CN111394675B

CN111394675B - Method for reducing hot galvanizing zinc vapor

Info

Publication number: CN111394675B
Application number: CN202010296299.5A
Authority: CN
Inventors: 裴英豪; 王茹玉; 沈新玉; 朱涛; 刘茂林; 夏雪兰; 张四方
Original assignee: Maanshan Iron and Steel Co Ltd
Current assignee: Maanshan Iron and Steel Co Ltd
Priority date: 2020-04-15
Filing date: 2020-04-15
Publication date: 2021-10-29
Anticipated expiration: 2040-04-15
Also published as: CN111394675A

Abstract

The invention discloses a method for reducing hot galvanizing zinc vapor, which is characterized in that metal particles are added into zinc liquid in a zinc liquid closed cavity, and a metal compound isolation layer floating on the surface of the zinc liquid is formed through the reaction of the metal particles and iron in the zinc liquid so as to reduce zinc evaporation. According to the invention, particles are added on the surface of the molten zinc in a closed cavity of the molten zinc in a steel strip of a continuous hot galvanizing production line, the particles react to form a compound, and the compound floats on the surface of the molten zinc, so that the surface of the molten zinc is isolated, and the zinc is difficult to evaporate.

Description

Method for reducing hot galvanizing zinc vapor

Technical Field

The invention belongs to the technical field of surface treatment of cold-rolled steel plates, and particularly relates to a method for reducing hot-dip galvanizing zinc vapor.

Background

The cold rolled steel sheet is sometimes used after surface treatment. Surface galvanization is a common method, and is divided into electrogalvanizing and hot galvanizing. Especially, the continuous hot dip galvanizing is increasingly performed in a large amount, and mainly annealing and surface treatment after cold rolling of a steel sheet to a desired thickness are performed in one line.

The continuous hot galvanizing production line of the cold-rolled sheet mainly produces carbon non-alloy low-strength cold-rolled steel coils in the past. After the cold-rolled steel coil is annealed, the surface oxidation is slight, the oxide is easy to reduce, and the direct hot galvanizing can be finished. Under the condition, the hydrogen content in the protective gas used by the production line is low, and when the steel coil enters a zinc pot after annealing, reducing and cooling, zinc is oxidized and covers the surface of the zinc liquid, and the zinc is not evaporated.

With the change of market demands, the continuous hot galvanizing production line of the cold-rolled sheet requires the production of high-strength steel coils. The steel coil is inevitably alloyed, and because of the increase of the alloy content, the oxide covered on the surface of the steel after annealing is increased. As a result, the incubation period of hot galvanizing is increased, the hot galvanizing is difficult, and the problems of plating leakage and the like seriously affect the production of the high-strength steel thin steel coil. In order to solve the above problems, the content of hydrogen in the protective gas in the closed passage into which the steel strip enters is greatly increased. As a result, when the steel strip is galvanized, the oxide on the surface of the molten zinc is reduced, the zinc is evaporated in a large amount and moves along the channel of the steel strip in a reverse direction, and the zinc vapor contacts iron-containing products (including the steel strip itself) to form zinc-iron compound solid or powder, so that the quality of the surface of the galvanized steel strip is seriously reduced.

Aiming at the problem that the surface quality is reduced after galvanizing caused by the fact that a steel strip enters a closed cavity of molten zinc in a continuous hot galvanizing production line, the following solving technologies exist:

the han steel company filed patent application No. 201320336150.0, zinc vapour absorption device for hot galvanizing furnace noses, is a continuation of passive removal of evaporated zinc vapour to avoid problems.

The patent of Shanghai Meishan Steel works Ltd is a zinc ash removing device with application number of 201220713338.8, and the scheme is that the device cleans the formed zinc ash.

The prior art is to deal with the problems existing after zinc evaporation, and how to reduce the adverse effects generated by zinc and products thereof, and the prevention effect is limited.

Disclosure of Invention

The invention aims to solve the technical problems in the prior art. Therefore, the invention provides a method for reducing hot galvanizing zinc vapor, which aims to isolate the surface of a zinc liquid and reduce the galvanizing quality problem caused by zinc evaporation.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for reducing hot galvanizing zinc vapor is characterized in that metal particles are added into zinc liquid in a closed cavity of the zinc liquid, and a metal compound isolation layer floating on the surface of the zinc liquid is formed through the reaction of the metal particles and iron in the zinc liquid so as to reduce zinc evaporation.

Preferably, the method comprises the steps of:

opening a discharge valve of a particulate matter storage tank, and conveying metal particles to a closed cavity through a particle conveying pipeline;

and secondly, adding the metal particles led out by the particle conveying pipeline into the zinc liquid along the width direction of the zinc liquid to form the metal compound isolation layer floating on the surface of the zinc liquid.

The metal particles are guided to the zinc liquid along the width direction of the zinc liquid surface by the swinging pipe and the swinging executing mechanism which pulls the swinging pipe to swing back and forth.

The swing executing mechanism comprises a first steel wire rope pulling and swinging mechanism and a second steel wire rope pulling and swinging mechanism which are arranged on two sides of the swing pipe and used for pulling the swing pipe to swing back and forth through the winding and unwinding of the steel wire ropes.

The first steel wire rope pulling and swinging mechanism and the second steel wire rope pulling and swinging mechanism are symmetrically distributed on two sides of the swinging pipe.

The first steel wire rope pulling and swinging mechanism comprises a first steel wire rope, a first guide wheel and a first motor, the first guide wheel is arranged on the side wall of the liquid zinc closed cavity, the second steel wire rope pulling and swinging mechanism comprises a second steel wire rope, a second guide wheel is arranged on the other side wall of the liquid zinc closed cavity, the second guide wheel and the second motor are arranged on the other side wall of the liquid zinc closed cavity, the first motor drives the swinging pipe to swing through the first steel wire rope which externally winds the first guide wheel, and the second motor drives the swinging pipe to swing through the second steel wire rope which externally winds the second guide wheel.

The metal particles led out from the particle conveying pipeline are guided to each discharge port of the distribution beam in a shunting way through the shunting guide mechanism, so that the metal particles are led into the zinc liquid along the width direction of the zinc liquid level.

The flow dividing guide mechanism comprises a particle distributor and a plurality of directional groove plates, an inlet of the particle distributor is connected with a discharge port of the particle storage tank through a particle conveying pipeline, and an outlet of the particle distributor is respectively connected with discharge ports of the distribution beam through the directional groove plates.

The particle distributor comprises a distributor body and a plurality of guide plates arranged in the distributor body and used for guiding the particles to outlets of the distributor body respectively.

The metal particles are aluminum particles or aluminum-foil-wrapped aluminum particles.

The invention has the beneficial effects that: according to the invention, particles are added on the surface of the molten zinc in a closed cavity of the molten zinc in a steel strip of a continuous hot galvanizing production line, the particles react to form a compound, and the compound floats on the surface of the molten zinc, so that the surface of the molten zinc is isolated, and the zinc is difficult to evaporate. Because the evaporation capacity of zinc is greatly reduced, the pollution degree of the cold-rolled steel plate is reduced, and the surface quality of the galvanized product is obviously improved.

Drawings

The description includes the following figures, the contents shown are respectively:

FIG. 1 is a schematic structural view of a first adding device of the present invention;

FIG. 2 is a schematic structural view of a second adding device of the present invention;

FIG. 3 is a schematic diagram of the configuration of the particle dispenser of FIG. 2;

FIG. 4 is a scanning electron micrograph of a hot dip galvanized product produced by the method of example 1;

FIG. 5 is a scanning electron microscope image of a hot dip galvanized product in a conventional production flow.

Labeled as:

1. particle storage tank, 2, swing pipe, 3, particle conveying pipeline, 4, first wire rope, 5, first leading wheel, 6, first motor, 7, second wire rope, 8, second leading wheel, 9, second motor, 10, metal flexible connecting pipe, 11, distribution beam, 12, particle distributor, 13, directional fluted plate, 14, distributor main part, 15, deflector.

Detailed Description

The following detailed description of the embodiments of the present invention will be given with reference to the accompanying drawings for a purpose of helping those skilled in the art to more fully, accurately and deeply understand the concept and technical solution of the present invention and to facilitate its implementation. It should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. In the following embodiments, the terms "first" and "second" do not denote an absolute structural and/or functional distinction or a sequential order of execution, but are merely used for convenience of description.

The invention relates to a method for reducing hot galvanizing zinc vapor, which is characterized in that metal particles are added into zinc liquid in a closed cavity of the zinc liquid, and a metal compound isolation layer floating on the surface of the zinc liquid is formed through the reaction of the metal particles and iron in the zinc liquid so as to reduce zinc evaporation. The method changes the surface components of the zinc liquid in a closed cavity (a zinc nose, a elephant nose, a furnace nose and the like) of the zinc liquid entering a steel belt of the continuous hot galvanizing production line, and the melting point of the surface components is higher than that of the zinc liquid of the current hot galvanizing, so that a certain isolation effect is formed on the zinc liquid. The evaporation of the zinc liquid under the isolating layer is difficult, thereby reducing the evaporation of the zinc liquid. Wherein, the metal particles can be aluminum particles or aluminum-foil-wrapped aluminum particles, and aluminum is added into the zinc liquid to enable iron and aluminum in the zinc liquid to form a compound floating on the surface of the zinc liquid. The addition of the metal particles to the zinc liquid in the closed cavity can be realized by two structural forms of devices. The method comprises the following specific steps:

as shown in FIG. 1, the device for adding particulate matters comprises a particulate matter storage tank 1, an oscillating pipe 2, a particle conveying pipeline 3 for conveying particles in the particulate matter storage tank 1 into the oscillating pipe 2, and an oscillating actuator for pulling the oscillating pipe 2 to oscillate back and forth so as to guide the particles to the zinc liquid along the width direction of the zinc liquid surface in a zinc liquid closed cavity. The zinc liquid closed cavity can be a zinc nose, a trunk or a furnace nose, and the long edge of the surface of the zinc liquid in the closed cavity is far larger than the narrow edge. The swing pipe is a tubular object which can swing along the width direction of the zinc liquid level (the width direction of the steel plate), one end of the tubular object is fixed and can rotate at the same time, the swing pipe is pulled by the swing executing mechanism to reciprocate by taking a rotating connection point as a fixed shaft, the particulate matters in the particulate matter storage tank are conveyed into the swing pipe through the particle conveying pipeline, and the particulate matters are spread to the whole width of the zinc liquid through the swinging tubular object. The particle conveying pipeline can be provided with a valve so as to control whether to feed or not.

To facilitate the swinging, the outlet of the particle transport pipe 3 is connected to the swinging pipe 2 through a metal hose connection pipe 10. During the concrete connection, the entrance point of metal flexible coupling pipe passes through flange and particle conveying line's exit linkage, and the exit end of metal flexible coupling pipe passes through the flange and is connected with the material mouth that connects of swing pipe, because particle conveying line is fixed, when needs swing, the swing pipe uses the junction of particle conveying line and metal flexible coupling pipe as the fixed point, does the circular motion. In order to facilitate the introduction of the material into the swing pipe, the receiving opening of the swing pipe is preferably in a horn shape.

The swing executing mechanism comprises a first steel wire rope pulling and swinging mechanism and a second steel wire rope pulling and swinging mechanism which are arranged on two sides of the swing pipe 2 and pull the swing pipe to swing back and forth through the winding and unwinding of the steel wire ropes. In order to facilitate the control and arrangement of the steel wire rope pulling and swinging mechanism, the first steel wire rope pulling and swinging mechanism and the second steel wire rope pulling and swinging mechanism are symmetrically distributed on two sides of the swinging pipe. Each part structure of two wire rope pull pendulum mechanisms is the same, conveniently controls the swing pipe and is in the same range along circumferencial direction reciprocating motion. The steel wire rope pulling and swinging mechanism can be realized by adopting the existing pulling machine. Preferably, as shown in fig. 1, the first wire rope pulling and swinging mechanism includes a first wire rope 4, a first guide wheel 5 and a first motor 6 which are arranged on a side wall of the molten zinc closed cavity, the second wire rope pulling and swinging mechanism includes a second wire rope 7, a second guide wheel 8 and a second motor 9 which are arranged on the other side wall of the molten zinc closed cavity, the first motor 6 drives the swinging pipe to swing through the first wire rope 4 which externally winds the first guide wheel 5, and the second motor 9 drives the swinging pipe 2 to swing through the second wire rope 7 which externally winds the second guide wheel 8. When the device is specifically arranged, as shown in fig. 1, the first guide wheel and the first motor can be fixed on the outer wall of the left side of the closed cavity, the second guide wheel and the second motor can be fixed on the outer wall of the right side of the closed cavity, the first steel wire rope penetrates through the outer wall of the left side of the closed cavity and is connected with an output shaft of the first motor in a winding mode around the first guide wheel, and the second steel wire rope penetrates through the outer wall of the right side of the closed cavity and is connected with an output shaft of the second motor in a winding mode around the second guide wheel. The closed cavity is closed by micro-positive pressure, so that air is prevented from entering. Of course, the first guide wheel and the second guide wheel can also be arranged on the inner walls of the two sides of the closed cavity, the corresponding motors penetrate through the corresponding outer walls and extend into the closed cavity, and at the moment, the output shafts of the motors are sealed by shaft sleeves at the penetrating positions of the closed cavity. The first steel wire rope and the second steel wire rope are the same in specification, and the two steel wire ropes are fixedly connected to two sides of the outlet of the swing pipe respectively. The fixed connection is preferably a detachable fixed connection. The first guide wheel and the second guide wheel are the same guide wheel, the structure and the size are the same, and the first motor and the second motor are the same motor. When the automatic rope releasing device works, the first motor and the second motor are synchronously started, so that when the first motor pulls the first steel wire rope to contract, the second steel wire rope is in a rope releasing state; when the second motor pulls the second steel wire rope to contract, the first steel wire rope is in a rope releasing state, so that the two steel wire ropes pull the swing pipe to do circular reciprocating motion by taking the outlet of the particle conveying pipeline as a fixed point, and the motion track of the outlet of the swing pipe is a section of circular arc.

In order to facilitate blanking, the lower part of the particulate matter storage tank is of a conical structure, and a discharge hole is formed in the tip of the bottom of the conical structure. And opening a discharge valve at the bottom end of the particulate matter storage tank, and conveying the particulate matters to a swing pipe in the closed cavity through a particulate matter conveying pipeline under the action of gravity.

As shown in fig. 2 and fig. 3, another possible particulate matter adding device includes a particulate matter storage tank 1, a distribution beam 11, and a diversion guide mechanism for diverting particulate matters conveyed from the particulate matter storage tank 1 to respective discharge ports of the distribution beam 11, wherein the distribution beam 11 is disposed in a closed chamber, and the respective discharge ports of the distribution beam 11 are arranged along a width direction of a zinc liquid in the closed chamber. The zinc liquid closed cavity can be a zinc nose, a trunk or a furnace nose, and the long edge of the surface of the zinc liquid in the closed cavity is far larger than the narrow edge. By adopting the device, the particles can be added along the longitudinal direction (the width direction) of the closed cavity of the zinc liquid, so that the reactants of the particles can be relatively uniformly distributed in the width direction of the zinc liquid surface.

As shown in FIG. 3, the diversion guide mechanism comprises a particle distributor 12 and a plurality of directional fluted plates 13, wherein the inlet of the particle distributor 12 is connected with the discharge port of the particle storage tank 1 through the particle conveying pipeline 3, and the outlet of the particle distributor 12 is respectively connected with the discharge ports of the distribution beam 11 through the plurality of directional fluted plates 13. The particle distributor has the function of guiding the particle shunt to the directional fluted plates in different directions, and the grooves enable the particles to reach a specified position along the fixed channel, namely the particles can be respectively guided to the corresponding discharge holes of the distribution beam through the grooves of the directional fluted plates.

The particle distributor may be implemented in a conventional structure, and as a preferred structure, the particle distributor includes a distributor body 14 and a plurality of guide plates 15 provided in the distributor body 14 for guiding the particles to outlets of the distributor body, respectively. In order to facilitate the particles to be better led out from the discharge holes at two sides of the distributor main body, a plurality of guide plates are obliquely downwards and staggered in the distributor main body. The number of the discharge ports arranged on the distributor main body is the same as that of the directional fluted plates, the tail ends of the guide plates are at a certain distance from the corresponding discharge ports, so that part of particles can be led out from the discharge ports, and part of particles continue downwards under the action of gravity and are led out through different discharge ports in sequence, so that the particles are respectively guided to the directional fluted plates and then are guided to the distribution beam through the directional fluted plates. The connecting lines between the discharge ports of the distribution beam are on the same straight line. The length direction equipartition of distribution beam sets up a plurality of above-mentioned discharge gates for the granule can be relatively more even direction molten zinc liquid level. When the distribution device is specifically arranged, five discharge ports are uniformly distributed in the length direction of the distribution beam, five corresponding directional groove plates are also arranged, the distributor body is provided with five discharge ports, and the guide plates are arranged at the corresponding positions of the discharge ports on the two side walls of the distributor body so that particles can be guided to the corresponding discharge ports through the guide plates. As shown in fig. 2, the falling particles, after being decelerated by the plurality of guide plates in the distributor body 14, partially flow out from the corresponding outlets and fall into the corresponding directional fluted plates, and the rest of the particles continue to fall and fall from the remaining outlets at the bottom to the corresponding directional fluted plates.

The method for reducing hot galvanizing zinc steam by adopting the two particle adding devices comprises the following steps:

and secondly, adding the metal particles led out by the particle conveying pipeline into the zinc liquid along the width direction of the zinc liquid to form the metal compound isolation layer floating on the surface of the zinc liquid. The following is exemplified by the addition of aluminum pellets and iron foil wrapped aluminum pellets:

example 1

In this embodiment, a first particle adding device is adopted, and the metal particles are aluminum particles. The particle adding device is used for scattering aluminum particles into the zinc liquid in the closed cavity of the zinc liquid, the aluminum content in the zinc pot is controlled to be not higher than 0.3%, and the aluminum content in the zinc liquid on the surface layer is not higher than 0.8% due to the formation of iron-aluminum compounds on the surface of the zinc nose. Specifically, the particles are stored in a particle storage tank 1, are conveyed into a metal flexible connecting pipe through a particle conveying pipeline, are conveyed into a swinging pipe 3 with a horn-shaped opening, and are guided to the liquid level of the zinc liquid through an outlet of the swinging pipe. The swinging pipe is driven by the motors at two sides to do reciprocating swinging motion by corresponding guide wheels and traction steel wire ropes. Due to the periodic oscillation of the oscillating pipe, the added particulate matters are relatively uniformly distributed on the longitudinal (width direction) surface of the zinc liquid. The aluminum reacts with iron in the zinc liquid (when the steel strip is galvanized, the liquid zinc is in contact with the surface of the steel strip, the iron is corroded into the zinc liquid, and the liquid zinc contains a certain amount of iron) to form a compound film layer formed by continuous iron and aluminum in thickness, and the compound floats on the surface of the zinc liquid to form a zinc liquid isolation layer to retard the evaporation of the zinc. Protecting and keeping the galvanized and the space clean. When the hot galvanizing is carried out on the product by adopting the method, as shown in figure 4, the product with good coating can be formed. FIG. 5 is a scanning electron microscope image of hot dip galvanizing in a normal production flow, and it can be seen from the image that a zinc layer is obviously peeled off.

Example 2

In this embodiment, a second particle adding device is adopted, and the metal particles are aluminum particles wrapped by iron foil. The aluminum particles wrapped by the iron foil are scattered into the zinc liquid in the closed cavity of the zinc liquid by the particle adding device, the aluminum content in the zinc pot is controlled to be not higher than 0.3 percent, and on the surface of the zinc nose, the aluminum content in the zinc liquid on the surface layer is not higher than 0.8 percent due to the formation of iron-aluminum compounds. The iron foil is a very thin wrapping layer, and iron in the iron foil is mainly used for rapidly forming iron-aluminum compounds on the surface of the zinc liquid together with aluminum and floating on the surface of the zinc liquid to isolate zinc vapor volatilization. Specifically, the particles are stored in a particle storage tank, are conveyed into a particle distributor through a particle conveying pipe, are dispersed into the grooves of the directional fluted plate 4 in different directions through the particle distributor 3, fall down after reaching the discharge ports of the distribution beams corresponding to different positions of the zinc liquid level along the grooves of the directional fluted plate, are dispersed and added, and the formed compound can float on the zinc liquid surface. The aluminum reacts with iron in the zinc liquid (when the steel strip is galvanized, the liquid zinc is in contact with the surface of the steel strip, the iron is corroded into the zinc liquid, and the liquid zinc contains a certain amount of iron) to form a compound film layer formed by continuous iron and aluminum in thickness, and the compound floats on the surface of the zinc liquid to form a zinc liquid isolation layer to retard the evaporation of the zinc. Protecting and keeping the galvanized and the space clean.

The invention is described above with reference to the accompanying drawings. It is to be understood that the specific implementations of the invention are not limited in this respect. Various insubstantial improvements are made by adopting the method conception and the technical scheme of the invention; the present invention is not limited to the above embodiments, and can be modified in various ways.

Claims

1. A method for reducing hot galvanizing zinc vapor is characterized in that metal particles are added into zinc liquid in a closed cavity of the zinc liquid, and a metal compound isolation layer floating on the surface of the zinc liquid is formed through the reaction of the metal particles and iron in the zinc liquid so as to reduce zinc evaporation;

the method specifically comprises the following steps:

secondly, adding the metal particles led out by the particle conveying pipeline into the zinc liquid along the width direction of the zinc liquid to form the metal compound isolation layer floating on the surface of the zinc liquid;

the metal particles are aluminum particles or aluminum-foil-wrapped granular matters;

controlling the aluminum content in the zinc pot to be not higher than 0.3 percent;

and controlling the aluminum content in the surface layer zinc liquid in the closed cavity to be not higher than 0.8%.

2. The method for reducing hot galvanizing zinc vapor according to claim 1, wherein the metal particles are guided to the zinc liquid along the width direction of the zinc liquid surface by the oscillating pipe and an oscillating actuator which pulls the oscillating pipe to oscillate back and forth.

3. The method for reducing hot galvanizing zinc vapor as claimed in claim 2, wherein the swing actuator comprises a first wire rope pulling and swinging mechanism and a second wire rope pulling and swinging mechanism which are arranged on two sides of the swing pipe and pull the swing pipe to swing back and forth through winding and unwinding of a wire rope.

4. The method for reducing hot galvanizing zinc vapor according to claim 3, wherein the first wire rope pulling and swinging mechanism and the second wire rope pulling and swinging mechanism are symmetrically distributed on two sides of the swinging pipe.

5. The method for reducing hot galvanizing zinc vapor as claimed in claim 3, wherein the first wire rope pulling and swinging mechanism comprises a first wire rope, a first guide wheel and a first motor, the first guide wheel is arranged on one side wall of the zinc liquid closed cavity, the second wire rope pulling and swinging mechanism comprises a second wire rope, a second guide wheel is arranged on the other side wall of the zinc liquid closed cavity, and a second motor, the first motor drives the swinging pipe to swing through the first wire rope externally wound around the first guide wheel, and the second motor drives the swinging pipe to swing through the second wire rope externally wound around the second guide wheel.

6. The method for reducing hot galvanizing zinc vapor according to claim 1, wherein the metal particles led out from the particle conveying pipeline are shunted and guided to the discharge ports of the distribution beam through a shunting guide mechanism, so that the metal particles are led into the zinc liquid along the width direction of the zinc liquid level.

7. The method for reducing hot galvanizing zinc vapor of claim 6, wherein the diversion guide mechanism comprises a particle distributor and a plurality of directional fluted plates, an inlet of the particle distributor is connected with a discharge port of the particle storage tank through a particle conveying pipeline, and an outlet of the particle distributor is respectively connected with discharge ports of the distribution beams through the plurality of directional fluted plates.

8. The method of reducing hot dip zinc vapor as set forth in claim 7 wherein said pellet distributor comprises a distributor body and a plurality of guide plates disposed within said distributor body for directing the pellets toward respective outlets of said distributor body.