JPH0448021A - Method and device for degassing - Google Patents

Abstract

PURPOSE:To easily remove the gaseous components in a melt with a small amt. of gaseous Ar by dropping the partial pressure of the gaseous components in the melt on the outside partitioned from the melt with a porous member which allows the diffusion of gases but does not allow the infiltration of the melts in an inert gaseous atmosphere. CONSTITUTION:The melt 2 is brought into contact with one surface of the porous member 1 which allows the diffusion of only the gases but does not allow the infiltration of the melts, such as molten metal, molten matte and molten slag. The other surface is formed as the inert gaseous atmosphere 3 of Ar, etc., and the atmosphere 3 is maintained under the pressure lower than the partial pressure of the gaseous components in the melt 2. Then the gaseous components in the melt 2 move from the side of the higher partial pressure thereof to the lower pressure side, i.e., from the inside of the melt 2 into the atmosphere 3. The impurity components in the melt 2 or the valuable components which are of value to be recovered and form the gaseous phase are easily nucleus-formed on the wall surface of the porous member 1. The formed gases 4 diffuse through the porous member 1 and are separated from the melt 2.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a method for removing solute components that generate a gas phase from a melt such as a molten metal, a molten matte, and a molten slag through a porous member; The present invention relates to a degassing method and device for recovery.

[Prior Art] Conventionally, there are degassing methods such as the RH method and the DH method as technologies for removing or recovering solute components that generate a gas phase from melts such as molten metal, molten matte, and molten slag. . In the RH method and the DH method, a large amount of argon gas is blown into the molten metal under vacuum or reduced pressure to lower the partial pressure of the gas component in the molten metal and remove this gas component.

[Problems to be Solved by the Invention] However, the conventional degassing methods using the RH method and the DH method use a large amount of argon gas, and therefore have a drawback of high running costs.

In addition, since a large amount of argon gas is blown into the molten metal, splashes are likely to occur from the molten metal, and base metal adheres to the walls of the apparatus, making removal work complicated. Furthermore, because this splash occurs, the equipment has to be made larger.
Equipment costs are also high.

The present invention has been made in view of such problems, and includes:
Provided is a degassing method and device that can easily remove gas components in a melt without using a large amount of argon gas, and can degas the melt with a simple device at low cost. The purpose is to

[Means for Solving the Problems] The degassing method according to the present invention partitions the melt from the outside world with a porous member that allows gas to pass through but not the melt, and places the outside world side in an inert gas atmosphere. The method is characterized in that the gas component is removed by lowering the partial pressure of the gas component in the melt.

Further, the degassing device according to the present invention includes a storage container containing a molten material, and a material formed of a porous material that permeates gas but not the molten material and is immersed in the molten material in the storage container. a bottom cylindrical partition member; an inert gas feeding means for feeding an inert gas into the partition member to reduce the partial pressure of the gas component in the melt inside the partition member; or a gas generated by a reaction between the molten material and the partition member, the apparatus further comprises a discharge means for discharging the gas produced by the reaction between the melt and the partition member from inside the partition member.

[Operation] FIG. 1 is a schematic diagram showing the principle of the present invention. The porous member 1 is a member made of a porous material that allows only gas to pass therethrough and does not allow melts such as molten metal, molten matte, and molten slag to pass therethrough. Then, the molten material 2 is brought into contact with one surface of the porous member 1, and the other surface is made into an inert gas atmosphere 3 such as Ar or N2, and the atmosphere 3 on the other surface side is changed to the atmosphere 3 in the molten material 2. Make the partial pressure lower than the partial pressure of the gas component. Then, the gas components in the melt 2 move from the higher partial pressure to the lower partial pressure, that is, from the melt 2 to the inert gas atmosphere 3.

Therefore, impurity components in the melt 2 or valuable components worth recovering that generate a gas phase easily nucleate on the wall surface of the porous member 1, and the generated gas 4 It passes through the mass member 1 and is separated from the melt 2.

The inventors of the present invention have come up with the idea that gas components can be removed from a molten material based on such a principle, and have completed the present invention.

Thus, the gas-generating components dissolved in the melt are removed in the form of gas according to the reaction formula below.

Tojugawara → N2 ... (1) Ratio + ratio → H2 ... (2) U + Ω- → CO ... (3) Name +2.0- → SO2 ... (4) Also, molten material After the impurities inside react with the components of the porous member and become gas,
It may also be removed by passing through the porous member.

When the porous member is an oxide (MXOY), carbon in the melt is removed as a gas according to the following reaction formula.

yL+Mx Oy (solid) +x, li+3'c.

(5) Furthermore, when the porous member is made of carbon or contains carbon as one component, oxygen in the melt is removed according to the following reaction formula.

100 (solid) → CO (6) Furthermore, the separation and recovery of the valuable component (M) with a high vapor pressure in the melt is carried out by gasifying the valuable component according to the following reaction formula.

xM-+Mx (gas)...(7
) MOY → MoV (gas) ... (8)
M S v → MSY (gas) ... (9
) In this way, impurity components such as N, H, C, O, and S in the melt and the free components are removed or recovered from the melt.

In order to separate the gas from the melt by the difference in partial pressure of gas components between the melt side and the other side via the porous member, it is conceivable to create a vacuum or reduced pressure atmosphere on the other side.

However, if the pressure on the other side is extremely reduced, there is a risk that the melt will penetrate into the porous member, solidify within the pores of the porous member, and block the pores. In this case, the gas separation efficiency will be reduced. Therefore, in the present invention,
The other surface of the porous member corresponding to the surface that contacts the melt is placed in an inert gas atmosphere. As a result, an atmosphere in which the partial pressure of the gas component is low is obtained on the other side, and even if the pressure on the other side is not extremely reduced, the gas component is in a low partial pressure on both sides of the porous member. A difference is generated and the gas components can be separated from the melt.

Furthermore, in the present invention, impurities in the melt can be reduced by adjusting the concentration of components in the porous member that react with impurities or valuable components in the target melt. Alternatively, it is also possible to control the reaction rate between the valuable component and the component in the porous member.

In addition, in order to promote mass transfer in the molten material around the porous member, the molten material is stirred by, for example, blowing an inert gas into the molten material, or by rotating or rocking the porous member. Preferably, a stirring means is provided. Also,
Decreasing the temperature of the melt due to heat radiation to the atmosphere and storage container,
In order to avoid the occurrence of inconveniences caused by a decrease in the temperature of the melt due to immersion of the porous member in the melt and a decrease in the temperature of the melt due to an endothermic reaction between the components of the porous member and the melt, The porous member and the melt can be heated by applying electricity to the porous member, by embedding a resistance wire in the porous member in advance and applying electricity to the resistance wire, or by external heating (for example, plasma heating). A heating means that can be used may be provided.

As the porous member, AI 203, MgO.

Cabs Sioa, Fe20a% Fe*
04, Cra O3, BNN S i3N4 and Si
Various materials can be used, such as metal oxides such as C and C, metal non-oxides, carbon, and mixtures thereof, but materials that do not react with the main component of the melt are preferred. In this way, by not reacting with the main component, erosion of the porous member that comes into contact with the melt is prevented.

Furthermore, in order to allow only the gas to pass through and not the molten material, a partition member made of a porous material that is difficult to get wet with the molten material is used. Furthermore, the porosity of the porous partition member is 40
% or less.

Furthermore, although it varies depending on the wettability of the partition member to the melt, it is preferable that the pore diameter of the partition member is about 200 μm or less.

Furthermore, in order to prevent molten material from entering the vacuum system even if it enters the porous immersion tube, a filter with low pressure loss is installed at the top of the porous immersion tube to prevent the molten material from entering the porous immersion tube. It is preferable to coagulate and trap it in a filter.

Next, an application example in which the present invention is applied to the removal and recovery of gas generating components from a melt will be described.

(1) First, the present invention can be used in decarbonization, denitrification, and dehydrogenation processes for removing carbon, nitrogen, or hydrogen from molten iron.

When illegally removing carbon from molten iron, the main component of the partition member is Al2O3 or MgO, and Fe 2031Fe3041 is used as the main oxidizing agent for carbon in molten iron.
Blend MnO, Sio2, etc. By increasing the blending ratio of these main oxidizing agents, the rate of oxygen removal from molten iron can be increased. However, if the blending ratio of the main oxidizing agent is too high, it will lower the melting point or mechanical strength of the partition member, and especially if the carbon concentration in the molten iron is low, the oxygen concentration in the molten iron will increase. Depending on the purpose, the blending ratio of the main oxidizing agent is determined with reference to the already established phase diagram.

On the other hand, if illegal methods are used to remove nitrogen from molten iron, the partition member may contain stable oxides such as Cab, Ar1, etc.
03. MgO etc. are used.

Further, when using an illegal method to simultaneously remove carbon and nitrogen from molten iron, the blending ratio of the main oxidizing agent is changed depending on the target moisture content of carbon and nitrogen in molten iron.

(2) The present invention can also be applied to a deoxidation process for removing oxygen from molten steel.

(2) Furthermore, the present invention can also be applied to a dehydrogenation process for removing hydrogen from molten aluminum.

(2) Furthermore, the present invention can be applied to decarbonization, denitrification, and dehydrogenation of molten silicon.

(2) On the other hand, according to the present invention, zinc in the melting vessel can be recovered.

■ Desulfurization and removal of sulfur and oxygen from molten copper matte
The present invention can also be applied to the process of deoxidizing.

■ Valuable metals in the molten copper matte or nickel matte (As+Sb, Bi, Set Te+Pb,
The present invention can also be applied to the recovery of Cd, etc.).

■ Furthermore, valuable gold n (A s + S
The present invention can also be applied to the case of recovering (b+ Bit Se, Te, pb, cd, Zn, etc.).

[Embodiments] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a schematic cross-sectional view showing a degassing device according to an embodiment of the present invention.

The molten material 2 is stored in a storage container 5, and this storage container 5
A bubble generator 9 made of bottom-blown porous brick is installed at the bottom of the
is provided. Inert gas is supplied to this bubble generator 9 via a pipe 8C.

The lower half of the degassing member 6 is immersed in the melt 2 . This degassing member 6 has a cylindrical shape with a closed lower end, and the molten material 2
The lower half that is immersed in the interior has pores that allow gas to pass through but prevent molten material 2 such as molten metal, molten slag, and molten matte from penetrating. Molded from quality materials. A portion formed of a porous material in the lower half of this degassing member 6 is a partition member 6a.

Further, the upper half of the degassing member 6 is formed of a dense member 6b that does not allow gas to pass through. This partition member 6a
The degassing member 6b and the dense member 6b may be created separately and then joined together to integrate them, or the degassing member 6b may be made of a porous material.
After creating the entire dense member 6b, this portion may be made gas-impermeable by coating the portion with a gas-impermeable dense material.

A gas-impermeable dense member 6 exposed above the melt 2
A connecting member 7 is fixed to the upper end of the
Alternatively, a pipe 8a connected to an inert gas supply source (not shown) such as N2 and a pipe 8b for discharging the degas components separated from the melt 2 from the degas member 6 are connected to the degas member 6. They are connected so that they can communicate.

In the degassing device configured in this way, the pipe 8C
An inert gas such as Ar gas or N2 gas is supplied to the bubble generator 9 through the bubble generator 9 to generate bubbles in the melt 2 and stir the melt 2. Further, an inert gas such as Ar gas or N2 gas is supplied from an inert gas supply source to the inside of the degassing member 6 via the piping 8a to create an inert gas atmosphere inside the degassing member 6. Then, the degas components in the melt 2 pass through the partition member 6a and move inside the degas member 6 due to the difference in partial pressure. Then, it is discharged to the outside of the degassing member 6 via the pipe 8b. In this manner, the molten material 2 can be degassed by the apparatus of this embodiment.

In addition, in the above-mentioned embodiment, as the melt stirring means,
The case has been described in which inert gas is blown into the melt 2 through the bubble generator 9 made of bottom-blown porous bricks. For example, a lance pipe is installed above the storage container 5, and the lower end of this lance pipe is connected to the storage container. By dipping into the melt 2 in the lance pipe 5, an inert gas may be blown into the melt 2 through this lance pipe. Alternatively, the degassing member 6 may be moved within the melt 2, thereby stirring the melt 2.

[Effects of the Invention] As explained above, according to the present invention, the molten material and the outside world are partitioned by a porous member that allows gas to pass through but not the molten material, and the outside world side is separated from the molten material in an inert gas atmosphere. Since this gas component is removed from the melt by lowering the partial pressure of the gas component therein, the degassed component can be transferred to the outside world due to the difference in the partial pressure. Furthermore, in the apparatus of the present invention, since the area of the porous member in contact with the melt can be set arbitrarily large, the concentration of solute components in the melt can be reduced to an extremely low concentration.

Unlike the conventional degassing method that blows in a large amount of argon gas, the present invention only needs to supply a small amount of inert gas to the extent that the partial pressure of the degassed component inside the partition member decreases, and the unit consumption rate of argon gas is can be significantly reduced. Furthermore, since the amount of argon gas used is extremely small, the occurrence of splash can be suppressed, and the adhesion of metal to the wall surface of the apparatus can be reduced. Therefore, according to the present invention, it is possible to reduce the cost of the device by downsizing the device, and also to significantly reduce the running cost of the device.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the principle of the present invention, and FIG. 2 is a schematic sectional view showing a degassing device according to an embodiment of the present invention. 1; porous member, surrounding air, 4; gas, 5 6a; partition member, member, 8a, 8b. 2; Melt, 3; Inert gas atmosphere; Storage container, 6; Degassing member, 6b; Dense member, 7; Connection 8b; Piping, 9; Bubble generator

Claims (4)

[Claims] (1) By partitioning the melt from the outside world with a porous member that allows gas to pass through but not the melt, and by lowering the partial pressure of the gas components in the melt by placing the outside world in an inert gas atmosphere. , a degassing method characterized by removing the gas component. (2) a storage container that stores a molten material; a bottomed cylindrical partition member formed of a porous material that allows gas to pass through but not the molten material and is immersed in the molten material in the storage container; an inert gas feeding means for feeding an inert gas into the interior of the partition member to reduce the partial pressure of the gas component in the melt inside the partition member; 1. A degassing device comprising: a discharge means for discharging gas generated by reaction with the partition member from inside the partition member. (3) The degassing device according to claim 2, further comprising a stirring means for stirring the melt. (4) The degassing device according to claim 2 or 3, further comprising a heating means for electrically heating the partition member.