JPS60155630A - Method for recovering zinc from material containing zinc compound - Google Patents

Abstract

PURPOSE:To recover inexpensively and easily zinc with high concn. by sintering the briquettes consisting of a zinc compd. and carbonaceous material in a strong reducing atmosphere, metallizing and evaporating the zinc compd. and oxidizing the same in a strong oxidizing atmosphere. CONSTITUTION:A zinc-contg. dust raw material is charged into a kneading machine 1 and the concn. of the carbon and zinc contained is adjusted by a carbonaceous reducing agent and low zinciferous iron material. The raw material is briquetted by a briquetting machine 2 and further a low zinciferous material is coated thereon by a briquetting machine 3. The briquettes are charged into a laminar state between the sintering raw material 5 of a DL type sintering device and bedding ore 6. The top surface of a sintering raw material 5 is ignited by an ignition furnace 6 and the raw material is burned by charged air 9 in the stage of moving in the sintering device. The zinc compd. subjected to reduction there is metallized and evaporated. The evaporated zinc is made into zinc oxide in the oxidizing gaseous flow and is separated from the other waste gas. Coarse particle dust is removed by a dust collector 12 and the zinc oxide is captured by a dust collector 13.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recovering zinc from materials containing zinc compounds, such as metal refining raw materials or dust generated from metal refining processes.

For example, various types of dust generated at steel plants are collected and reused from the standpoint of effective resource utilization and environmental protection. However, in this case, the zn compound poses the biggest problem. Zn
In some cases, dust with a low concentration is directly supplied to a sintering machine, converter, electric furnace, etc., but in order to avoid blast furnace dust with a high Zn concentration and reusing it as a raw material for steelmaking, it is necessary to remove Zn as a pretreatment. It is necessary to carry out processing. At present, typical methods for removing Zn include classification separation using a wet cyclone and reduction evaporation using a rotary kiln.

The former wet cyclone method takes advantage of the property of Zn concentrating on the fine grain side, and the removal rate (removal rate of Zn) by this method is about 60 to 80%. This method takes advantage of the fact that the boiling point is about 9'l O'0, and zn in the dust is mainly removed by the following reaction.

C(S)-1-002(g)=200(su)(Bourdower reaction)-(11 znO(S)+Co(g)=Zn(g)+C02(1
/) '(Reduction of ZnO and evaporation of Zn) - (2) Zn(
Q)+%02(S)=ZnO(S) (oxidation and recovery of Zn) -+3] The removal rate of Zn by rotary kiln method is 80-95
%.

Although the wet cyclone method has a lower processing cost than the rotary kiln method, it has the disadvantage of a low Zn removal rate. In comparison, the rotary kiln method has a high Zn removal rate, but the processing cost is high and it is still unprofitable even considering the benefit of turning iron-containing dust into reduced pellets. For these reasons, the value of dust as a steelmaking resource is low, and the current situation is that dust is disposed of for environmental reasons rather than from the standpoint of effective resource utilization.

The present invention solves these problems and provides an inexpensive dust treatment method (
The purpose of this invention is to provide a method for recovering zinc that combines the effective use of dust and environmental measures based on Zn removal method (1). This makes it possible to collect highly concentrated zinc and supply it as a high value-added raw material to the subsequent metal zinc refining process. Furthermore, it is an object of the present invention to provide a method for recovering zinc that is suitable for not only dezincing dust generated in steel works but also dezincing raw materials for metal refining or dust generated from metal refining processes and recovering zinc. shall be.

In order to achieve the above object, the present invention mixes a material containing a zinc compound with a carbonaceous material if necessary, supplies the material onto a bedding ore in a sintering machine, and injects the material into a combustion temperature range. After metallizing and evaporating the zinc compounds in the substance by creating a locally strong reducing atmosphere, zinc oxide is produced by oxidizing the vaporized zinc in a strong oxidizing atmosphere, and the state The sintering machine is characterized by being discharged from the sintering machine.

An explanation will be given below based on one embodiment of the present invention.

In this embodiment, dust discharged from a steel mill is selected as the substance containing zinc compounds, and a normal DL type sintering machine is used as the sintering machine.

In FIG. 1, A shows the dust kneading and briquetting process, and B shows the sintering and dust dezincing process using a DL type sintering machine. The Zn-containing dust raw material is sent to the mixer 1, where a carbonaceous reducing agent and a low-Zn iron-containing substance are added as necessary.
The carbon-containing concentration and the Zn-containing concentration are adjusted. Carbon, Z
The dust with adjusted n concentration is sent to the briquetting machine 2 and is briquetted. When further coating is applied, it is sent to the briquette machine 3, and the low zn
Covering the briquette by the briquette machine 2 with the substance.

The coating material is for shielding the zinc-containing dust from the strongly oxidizing atmosphere in the subsequent dezincing process, and naturally needs to have zero or a very small amount of zinc, but limestone and dolomite are preferable. Subsequently, the aggregate mineral is sent to a sintering machine, and as shown in FIG. 1, it is charged in a layer between the sintering raw material and bedding ore 6 which is charged to protect the grate bar.

The upper surface of the sintering raw material is first ignited by the ignition furnace 16, and then it is combusted by the charge air 9 in the process of moving over the sintering machine. The sintered ore combustion zone moves continuously from the upper surface downward, and after the combustion of the lowest layer is completed, it is discharged to the cooler.

For this reason, 7. Combustion of n dust pellets occurs close to the ore discharge side.

When the Zn-containing dust pellet layer starts to burn, the above-mentioned fl
+ +2) reaction occurs and metallic zinc is evaporated and removed from the pellet. When the Zn-containing dust pellets are coated with a coating agent, the pellets are shielded from the oxidizing atmosphere as described above, and the reaction (2) above is promoted.
The evaporated Zn becomes zinc oxide through the reaction (3) above in the oxidizing gas flow, and is led to the dust collector along with the dust generated during the sintering process.

At this time, as shown in Fig. 1, the exhaust gas in the part where the first layer of the dust berene is burning (the place near the aforementioned ore discharge side) is separated from other exhaust gases and collected (roughly coarsened with dust collector particles 12). By removing the hard dust, recycling this dust as a dust raw material, and collecting zinc oxide with the dust collector 13, it becomes possible to selectively collect dust with a high ZN concentration.

Below, experimental results regarding the removal of Zn from Zn-containing dust using one small sintering machine will be shown. The In removal rate after the experiment was calculated using the following calculation formula.

Zn: Zn (%) zn' in pellet before Zn removal;
〃 (%) T, Fe after removing Zn: T, Fe (%) in the pellet before removing Zn
, Fθ′: (%) after deznization A disk type φ600 granulator was used for briquetting the raw material dust. The small sintering experimental equipment used in this experiment (Figure 2) was designed to simulate the operating conditions of an actual sintering machine.
Operation was performed under actual machine conditions of 0 mW and superficial velocity of 0.33 Nm/8θC1. However, considering the ease of collecting pellet samples after the experiment, approximately 100 grams of Zn-containing pellets (approximately 2% of the sintered raw material) were charged on top of the sintered raw material.
Air within the combustion chamber was charged from below (see Figure 2).

FIG. 3 shows the effects of carbon content, Zn content, and coating on the Zn removal rate. From these results, we can determine the carbon content, Zn content, and Zn removal.
rates have a strong relationship. Therefore, in order to obtain the optimum Zn removal rate as a raw material to be charged into a blast furnace, it is necessary to adjust the amount of carbon-containing Zn, and in some cases, a coating treatment is also required.

The present invention has the above configuration, and by supplying a zinc-containing substance between bedding ore and sintered ore, the substance acts as a binder between bedding ore and sintered ore. , it is integrated with the product discharged from the sintering machine, resulting in an increase in the product particle size. Furthermore, since Zn evaporates only in the combustion zone at the bottom of the sintered raw material of the sintering machine, selective dust collection as described above is possible, and there is no risk of redeposition of Zn within the raw material.

In addition, in the above example, the Zn removal treatment using a sintering machine for Zn dust generated at a steelworks and its recovery method are explained in detail, but as can be inferred from the above experimental results, As a condensing machine, oxidized pellet firing equipment and the like are considered to fall under this category, and it goes without saying that the use of a sowing machine also falls within the technical scope of the present invention.

As explained above, by processing Zn-containing dust according to the present invention 1, not only can sintered ore with a low Zn concentration be supplied to a blast furnace, but also Zn in the Zn-containing dust can be easily recovered at low cost. .

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of the present invention, Fig. 2 is a schematic diagram of a small sintering experimental device used in the experiment, and Fig. 3 is a case in which carbon-containing and Zn-containing pellets are coated with 6 pieces of lime. It is a graph showing the influence on the Zn removal rate. A... Mixed wires, briquette process B... Dezincing process! ...
Kneading machine 2...Bulking machine 3...Bulking machine 4...Sintering raw material hopper 5...Sintering raw material 6...Bed ore?
...Zn dust-containing group mineral 8...Sintered ore 9...
Charged air 10... Wind box 11... Dust collector 12.
...Dust collector (pre-duster) 13...Dust collector 14
...Plower 15...Chimney 16...Continuation of ignition furnace page 1 @Int, C1,' Identification symbol, internal reference number C22
B 19/34 7128-4K [Phase] Inventor Tadamitsu Eiji Soseki-cho, Niihama City 0 Inventor Seiji Sugimori No. 5-2, Soseki-cho Factory, Niihama City Sumitomo Heavy Industries, Ltd. Niihama°5-2 Sumitomo Heavy Industries Co., Ltd. Niihama Procedural Amendment April 25, 1985 Manabu Shiga, Commissioner of the Patent Office 1, Indication of Case Patent Application No. 11068-1982 2, Name of Invention Zinc Compound Method 3 of recovering zinc from contained substances,
Name of the person making the amendment (210) Sumitomo Heavy Industries, Ltd. 4, Agent (1) Amend the claims in the specification as follows. The zinc compounds in the substance are briquetted and the briquette mineral is supplied onto the bedding ore in a DL type sintering machine, and a strong reducing atmosphere is generated locally in the sintering temperature range of the substance. After metallization and evaporation and separation from the substance, zinc oxide is produced by oxidation of vaporized zinc in a strongly oxidizing atmosphere, and the zinc compound is discharged from the sintering machine in this state. A method of recovering zinc from materials. (2) On page 1, line 15 of the specification, "metal refining raw materials" is corrected to "pretreatment process for gold wire raw materials." Book III, page 4, line 14, ``metal refining raw materials'' is corrected to ``pretreatment process for additional raw materials.'' Page 5, lines 3 to 11 of the specification: ``For the above purpose,
...It is a feature. Correct this as follows. "In order to achieve the above object, the present invention mixes a carbonaceous material with a material containing a zinc compound, if necessary, and after briquette, supplies the briquette onto the bedding ore in a DL type sintering machine. After metallizing and evaporating the zinc compound in the substance by generating a strongly reducing atmosphere locally in the sintering temperature range,
This method is characterized in that zinc oxide is produced by oxidizing vaporized zinc in a strongly oxidizing atmosphere, and is discharged in this state from the sintering machine. (5) Correct Figure 2 as attached.

Claims (1)

[Claims] A material containing a carbonaceous material and a zinc compound is supplied onto the bedding ore in a sintering machine, and a strongly reducing atmosphere is generated locally in the combustion temperature range of the material, thereby reducing the zinc compounds in the material. Contains a zinc compound characterized in that after metallization evaporation and separation from the substance, zinc oxide is produced from the oxidation of vaporized zinc in a strongly oxidizing atmosphere and discharged in that state from the sintering machine. method of recovering zinc from materials that contain it.