JPS6026284A - Method of simultaneously treating electric furnace dust and slag - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for simultaneously treating electric furnace dust and various molten slags (herein referred to simply as slags) produced in iron and steel manufacturing processes.

Electric furnace dust is made up of fine particles and contains harmful heavy metals such as zinc, cadmium, and lead in the form of enemies, so it is difficult to handle and it is legally prohibited to dispose of it as is. There is.

Conventionally, after recovering heavy metals from dust using an 0-tally + run, a vertical electric furnace, etc., the rendered harmless residue is dumped. However, this method has a major drawback in that it requires a large amount of energy. On the other hand, a large amount of slag is generated in each process of steelmaking, but conventionally this has been mainly disposed of as waste. However, simply disposing of slag is a big problem from the standpoint of effective resource utilization. Therefore, electric furnace dust and sludge, which are difficult to handle, are first added with a reducing agent and turned into briquettes or pellets, and then charged together with the slag into a reactor equipped with a heat-retaining heating device to volatilize Zn, C.
d, Pb, etc. are collected by suction, and F*, Mn, and Ni are collected.

A method of beneficiation and recovery of Cr, etc. has been proposed. According to this method, the electric furnace dust is turned into briquettes or pellets, so the problem of difficulty in handling is solved; It is necessary to add a large amount of thermal energy to the mixture. (i) Because the surface area of the briquettes or pellets is significantly reduced, even if a large amount of thermal energy is applied, unreacted portions remain. Easy, Zn, Cd
, it is difficult to sufficiently recover Pb, etc.; (ii)
Volatize and recover Yn, Cd, Pb, etc. and Ft
Unreacted Zn, Cd,
Since Pb and the like remain, there are problems in that it is difficult to reuse or dispose of this as it is.

As a result of various studies in view of the above-mentioned current situation, the inventor of the present invention formed or granulated electric furnace dust into a minimum size that does not float or inhibit the reaction with the slag, and then tilted it. And/or when the above-mentioned molded product or granulated product and slag are mixed and reacted in a reaction tank in which the contents can be stirred by blowing air, oxygen, etc., the drawbacks of the above-mentioned conventional method can be avoided. It was found that the problem was virtually eliminated. That is, the present invention relates to the following method.

■ Granulated or flaked electric furnace dust and molten slag are added to the slag stored in the reaction tank, stirred to cause a mixing reaction, and then transferred to a cooling container while the surface portion of the mixture is in a molten state. A method for simultaneously treating electric furnace dust and slag (hereinafter referred to as the first invention of the present application), characterized in that electric furnace dust and slag are cooled.

■ Granulated or flaked electric furnace dust and molten slag are added to the slag stored in a reaction tank, stirred in the presence of a lubricating agent to cause a mixing reaction, and then the surface portion of the mixture is in a molten state. A method for the simultaneous treatment of electric furnace dust and slag, which is characterized by transferring the solid material to a cooling container for cooling, pulverizing the obtained solid material, and magnetically separating the ferromagnetic products. (hereinafter referred to as the second invention).

In the present invention, since the thermal energy of the slag is effectively utilized, no external heat supply is required. Furthermore, from the gas generated by mixing and reacting granulated or flaked electric furnace tast with slag, ZN can be recovered at a recovery rate of 60% or more, and Cd and PB at a recovery rate of about 60 to 97%. can be recovered at a high rate.

Furthermore, the solid reaction product obtained in the first invention of the present application becomes an artificial stone with excellent water resistance, chemical resistance, abrasion resistance, etc. Moreover, the physical properties of the artificial stone can be adjusted by changing the mixing ratio of the slag and electric furnace dust, and the amount of reducing agent added to about 1.5% of the dust weight if necessary. For example, if no reducing agent is added, the stone will be hard and dense, and as the mixing ratio of electric furnace slag to slag increases, the ratio of artificial stone will increase.

Moreover, it is safe because virtually no heavy metals are leached from this artificial stone. Therefore, such artificial stones can be widely used as roadbed materials, construction materials, landfill materials, etc.

In the second invention of the present application, V-nail metal in the dust is reduced by a reducing agent and reacts with sulfur in the slag to become a sulfide.

If the sulfur content is insufficient, add gypsum, etc. This heavy metal sulfide and Ft, Ni, C.

A liquid phase consisting of sulfides, etc., exists as a liquid phase between the oxide A[1] and the oxide A[1], and the liquid phase solidifies independently during that time. Therefore, since there are crystal interfaces in the solid reaction product that are not chemically bonded, it is easy to separate at the interface and easy to grind.

Sulfide powder containing ferromagnetic substances such as Ft sulfide can be magnetically sorted and is useful as a metal raw material, and the remaining purified oxide powder (silica, alumina, calcia , Macnesia, etc.) are useful as raw materials for Shichimeshito, fertilizers, etc. The above sulfide is presumed to be a so-called bertholed compound. When the sulfide phase and the oxide phase are made to coexist, by appropriately selecting reaction conditions, it is possible to make the sulfide phase almost uniformly mixed in the oxide.

The particle size of electric furnace dust is usually several micrometers,
Since it is difficult to handle, in the present invention it is granulated or flaked in advance. The granules or flakes are preferably made as small as possible to promote the reaction without causing floating or scattering. In addition, when it comes into contact with the slag, it is rapidly divided into small pieces to increase the surface area and increase the reaction rate.In order to increase the reaction rate, the organic granulating agent is made into a flexible form containing water or thermally decomposed to generate gas. It is preferable to perform granulation using (for example, likuninsulfonic acid, sucrose, molasses, []-starch, PVA, etc.). The pressure during molding is not particularly limited, but
For example, in the case of dyeing, approximately 100 to 1000 kg/
Generally, it is about d. Considering ease of handling and reaction speed, granules have a diameter of 2 to 3 M'IR, and flakes have a length of 5 to 10 II! H level, horizontal lO
It is preferable that the number of gates is about 25 gates and the thickness is about 2 to 3 rxyx or less.

The mixing ratio of electric furnace dust and slag is not particularly limited,
Although it can be appropriately selected within a wide range, the electric furnace dust is usually 5 to 40% by weight, preferably 5 to 30% by weight based on the slag.
It is preferable to mix them in proportions of % by weight. The slag treated in the present invention must be in a molten state, and its temperature is usually 1300 to 1400°C.

The method of the present invention is carried out, for example, as follows. 1st
As shown in the figure, slag is placed in the reaction tank (1) in advance, and then granulated or flaked electric furnace dust and slag are further added thereto. The slag is poured from the top with the hood (3) open, and the electric furnace dust is poured from the dust inlet (5). At this time, if necessary, a reducing agent and/or other additives may be mixed with the electric furnace dust and added. Next, the hood (3) is closed, and the contents in the reaction tank (1) are stirred to rapidly advance the reaction. Stirring is shown in Figure 2 (1
-12), (1-b) and (I-C) rocking agitation by tilting device (7), air or oxygen supply line (
Any of the following methods may be used: stirring by air or oxygen blown out from the outlet (b) and zero saliva via 9), stirring by a stirring plate (not shown), or the like. The mixed reaction between the electric furnace dust and the slag generates gases containing oxidation, zinc oxide, cadmium oxide, lead oxide, etc., which are then passed through the soufflé pipe (1G) to the dust collector, which is opened to the hood (3). (17) to collect the metal components, and then collect each metal according to a conventional method.

After the reaction is completed, while the surface of the contents in the reaction tank (1) is in a molten state, tilt the reaction tank to the position (1-d) in Figure 2 and pour it into the cooling container Q'). Then, the reaction product is cooled and solidified. As mentioned above, the solidified product is made into artificial stone or separated into sulfide and oxide and reused for their respective purposes.

In addition, the reaction tank (1) is lined with refractory material and lined with iron shell (
(e) It is preferable to have a structure in which it is externally covered.

When a reducing agent is used in the present invention, not only the recovery rate of heavy metals is improved, but also the separation and purification of sulfides and oxides in the solid product becomes better. As the reducing agent, all known organic and inorganic ones can be used, but carbon-based ones such as pulverized coal, pulverized coke, and ℃ molasses are preferable. The amount of the reducing agent to be used is not particularly limited, but it is usually about 2 to I'1% by weight based on the electric furnace tact.

The reducing agent may be mixed or sprinkled on the granules or flakes of the electric furnace dust, may be blown into the granules or flakes of the electric furnace dust, may be blown in together with air or oxygen, or may be added at the same time when the electric furnace dust and the slag are mixed. However, granulation or slag formation after mixing the electric furnace dust and the reducing agent should be avoided as this will delay the reaction between the dust and the slag.

Examples are given below to further clarify the present invention.

In the examples, % means weight %.

Example 1 As electric furnace dust, 5iO26, 50%, "2'30
．． 78%, F/20348-19%, Ca04,72
%, MyO6, 33%, ZnO2, 2,60%, MnO
4,57%, CdOQ, 02% and pbo t, 24%
Dust containing the following ratio was used.

Electric furnace reduced slag, 5sO237-78%, Al 0
3 14.82%, Ca032.92%, M(107,48
%, Ft 2030-05% and UMnO2, 60% slag was used.

51111
It was formed into flakes with a size of 2.5 feathers, and then air-dried. On the other hand, about 10 molten slags were added to Surakban.
The flakes and about 250 kg (i) of seven millimeters were added to 0 kq along with about 1200 kg of electric furnace slag at a temperature of 1320 °C, and stirred with an iron ladle.The generated gas was introduced from above the slag pan to a gas collection device to oxidize heavy metals. Collected things.

The volatilization rate of each oxide based on the content in the treated electric furnace dust was about 67.97% for zinc oxide, almost 100% for cadmium oxide, and 67.36% for zinc oxide. The outbreak of jJs lasted about 10 minutes. When the residue after gas generation was left for about 24 hours, an artificial stone with excellent mulberry resistance, water resistance, abrasion resistance, etc. was obtained.

The physical properties of this artificial stone were as follows.

Specific gravity: 3.15 Hardness (microscale): 520 Acid resistance Stronger alkali resistance than cosicrete Water resistance: No change after being immersed in a 1% caustic soda solution for over 30 days Water resistance: No change after being immersed in a 1% caustic soda solution for over 30 days It was pulverized and the amounts of cadmium and lead released from the bath were examined according to the method specified in the Environment Agency Notification No. 4, but none were detected.

Furthermore, when the artificial stone was irradiated with ultraviolet rays to examine its stability with lime according to JIS A3011, it was found that this artificial stone was extremely chemically stable.

When the minerals contained in the artificial stone were examined by X-ray powder diffraction, akermanite (melilite), casgodine, marwinite, l 2 Coo 7A1203, and dicalcium ferrite were recognized. The stone obtained by cooling the electric furnace reduction slag contains minerals such as akermanite (mellilite), cassidine, and ferromagnetic sujinel.

Example 2 Electric Furnace Dust] Artificial stone was obtained in the same manner as in Example 1, except that 0.00 kq was used and ℃ Migara was not used.

Attempts were made to cut this artificial stone into cubes using a Tie 177 cutter, but cutting was difficult as it took a long time and the loss of ties was large.

Specific gravity 3.08 Hardness (micro hardness) 514 Compressive strength 2.
5 ton / cJ Acid resistance Stronger alkali resistance than concrete No change after being immersed in a 1% caustic sorter solution for over 30 days Water resistance No change after being immersed in a 1% caustic sorter solution for over 30 days In addition, this artificial stone can be finely ground to comply with the Environmental Agency notification. The amount of leached cadmium and lead was investigated according to method No. 4, but none were detected.

Furthermore, when the artificial stone was irradiated with ultraviolet rays to examine its stability with lime according to JIS A301+, it was found that this artificial stone was extremely chemically stable.

When the minerals contained in the artificial stone were examined by X-ray powder diffraction, the minerals contained in the artificial stone were found to be akermanite (melilite), kasudidine, marwinite, and 12 Ca.

7 Al2O3 was observed.

On the other hand, we were able to recover zinc oxide, cadmium oxide, and lead oxide from the gas generated when dust and slag were mixed.

When the respective volatilization rates are calculated from the processed tast, zinc oxide 5
An artificial stone was obtained in the same manner as in Example 1 except that 9.12% oxidized Cadmirami electric furnace Tast 170k was used and Shichisan Kara was not used.

Specific gravity: 3.13 Hardness (microscopic): 398 Compressive strength: 1.
'9 ton 10J Acid resistance - Stronger alkali resistance than Cosicrete No change after being immersed in a 1% caustic sorter solution for over 30 days Water resistance No change after being immersed in a 1% caustic sorter aqueous solution for over 30 days Also, this artificial stone is finely pulverized and approved by the Environment Agency. The amount of leached cadmium and lead was investigated according to the method No. 4, but none were detected.

Furthermore, when the artificial stone was irradiated with ultraviolet rays to examine its stability with lime according to JIS A3011, it was found that this artificial stone was extremely chemically stable.

When the minerals contained in the artificial stone were examined by X-ray powder diffraction, akermanite (melilite), kasuddin, marwinite, and I 2 CaO 7 Al 2 O 3 were recognized.

On the other hand, we were able to recover zinc oxide, cadmium oxide, and lead oxide from the nozzle generated when the dust and slurry were mixed. The volatilization rate was 61.44% for zinc oxide, nearly 100% for cadmium oxide, and 65.54% for lead oxide.

Example 4 Ss O24,4, Q%, Al20 as electric furnace dust
30.81%, Fe 20344-94%, Ca01.
57%, Myo 0.02%, ZnO24, 67%, p
bo 1.53%, Mn 04.36%, CdOO, 02
% of slutast was used, and slag containing S#0237.97 was used as the electric furnace reduced slag.

A reaction product was obtained in the same manner as in Example 1, except that electric furnace Tast 50 was used as a substitute for rice husk and 3% of the reducing agent Please was used as a rice husk substitute.

In the obtained solid product, oxides mainly composed of SiO2 and CaO and metal sulfides mainly composed of Fz, Mn, etc. exist clearly separated, and it is extremely easy to separate them from the interface. Shattered. After pulverization, 13.12% of ferromagnetic components such as Ft3S4 were separated and removed by magnetic separation.

The volatilization rate of heavy metal oxides during electric furnace tast is zinc oxide 7
6.16%, almost 100% cadmium oxide, 93% lead oxide
．． It was 7%.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an outline of a reaction tank used in an embodiment of the present invention, and FIG. 2 is a diagram showing the tilting of the reaction tank. (1)...Reaction tank, (3)...Hood, (5)...
・Dust inlet, (7)...Tilt device, (9)...
Air or oxygen supply line, (b), α force...outlet, QO...flexible pipe, α force...dust collector,
θ groan...cooling container. (Above) Agent: Eiji Saegusa, Patent Attorney Voluntary amendment to amend the procedure in Figure 1, Figure 2-b) August 26, 1980 1 Indication of the case 1988 Patent Application No. 133062 2 Name of the invention Electricity Simultaneous processing method for furnace dust and slag 3 Relationship with the case of the person making the amendment Patent applicant Convex material Kaoru 4 Spontaneity of the agent 6 Section 7 of “Detailed description of the invention” in the specification subject to amendment Attachment of attached sheet of contents of amendment Contents of amendment 1 Page 3 of the specification, line 12 rYn J is replaced by rZn
Correct it with J. 2. Page 8 of the specification, lines 12-13 “Usually 1300-14
00℃" should be corrected to ``Normally 1300-1500℃.'' 3 Mei@, page 9, lines 8-9 [stirring with oxygen, stirring with a stirring plate (not shown), etc.] should be corrected to "stirring with oxygen, etc."(that's all)

Claims (1)

[Claims] ■ Granulated or flocculated electric furnace dust and molten slag are added to the slag stored in a reaction tank, and after stirring and causing a mixing reaction, the surface portion of the mixture is in a molten state. 1. A method for simultaneously treating electric furnace dust and slag, which comprises transferring the dust and slag to a cooling container for cooling. ■ Granulated or flaked electric furnace tast and molten slag are added to the slag stored in a reaction tank, stirred in the presence of a reducing agent to cause a mixing reaction, and then the surface portion of the mixture becomes molten. 1. A method for simultaneously processing electric furnace dust and slag, which comprises transferring the powder to a cooling container for cooling, pulverizing the obtained solid material, and magnetically separating ferromagnetic products.