JPS58185733A - Treatment of steel dust containing zinc produced in steel making for reutilizing as resources - Google Patents

Abstract

PURPOSE:To recover Zn from steel making dust contg. zinc by separating Zn as vapor and condensing to liq. state by heating the dust with a heat medium to allow the zinc to react with a reducing material in an induction type electric furnace provided with a condenser in a cover part. CONSTITUTION:The pellets of steel making dust contg. Zn and a reducing agent such as powder coke are charged into a reaction retort 1 consisting of a low frequency induction furnace. A heat medium 6 such as iron scrap or the like in the retort is heated inductively by low-frequency induced electric powder, and the pellets of the steel making dust and the coke are allowed to react by the heat generated by heating so that ZnO in the pellets is reduced to Zn and is evaporated as the vapor of Zn. The vapor is condensed as liquid Zn 8 in a condenser 3 provided in a cover body 2 and zinc is thus recovered. The Fe component in the dust absorbs the C in the reducting agent and adds the same as molten cast iron in a heat medium 6, thereby increasing the heat capacity of the heat medium. The formed molten slag and a part of the increasing heat medium are removed by tilting the retort 1 and again the pellets and the reducing agent are added thereto so that the Zn is reduced and recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recycling zinc-containing steel dust containing zinc oxide and iron oxide as main components.

Zinc-containing steelmaking dust (hereinafter referred to as dust) is a part of industrial waste generated during the oxidation refining stage of electric steelmaking furnaces that use iron scrap as the main raw material, but it contains trace amounts of cadmium along with zinc and iron. Dumping untreated wood is prohibited due to environmental pollution. For this reason, the dust needs to be treated to remove cadmium, but since cadmium can be recovered together with zinc, a recycling process is performed for the purpose of recovering zinc.

For example, in a rotary kiln method in which dust and reducing charcoal are heated together in a flame, zinc is recovered as crude zinc oxide. However, since this crude zinc oxide has a low commercial value, it has the disadvantage that the cost of recycling is high. Moreover, the reduced iron obtained at the same time is of below economic grade and cannot be used as an iron source, resulting in further increase in processing costs. Therefore, it has been desired to develop a low-cost processing method that can recover zinc and iron in dust as distilled zinc and molten cast iron, which have high commercial value.

The applicant of the present invention first developed an induction electric furnace and a hot wire made of gold 4, which can be charged into the induction electric furnace and capable of induction heating, as a device that can meet the above requirements. ,
An apparatus for hot treatment of minerals, waste, etc., comprising a contact promotion device that continuously brings the object to be treated into contact with a hot wire that is red-hot or melted by induction heating (Unexamined Japanese Patent Publication No. FM156-40070 No. 11!iI!Example) 31) was proposed. The previous application argued that the device was too complex to handle all kinds of mixtures, from miscellaneous materials like municipal waste to industrial waste like dust, all at once without separating them. There were drawbacks. For this reason, Dust Only Fist Dokkoko B11# is a general purpose! 4! There was a strong desire for simplification of operations and further reduction of I/O operations using the plant.

In order to meet the above demands, this invention utilizes a general-purpose crucible-shaped induction furnace as a reaction retort, and
The present invention provides a processing method that is extremely simple to operate and is low in cost due to the simplification of the equipment in the process.

That is, the present invention heats a material to be treated consisting of zinc-containing steel dust and reduction grade in an induction electric furnace equipped with a condenser in part I using a hot wire made of metal and capable of induction heating, Recycling of zinc-containing steel dust, characterized in that metals that are reduced and volatilized from lead-containing steel dust are collected in the condenser, and other metals that do not volatilize are collected in the furnace. This is an am processing method.

In this invention, the induction furnace No. 11 can be either high frequency or low frequency, but in the case of semi-continuous processing where there is residual metal, the hot wire for starting operation has a capacity of 1 to 1 for melting cast iron.
A low frequency induction furnace of about 10 tons is advantageous, and a high frequency induction furnace is preferred in the case of patch processing where the starting hot wire is scrap iron. On the other hand, dust has the same reactivity and ease of handling as in the rotary kiln method.
Preferably, it is resized to about 5 to 20 pieces. In addition, the degree of reduction is good (diameter is 2 to 2 degrees),
), Yawo □yo 3,7a, -8゜o. .

There is no need to use it. Furthermore, as in the known horizontal retort method, a simple refractory box-like container is sufficient as the condenser, but a known spruce-up condenser made of graphite may also be used. will be explained using drawings. The first embodiment is an example of semi-continuous treatment using a low frequency induction furnace, and FIG. 1 shows a reaction retort used in the present invention. The main body part 1 of the retort is a crucible-shaped paper frequency induction furnace known for melting cast iron, and a lid part 2 is mounted on the upper end of the retort through a sealing mortar, and the tap water fl m is detachable. The above-mentioned 8 part 2 is provided with a lid plug 1b.
A and a gas discharge port 1]]2b are provided, and a workpiece supply hopper 5 is provided on the top surface thereof in communication with the supply]]2a, and a gas discharge port 1! ! 1. A condenser 311 made of a refractory box and a 7° IJ LJ 7 made of a refractory box σdi are provided in series. Then, dust and coke gel can be supplied to the supply hopper 5 at a predetermined ratio by two splinter feeders (not shown).

On the other hand, when starting the "C1 performance," the molten metal from Star R Inogugro 7 is used as PvIk, and from the next time onwards, the remaining melt is used as hot wire. A heat ray layer 6 of about 30% is formed.Next, a heat ray layer 6 is formed.
A material to be treated 7 containing a mixture of dust and coke spritz at a ratio of 7:3 is supplied from the supply hopper 5 onto the surface of the hopper. As a result, the zinc oxide in the dust is reduced and volatilized to turn into benthic acid.
It is sent to the condenser 3 from the gas outlet 2b together with the search gas,
It is cooled, liquefied, and recovered as liquid zinc 8.

Further, part of the zinc that cannot be liquefied in the condenser 3 is recovered as zinc powder in the prolong 4, and the exhaust gas is discharged into the atmosphere from the gas outlet 4a of the prolong 4. Of course, the dominium is recovered at the same time as the zinc.

On the other hand, the iron oxide in the dust absorbs carbon during reduction, melts it, and separates from the slag to form cast iron.This cast iron acts as a heating medium, so a heating medium is generated, forming a generated heating medium. to increase the total amount of heat transfer medium. As a result, the rate of supply of heat from the heating medium increases, and the dust is processed at a high speed. In this way, when the molten metal and slag as a heating medium have increased to about 80% of the furnace volume, the furnace body is tilted, and the next heating medium is left in the furnace and the increased amount is tapped out. is collected.

The second embodiment shown below is an example in which iron scrap is charged at the same time as the object to be processed, and patch processing is performed using a high frequency induction furnace. This will be explained with reference to FIG. 1. After the workpiece is mixed to about 60% of the furnace volume, a small amount of iron scrap is charged, and the workpiece is again charged on top of it. and lid part 2
When closed and energized, the iron scraps are heated by induction, heating and reducing the surrounding workpiece and melting it. Droplets resulting from this melting descend into the object to be treated and melt the entire object, and zinc is recovered in the same manner as in the first embodiment, and cast iron is recovered at a total ratio of 1.

As explained above, in this invention, the object to be treated is heated using a heating medium in an induction furnace equipped with an IJk111 vessel in the lid, so it is easy to isolate it from the atmosphere, and zinc It is possible to easily recover metals and iron with high commercial value, and therefore the processing cost is extremely low and the operation is simple.

[Brief explanation of the drawing]

FIG. 1 shows the reaction of an embodiment of this invention? /L-to. 1 @Retort main body consisting of 4-type electric furnace, la
: Tap spout, 1b: G stopper, 2' lid, 2a; Processing material supply #
day, 2b: gas outlet, 3: m condenser, 4: prolong,
4a5 Prolong gas outlet, 5 Processing material supply hopper, 6 Heat medium layer, 7° Processing object, 8: Liquid zinc patent applicant Takeshi 1) -1/- Kisho 1 Fig.

Claims (1)

[Scope of Claims] [1] A workpiece consisting of zinc-containing steel dust and reducing carbon is heated in an induction electric furnace equipped with a condenser in the lid using a hot wire made of metal capable of induction heating. The zinc-containing steel dust is characterized in that metals that are reduced and volatilized from the zinc-containing steel dust are collected in the condenser, and other metals that do not volatilize are collected in the furnace. Recycling processing method. (2) The zinc-containing steel dust according to claim 1, which is heated by increasing the total amount of heat rays generated from recovered metals in the furnace and accelerating the rate of heat supply to the object to be treated. recycling method. (3) The increased amount of hot wire generated by the heat generation strategy is used as recovered metal, a part of which is left as a residual metal when tapping the hot water, and is processed semi-continuously while tapping the remaining hot water as the hot wire for starting the next operation. The method for recycling blood-containing lead steelmaking dust according to item 1 or 2. (4) A hot wire for starting operation consisting of iron scrap charged simultaneously with the material to be treated, and the generation consisting of recovered metal. Claim 1 or 2, in which patch treatment is performed by discharging the entire amount of hot water together with the hot wire.
1. A method for internal treatment of zinc-containing steel dust as described in Section 1.