JP2828577B2 - Pipe transport method for zinc oxide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe transport of powdery zinc oxide supplied to replenish zinc ions consumed in a plating solution in continuous electrogalvanizing of a metal strip using an insoluble anode. It is about the method.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for improved corrosion resistance in automobiles, home electric appliances and the like, and in addition to conventionally used galvanized steel sheets, there has been a demand for recently developed alloy-coated steel sheets such as zinc-nickel plated steel sheets. Has also increased significantly. In order to cope with such an increase in demand, high-speed plating with a high current density that enables high-efficiency production has been adopted.However, in the high-speed plating, the anode replacement is more required than in the soluble anode method, which requires frequent anode replacement. It goes without saying that a system in which unnecessary metal ions are continuously supplied using an insoluble anode such as an iridium-based one which is unnecessary is advantageous.

As a plating solution, a sulfuric acid-based electrolytic solution is usually used. In addition, as a method of replenishing zinc ions in the plating solution, there are a method of dissolving metal zinc by directly contacting the plating solution and a method of dissolving a metal compound such as zinc oxide. Since the method of directly dissolving granular or massive metallic zinc has a low dissolution rate, it is more efficient to dissolve a powdered zinc compound.
According to Japanese Patent Application Laid-Open No. 58-13639, it is described that zinc oxide or a basic salt in a powder state is previously dispersed in water and then charged into a plating bath.

[0004] Zinc oxide powder is usually packed in a bag-like container such as a flexible container before being shipped, and is stored in a hopper provided in a manufacturing facility, and the required amount is cut out and used. Is common. Then, when receiving the hopper, the contents of the bag-shaped container such as a flexible container hung by a crane or the like are untied and the contents are dropped. It is dangerous work because you will enter. Further, at this time, there is a problem of causing environmental pollution such as dusting and spillage.

Accordingly, the present inventors have already filed Japanese Patent Application No. 5-1.
No. 27433, in the form of powder suitable for pneumatic transportation of powdery zinc oxide through a pipe from a special lorry vehicle capable of pneumatic transportation into a hopper, that is, into a granular form having a compression degree of 50% or less and an average particle diameter of 50 μm or more. We propose granulated zinc oxide with excellent transportability. However, even if such a zinc oxide powder is used, an accident that the inside of the pipe is often blocked has occurred.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a zinc oxide pipe which does not cause blockage in the pipe when pulverized zinc oxide is pneumatically transported into the hopper through a pipe from a special lorry vehicle capable of pneumatic transport. The purpose is to propose a transportation method.

[0007]

SUMMARY OF THE INVENTION According to the present invention, when a powdery zinc oxide is pneumatically transported into a hopper through a pipe from a special lorry vehicle capable of pneumatic transport, the pipe is made of SUS.
304 is used as an internal polishing pipe, the volume mixing ratio of zinc oxide and air is set to 10% or less, a pipe for supplying auxiliary air is provided in the middle of the pipe, and air of 2 kgf / cm ² × ² Nm ³ / min or more is supplied. The air velocity in the pipe is 10 m / s
A method for transporting zinc oxide in a pipe, characterized in that:

[0008]

[Operation] In the case of powdery zinc oxide (ZnO), powder is clogged at a bent portion of a pipe and the like, and pneumatic transportation is difficult. Pneumatic transportation of special lorry vehicles through pipes into hoppers is now possible.

[0009] Zinc oxide is easily clogged at a bent portion of the pipe, and when a general carbon steel pipe for pipe SGP is used for the pipe, even if the pipe is transported under the above-described conditions, the inner surface of the pipe is Z-coated.
Adhesion of nO was observed. Therefore, the pipe material was changed to SUS30
For the first time, it has been found that the problem of adhesion of ZnO to the inner surface of the pipe can be avoided by using the inner surface polishing pipe of No. 4 as a polished pipe. When the volume mixing ratio of zinc oxide and air is more than 10%,
Since ZnO adheres to the inner surface of the pipe or becomes clogged,
It was limited to 10% or less. The volume mixing ratio between zinc oxide and air is defined as V _ZnO / (V _ZnO + V _air ) × 100. Here, V _ZnO is the volume (m ³ ) of ZnO, V _air
Is the Nm ³ volume of air.

Further, it is necessary to provide a pipe for supplying auxiliary air in the middle of the pipe and to supply air of 2 kgf / cm ² × ² Nm ³ / min or more. Input pressure is 2kgf / c
If it is less than m ² and the amount is less than ² Nm ³ / min, adhesion or blockage of ZnO on the inner surface of the pipe cannot be avoided. Also, the air velocity in the pipe is 10 m /
If it is less than s, similarly, adhesion or blockage of ZnO on the inner surface of the pipe cannot be avoided.

[0011]

FIG. 1 is a schematic diagram showing a method for carrying out a method for transporting zinc oxide in a pipe according to the present invention. Powdery zinc oxide (Zinc flower according to French method, JIS special product) is manufactured by changing the pipe diameter, material, volume mixing ratio of zinc oxide and air, input pressure of auxiliary air, and air flow velocity in the pipe. Table 1 shows the results of pneumatic transportation.

The transport condition at this time is that the transport height is 20 m.
An air transport vehicle was used, and the transport destination was opened to the atmosphere by a hopper equipped with a bag filter. A pneumatic transport vehicle is a special lorry vehicle that has a compressor mounted on the vehicle and can directly transport pulverized materials in the tank to receiving equipment on the ground. In addition,
In Table 1, the lower part of the pipe indicates the portion before the supply of the auxiliary air, and the upper part of the pipe indicates the part after the supply of the auxiliary air. In the judgment, ○ is Z
No adhesion and no blockage of nO, △ indicates adhesion of ZnO,
X indicates no occlusion, and x indicates occlusion.

[0013]

[Table 1]

The following can be seen from Table 1. (1) From Test Nos. 1, 2 and No. 3, the pressure of the auxiliary air for transporting ZnO needs to be 2 kgf / cm ² or more. This is because ZnO flows back to the auxiliary air supply pipe side unless the pressure is higher than the pressure of the ZnO pumping vehicle. (2) No. 4 also supports (1). (3) When the pipe was set to 100A (JIS-specified pipe diameter) and the air flow velocity in the pipe was set to 11 m / s, as shown in No. 5, good transport was possible. (4) At this time, the auxiliary air input amount is set to 2.0
It better be lowered to Nm ³ / min, but deposited in 1.5 Nm ³ / min as No7 was observed in the pipe. Therefore, it is preferable that the auxiliary air input amount be 2.0 Nm ³ / min or more. (5) When the transport amount of ZnO was changed from the condition of No6 as in No8, it was blocked. This is considered to be because the volume mixing ratio of zinc oxide and air was increased to 12%. Therefore, 10% or less is good. (6) When the piping material was changed from the condition of No. 6 like No. 9, adhesion of ZnO was observed. (Polishing is JIS
# 300) This is considered to be due to the increased friction between the inside of the pipe and zinc oxide and air. (7) No10 was similar to (1). (8) No. 11 was similar to (3). However, Zn
The air consumption of the O pumping vehicle is large, which is economically undesirable.

[0015]

According to the present invention, zinc oxide can be directly received into a hopper by pneumatic transportation from an air carrier without using a flexible container, dusting and other environmental problems can be eliminated, and dangerous work can be eliminated. It has many excellent effects.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-171700 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C25D 21/14

Claims (1)

(57) [Claims] 1. When pulverized zinc oxide is pneumatically transported into a hopper through a pipe from a special lorry vehicle capable of pneumatic transport, the pipe is used as an inner surface polishing pipe of SUS304, and the volume mixing ratio of zinc oxide and air is 10%. % Or less,
2kgf / c by installing a pipe for supplying auxiliary air in the middle of the pipe
A zinc oxide pipe transport method, characterized in that air of m ² × ² Nm ³ / min or more is introduced and the air flow rate in the pipe is 10 m / s or more.