JP2018141178A - Desulfurizing agent addition apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus capable of uniformly supplying a desulfurizing agent and a flux to crude ferronickel molten metal for desulfurization treatment of crude ferronickel molten metal in ferronickel refining.SOLUTION: The desulfurizing agent addition apparatus 1 according to the present invention includes: a desulfurizing agent feeder 11 for supplying a desulfurizing agent; a flux feeder 12 for supplying a flux; and a belt conveyor 13 for receiving and conveying the desulfurizing agent supplied from the desulfurizing agent feeder 11 and the flux supplied from the flux feeder 12. The desulfurizing agent feeder 11 and the flux feeder 12 are provided in this order from an upstream side of the belt conveyor 13, the desulfurizing agent feeder 11 has a discharge port 11a capable of placing the desulfurizing agent on the belt conveyor 13 so as to spread over a range of 50% or more in a belt width direction of the belt conveyor 13, and the flux feeder 12 is fixed to a moving device movable in the belt width direction to place the flux at a substantially center of the desulfurizing agent placed on the belt conveyor 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a desulfurization agent addition facility, and relates to a facility for adding a desulfurization agent used for 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 ferronickel production method, that is, a ferronickel smelting method, using nickel oxide ore as a raw material, (preliminary) drying step, firing and partial reduction step, reduction melting step, desulfurization step, casting step, And a dry smelting method.

  Specifically, first, in the (preliminary) drying step, the raw material ore is blended so as to have a predetermined mixing ratio, and then subjected to a drying process using a rotary kiln (rotary dryer), and the adhering moisture contained in the raw material ore ( 35% by mass to 45% by mass) is removed. For example, the adhering moisture contained 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 firing and partial reduction step, a carbonaceous reducing agent (coal) and a melt as necessary are added to the obtained dried ore, and the resulting mixture is put into a rotary kiln and fired at about 800 ° C to 900 ° C. By calcining at a temperature, the remaining moisture (adherent water, crystal moisture) contained in the dried ore is completely removed and a partially reduced calcined ore (calcined ore) is generated.

  Next, in the reduction melting step, the obtained calcined ore is reduced and melted in a reduction furnace such as an electric furnace or a blast furnace to produce crude ferronickel (metal) and slag. The crude ferronickel produced in this reduction furnace contains iron as a main component, contains nickel of about 16% by mass to 25% by weight according to the set amount of the carbonaceous reducing agent, and sulfur derived from the fuel. Contains many impurities. The slag produced separately from the crude ferronickel contains most of the iron oxide in the raw ore and silicon dioxide and magnesium oxide. It is used as fine aggregate for construction and civil engineering materials.

  When the crude ferronickel (crude ferronickel melt) obtained in the reduction melting process requires desulfurization treatment according to the product specifications, it was subsequently transferred to the desulfurization process and used a ladle or the like. A desulfurization process is performed by a mechanical stirring device or an electric induction stirring device.

  Specifically, in the desulfurization step, a desulfurizing agent such as calcium carbide is added to the crude ferronickel melt, and the mixture is stirred using a mechanical stirrer or an electric induction stirrer. Is fixed in slag (hereinafter also referred to as “refined slag”) as calcium sulfide (CaS), separated and removed to obtain a purified ferronickel melt.

  In the casting process, the obtained refined ferronickel melt is poured into a mold, or coarsened through a rotating disk-shaped medium, and then cooled to produce an ingot or flaky ferronickel (product). Get.

  In ferronickel smelting, in the desulfurization treatment (desulfurization process) for the crude ferronickel obtained through the reduction melting process, as described above, a mechanical stirring device using a ladle or the like, an electric induction stirring device, etc. A predetermined desulfurization apparatus is used. In the desulfurization equipment, a desulfurization agent addition facility used for the desulfurization treatment is attached, and from the desulfurization agent addition facility, the crude ferronickel melt in the desulfurization device is charged and the desulfurization agent is added into the ladle. It is processed.

  Conventionally, in a desulfurization agent addition facility for adding a desulfurization agent into a desulfurization device, the desulfurization agent and the solvent are directly charged into the hopper, and the desulfurization agent naturally falls in an hourglass manner from the outlet of the hopper. A desulfurizing agent was supplied to the crude ferronickel melt accommodated in the ladle.

  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 related to a mixing and cutting device for different types of powders, but does not disclose an adjustment mechanism for maintaining the mixing ratio after cutting constant.

JP-A-6-055527

  The present invention has been proposed in view of such circumstances, and in performing desulfurization treatment on the crude ferronickel melt in ferronickel smelting, the desulfurizing agent and the solvent are used for the crude ferronickel melt. It aims at providing the equipment which can supply uniformly.

  The inventors of the present invention have made extensive studies in order to solve the above-described 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 feeder is used to place the solvent at the approximate center of the desulfurizing agent placed on the belt conveyor. The desulfurization agent and the solvent conveyed by the belt conveyor are added to the desulfurization apparatus so that the desulfurization agent and the solvent can be supplied uniformly, and the present invention has been completed. It was.

  (1) A first invention of the present invention is a facility for adding a desulfurization agent used for a desulfurization treatment in ferronickel smelting to a desulfurization apparatus for performing the desulfurization treatment, and supplying the desulfurization agent A feeder, a solvent feeder that supplies a solvent, the desulfurization agent that is supplied from the desulfurization agent feeder, and a belt conveyor that places and conveys the solvent that is supplied from the solvent feeder, and The desulfurization agent feeder and the solvent feeder are provided in order from the upstream side with respect to the belt conveyor, and the desulfurization agent feeder extends in a range of 50% or more in the belt width direction of the belt conveyor. The solvent feeder has a discharge port on which a desulfurization agent can be placed, and the solvent feeder is fixed to a moving device that can move in the belt width direction, and is placed on the belt conveyor. And it is placed on the solvent substantially at the center of the desulfurizing agent is a desulfurizing agent added facilities.

  (2) According to a second aspect of the present invention, in the first aspect, a chute having a hopper is provided on the downstream side of the belt conveyor, and the hopper is partitioned by a partition plate. A desulfurization agent addition facility having a plurality of storage chambers.

  ADVANTAGE OF THE INVENTION According to this invention, in performing a desulfurization process with respect to the crude ferronickel melt in ferronickel smelting, the installation which can supply a desulfurization agent and a solvent uniformly with respect to a crude ferronickel melt is provided. be able to.

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

  Hereinafter, a specific embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, A various change is possible in the range which does not change the summary of this invention.

<1. Equipment for adding desulfurization agent>
The desulfurization agent addition facility according to the present embodiment is a facility for adding a desulfurization agent used for desulfurization treatment to crude ferronickel in ferronickel smelting to a desulfurization apparatus that performs the desulfurization treatment.

  FIG. 1 is a schematic diagram showing a configuration of a desulfurization agent addition facility. FIG. 1 shows a desulfurization agent addition facility 1 and a desulfurization apparatus 2 to which a desulfurization agent is supplied from the desulfurization agent addition facility 1. As will be described in detail later, in the desulfurization agent addition facility 1, the desulfurization agent and the medium solvent supplied from the feeder (11, 12) are transported to the chute 14 provided in the upper part of the desulfurization device 2, and the chute 14 is passed through the chute 14. Add desulfurizing agent and 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 through the chute 14. The interior of the hopper 15 is divided into a plurality of storage chambers, and a desulfurizing agent and a medium solvent are stored in each of the storage chambers. Added. Therefore, it is important that the desulfurization agent and the medium solvent are uniformly charged in each storage chamber.

  Hereinafter, the configuration of the desulfurization agent addition facility 1 will be described more specifically.

  As shown in FIG. 1, the desulfurization agent addition facility 1 includes a desulfurization agent feeder 11 that supplies a desulfurization agent, a solvent feeder 12 that supplies a solvent, and a belt conveyor 13 that conveys the desulfurization agent. Further, the desulfurization agent addition facility 1 is provided with a chute 14 continuously downstream of the belt conveyor 13, and the crude ferronickel molten metal charged into the ladle in the desulfurization apparatus 2 from the chute 14. A desulfurizing agent is added to. As shown in FIG. 1, in the desulfurization agent addition facility 1, a desulfurization agent feeder 11 and a 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 that supplies a desulfurizing agent used in the desulfurization process, and supplies and places a predetermined amount of the desulfurizing agent stored in the hopper 16 on the belt conveyor 13.

  The desulfurization agent used for the desulfurization treatment is not particularly limited as long as it can fix sulfur in the crude ferronickel melt as calcium sulfide (CaS). Examples include calcium carbide, lime, and mixtures thereof. Among these, it is preferable that the wettability with the crude ferronickel molten metal is good, and it is particularly preferable to use a desulfurizing agent mainly composed of calcium carbide capable of obtaining 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 particle size is fine and hardly aggregates. Thereby, a reaction interface area can be enlarged and the heat retention of ferronickel molten metal can be improved. In addition, calcium sulfide obtained by fixing sulfur becomes slag (desulfurized slag) and is removed.

  Here, the desulfurizing agent feeder 11 has a discharge port 11 a on which the desulfurizing agent can be placed so as to spread in 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 mounted without being unevenly distributed with respect to the belt conveyor 13.

  As a specific aspect of the discharge port of the desulfurization agent feeder 11, for example, a discharge port that has a length of 50% or more in the belt width direction of the belt conveyor 13 and can supply the desulfurization agent while swinging is used. be able to. Moreover, it can be set as the discharge port provided with the movable apparatus which can be moved in the range of 50% or more of the belt width direction of the belt conveyor 13. In addition, the specific aspect of a 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 the desulfurizing agent is added, a solvent (medium solvent) such as lime or silica sand is added together with the desulfurizing agent. Thereby, in the desulfurization process using a desulfurization agent, desulfurization slag can be formed more efficiently and effectively.

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

  That is, a chute 14 is provided on the downstream side of the belt conveyor 13, and a desulfurizing agent and a solvent are added to the desulfurization device 2 through the chute 14. 14 is temporarily stored in a hopper 15 provided in the hopper 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 with a partition, and is composed of two storage chambers. In these storage chambers, the desulfurization agent and the medium solvent conveyed by the belt conveyor 13 are dropped from the belt conveyor 13 and charged. At this time, the desulfurization agent and the medium solvent are evenly distributed in each storage chamber. It is important to be charged.

  Taking the case where the inside of the hopper 15 is divided into two storage chambers (a first storage chamber and a second storage chamber) as an example, when the desulfurization agent and the solvent medium are not charged uniformly into each storage chamber For example, a situation may arise in which the medium solvent is charged unevenly in the first storage chamber, and the medium solvent is hardly charged in the second storage chamber. In addition, for example, a situation may occur in which most of the desulfurizing agent and the medium solvent are charged in the first storage chamber, and neither the desulfurizing agent nor the medium solvent is charged in the second storage chamber. When such a situation occurs, the desulfurization agent and the medium solvent are added to the desulfurization device in order from the first storage chamber and the second storage chamber from the chute 14, so that desulfurization in the desulfurization device is performed. Processing conditions are not constant, and stable processing cannot be performed.

  Therefore, in the desulfurizing agent addition apparatus 1 according to the present embodiment, as described above, the desulfurizing agent feeder 11 is placed so that the desulfurizing agent is 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 medium is placed at substantially the center of the desulfurizing agent placed on the belt conveyor.

  Specifically, the solvent feeder 12 is fixed to a moving device 12 a that can move in the belt width direction, and the solvent medium is placed at substantially the center of the desulfurizing agent placed on the belt conveyor 13. As the moving device 12a, for example, a device that can move right and left in the belt width direction above the belt conveyor 13 can be cited. In addition, although not shown, a sensor that detects the desulfurization agent placed on the belt conveyor 13 is provided, and the device detects the desulfurization agent and can move in the belt width direction according to the placement range of the desulfurization agent. Can do.

  Then, the solvent feeder 12 is moved to a predetermined position in the belt width direction by the moving device 12a, that is, the position of the desulfurizing agent placed on the belt conveyor 13, and the solvent solvent is placed in the center of the desulfurizing agent. Place. In addition, the approximate center of the desulfurizing agent refers to a position in the approximate center of a predetermined range where the desulfurizing agent placed on the plane is present, and it is not a position where the range of the desulfurizing agent is biased.

(Belt conveyor)
The belt conveyor 13 carries the desulfurizing agent supplied from the desulfurizing agent feeder 11 and the medium solvent supplied from the solvent feeder 12 for conveyance. The belt conveyor 13 is provided with a desulfurizing agent feeder 11 and a solvent feeder 12 in order from the upstream side 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 conveyance belt 13a moves at a predetermined speed, and conveys them to the downstream side in a state where the desulfurizing agent and the solvent are placed. Then, the desulfurizing agent and the medium solvent conveyed by the belt conveyor 13 are naturally dropped into the hopper 15 (the hopper 15 provided on the chute 14) provided continuously on the downstream side of the belt conveyor 13 and charged. Is done.

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

  In addition, it does not specifically limit as the belt conveyor 13, The thing of a well-known aspect is applicable.

(shoot)
The chute 14 adds the desulfurization agent and the medium solvent conveyed via the belt conveyor 13 to a desulfurization apparatus that performs a desulfurization process.

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

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

  Then, to the desulfurization apparatus 2, a desulfurizing agent and a medium solvent are added in order from each storage chamber in the hopper 15 through the chute 14. Therefore, even when the desulfurization agent and the solvent are added to the desulfurization apparatus 2 from any storage chamber, the desulfurization treatment conditions for the crude ferronickel melt are substantially constant and stable. Processing is performed.

  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 is obtained by adding a desulfurizing agent and a medium solvent using a conventional desulfurizing agent addition facility, and the “◇” plot is the desulfurizing agent added by the desulfurizing agent addition facility 1. And the desulfurization treatment was performed by adding the solvent and the solvent, and the “Δ” plot shows that the desulfurization agent and the medium solvent (75% of the desulfurization agent amount) were added by the desulfurization agent addition equipment 1. The “◯” plot shows the desulfurization treatment performed by adding the desulfurization agent and the medium solvent (50% of the desulfurization agent amount) with the desulfurization agent addition facility 1. It is.

  Note that the “reaction efficiency index” shown on the vertical axis in FIG. 2 is the sulfur quality (wt%) in the crude ferronickel melt, the sulfur grade (wt%) in the crude ferronickel melt after desulfurization treatment, and Numerical value of the percentage (%) obtained by dividing the weight of sulfur actually removed by the desulfurization treatment by the weight of sulfur that can be removed ideally by the desulfurization agent added during the desulfurization treatment, obtained from the weight of each crude ferronickel melt It is. Further, the “desulfurization amount index” shown on the horizontal axis of FIG. 2 is a numerical value of sulfur quality (% by weight) in the crude ferronickel melt.

  “□” in FIG. 2 is the case where the sulfur quality of the crude ferronickel melt is in the range of about 0.35 to 0.65, and the desulfurization treatment is performed with a conventional apparatus. The variation of the index is as wide as about 15-20. This is considered to be due to the fact that the addition rate of the solvent to the desulfurizing agent varies in the conventional apparatus (Note that, as shown by the solid line in the figure, the reaction efficiency index improves as the sulfur quality increases. There is a reasonable tendency to do this.)

  On the other hand, “◇”, “△”, and “◯” in FIG. 2 indicate that the sulfur grade of the crude ferronickel melt is in the range of about 0.35 to about 0.45, and the desulfurization agent addition equipment according to the present embodiment. 1 is a case where a desulfurizing agent and a solvent are added to perform desulfurization treatment, but the variation in the reaction efficiency index is about 10 or so. This is considered to be due to the fact that in the desulfurizing agent addition facility 1, the addition rate of the medium solvent with respect to the desulfurizing agent is constant as compared with the conventional case.

  Moreover, by using the desulfurization agent addition equipment 1, the addition rate of the medium solvent to the desulfurization agent becomes constant as described above, and the validity of the addition rate of the medium solvent is confirmed by the variation in the reaction efficiency being reduced. I was able to do it.

  That is, as shown in FIG. 2, by using the desulfurization agent addition facility 1 according to the present embodiment, the addition rate of the solvent to the desulfurization agent becomes constant as compared with the conventional facility, which is equivalent to the conventional one. It is possible to effectively reduce the amount of the solvent for ensuring the desulfurization amount.

  Specifically, according to the desulfurizing agent addition equipment 1, for example, the reaction efficiency index in which the plot of “◇” is about 68 to 78 when the amount of the solvent is 100% as usual with respect to the amount of the desulfurizing agent. It can be seen that even in the case of “Δ” where the amount of the solvent is 75% with respect to the amount of the desulfurizing agent, an equivalent reaction efficiency of about 70 to 77 can be realized. Furthermore, in the case of “◯” where the amount of the solvent is 50% with respect to the amount of the desulfurizing agent, the reaction efficiency index is reduced to about 62 to 70, and it is understood that the amount of the solvent added is insufficient. .

  Therefore, it can be seen that it is appropriate to set the medium solvent to 75% with respect to the amount of the desulfurizing agent if at least 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 performs a desulfurization process in ferronickel smelting. For example, as shown in FIG. 1, the desulfurization apparatus 2 is constituted by a ladle 21, and a crude ferronickel molten metal is charged into the ladle 21, and is roughly roughened by a stirrer 22 suspended from above the ladle 21. Treat the ferronickel melt with stirring.

  In the desulfurization treatment, a desulfurizing agent is added for fixing sulfur contained in the crude ferronickel melt in the form of calcium sulfide that is desulfurized slag. In addition to the desulfurizing agent, a solvent is added to promote the generation of desulfurized slag.

  In the desulfurization apparatus 2, a desulfurization agent and a medium solvent are added from the desulfurization agent addition facility 1. As described above, the desulfurizing agent addition facility 1 according to the present embodiment places the desulfurizing agent in a range of 50% or more in the width direction of the belt conveyor 13, and the medium solvent is located at the approximate center of the desulfurizing agent. Is transported in a state where the desulfurizing agent and the medium solvent are uniformly placed. As a result, even when the desulfurizing agent and the medium solvent are added into the desulfurization apparatus 2 via the chute 14, the desulfurizing agent and the medium solvent can be always added at a constant rate, so that the crude ferronickel The desulfurization process with respect to a molten metal can be performed stably.

DESCRIPTION OF SYMBOLS 1 Desulfurization agent addition equipment 2 Desulfurization apparatus 11 Desulfurization agent feeder 11a Discharge port 12 Solvent feeder 12a Moving device 13 Belt conveyor 13a Conveyor belt 14 Chute 15,16 Hopper 21 Ladle 22 Stirrer

Claims (2)

A facility for adding a desulfurizing agent used in a desulfurization process in ferronickel smelting to a desulfurization apparatus that performs the desulfurization process,
A desulfurizing agent feeder for supplying the desulfurizing agent;
A solvent feeder for supplying the solvent;
A belt conveyor for carrying the desulfurizing agent supplied from the desulfurizing agent feeder and the solvent supplied from the solvent feeder;
For the belt conveyor, in order from the upstream side, the desulfurizing agent feeder and the solvent feeder are provided,
The desulfurizing agent feeder has a discharge port on which the desulfurizing agent can be placed so as to expand to a range of 50% or more in the belt width direction of the belt conveyor,
The said solvent feeder is being fixed to the moving apparatus which can move to a belt width direction, The desulfurization agent addition equipment which mounts the said solvent in the approximate center of the said desulfurization agent mounted on the said belt conveyor. On the downstream side of the belt conveyor, a chute with a hopper is provided,
The desulfurization agent addition facility according to claim 1, wherein the hopper includes a plurality of storage chambers separated by a partition plate.

Images