JPS6227581A - Equipment for discharging sludge from continuous pickling tank - Google Patents

Abstract

PURPOSE:To discharge sludge from a continuous pickling tank without suspending pickling by placing means to stir sludge accumulated in a sludge chamber connected directly to the pickling tank and to send the sludge to a sludge separator together with part of a pickling soln. CONSTITUTION:A scraper 3 is moved in a continuous pickling tank 2 to scrape up sludge settled in the tank 2 and to drop the sludge into a sludge chamber 4. The sludge in the chamber 4 is whirled up by a flow of a pickling soln. stirred with a stirrer 5, and it is led out of the chamber 4 together with part of the pickling soln. through a leading path 6 in the form of a slurry. This slurry is sent to a sludge separator 7 connected directly to the path 4 to separate the sludge by gravity sedimentation or other method. The separated sludge is discharged through a valve opening or shutting device 9.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a continuous pickling tank for metal materials, in which slurry deposited on the inner surface of the pickling tank is successively mixed with a part of an acid solution to form an acid slurry. This relates to equipment that discharges water outside the washing tank.

(Prior Art) When removing surface oxide scale generated when hot working or heat treating a metal material by pickling, slurry may be generated and deposited in a pickling tank. In particular, when a steel material such as stainless steel is pickled with a pickling solution containing butic acid (HF), as is known from Japanese Patent Publication No. 55-2476, fluorine is mainly found at the bottom of the pickling tank. The slurry consisting of iron oxides tends to accumulate as a hard precipitate, and its removal requires a great deal of time and effort.

Conventionally, the slurry generated in a continuous pickling tank for metal materials is left to accumulate while the continuous pickling tank is in operation, and when draining, the pickling operation is periodically stopped and the acid in the tank is drained. After discharge, the waste was mainly removed and discharged out of the tank using mechanical methods.

In this method, the pickling operation is forced to be interrupted periodically to remove the slurry gold, and the operating efficiency of the continuous pickling tank cannot be improved. Even when solidified into rock formation, it took a lot of time and effort to remove the reeds and discharge them outside the tank.

In addition to this, conventional equipment also includes a total of 1 ton of acid solution in the pickling tank.
Some systems stir the acid solution and circulate it between slurry separation equipment installed on the successive side, but large-scale equipment is required to circulate the entire amount of acid solution.

It is known from Japanese Patent Application Laid-Open No. 5858-55 that a screw conveyor is used as a means for transporting the solids that have settled at the bottom of the tank out of the tank. It was first developed in 1972 that the attached feeding member (flight) was used to pull the material into the pit groove provided at one end of the tank.
555 (known from Publication No. 1B).

However, the former is not suitable for carrying out slurry that has accumulated over a wide area in the tank, and the latter is not suitable for carrying out continuous pickling treatment. When the pickling solution used contains butic acid, it is difficult to use a screw conveyor, a t-ane, etc. due to acid resistance problems.

(Problems to be Solved by the Invention) The present invention aims to reduce slurry that accumulates inside a continuous pickling tank that continuously pickles metal materials, especially strips, without interrupting the pickling process. The purpose is to discharge it outside the tank using large-scale equipment.

(Means for Solving the Problems) The slurry discharge equipment of the present invention includes a scraper 3 that moves in a continuous pickling tank 2 in which metal materials are continuously pickled, and a sludge discharger installed in the continuous pickling tank 2. It is characterized by a chamber 4, a liquid stirring device 5 provided in the slurry chamberer 4, a liquid outlet path 3 provided in the slurry chamberer 4, and a slurry separation device 7 connected to the liquid outlet path 6.

The configuration of the present invention will be explained in detail below based on the drawings.

FIG. 1 is a sectional view showing an example of the equipment of the present invention. A pickling liquid is stored in the continuous pickling tank 2, and the metal material 1 is sent in the direction of the arrow to pass through the pickling liquid and to be continuously pickled.

A scraper 5 for scraping up slurry is provided in the continuous pickling tank 2 so as to be movable throughout the tank, and in the example shown in FIG. It is being For example, as shown in FIG. 2, the scraper 3 is supported by a concave scraper traveling device 10 and moves back and forth between the strip-shaped metal material 1 and the continuous pickling tank 2.

In FIG. 2, 11 is a lift cylinder for adjusting the vertical position of the scraper 3, 12 is a cover of the continuous pickling tank 2, and 15 is the slurry being scraped up by the scraper 3. Note that the scraper 5 is preferably provided so as to be movable along both the bottom and side surfaces of the continuous pickling tank 2.

The continuous pickling tank 2 is provided with a slurry chamberer 4 having a lowered bottom surface into which the slurry scraped by the scraper 6 is dropped.

Although FIG. 1 shows an example in which the slurry chamberers 4 are provided at both ends of the continuous pickling tank 2, they may be provided at one end or any arbitrary position instead of both ends.

The slurry chamberer 4 is provided with a liquid stirring device 5 that causes the slurry dropped into the chamber to rise into the pickling liquid. As shown in FIG. 1, the liquid stirring device 5 is preferably of an air bubbling type with piping provided at the bottom of the slurry chamber, but it is also possible to use an impeller or magnetic stirring type.

The slurry chamberer 4 preferably includes a baffle plate 8 that serves as a barrier to prevent the slurry that has risen into the pickling liquid from flowing into the continuous pickling tank 2 . The slurry chamberer 4 is provided with a liquid outlet path 6 for discharging the slurry that has flowed up further together with the pickling liquid.

The liquid outlet path 6 is preferably an overflow groove provided at the top of the slurry chamberer 4 as shown in FIG. . A slurry separator 7 is connected to the liquid outlet path 6 .

As shown in FIG. 1, the slurry separator 7 is of a gravity sedimentation separation type, and is preferably provided with a valve opening/closing device 9t at the bottom for cutting out the sedimented slurry. , filtration method, etc. can also be used. The slurry separation device 7 is preferably provided with a rotary scraper 14 that rotates along the inner surface of the separation tank as shown in FIG.

The slurry discharge equipment of the present invention is particularly effective in cases where the slurry accumulates hard, such as when treating steel materials such as stainless steel using a pickling solution containing butylic acid (HF). The pickling solution is 40-400 y/L HF'
and a highly concentrated nitrate solution containing 100 to 400 y/L of HNO3.

(Function) In Fig. 1, the metal material 1 is immersed in the pickling solution stored in the continuous pickling tank 2, a part of the surface layer is dissolved, and the surface oxidation scale is removed in the pickling solution. It is peeled and pickled.

As the pickling process progresses, some of the peeled and dissolved material will be removed.
In the form of a slurry, some of it becomes a precipitate due to reaction with the acid and is deposited as a slurry on the bottom and side walls of the pickling tank.

The deposited slurry is generally a soft deposit immediately after it is deposited, but if left untreated, it will gradually solidify and become a hard lump. When pickling, iron fluoride is produced and becomes rock-like.

In the equipment of the present invention, the scraper 3 moves periodically or continuously in the pickling tank 2 and scrapes the deposited slurry into the slurry chamber 4, so that no slurry accumulates in the pickling tank. The slurry dropped into the slurry chamberer 4 is blown up by the flow of the pickling liquid stirred by the liquid stirring device 5, passes through the liquid outlet passage 6, and exits the slurry chamberer 4 together with the pickling liquid. derived.

In the slurry chamberer 4, the slurry and acid solution are held in a slurry form by stirring, and the slurry is transferred to the slurry chamberer 4.
Prevents deposits and solidification on the bottom and inner walls of the

When the slurry chamberer 4 includes a baffle plate 8 as shown in FIG. 1, the agitated slurry is prevented from adhering to the metal material 1.

When the liquid outlet path 6 is an overflow groove as shown in FIG. 1, slurry deposited in the groove can be easily removed.

The slurry-like slurry and pickling liquid led out of the sludge chamber 4 are separated into slurry and pickling liquid by a slurry separator 7 connected to the liquid outlet path 6, and in the example shown in FIG. After sedimentation, the separated slurry is cut out by the action of the pulp being opened and closed by the pulp opening/closing device 9.

The separated pickling liquid is returned to the continuous pickling tank 2 either directly or after being purified. If slurry adheres to the wall of the slurry separator 7, it is removed by a rotary scraper 14 as shown in FIG.

(Example) A continuous pickling tank with a length of 20 m, a width of 2.2 fn, and a depth of 1.4 m was equipped with HF 200 y/l and HNOs 150
y/L and a temperature of 70'C, to a depth of 1.1 m, and the scraper was automatically reciprocated over the entire length of the continuous pickling tank at a speed of 2 ml/min.

The slurry chamber has a length of 1. Om width 2-2m, depth 1
．． It is 7m long, and the air is always 720i from the bottom.
/ minutes, and bubbling was performed. The separation tank was equipped with a rotating scraper made of Teflon and rotated at a speed of 1 time/minute.

The pickling tank was operated continuously for 6 days under the above conditions, and a total of 150
A 0-ton stainless steel 304 hot coil and T1 high alloy steel were pickled, but no solidified slurry was observed in the pickling tank or on any of the equipment in this facility.

(Effects of the Invention) The present invention is a device for discharging slurry outside the tank in a continuous pickling tank for metal materials configured as described above. The slurry inside is
Since the slurry is automatically discharged outside the tank, there is no need to interrupt the continuous pickling work that was previously required for slurry discharge, and the operating rate of the continuous pickling tank is greatly improved. That will happen.

Furthermore, in the prior art, the work of discharging slurry from a continuous pickling tank was accompanied by many difficulties and dangers, especially when the slurry was deposited in the form of rock on the inner surface of the continuous pickling tank. This difficulty and danger is also eliminated.

In addition, the present invention collects sludge in a slurry chamber with a relatively small internal volume and processes the slurry in the sludge chamber, so the equipment is small-scale and can be installed in an existing continuous pickling tank.

[Brief explanation of drawings]

FIG. 1 is a detailed explanatory diagram of the present invention, FIG. 2 is a perspective view of the movement of the scraper in the present invention, and FIG. 3 is an explanatory diagram of the slurry separation apparatus in the present invention provided with a rotating scraper. 6 varnish scraper 4 = flage champer 5:
Liquid stirring device 6: Liquid outlet path 7: Sludge separation device

Claims (1)

[Scope of Claims] 1. A scraper 3 that moves in a continuous pickling tank 2 in which metal materials are continuously pickled, a sludge chamber 4 provided in the continuous pickling tank 2, and a liquid stirrer provided in the sludge chamber 4. A sludge discharge facility for a continuous pickling tank comprising a device 5, a liquid outlet path 6 provided in a sludge chamber 4, and a sludge separator 7 connected to the liquid outlet path 6. 2. The sludge discharge equipment for a continuous pickling tank according to claim 1, in which the scraper 3 can reciprocate along the bottom and side walls of the continuous pickling tank 2. 3. Claim 1, wherein the sludge chamber 4 is provided with a baffle plate 8 that forms a barrier with the continuous pickling tank 2.
Sludge discharge equipment for the continuous pickling tank described in item 1 or 2. 4. The sludge discharge equipment for a continuous pickling tank according to claim 1 or 3, wherein the liquid stirring device 5 is of an air bubbling type. 5. The continuous pickling tank discharge equipment according to claim 1 or 4, wherein the liquid outlet path 6 is an overflow groove installed in the sludge chamber 4. 6. The sludge discharge equipment for a continuous pickling tank according to claim 1 or 5, wherein the sludge separator 7 is of a gravity sedimentation separation type and has a valve opening/closing device 9 at the bottom for cutting out the settled sludge. 7. Claim 1, wherein the metal material is steel and the pickling liquid in the continuous pickling tank 2 is a pickling liquid containing HF.
Sludge discharge equipment for the continuous pickling tank described in paragraph 6 or paragraph 6. 8 The pickling liquid in the continuous pickling tank 2 contains 40 to 400 g of HF.
The sludge discharge equipment for a continuous pickling tank according to claim 1 or 7, wherein the pickling liquid is a pickling liquid containing 100 to 400 g/l of HNO_3 and 100 to 400 g/l of HNO_3.