A method for purifying hot-dip galvanizing zinc liquid

Abstract

The invention relates to the technical field of hot-dip galvanizing, and in particular to a method for purifying hot-dip galvanizing zinc liquid. First, the temperature of the zinc liquid is increased to a first set temperature to increase the solubility of zinc slag containing rare earth elements, and the zinc liquid is kept warm at the first set temperature for a first set time; then a slag receiving pan is placed in a zinc pot, and the slag receiving pan is arranged at the bottom of the zinc pot; then, the temperature of the zinc liquid is reduced to a second set temperature, and the zinc liquid is kept warm at the second set temperature for a second set time, so that the zinc slag is precipitated from the zinc liquid and deposited in a pan cavity of the slag receiving pan; then, the slag receiving pan containing the deposited zinc slag is taken out of the zinc pot, so as to remove the zinc slag in the zinc liquid; therefore, the method for purifying hot-dip galvanizing zinc liquid does not need to be configured with a special filtering device and an extraction device, so that a large amount of zinc liquid is wasted and the zinc slag is blocked in the filter mesh of the filter during extraction, and is particularly suitable for removing the zinc slag in the zinc liquid with a very small zinc slag size and a low content.

Description

Technical Field

[0001] The invention relates to the technical field of hot-dip galvanizing, in particular to a method for purifying hot-dip galvanizing zinc liquid. Background Art

[0002] Hot-dip galvanized strip steel is widely used in the fields of automobiles, home appliances, and construction. In recent years, hot-dip galvanizing technology has gradually transformed to coatings with high-aluminum, medium-aluminum, and low-aluminum alloy composition systems, including zinc-aluminum-silicon system, zinc-aluminum-magnesium system, etc. In order to improve the comprehensive performance of hot-dip galvanized products such as corrosion resistance, the method of adding strontium or rare earth elements is often used in the design of zinc liquid composition. However, the zinc slag in the zinc liquid with added strontium or rare earth elements has the characteristics of small particles and low content. The zinc slag deposited at the bottom of the zinc liquid is difficult to grab with traditional grab buckets. Therefore, a special filter is often configured to draw the zinc liquid to the filter for filtration. The method of filtering and removing zinc slag requires the configuration of a special filtering device. Extracting zinc liquid will cause a large amount of zinc liquid waste and increase costs, and the zinc slag is blocked in the filter mesh of the filter and is not easy to clean. Summary of the invention

[0003] The technical problem to be solved by the present invention is that, currently, the method of filtering and removing zinc slag requires the configuration of a special filtering device, which not only leads to a large amount of waste of zinc liquid and increases costs, but also the zinc slag is blocked in the filter mesh of the filter and is difficult to clean.

[0004] The hot-dip galvanizing zinc liquid purification method of the present invention comprises the following steps:

[0005] Step S1, raising the temperature of the zinc liquid to a first set temperature to increase the solubility of the zinc slag containing rare earth elements, and keeping the zinc liquid at the first set temperature for a first set time, so that the zinc slag dissolves into the zinc liquid;

[0006] Step S2, placing a slag receiving pan into the zinc pot, and arranging the slag receiving pan at the bottom of the zinc pot;

[0007] Step S3, lowering the temperature of the zinc liquid to a second set temperature to reduce the solubility of the zinc slag in the zinc liquid, and keeping the zinc liquid at the second set temperature for a second set time, so that the zinc slag precipitates from the zinc liquid and is deposited in the disc cavity of the slag receiving pan;

[0008] Step S4, taking the slag receiving pan out of the zinc pot.

[0009] As a preferred solution, the step S1 includes:

[0010] Step S01, measuring the deposition thickness of the zinc slag at the bottom of the zinc pot to determine the depth of the disc cavity, and making the depth of the disc cavity greater than the deposition thickness of the zinc slag.

[0011] As a preferred solution, the ratio of the depth of the disc cavity to the deposition thickness of the zinc slag is greater than or equal to 1.2 and less than or equal to 1.5.

[0012] As a preferred embodiment, an overflow hole is provided on the upper part of the side wall of the disc cavity, and the ratio of the distance from the overflow hole to the top of the disc cavity to the depth of the disc cavity is greater than or equal to 0.2 and less than or equal to 0.5.

[0013] As a preferred solution, the first set temperature is greater than or equal to 470° C. and less than or equal to 485° C.; and the first set time is greater than or equal to 10 hours.

[0014] As a preferred solution, the second set temperature is greater than or equal to 445° C. and less than or equal to 455° C.; and the second set time is greater than or equal to 36 hours.

[0015] As a preferred solution, in step S4, after the slag receiving pan is taken out, the slag receiving pan is cooled, and after the zinc slag in the slag receiving pan is cooled, the zinc slag is poured out from the slag receiving pan.

[0016] As a preferred embodiment, there are multiple slag receiving pans, each of which is horizontally spaced apart at the bottom of the zinc pot, and each of which is spaced apart around a slag receiving pan is connected with multiple slings at intervals, and one end of each sling away from the slag receiving pan extends upward to the outside of the zinc liquid and is connected to a lifting device.

[0017] As a preferred solution, the lifting device comprises a lifting beam, a lifting ring, a lifting rope and a hoist, each of the slag receiving plates is arranged at intervals along the axial direction of the lifting beam, and one end of each of the lifting ropes away from each of the slag receiving plates is connected to the lower end of the lifting beam;

[0018] A first lifting ear arranged near the first end of the lifting beam and a second lifting ear arranged near the second end of the lifting beam are fixed on the lifting beam, one end of the lifting rope is connected to the first lifting ear, the other end of the lifting rope is connected to the second lifting ear, the lifting ring is connected to the middle part of the lifting rope, and the winding rope of the winch is connected to the lifting ring.

[0019] As a preferred solution, the horizontal spacing distance between two adjacent slag receiving plates is greater than or equal to 100 mm and less than or equal to 150 mm.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The hot-dip galvanizing zinc liquid purification method of the present invention firstly increases the zinc liquid temperature to a first set temperature to increase the solubility of zinc slag containing rare earth elements, and keeps the zinc liquid at the first set temperature for a first set time, so that the zinc slag dissolves into the zinc liquid; then a slag receiving pan is placed in the zinc pot, and the slag receiving pan is arranged at the bottom of the zinc pot; then, the zinc liquid temperature is reduced to a second set temperature to reduce the solubility of the zinc slag in the zinc liquid, and the zinc liquid is kept at the second set temperature for a second set time, so that the zinc slag precipitates from the zinc liquid and deposits in the pan cavity of the slag receiving pan; then, the slag receiving pan containing the deposited zinc slag is taken out from the zinc pot, so as to remove the zinc slag from the zinc liquid; therefore, the hot-dip galvanizing zinc liquid purification method of the present invention does not need to be configured with a special filtering device and an extraction device, avoids the waste of zinc liquid during extraction and the clogging of the zinc slag in the filter mesh of the filter, and is particularly suitable for removing zinc slag with small size and low content. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the main view after the slag tray is placed into the zinc pot;

[0023] Figure 2 This is a top view of the slag tray after it is placed in the zinc pot;

[0024] Figure 3 This is a schematic diagram of hoisting the slag tray;

[0025] Figure 4 It is a cross-sectional view of the slag receiving pan;

[0026] Figure 5 It is a top view of the slag tray;

[0027] In the figure, 1. zinc pot; 2. slag tray; 3. lifting rope; 4. lifting device; 41. lifting beam; 411. first lifting eye; 412. second lifting eye; 42. lifting ring; 43. lifting rope; 5. probe rod; 6. zinc adding car; 61. zinc ingot; 7. grate; 71. furnace nose tip. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0029] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should be understood that the terms "first", "second", etc. are used in the present invention to describe various information, but such information should not be limited to these terms, which are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the "first" information may also be referred to as the "second" information, and similarly, the "second" information may also be referred to as the "first" information.

[0030] like Figures 1 to 5 As shown, a preferred embodiment of the hot-dip galvanizing zinc liquid purification method of the present invention comprises the following steps:

[0031] Step S1, raising the temperature of the zinc liquid to a first set temperature to increase the solubility of the zinc slag containing rare earth elements, and keeping the zinc liquid at the first set temperature for a first set time, so that the zinc slag dissolves into the zinc liquid;

[0032] Step S2, placing the slag receiving pan 2 into the zinc pot 1, and arranging the slag receiving pan 2 at the bottom of the zinc pot 1;

[0033] Step S3, lowering the temperature of the zinc liquid to a second set temperature to reduce the solubility of the zinc slag in the zinc liquid, and keeping the zinc liquid at the second set temperature for a second set time, so that the zinc slag precipitates from the zinc liquid and is deposited in the cavity of the slag receiving pan 2;

[0034] Step S4, taking the slag receiving pan 2 out of the zinc pot 1. Thus, the zinc slag in the zinc liquid is removed; therefore, the hot-dip galvanizing zinc slag removal method of the present invention does not need to be equipped with a special filtering device, which avoids the zinc slag being blocked in the filter mesh of the filter; and avoids a large amount of zinc liquid being wasted during extraction; the heating of the zinc liquid can be achieved by the heating device of the zinc pot itself, so that the hot-dip galvanizing zinc slag removal method of this embodiment is low in cost and easy to promote.

[0035] Wherein, before step S1, the following steps are included:

[0036] Step S01, measuring the deposition thickness of zinc slag at the bottom of the zinc pot 1 to determine the depth of the cavity, and making the depth of the cavity greater than the deposition thickness of the zinc slag, so that the depth of the cavity is sufficient to accommodate the deposited zinc slag.

[0037] Specifically, the ratio of the depth of the cavity to the deposition thickness of the zinc slag is greater than or equal to 1.2 and less than or equal to 1.5, so as to avoid the cavity being too deep, resulting in a large amount of zinc liquid being stored in the cavity and causing waste, and to avoid the cavity being too shallow, resulting in insufficient slag receiving pan capacity.

[0038] Furthermore, an overflow hole 21 is provided at the upper part of the side wall of the cavity, and the ratio of the distance from the overflow hole 21 to the top of the cavity to the cavity depth is greater than or equal to 0.2 and less than or equal to 0.5. When the zinc liquid in the cavity reaches the overflow hole, it flows out from the overflow hole to avoid splashing of the zinc liquid when the slag receiving pan 2 is hoisted out, reduce the waste of zinc liquid without slag, and avoid the safety hazard when the slag receiving pan is moved due to the zinc liquid in the slag receiving pan being too full. Specifically, the overflow holes 21 are evenly distributed around the top of the slag receiving pan 2.

[0039] In this embodiment, for the element contents in the zinc liquid of 1.5% Al, 1.3% Mg, 0.01% Sr and 0.02% rare earth, the first set temperature is set to be greater than or equal to 470°C and less than or equal to 485°C; the first set time is set to be greater than or equal to 10 hours, so that the zinc slag at the bottom of the zinc pot 1 can be fully contained in the zinc liquid.

[0040] After the zinc slag is fully dissolved, the second set temperature is greater than or equal to 445° C. and less than or equal to 455° C., and the second set time is greater than or equal to 36 hours, so that the zinc slag dissolved in the zinc liquid can be fully precipitated, and the precipitated zinc slag is in the disc cavity.

[0041] Specifically, 10 hours before the shutdown, the temperature of the zinc liquid in the zinc pot 1 is raised from 455 degrees to 480 degrees, and the high temperature of 480 degrees is maintained for 10-12 hours. After the shutdown, the slag pan 2 is immediately placed in the zinc pot 1 while maintaining the high temperature of the zinc liquid. Among them, there are multiple slag pans 2, each of which is horizontally arranged at the bottom of the zinc pot 1, and each slag pan 2 is connected to a plurality of slings 3 at intervals around the slag pan 2. The ends of each sling 3 away from each slag pan 2 extend upward to the outside of the zinc liquid and are connected to the lifting device 4. The placement of the slag pan 2 in the zinc pot 1 should be arranged in combination with the dimensions of the internal length A0 of the zinc pot 1, the internal width B0 of the zinc pot 1, and the upper open length A1 of the zinc pot 1. The horizontal interval between each slag pan 2 is 100 to 150 mm to avoid the adhesion of the slag pans 2. Figure 1 and attached Figure 2 It is a schematic diagram of placing two groups of slag receiving pans 2 in a zinc pot 1. The more slag receiving pans 2 are placed, the better, provided that they do not affect each other, but the arrangement is not limited to this.

[0042] When the slag pan 2 is placed in the zinc pot 1, when the slag pan 2 contacts the surface of the zinc liquid, a certain amount of zinc liquid is allowed to enter the slag pan 2 by manual assistance, so as to facilitate the slag pan 2 to sink to the bottom of the zinc pot 1. Specifically, a slag scoop welded with a hollow steel pipe of φ25mm×3500mm in length can be used to press the inner corner of the slag pan 2, and scoop part of the zinc liquid 11 into the slag pan 2.

[0043] Among them, the upper opening length A1 of the zinc pot 1 is mainly affected by the zinc adding car 6, the zinc ingot 61, the grate 7 and the furnace nose tip 71. By hoisting, the slag pan can be placed into the zinc pot 1 from the upper opening of the zinc pot 1, and then the slag pan 2 is moved to the left, so that the slag pan 2 is arranged to cover the bottom of the zinc pot 1. After the slag pan 2 is placed, the temperature of the zinc liquid is reduced to 450±5 degrees, and the temperature of the zinc liquid is maintained for at least 36 hours, so that the various components in the zinc liquid react fully and the suspended slag containing strontium or rare earth elements is fully precipitated into the pan cavity. In this embodiment, the slag pan 2 is hoisted out of the zinc pot after the zinc liquid is kept warm for 36 hours. In other embodiments of the present invention, the zinc pot 1 can be moved to a standby position and left for a period of time, such as about 20 days, and then the slag pan 2 is hoisted out of the zinc pot 1. After the slag pan 2 is taken out, the slag pan 2 is cooled, and after the zinc slag in the slag pan 2 is cooled, the zinc slag is poured out from the slag pan 2. The slag pan 2 can be reused after zinc removal. In this embodiment, a special crane configured with the zinc pot equipment is used to lift the slag pan 2 in and out.

[0044] like Figure 3As shown, the lifting device 4 includes a suspension beam 41, a suspension ring 42, a suspension rope 43 and a winch. Each slag receiving pan 2 is arranged at intervals along the axial direction of the suspension beam 41. One end of each suspension rope 3 away from each slag receiving pan 2 is connected to the lower end of the suspension beam 41. A first suspension ear 411 arranged near the first end of the suspension beam 41 and a second suspension ear 412 arranged near the second end of the suspension beam 41 are fixed on the suspension beam 41. One end of the suspension rope 43 is connected to the first suspension ear 411, and the other end of the suspension rope 43 is connected to the second suspension ear 412. The suspension ring 42 is connected to the middle of the suspension rope 43, and the winding rope of the winch is connected to the suspension ring 42. Specifically, in this embodiment, the suspension ring 42 is connected to the suspension beam 41 through the suspension rope, and multiple slag receiving pans 2 are connected to the lower part of the suspension beam 41 through the suspension rope. In this embodiment, the total height C1 of the slag pan 2 is matched with the internal height C0 of the zinc pot 1, and the suspension beam 41 is made of 15# I-beam, and the reinforcement ribs are welded at intervals of 250mm to meet the standards of the lifting equipment. The total height C1 of the slag pan 2 is C0-50mm; the material and size of the sling 3 should not only consider the time of high-temperature zinc liquid corrosion, but also consider the special situation of abnormal adhesion between the slag pan 2 and the bottom of the zinc pot 1. Usually, the bearing capacity of each sling 3 is selected to be equivalent to the sum of the dead weight of the slag pan 2 and the total weight of the zinc liquid in the pan cavity. Each slag pan 2 uses four slings 3 to ensure a safety factor of about 4. In this embodiment, the length of each sling 3 is 3200mm, the bearing capacity of the sling is 1 ton, and the material of the sling is 316L stainless steel. A plurality of first lifting ears are provided at the lower part of the hanging beam 41, and the first lifting ears are connected to the sling 3. Two second lifting ears are provided at the upper end of the hanging beam, and the second lifting ears are connected to the sling rope. The arrangement of the first lifting ears and the second lifting ears needs to ensure that the hanging beam 41 remains balanced after lifting the slag receiving plate 2. The distance B1 between the second lifting ear and the end of the hanging beam 41 matches the width of the groove edge of the zinc pot, so that the operator can remove the sling rope on the second lifting ear when standing on the groove edge. In other embodiments of the present invention, the lifting ring 42 is fixedly connected to the upper end of the hanging beam 41 through a connecting frame.

[0045] In this embodiment, three slag trays 2 are connected to the lower end of each suspension beam 41, and the distance B1 between the second suspension ear and the end of the suspension beam 41 is 500mm; the first suspension ear and the second suspension ear are made of φ16mm round steel. The depth of the tray cavity is 120-150% of the bottom slag thickness measured by 5 in the zinc pot 1. The size of the slag tray 2 takes into account the requirements of high-temperature zinc liquid corrosion and thermal deformation resistance, while taking into account the reduction of buoyancy to facilitate immersion in zinc liquid, and no secondary pollution to the zinc liquid. In this embodiment, the slag tray 2 is made of 20mm thick 316L stainless steel plate by welding, and the slag tray length AA×slag tray width BB×slag tray height CC=1500mm×750mm×150mm, and four third suspension ears are welded on both sides of the length direction of the slag tray 2 for connecting the sling 3, and the third suspension ears are made of φ12mm round steel.

[0046] In summary, the temperature of the zinc liquid is first increased to a first set temperature to increase the solubility of the zinc slag containing rare earth elements, and the zinc liquid is kept at the first set temperature for a first set time, so that the zinc slag is dissolved in the zinc liquid; then a slag receiving pan is placed in the zinc pot, and the slag receiving pan is arranged at the bottom of the zinc pot; thereafter, the temperature of the zinc liquid is lowered to a second set temperature to reduce the solubility of the zinc slag in the zinc liquid, and the zinc liquid is kept at the second set temperature for a second set time, so that the zinc slag is precipitated from the zinc liquid and deposited in the disc cavity of the slag receiving pan; thereafter, the slag receiving pan containing the deposited zinc slag is taken out from the zinc pot, thereby removing the zinc slag from the zinc liquid; therefore, the hot-dip galvanizing zinc slag removal method of the present invention does not need to be configured with a special filtering device, thereby avoiding the zinc slag being blocked in the filter mesh of the filter; moreover, the heating of the zinc liquid can be achieved by the heating device provided by the zinc pot itself, so that the hot-dip galvanizing zinc slag removal method of this embodiment is low in cost and easy to promote.

[0047] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for purifying hot-dip galvanizing zinc solution, characterized in that: The following steps are involved: Step S1, raising the temperature of the zinc liquid to a first set temperature to increase the solubility of the zinc slag containing rare earth elements, and keeping the zinc liquid at the first set temperature for a first set time, so that the zinc slag dissolves into the zinc liquid; Step S2, placing a slag receiving pan (2) into the zinc pot (1), and arranging the slag receiving pan (2) at the bottom of the zinc pot (1); Step S3, lowering the temperature of the zinc liquid to a second set temperature to reduce the solubility of the zinc slag in the zinc liquid, and keeping the zinc liquid at the second set temperature for a second set time, so that the zinc slag precipitates from the zinc liquid and is deposited in the disc cavity of the slag receiving pan (2); Step S4, taking the slag receiving pan (2) out of the zinc pot (1); before step S1, the steps include: Step S01, measuring the deposition thickness of the zinc slag at the bottom of the zinc pot (1) to determine the depth of the disc cavity, and making the depth of the disc cavity greater than the deposition thickness of the zinc slag; The ratio of the depth of the disc cavity to the deposition thickness of the zinc slag is greater than or equal to 1.2 and less than or equal to 1.5; An overflow hole (21) is provided at the upper portion of the side wall of the disc cavity, and the ratio of the distance from the overflow hole (21) to the top of the disc cavity to the depth of the disc cavity is greater than or equal to 0.2 and less than or equal to 0.

5.

2. The hot-dip galvanizing zinc liquid purification method according to claim 1, characterized in that: The first set temperature is greater than or equal to 470° C. and less than or equal to 485° C.; and the first set time is greater than or equal to 10 hours.

3. The hot-dip galvanizing zinc liquid purification method according to claim 1, characterized in that: The second set temperature is greater than or equal to 445° C. and less than or equal to 455° C.; and the second set time is greater than or equal to 36 hours.

4. The hot-dip galvanizing zinc liquid purification method according to claim 1, characterized in that: In the step S4, after the slag receiving pan (2) is taken out, the slag receiving pan (2) is cooled, and after the zinc slag in the slag receiving pan (2) is cooled, the zinc slag is poured out from the slag receiving pan (2).

5. The hot-dip galvanizing zinc liquid purification method according to claim 1, characterized in that: There are a plurality of slag receiving pans (2), each of which is horizontally spaced apart at the bottom of the zinc pot (1), and a plurality of slings (3) are spaced apart and connected to the circumference of each slag receiving pan (2), and one end of each sling 3 away from each slag receiving pan (2) extends upward to the outside of the zinc liquid and is connected to a lifting device (4).

6. The hot-dip galvanizing zinc liquid purification method according to claim 5, characterized in that: The lifting device (4) comprises a lifting beam (41), a lifting ring (42), a lifting rope (43) and a hoist; the slag receiving plates (2) are arranged at intervals along the axial direction of the lifting beam (41); and one end of each lifting rope (3) away from each slag receiving plate (2) is connected to the lower end of the lifting beam (41); A first lifting ear (411) arranged near the first end of the lifting beam (41) and a second lifting ear (412) arranged near the second end of the lifting beam (41) are fixed on the lifting beam (41); one end of the lifting rope (43) is connected to the first lifting ear (411), and the other end of the lifting rope (43) is connected to the second lifting ear (412); the lifting ring (42) is connected to the middle part of the lifting rope (43), and the winding rope of the winch is connected to the lifting ring (42).

7. The hot-dip galvanizing zinc liquid purification method according to claim 5, characterized in that: The horizontal spacing distance between two adjacent slag receiving plates (2) is greater than or equal to 100 mm and less than or equal to 150 mm.

Images