, but it is preferable that the desulfurizing agent has a fine particle size and is difficult to aggregate. As a result, the reaction boundary area can be increased, and the heat retention of the ferronickel melt can be improved. Calcium sulfide obtained by fixing sulfur becomes slag (desulfurized slag) and is removed.

Here, the desulfurizing agent feeder 11 has a discharge port 11a on which the desulfurizing agent can be placed so as to spread over a range of 50% or more in the belt width direction of the belt conveyor 13. According to the desulfurizing agent feeder 11, the desulfurizing agent can be supplied and placed on the belt conveyor 13 without being unevenly distributed.

As a specific embodiment of the discharge port of the desulfurizing agent feeder 11, for example, a discharge port having a length of 50% or more in the belt width direction of the belt conveyor 13 and capable of supplying the desulfurizing agent while swinging. be able to. Further, the discharge port may be provided with a movable device that can move within a range of 50% or more in the belt width direction of the belt conveyor 13. The specific mode of the discharge port is not limited to these.

(Solvent feeder)
The solvent feeder 12 is a device that supplies a solvent to be mixed with the desulfurizing agent. When adding a desulfurizing agent, a solvent (solvent) such as lime or silica sand is added together with the desulfurizing agent. This makes it possible to form desulfurized slag more efficiently and effectively in the desulfurization treatment using a desulfurizing agent.

The solvent feeder 12 is provided on the belt conveyor 13 on the downstream side of the desulfurizing agent feeder 11, and the solvent is supplied and placed on the desulfurizing agent supplied and placed from the desulfurizing agent feeder 11. At this time, it is desirable that the solvent is uniformly supplied to the desulfurizing agent placed on the belt conveyor 13.

That is, a chute 14 is provided on the downstream side of the belt conveyor 13, and the desulfurization agent and the medium solvent are added to the desulfurization apparatus 2 via the chute 14, but the desulfurization agent and the medium solvent are chute. It is temporarily stored in the hopper 15 provided in 14. As described above, the inside of the hopper 15 is divided into a plurality of storage chambers. For example, the inside of the hopper 15 is divided into two parts separated by a partition, and is composed of two storage chambers. The desulfurizing agent and the solvent medium conveyed by the belt conveyor 13 fall from the belt conveyor 13 and are charged into the storage chambers. At this time, the desulfurizing agent and the medium solvent are evenly distributed in each storage chamber. It is important to be charged.

As an example, when the inside of the hopper 15 is divided into two storage chambers (first storage chamber and second storage chamber), when the desulfurizing agent and the solvent are not evenly charged into each storage chamber. For example, a situation may occur in which the medium solvent is unevenly charged into the first storage chamber and the medium solvent is hardly charged into the second storage chamber. Further, for example, a situation may occur in which most of the desulfurizing agent and the solvent are charged in the first storage chamber, and the desulfurizing agent and the solvent are hardly charged in the second storage chamber. When such a situation occurs, the desulfurization agent and the solvent are added to the desulfurization apparatus in this order from the first storage chamber and the second storage chamber from the chute 14, so that the desulfurization in the desulfurization apparatus occurs. The processing conditions are not constant, and stable processing cannot be performed.

Therefore, in the desulfurizing agent adding device 1 according to the present embodiment, as described above, the desulfurizing agent is placed in the desulfurizing agent feeder 11 so as to spread over a range of 50% or more in the belt width direction of the belt conveyor 13. The solvent feeder 12 is characterized in that the solvent is placed substantially at the center of the desulfurizing agent placed on the belt conveyor.

Specifically, the solvent feeder 12 is fixed to a moving device 12a that can move in the belt width direction, and the solvent is placed substantially at the center of the desulfurizing agent placed on the belt conveyor 13. Examples of the moving device 12a include a device that can move left and right above the belt conveyor 13 in the belt width direction. Further, although not shown, the device shall be provided with a sensor for detecting the desulfurizing agent mounted on the belt conveyor 13, and shall be a device capable of detecting the desulfurizing agent by the sensor and moving in the belt width direction according to the mounting range of the desulfurizing agent. Can be done.

Then, the solvent feeder 12 is moved by the moving device 12a to a predetermined position in the belt width direction, that is, the position of the desulfurizing agent placed on the belt conveyor 13, and the solvent is placed at the center of the desulfurizing agent. Place it. The substantially center of the desulfurizing agent means a position substantially at the center of a predetermined range in which the desulfurizing agent placed on a flat surface exists, and means that the range of the desulfurizing agent is not biased.

(Belt conveyor)
The belt conveyor 13 carries the desulfurizing agent supplied from the desulfurizing agent feeder 11 and the solvent supplied from the solvent feeder 12 on the belt conveyor 13. A desulfurizing agent feeder 11 and a solvent feeder 12 are provided in order from the upstream side on the belt conveyor 13 at a position above the belt conveyor 13, and the desulfurizing agent and the solvent are placed in this order.

In the belt conveyor 13, the transport belt 13a moves at a predetermined speed, and in a state where the desulfurizing agent and the medium solvent are placed, they are conveyed to the downstream side. Then, the desulfurizing agent and the medium solvent conveyed by the belt conveyor 13 naturally fall into the hopper 15 (the hopper 15 provided on the chute 14) continuously provided on the downstream side of the belt conveyor 13 and charged. Will be done.

In the desulfurizing agent addition equipment 1 according to the present embodiment, the desulfurizing agent is placed in a range of 50% or more in the width direction of the belt conveyor 13, and the medium solvent is placed at a position substantially at the center of the desulfurizing agent. Placed and transported. That is, in the belt conveyor 13, the desulfurizing agent and the medium solvent are conveyed evenly and charged into the hopper 15.

The belt conveyor 13 is not particularly limited, and a known embodiment can be applied.

(shoot)
The chute 14 adds the desulfurizing agent and the medium solvent conveyed via the belt conveyor 13 to the desulfurization apparatus that executes the desulfurization treatment.

A hopper 15 is connected to the chute 14, and the desulfurizing agent and the solvent medium that are naturally dropped from the belt conveyor 13 and charged are temporarily stored inside the hopper 15. The inside of the hopper 15 is divided into a plurality of storage chambers, and a desulfurizing agent and a medium solvent are charged into each storage chamber.

In particular, in the desulfurizing agent addition equipment 1 according to the present embodiment, the desulfurizing agent is placed on the belt conveyor 13 in a range of 50% or more in the width direction, and the medium solvent is located at a position substantially at the center of the desulfurizing agent. Is placed and transported. That is, since the desulfurizing agent is placed substantially uniformly in the width direction of the belt conveyor 13 and the medium solvent is placed substantially at the center of the desulfurizing agent, the desulfurizing agent and the medium solvent are placed uniformly. Is conveyed by the belt conveyor 13. As a result, when the product is conveyed by the belt conveyor 13 and naturally falls into the hopper 15, the desulfurizing agent and the solvent are evenly charged into each of the storage chambers divided into a plurality of units. .. For example, when two storage chambers are provided inside the hopper 15, the desulfurizing agent and the medium solvent are charged into each storage chamber by half of each.

Then, the desulfurization agent and the medium solvent are added to the desulfurization apparatus 2 in order from each storage chamber in the hopper 15 via the chute 14. Therefore, even when the desulfurization agent and the medium solvent are added to the desulfurization apparatus 2 from any of the storage chambers, the desulfurization treatment conditions for the crude ferronickel melt are substantially constant and stable because they are added substantially evenly. Processing is done.

Here, FIG. 2 is a graph showing the relationship between the desulfurization reaction efficiency and the desulfurization amount index by the desulfurization treatment. In FIG. 2, the “□” plot shows the desulfurization treatment by adding the desulfurization agent and the medium solvent by the conventional desulfurization agent addition equipment, and the “◇” plot shows the desulfurization agent by the desulfurization agent addition equipment 1. Desulfurization treatment was performed by adding the desulfurization agent and the medium solvent. In the “△” plot, the desulfurization agent and the medium solvent (75% of the amount of the desulfurization agent) were added by the desulfurization agent addition facility 1. The “○” plot shows the desulfurization treatment performed by adding the desulfurization agent and the medium solvent (50% of the amount of the desulfurization agent) by the desulfurization agent addition facility 1. Is.

The "reaction efficiency index" shown on the vertical axis of FIG. 2 refers to the sulfur grade (% by weight) in the crude ferronickel melt, the sulfur grade (% by weight) in the crude ferronickel melt after the desulfurization treatment, and the sulfur grade. A numerical value (%) obtained by dividing the weight of sulfur actually removed by the desulfurization treatment from the weight of each crude ferronickel melt by the weight of sulfur that can be ideally removed by the desulfurization agent added during the desulfurization treatment. Is. The "desulfurization amount index" shown on the horizontal axis of FIG. 2 is a numerical value of the sulfur grade (% by weight) in the crude ferronickel melt.

“□” in FIG. 2 shows the case where the sulfur grade of the crude ferronickel melt is in the range of about 0.35 to about 0.65 and the desulfurization treatment is performed with a conventional device. The variation of the index is as wide as about 15 to 20. It is considered that this is due to the fact that the addition rate of the medium solvent to the desulfurizing agent varies in the conventional equipment (as shown by the solid line in the figure, the higher the sulfur grade, the higher the reaction efficiency index. There is a reasonable tendency to do so.)

On the other hand, "◇", "△", and "○" in FIG. 2 indicate the sulfur grade of the crude ferronickel melt in the range of about 0.35 to about 0.45, and the desulfurizing agent addition equipment according to the present embodiment. In the case where the desulfurization treatment was performed by adding the desulfurization agent and the medium solvent using No. 1, the variation of the reaction efficiency index was within about 10. It is considered that this is because the desulfurizing agent addition equipment 1 has a constant addition rate of the medium solvent to the desulfurizing agent as compared with the conventional case.

Further, by using the desulfurizing agent addition equipment 1, the addition rate of the medium solvent to the desulfurization agent becomes constant as described above, and the variation in the reaction efficiency becomes small, so that the validity of the medium solvent addition rate is also confirmed. You can now do it.

That is, as shown in FIG. 2, by using the desulfurizing agent addition equipment 1 according to the present embodiment, the addition rate of the medium solvent to the desulfurizing agent becomes constant as compared with the conventional equipment, which is equivalent to that of the conventional equipment. The amount of medium and solvent for securing the amount of desulfurization can be effectively reduced.

Specifically, according to the desulfurizing agent addition equipment 1, for example, the plot of “◇” in the case where the amount of the medium solvent is 100% with respect to the amount of the desulfurizing agent is a reaction efficiency index of about 68 to 78. It can be seen that even in the case of “Δ” in which the amount of the medium solvent is 75% of the amount of the desulfurizing agent, the same reaction efficiency of about 70 to 77 can be realized. Further, in the case of "○" in which the amount of the medium solvent is 50% of the amount of the desulfurizing agent, the reaction efficiency index is lowered to about 62 to 70, indicating that the amount of the medium solvent added is insufficient. ..

Therefore, it can be seen that it is appropriate to set the solvent as 75% with respect to the amount of the desulfurizing agent, at least when the sulfur grade of the crude ferronickel melt is in the range of 0.35 to 0.45.

<2. Desulfurization equipment>
The desulfurization apparatus 2 is a desulfurization apparatus that executes a desulfurization treatment in ferronickel smelting. The desulfurization apparatus 2 is composed of, for example, a ladle 21 as shown in FIG. 1, and a crude ferronickel melt is charged into the ladle 21 and coarsely prepared by a stirrer 22 hanging from above the ladle 21. Treat the ferronickel melt with stirring.

In the desulfurization treatment, a desulfurizing agent is added to fix the sulfur contained in the crude ferronickel melt in the form of calcium sulfide which is a desulfurization slag. In addition, a solvent is added together with the desulfurizing agent in order to promote the formation of desulfurized slag.

In the desulfurization apparatus 2, the desulfurization agent and the medium solvent are added from the desulfurization agent addition equipment 1. As described above, in the desulfurizing agent addition equipment 1 according to the present embodiment, the desulfurizing agent is placed in a range of 50% or more in the width direction of the belt conveyor 13, and the medium solvent is located at a position substantially at the center of the desulfurizing agent. Is placed, and the desulfurizing agent and the medium solvent are uniformly placed and conveyed. As a result, even when the desulfurization agent and the medium solvent are added into the desulfurization apparatus 2 via the chute 14, the desulfurization agent and the medium solvent can be added at a constant ratio at all times, so that the crude ferronickel The desulfurization treatment for the molten metal can be performed stably.

1 Desulfurizing agent addition equipment 2 Desulfurizing equipment 11 Desulfurizing agent feeder 11a Discharge port 12 Solvent feeder 12a Moving device 13 Belt conveyor 13a Conveying belt 14 Chute 15, 16 Hopper 21 Ladle 22 Stirrer

Claims (2)

Equipment for adding the desulfurizing agent used for the desulfurization treatment in ferronickel smelting to the desulfurization equipment that executes the desulfurization treatment.
With the desulfurizing agent feeder that supplies the desulfurizing agent,
A solvent feeder that supplies the solvent and
A belt conveyor on which the desulfurizing agent supplied from the desulfurizing agent feeder and the solvent supplied from the solvent feeder are placed and conveyed is provided.
The desulfurizing agent feeder and the solvent feeder are provided in order from the upstream side of the belt conveyor.
The desulfurizing agent feeder has a discharge port on which the desulfurizing agent can be placed so as to extend over a range of 50% or more in the belt width direction of the belt conveyor.
The solvent feeder is fixed to a moving device that can move in the width direction of the belt, and the desulfurizing agent is placed in the central portion of a predetermined range in which the desulfurizing agent placed on the belt conveyor is present. Additive equipment. A chute with a hopper is provided on the downstream side of the belt conveyor.
The desulfurization agent addition equipment according to claim 1, which has a plurality of storage chambers separated by a partition plate inside the hopper.

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