JPS582264A - Treatment of steel dust - 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 an electric furnace for steelmaking and a method for treating slag dust generated in a converter.

Dust generated from steelmaking furnaces and collected by dust collectors is
Since it contains water-soluble heavy metals and is eluted, it cannot be used in landfills, so heavy metals such as lead and zinc are recovered. Shimikameko dust accounts for 0.7 to 1.6% of steel ingot production.
(Weight - the same applies hereafter) The amount of dust is so large that it reaches K, and the reality is that the cost of dust treatment is increasing.

The present invention was made based on the above circumstances, and its object is to manufacture bricks by blending steelmaking dust with refractory raw materials, and to remove heavy metal fumes contained in the steelmaking dust during the firing process of the bricks. It is an object of the present invention to provide a method for disposing of steelmaking dust that can reduce the processing cost of steelmaking dust by collecting and recovering it with a dust collector, and can reliably prevent heavy metal pollution.

An embodiment of the present invention will be described with reference to a flow sheet shown in FIG.

First, steelmaking dust is blended with a refractory material, such as a silica brick material. Shamotsu as raw material for this silica brick)
(5K26) *Use fireclay and Maguro brick scraps. Here, magkuro brick refers to a brick containing magnesia and chromium.

An example of the main composition of the raw materials to be blended is shown in Table 1 below.

Further, the ratio of the raw materials to be blended is preferably within the following range.

Steel dust...30-50 chishyamotsuto (8 to 26) -30-5 (1) Fireproof clay...10-20% makkurorenka dust...5
~10% Specific formulation examples and raw material sizes are shown in Table 2 below.

Table 2 The nine raw materials blended as described above were crushed using a crusher, crushed using a two-player machine and a friend mill, and then sieved using a vibrating sieve.

Next, add an appropriate amount of water from 7 to 19% to the sieved raw materials,
Knead by wet pan and bag mill. The amount of water added varies depending on the molding machine used in the next molding process, and if it is an auger machine or a hydraulic press, it will be 16 to 1.
For an 8s1 tile press machine, it is 17-191b%.For a friction press machine, it is 7-10%.

The raw materials kneaded and kneaded as described above are passed through an auger machine,
Hydraulic press machine or tile press machine ti is formed into the shape of a normal brick by a friction press machine.

Next, the molded body is fired in a tunnel kiln to obtain a brick product, and heavy metal fumes such as carp and zinc generated during the firing are collected by a dust collector to recover crude lead, crude zinc, and the like.

The recovery of the fired heavy metal fume will be described in detail. These steps are performed by the apparatus shown in FIG. This equipment combines a tunnel kiln for calcination and a dust collector for recovering heavy metal fumes. To be more specific, 10 in Fig. 2 is a tunnel kiln, and within this tunnel kiln 10, brick moldings 20 are loaded and nine carts 21 are gradually moved in a line. ing. This trolley 21 is loaded with an unfired brick molded body 20 and carried into the tunnel kiln 10 through an entrance located near one end of the tunnel kiln 10 by an entrance traverser (not shown). The brick product, that is, the brick molded body after firing, is moved sequentially through the tunnel kiln 10 by being pushed by the pressure 11, and finally, at a position near the other end of the tunnel kiln 10, an exit traverser (not shown) is passed through the outlet 12 and the brick product, that is, the brick molded body after firing. A burner 13 for burning heavy oil, propane, etc. is arranged in the intermediate part of the tunnel kiln 10, which is carried out with the kiln 20 loaded. A dust collection duct 30 is connected to the end of the tunnel kiln 10 on the entrance side. A part of the hot air in the heating zone A is sucked together with the heavy metal fume through the dust collecting duct 30 as described in e, and the brick molded body 20 is preheated by this hot air before entering the heating zone AK. Therefore, the area from the import entrance to the starting end of the heating zone A becomes the preheating zone B. In addition, one end of an exhaust balance duct 14 is connected to a portion near the outlet 12, and a part of the hot air in the heating zone A is sucked into the exhaust balance fan 15 provided in the exhaust balance duct 14. The brick molded body 20 coming out of the heating zone A is gradually cooled by this hot air without being rapidly cooled. Therefore, the area from the end of the heating zone A to the vicinity of the outlet 12 is the slow cooling zone C. becomes. The other end of the exhaust balance duct 14 is connected to the heating zone A and the preheating zone B through the branch 1, thereby allowing hot air to circulate. In addition,
A valve 16 is provided at each branch portion of the duct 13 to control the amount of recirculated hot air.

A dust collector 31 consisting of, for example, a back filter is connected to the other end of the gourd collection duct 30 described above. At the upper end of this dust collector 31 is an exhaust duct 3 having an exhaust fan 32.
3 is connected. Further, a pelletizer 35 having a rotating disk is arranged below the dust collector 31 via a hopper 34. These effects will be described later.

Next, using the apparatus shown in FIG. 2 described above, the brick molded body 2 is
The process of forming 0 and collecting the heavy metal fume generated from this will be explained in detail with reference to FIG. FIG. 3 shows the firing temperature of the brick molded body 20 in the tunnel kiln 10 and the time cost conversion of the degree of weight loss of the brick molded body 200. The degree of weight loss is expressed by the ratio (%) of the weight during the firing process to the weight after air drying. First, the brick molded body 20 is heated to a temperature of 630°C to 830°C while moving through the preheating zone B and heating zone A of the tunnel kiln 10.
Lead contained in steelmaking furnace dust in this temperature range,
Heavy metals such as zinc become fume and volatilize. What evaporates in the form of fumes is mostly water-soluble lead and zinc chloride, but lead.

It also includes zinc oxides that are partially reduced by carbonaceous materials and volatilized as fume. These lead and zinc chlorides and reduced lead and zinc fumes are oxidized by the air inside the tunnel kiln 10, and
The dust collector 31 is passed through the dust collection duct 30 by the suction of the 7-ton 32.
and was captured here. The collected crude lead and crude zinc dust is sent from the lower end of the dust collector 31 through a hopper 34 to a pelletizer 35, where it is pelletized.

Due to the generation of fumes, 200 brick molded bodies are collected and collected by one collection machine, and the heavy metals that remain inside the bricks without becoming fumes are also fixed in the bricks as insoluble minerals such as oxides during firing. Therefore, heavy metals can be reliably treated and pollution can be prevented. Further, the dust collected and collected by the dust collector contains a large amount of lead, zinc, etc., and is of high quality.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet diagram showing one embodiment of the method for treating steelmaking dust according to the present invention, and FIG. 2 is a diagram showing the equipment used to perform brick firing and heavy metal fume collection in the process of the present invention. The schematic diagram and FIG. 3 are diagrams showing changes over time in the firing temperature of a brick molded body and the degree of weight loss of this molded body. 10...Tunnel kill/20...Brick molded body 31...Dust collector Applicant Tokyo Steel Co., Ltd. Agent Patent attorney Noboru Watanabe

Claims (3)

[Claims] (1) The dust collected by the dust collector of the steelmaking furnace is mixed with the refractory material raw material, an appropriate amount of water is added to this, kneaded and formed, and this is then fired to obtain a brick product. A method for processing steelmaking dust, which comprises collecting heavy metal fumes generated in a dust collector using a dust collector. (2) The firing is performed in a tunnel kiln, and heavy metal fumes generated during the firing are collected by being sent to a dust collector communicating with the tunnel kiln. Disposal method for steelmaking dust described. (3) Steelmaking dust 30 to 50 weight - 9 chamotte as a refractory material raw material 30 to 50 weight - 2 fireclay 10
2. The method for treating steelmaking dust according to claim 1, wherein 5 to 10% by weight of maguro brick waste is blended.