JPH09184024A - Vacuum heat treating device for powder and granular material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly and stably recover valuable metals in powder and granular materials at a good yield by connecting at least two condensers varying in cooling temp. to a treating chamber for heat treating the powder and granular materials in vacuum. SOLUTION: At least the two condensers 72, 71, etc., varying in the cooling temp. are connected to the treating chamber 21 of this device. In the case of connection of, for example, the two condensers, the condenser (hereafter, A) of the relatively high cooling temp. is connected as one thereof and the condenser (hereafter, B) of the relatively low cooling temp. as another one. When the powder and granular materials are heated under vacuum, extraneous materials, such as moisture and fats and oils, coexisting in the powder and granular materials evaporate in the initial stage of the low temp. and, therefore, these materials are captured by A. A reducing gas is supplied from a gas supply pipe 51 to reduce the metal oxides in the powder and granular materials to the corresponding metals in the subsequent state of the high temp. and, thereafter, these metal vapors are condensed in B and are separately recovered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum heat treatment apparatus for granular materials. For example, dust captured by a dust collector in a steelmaking plant contains metal oxides such as iron oxide (Fe ₂ O ₃ , Fe ₃ O ₄ ), zinc oxide (ZnO), and lead oxide (PbO). I have. Discarding such dust as it is wastes resources, and it is desired to recover valuable metals such as iron, zinc and lead from the dust. The present invention relates to an apparatus for recovering valuable metals such as iron, zinc, and lead from a granular material represented by dust as described above by heat-treating the granular material in a vacuum atmosphere.

[0002]

2. Description of the Related Art Conventionally, as a vacuum heat treatment apparatus for recovering valuable metals such as iron, zinc, and lead from powders and granules, a closed vessel and a treatment chamber formed by being surrounded by a heat insulating material in the vessel are known. ,
It is proposed to provide a heater provided in the processing chamber, a vacuum pump connected to the container to make the processing chamber a vacuum atmosphere, and a condenser interposed between the container and the vacuum pump. As a condenser used in such a vacuum heat treatment apparatus, a water-cooled condensation chamber, a first vacuum chamber formed below the condensation chamber, and a first vacuum chamber are described. And a second vacuum chamber formed in the lower part of the device (Japanese Utility Model Laid-Open No. 5-30149). This conventional apparatus supplies powder to the processing chamber and heats it in a substantially vacuum atmosphere to condense the generated zinc or lead vapor in a condenser while leaving iron in the processing container. is there.
However, these particles contain components that evaporate at high temperatures, such as zinc and lead, and components that evaporate at low temperatures, such as water, oils and fats, and chlorides. There is a drawback in that chlorides and the like are mixed when the valuable metal is recovered, and the valuable value of the recovered zinc, lead, or the like is lowered.

[0003]

The problem to be solved by the present invention is that, in the conventional apparatus, valuable metals such as iron, zinc and lead cannot be stably recovered with high purity from the granular material.

[0004]

DISCLOSURE OF THE INVENTION The present invention, however, is an apparatus for recovering valuable metal from a powder or granular material by heat-treating the powder or granular material in a processing chamber formed in a closed container in a vacuum atmosphere. In addition, at least two condensers having different cooling temperatures, which can communicate with the processing chamber, are connected to the container, and the reducing gas supply pipe and / or the reducing gas which can communicate with the processing chamber are connected to the container. The present invention relates to a vacuum heat treatment apparatus for powder particles, which is characterized in that a material supply pipe is connected.

[0005] Also in the present invention, a closed system container, a processing chamber surrounded by a heat insulating material in the container, a heating source provided in the processing chamber, and a processing source connected to the container. A vacuum pump for evacuating the chamber to a vacuum atmosphere, and a condenser interposed between the container and the vacuum pump are provided. A processing container is usually housed in the processing chamber, and is preferably equipped with a stirring means for powdery particles.

In the present invention, at least two condensers having different cooling temperatures, which can communicate with the processing chamber, are connected to the container. The connection form may be serial or parallel. For example, when connecting two condensers in series or in parallel, one is connected to a condenser having a relatively high cooling temperature and the other is connected to a condenser having a relatively low cooling temperature. . When the powder or granules are heat-treated in a vacuum atmosphere, impurities such as water and fats and oils mixed in the powder and granules are vaporized at an early stage where the heating temperature is low. In a middle stage to a final stage where the heating temperature is high, the metal oxide in the powder is reduced by a reducing gas and / or a reducing material as described later. Typically, zinc and lead evaporate, so these vapors are condensed in a condenser with a relatively high cooling temperature,
It recovers zinc and lead. More specifically, when three condensers are connected in series, the cooling temperature of the upstream condenser is raised and the cooling temperature of the downstream condenser is lowered, and the cooling temperature of the middle condenser is reduced. If it is set in the middle, the upstream condenser can separate and collect lead while the downstream condenser can condense impurities, and the middle-stream condenser can separate and collect zinc.

When one condenser which can communicate with the processing chamber is connected to the container and the components evaporated from the granular material are condensed at one time by this condenser, the quality of the zinc and lead recovered as a result depends on the impurities. Significantly impaired.

Further, according to the present invention, a reducing gas supply pipe and / or a reducing material supply pipe which can communicate with the processing chamber are connected to the container. As the reducing gas, hydrogen gas, carbon monoxide gas, hydrocarbon gas, a mixed gas thereof or the like can be used, but it is preferable to use hydrogen gas from the viewpoint of reducing power. Reducing gas easily disperses uniformly over the entire surface of the powder and granules, and has a strong reducing power, so the metal oxides such as iron oxide, zinc oxide, and lead oxide in the powder and granules can be reliably and quickly converted to the corresponding metals. Reduce to. Supplying a reducing agent, such as carbon, together with or instead of the reducing gas is also correspondingly effective as it allows the continuous reducing power of such reducing agent to be utilized.

It is preferable that the reducing gas and / or the reducing material be supplied to the processing chamber at a stage when the above-mentioned contaminants in the powder or granular material have almost evaporated. It is possible to mix the powder and granules and the reducing agent from the beginning and heat-treat the mixture in a vacuum atmosphere. However, in this case, the reducing agent itself is oxidized by the vapor of the impurities, especially the steam. In some cases, the zinc and lead that have been produced may not serve their original purpose, or that zinc and lead that have been reduced once and produced may be oxidized again.
Therefore, in the present invention, when the vapor of the impurities in the powder or granules has almost evaporated, in other words, during the heat treatment of the powder or granules in a vacuum atmosphere, reducing gas and / or
Alternatively, the reducing gas supply pipe and / or the reducing material supply pipe is directly connected to the container so that the reducing material can be supplied. As described above, the amount of the reducing gas and / or the reducing agent supplied to the processing chamber during the heat treatment of the powder or granular material is such that Fe ₂ O ₃ or Fe ₃ O ₄ in the powder or granular material is FeO. Reduced to Zn
It is preferable that the amounts of O and Zn are slightly larger than the equivalents for reducing Zn and PbO for Pb.

[0010]

1 is a longitudinal sectional view illustrating an embodiment of the present invention. A heat-insulating material 11a is lined in a closed container 11 and is surrounded by the heat-insulating material 11a.
The tube heater 31 is inserted into the processing chamber 21. A powder supply pipe 41 communicating with the processing chamber 21 is connected to the upper surface of the container 11, and a valve 41 a is interposed in the powder supply pipe 41. A reducing gas supply pipe 51 is connected to the upper part of the left side surface of the container 11, and a valve 51a is interposed in the reducing gas supply pipe 51,
An unillustrated reducing gas supply source is connected to the upstream side of the reducing gas supply pipe 51. Exhaust pipes 61 and 62 are connected to the upper right side surface of the container 11, and valves 61a and 62a are interposed in the exhaust pipes 61 and 62. Exhaust pipe 61,
The condensers 71 and 72 are connected to the downstream side of 62,
The cooling temperature of the condenser 71 is low and the cooling temperature of the condenser 72 is high, and vacuum pumps 81 and 82 are connected to the downstream sides of the condensers 71 and 72. The condensers 71 and 72 are connected in parallel to the container 11.

FIG. 2 is a vertical sectional view illustrating another embodiment of the present invention. A heat insulating material 12a is lined in the closed container 12, a processing chamber 22 is formed surrounded by the heat insulating material 12a, and a tube heater 32 is inserted into the processing chamber 22. A powder and granular material supply pipe 42 that communicates with the processing chamber 22 is connected to the upper surface of the container 12 and the powder and granular material supply pipe 42 is connected.
A valve 42a is interposed in the. A reducing material supply pipe 52 is connected to the upper left side surface of the container 12, a valve 52a is interposed in the reducing material supply pipe 52, and a closed system reducing material (not shown) is provided upstream of the reducing material supply pipe 52. A storage hopper is connected. An exhaust pipe 63 is provided on the upper right side surface of the container 12.
Are connected, and the exhaust pipe 63 is connected to the exhaust pipe 6 on the downstream side.
4 and the exhaust pipe 65, and the exhaust pipes 64, 65
Valves 64a and 65a are interposed in the. Exhaust pipe 6
The condensers 73 and 74 are connected to the downstream sides of the condensers 4, 65, the cooling temperature of the condenser 73 is low, and the cooling temperature of the condenser 74 is high, and a vacuum is provided on the downstream side of the condensers 73 and 74. The pump 83 is connected. The condensers 73 and 74 are connected in parallel to the container 12.

FIG. 3 is a vertical sectional view illustrating still another embodiment of the present invention. A heat insulating material 13a is lined in a closed container 13 formed into a cylindrical shape as a whole, a processing chamber 23 is formed surrounded by the heat insulating material 13a, and a panel heater 33 is provided inside the heat insulating material 13a. It is set up.
A powder or granular material supply pipe 43 communicating with the processing chamber 23 is connected to the upper surface of the container 13, and a valve 43 is connected to the powder or granular material supply pipe 43.
a is interposed. On the upstream side of the powder or granular material supply pipe 43, a closed powder or granular material storage hopper 43b is connected. An exhaust pipe 66 is connected to the upper portion of the right side surface of the powder and granular material storage hopper 43b, and the downstream side of the exhaust pipe 66 is connected to a vacuum pump 84 via a valve 66a. An inclined surface that descends toward the axis is formed in the lower portion of the container 13, and an outlet 23 that communicates with the processing chamber 23 is formed at the lower end of the inclined surface.
a has been established. A discharge pipe 23b having an inclined surface that rises toward the axis portion is connected to the outlet 23a, and a valve 23c is interposed in the discharge pipe 23b.
An exhaust pipe 67 is connected to an upper portion of a right side surface of a portion of the exhaust pipe 23b formed to have a large diameter, and a downstream side of the exhaust pipe 67 is connected to a vacuum pump 84 via a valve 67a.

An exhaust pipe 68 communicating with the processing chamber 23 is connected to the upper right side surface of the container 11, and a valve 68a is interposed in the exhaust pipe 68. An upstream condenser 75, a middle-stream condenser 76, and a downstream condenser 77 are connected in series in this order on the downstream side of the exhaust pipe 68, and a vacuum pump 84 is connected on the downstream side of the condenser 77. There is. A reducing material supply pipe 53 communicating with the processing chamber 23 is connected to the upper surface of the container 11, and a valve 53 a is interposed in the reducing material supply pipe 53. A closed reducing material storage hopper 53b is connected to the upstream side of the reducing material supply pipe 53. An exhaust pipe 69 is connected to the upper surface of the reducing material storage hopper 53b, a valve 69a is interposed in the exhaust pipe 69, and the downstream side of the exhaust pipe 69 merges with the downstream side of the exhaust pipe 66 to form a vacuum pump. It is connected to 84. The processing chamber 2 is provided on the upper left side of the container 13.
3 is connected to a reducing gas supply pipe 54 communicating with
A valve 54a is interposed in the reducing gas supply pipe 54, and a reducing gas supply source (not shown) is connected to the upstream side of the reducing gas supply pipe 54.

A rotary cylinder 91 is inserted in the axial portion of the processing chamber 23, and a plurality of plate-shaped blades 92 are attached to the rotary cylinder 91. The rotary cylinder 91 is supported by the container 13, and its upper part is taken out of the container 13 and connected to the drive motor 93. An elevating shaft 94 is inserted through the rotating cylinder 91, and the upper part thereof is taken out of the rotating cylinder 91 and connected to a cylinder mechanism 95. Elevating shaft 94
The lower portion of the valve passes through the outlet 23a to reach the discharge pipe 23b, and a valve 96 having an inclined surface that rises toward the axis is attached to the end of the valve. When the lifting shaft 94 rises,
A configuration in which the inclined surface of the valve 96 is in close contact with the inclined surface of the discharge pipe 23b to close the outlet 23a, and conversely when the lifting shaft 94 descends, the inclined surface of the valve 96 separates from the inclined surface of the discharge pipe 23b and opens the outlet 23a. Is.

In FIG. 3, when the powder and granules charged into the processing chamber 23 from the powder and granule storage hopper 43b are heated by the vacuum pump 84 and the panel heater 33 under a predetermined vacuum atmosphere while being stirred by the blades 92, Since the contaminants in the granular material evaporate, the vapor is condensed and collected by the condenser 77 having a low cooling temperature. When the heat treatment in the vacuum atmosphere is continued and the impurities are almost evaporated, the reducing agent is fed from the reducing agent storage hopper 53b into the processing chamber 23, and the reducing gas supply source (not shown) supplies the processing chamber 23. When reducing gas is supplied to PbO, PbO in the granular material becomes Pb, and ZnO becomes Z
Since it is reduced to n and evaporated, the Pb vapor is condensed and recovered by the condenser 75 having a high cooling temperature, and the Zn vapor is cooled between the cooling temperature of the condenser 75 and the cooling temperature of the condenser 77. It is condensed and collected by the condenser 76 in the middle.

[0016]

As is apparent from the above, the present invention described above has an effect that high-quality valuable metal can be stably recovered from a granular material in a high yield.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view illustrating an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view illustrating another embodiment of the present invention.

FIG. 3 is a vertical sectional view illustrating still another embodiment of the present invention.

[Explanation of symbols]

11, 12, 13 ... Containers 21, 22, 23 ...
Processing chamber, 31, 32 ... Tube heater, 33 ...
Panel heaters, 51, 54 ... Reducing gas supply pipes, 5
2, 53 ... Reducing agent supply pipe, 61-69 ... Exhaust pipe, 71-77 ... Condenser, 81-84 ... Vacuum pump, 92 ... Blade

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F27D 17/00 105 F27D 17/00 105K

Claims (4)

[Claims] 1. An apparatus for recovering valuable metal from a powder or granular material by subjecting the powder or granular material to heat treatment in a vacuum atmosphere in a processing chamber formed in a closed container, the container being in communication with the processing chamber. A vacuum heat treatment apparatus for powder particles, comprising at least two condensers having different cooling temperatures which are connected to each other. 2. An apparatus for recovering valuable metal from a powder or granular material by heating the powder or granular material in a vacuum atmosphere in a processing chamber formed in a closed system container, the container communicating with the processing chamber. At least two condensers having different possible cooling temperatures are connected to each other, and a reducing gas supply pipe and / or a reducing material supply pipe capable of communicating with the processing chamber are connected to the container. Vacuum heat treatment equipment for granules. 3. The vacuum heat treatment apparatus for powder particles according to claim 1, wherein the condensers are connected in series. 4. The vacuum heat treatment apparatus for powdery particles according to claim 1, wherein the condensers are connected in parallel.