JP3292271B2 - Waste brick treatment method for metal smelting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a waste smelter by pulverizing waste bricks generated when the furnace is repaired or dismantled.

[0002]

2. Description of the Related Art In order to reuse waste bricks generated from a metal smelting furnace, it is necessary to grind the waste bricks.

For example, magnesia-chromium fired bricks (commonly referred to as “magcro bricks”) used in flash smelting furnaces, reverberatory furnaces, converters, and the like in copper smelting are used for repair and repair of these furnaces.
At the time of dismantling, it is a source of a large amount of waste bricks, but contains a large amount of mat (copper-iron sulfide) and metallic copper because it is in contact with the high-temperature molten metal in the furnace. On the other hand, waste bricks such as a heating furnace are not impregnated with such mats and metallic copper, and thus the waste bricks are mechanically pulverized by a furnace material manufacturer and then reused as a stamp material. However, since the waste brick of the smelting furnace is impregnated with mats and metallic copper, the copper content reaches 10 to 20% by weight, and the powder or lump obtained by the pulverization method also contains a large amount of mats and the like. Therefore, they cannot be reused as furnace materials.

[0004] On the other hand, mats and metallic copper are valuable materials,
It is common practice to mechanically pulverize waste bricks impregnated with mats and metallic copper and then repeatedly melt them in a smelting furnace to recover the copper content in the waste bricks into molten metal. However, waste bricks containing matte and metallic copper have poor pulverizability, and have a particle size that can be repeatedly melted in a smelting furnace, preferably, to a size of 10 mm or less, it takes 2-3
Operation of mechanical grinding and classification of the stage is required. For this reason, the grinding cost increases.

A method of recycling magnesia bricks used in steel smelting is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 6-116617.
No. pp. 139 to 163. In this method, used magnesia bricks are crushed by a crushing machine (jaw crusher).
The MgO concentration in the slag is adjusted by pulverizing the slag to 0 mm or less and repeating this in a molten steel smelting furnace lined with a refractory containing MgO as a main component and dissolving it.

According to Japanese Patent Application Laid-Open No. 6-92701, in order to recycle waste bricks as building materials,
A method of pulverizing into a round material having a size of about 20 to 120 mm is proposed. In this method, waste brick is pulverized by a machine such as a pyrene, a jaw crusher, and a squaring device.

[0007] As described above, when it is necessary to pulverize waste bricks for reuse treatment, pulverization using a pulverizing machine is a commonly practiced method.

[0008]

The size of waste bricks generated when disassembling or repairing a smelting furnace varies from the size at the time of molding to the size of a larger block. And, since many waste bricks of several hundred mm in size are also generated, if this is to be crushed to, for example, 20 mm or less, a two-to-three-stage crusher and a classifying facility are required, so the equipment cost is large,
In addition, pulverization and classification in two or three stages is not an easy task. Therefore, a method of pulverizing more easily and finely is desired.

[0009] Further, since the copper content in the waste brick generated from the copper smelting furnace permeates into the brick in a mesh-like manner, in order to reliably recover the copper content from the waste brick, the waste brick is melted. It is desirable to make the pulverized particle size as small as possible so that it can be quickly dissolved in the brick portion when it is repeated in a smelting furnace. However, in order to further reduce the pulverization particle size, there is a problem that the number of pulverization / classification stages further increases, and the number of facilities and running costs increase.

[0010]

According to the present invention, there is provided a method for solving the above-mentioned problems, wherein a used waste brick of a metal smelting furnace is pulverized by bringing it into contact with steam of 2 atm or more. The present invention provides a method for treating a waste brick of a metal smelting furnace. Hereinafter, the configuration of the present invention will be described.

In the present invention, the waste brick is a basic refractory brick usually used in a metal smelting furnace, particularly a main brick containing MgO and / or CaO, and more preferably a magcro brick or a magnesia brick. It is known that MgO and CaO cause a hydration reaction (commonly referred to as “slaking”) by reaction with water.In the present invention, in a waste brick containing MgO or the like, the hydration reaction occurs inside the lump, Utilizing the local expansion of the volume, the dismantled waste bricks are broken into powder.To effectively utilize this reaction and volume expansion for the destruction of the waste bricks, the water vapor atmosphere has to be pressurized. By performing the steam treatment under the pressurized condition, the slaking is forcibly progressed, and the waste brick can be finely pulverized.

[0012] The temperature of the steam is preferably from 100 ° C to 310 ° C, and more preferably from 150 ° C to 250 ° C. When these are converted into saturated steam pressures, they are 1.0 atm or more and 100 atm or less, preferably 4.9 atm or more and 40 atm or less. Generally speaking, the higher the steam pressure, the faster the hydration reaction, and the pulverization is completed in a short time. On the other hand, if the water vapor pressure is increased, the production cost of the apparatus increases in order to ensure the hermeticity and pressure resistance of the reaction apparatus. Therefore, it is not preferable to increase the pressure more than necessary. Therefore, the preferable steam pressure is in the above range. The treatment with steam, which is a feature of the present invention, is preferably performed in an autoclave. In this case the standard processing time is between 8 and 12 hours.

The waste brick can be treated by the present method not only from a copper smelting furnace but also from a steel or other metal smelting furnace. Waste bricks of copper smelting furnaces are generally valuable components of Cu: 10 to 15% by weight,
Au: 30 ppm, Ag: 0.01% by weight, Pb0.1
%, Zn: 0.1%, etc. Waste bricks containing these components are pulverized according to the method of the present invention, and thereafter repeatedly used in a copper smelting furnace to recover valuable metals.

[0014]

The above hydration reaction is performed in the case of MgO with MgO + H ₂
O → Mg (OH) ₂ . At normal temperature and normal pressure, this hydration reaction proceeds slowly, and it takes several days or more to completely pulverize with a magcro brick or the like. When the magcro brick is immersed in water at room temperature, no change occurs in the brick even after 14 days. Further, even when exposed to steam at 105 ° C. (saturated steam pressure ≒ 1 atm) for 20 hours, cracks are finally generated. However, if the water vapor pressure is increased in this hydration reaction, the reaction rate increases, and it becomes possible to pulverize in a short time. More than M
Although gO has been described, similarly for CaO, short time pulverization is possible. Hereinafter, the present invention will be described in more detail with reference to examples.

[0015]

【Example】

Example 1 Waste magcro bricks of a copper smelting furnace were separated into two types of bricks: A: metal copper infiltrated bricks and B: copper sulfide (including iron) infiltrated bricks, and subjected to an experiment. Using the experimental autoclave (internal volume 1.0 liter), treatment experiments of waste bricks A and B were performed under the three conditions shown in Table 1.

[0016]

Table 1 Temperature (° C) Water vapor pressure (atmospheric pressure) Retention time (Hr) Condition i 225 28 7.0 Condition ii 200 17 7.0 Condition iii 150 5 7.0

Table 2 shows the degree of pulverization obtained as a result.

[0018]

[Table 2] Waste brick A Waste brick B Condition i Completely destroyed (powder) Completely destroyed (powder) Condition ii Completely destroyed (powder) Completely destroyed (partially granular) Conditions iii Semi-destructed (granular) Semi-destructed (granular)

From the above results, it was found that the waste brick could be pulverized sufficiently efficiently at a high temperature and a high pressure under the condition iii.

Example 2 Most of the waste magcro brick generated from a copper smelting furnace has a rectangular shape of about 120 mm × 150 mm × 250 mm, and the smallest one is smaller than a cube having a side length of 100 mm. The large waste brick was steam-treated using an autoclave (3.8 m ^{3 in} volume) for actual operation. The experimental conditions were a steam pressure (maximum) of 15.9 atmospheres and a holding time at the maximum pressure of 10 hours. As a result, the results of measuring the particle size distribution of the treated waste bricks are shown in Table 3.

[0021]

[Table 3] Particle size Waste brick A Waste brick B +30 mm −5 −30 / + 10 mm 78 −10 / + 3 mm 15 11 −3 mm 78 76

Comparative Example 1 Waste bricks A and B were immersed in water at room temperature, and the appearance and crushing strength were examined every day. As a result, these properties did not change at all even after 14 days in both of the waste bricks A and B.

Comparative Example 2 A waste brick (80 mm) was placed in a cylindrical container (with an inner volume of 5 liters).
Corner), and steam (steam pressure = 1 atm) was continuously flowed into the container. During that time, the temperature in the container changed between 100 and 105 ° C. After elapse of 20 hours, the waste brick was taken out of the container and examined. As a result, a crack having a width of about 1 mm and a length of about 3 mm was generated, and the crushing strength did not change.

Comparative Example 3 Using a crusher 1: a jaw crusher (output: 75 kW) and a crusher 2: a hammer crusher (output: 55 kW)
Experiments were also conducted on mechanical grinding. Experimental conditions The original size of the waste brick (B) is 200-400m
m, the first stage was crushed by the crusher 1 and the second stage was crushed by the crusher 2. Each pulverizer was pulverized as finely as possible without causing troubles such as biting. The results are shown in Table 4 (ratio to weight after grinding (% by weight)).

[0025]

[Table 4] After treatment with crusher 1 After treatment with crusher 2 +100 mm − − * −100 / + 80 mm 4.8 − * −80 / + 50 mm 22.2 − * −50 / + 30 mm 38.7 38.5 −30 / + 10 mm 25.9 41.4 -10 / + 5 mm 4.3 8.3 -5 mm 4.1 11.8 Remarks *: In the crusher 2, only 50 mm under is discharged due to its structure.

Comparison of Table 4 with Table 3 of Example 2 shows that the particle size after grinding is coarse. If it is attempted to grind to a particle size equivalent to that of Example 2 (slaking with high-pressure steam) by a mechanical pulverization method, one or two additional pulverizations are required.

[0027]

As a result, mechanical pulverization has been conventionally performed as a pretreatment when waste bricks are repeated in a smelting furnace. However, in the present invention, pulverization is performed using a chemical reaction, that is, a hydration reaction of oxides. Therefore, it can be easily crushed finely. By finely crushing, it becomes easy to collect valuable resources contained in the waste brick. That is, the finely ground waste brick is reliably melted in the repeated smelting furnace, valuables such as copper are recovered in the molten metal, and the brick is transferred to slag.

In addition to the purpose of recovering valuable resources, there are cases where waste bricks which are difficult to dispose of as landfills as industrial waste can be dissolved in slag in a smelting furnace and discarded, or when recycled as building materials. This is also effective as a pretreatment (crushing) method for waste bricks.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tetsuo Hirose 3382 Nippon Mining & Metals Co., Ltd., Saganoseki Smelter & Refinery, 3 Sagaseki-cho, North Sea District County, Oita Prefecture

Claims (3)

(57) [Claims] 1. At least 2 atm of used waste brick generated when a smelting furnace is repaired or dismantled is mechanically crushed from bricks in contact with molten metal in a copper smelting furnace without mechanical crushing in advance. A method for treating waste bricks in a metal smelting furnace, comprising crushing by contacting with water vapor. 2. The method according to claim 1, wherein the contact treatment is performed in an autoclave. 3. A method for treating waste bricks in a metal smelting furnace, comprising melting waste bricks crushed by the method according to claim 1 in a copper smelting furnace and collecting valuable resources.