JPH05306485A - Stainless-steel baseboard for copper electrolysis - Google Patents

Abstract

PURPOSE:To improve the electrodeposition property of a stainless-steel baseboard for copper electrolysis by specifying the surface roughness. CONSTITUTION:The surface of a stainless-steel sheet to be used as the baseboard for producing a starting sheet for copper electrolysis is ground to control the centerline average roughness (Ra) to 0.5-1.53mum. Consequently, the electrodeposition property and releasability of the deposit are ameliorated, and the durability of the baseboard is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stainless steel base plate for copper electrolysis which is excellent in electrodeposition property, peeling property and corrosion resistance.

[0002]

2. Description of the Related Art In a copper electrolysis method, a copper metal obtained by treating in a refining furnace in a copper smelting process is used as an anode, and a cathode made of copper, titanium or stainless steel is previously used as a cathode in an electrolytic cell for producing a seed plate. A thin copper plate (usually called a seed plate) with a thickness of about 0.6 mm, which is electrodeposited on a cathode called a plate, is used to electrolyze using a copper sulfate aqueous solution as an electrolytic solution to form a seed plate. 5-1 to the method of manufacturing product electric copper by electrodepositing metallic copper
There is a method in which copper is electrodeposited to a thickness of 0 mm and the copper is peeled off to obtain a product electric copper.

When a copper plate is used as the mother plate, it is necessary to apply a release agent (soap, varnish, heavy oil, etc.) in order to prevent the deposited copper from adhering to the mother plate, which makes the work complicated. In addition, there are problems such as corrosion of the electrolytic surface. The titanium mother plate does not need to be coated with a release agent and has good corrosion resistance, but since it is expensive, it has a problem of high initial investment.

On the other hand, since the stainless steel mother plate has a passive film on the surface, it is not necessary to apply a release agent,
Recently, stainless steel mother plates have come to be used because they are inexpensive. However, when a stainless steel plate is used as the mother plate, the electrodeposits are naturally peeled from the mother plate, or the electrodeposits are strongly electrodeposited on the mother plate and are difficult to peel off, or the mother plate surface is white. However, there is a problem that a state in which the electrodeposition property, the peeling property, and the corrosion resistance are not good is likely to occur such as discoloration to.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to provide a stainless steel base plate for copper electrolysis which is excellent in electrodeposition, peelability and corrosion resistance.

[0006]

The stainless steel base plate for copper electrolysis according to the present invention is a flat plate made of stainless steel whose surface has a center line average roughness (Ra) of 0.5 to 1.53 μm. There is a feature in one point.

[0007]

According to the present invention, as a result of investigating the characteristics of the stainless steel plate used as the mother plate for the production of the copper electrolysis seed plate, the polishing property is good, the flatness of the plate is high, and the variation in the plate thickness is small. In addition, it was important that the electrodeposition property, the peeling property and the corrosion resistance were excellent. There are two types of stainless steel plates, a hot rolled plate and a cold rolled plate, depending on the rolling method. In the hot-rolled plate (surface condition: No. 1 finish), the initial plate surface roughness is rough, so that it takes a lot of polishing man-hours, the flatness is low, the plate thickness varies widely, and the seed plate is electrodeposited. In some cases, it is strongly electrodeposited, so that there are problems such as poor peelability. On the other hand, cold rolled plate (surface condition: 2B finish)
However, if the plate surface roughness is small due to variations in manufacturing lots, etc., there is also a problem that peeling occurs between the electrolytic copper and the mother plate during energization, causing a short circuit, but the initial plate surface roughness is It is preferable to use a cold-rolled plate because it is fine and has good polishing properties, high flatness, and small variation in plate thickness.

Polishing the surface of the stainless steel base plate improves the electrodeposition, peelability and corrosion resistance, but the surface roughness of the ground stainless steel base plate is 0.5 μm in Ra (center line average roughness). If less than the above, peeling occurs between the stainless steel base plate and the seed plate during energization, causing a short circuit or partial peeling, and the electrolytic solution is trapped between the stainless steel base plate and the seed plate. Since pitting corrosion occurs partially, it is difficult to peel off the seed plate by repeating energization, and in the part where pitting corrosion occurs, the seed plate causes electrodeposition failure, so the stainless steel base plate It cannot be used as the surface roughness of. Further, if the surface of the polished stainless steel base plate has Ra of more than 1.54 μm, it becomes difficult to peel the seed plate from the stainless steel base plate.
Since the surface roughness of the stainless steel base plate cannot be adopted, the surface roughness of the stainless steel base plate is Ra 0.5-1.
It needs to be 53 μm.

[0009]

Example: A stainless steel base plate under the following conditions and a seed plate for copper electrolysis were produced under electrolysis conditions, and the peeling force of the seed plate and the surface roughness of the used stainless steel base plate were measured and the results are shown. Shown in 1. Further, the surface condition of the mother plate and the condition of the seed plate after the energization were also observed, and the results are shown in Table 1.

Electrolysis conditions Electrolyte 46 g / l Free sulfuric acid 190 g / l glue 80 g / ton (per amount of electrodeposited copper) Thiourea 60 g / ton (per amount of electrodeposited copper) Hydrochloric acid 30 mg / l Cathode Cast anode Anode size 1040 × 1026 × 36mm Number of anodes 26 Anodal stainless steel 316L / Cold rolled plate Made by Nippon Stainless Steel Co., Ltd. (Mother plate) (2B finish plate was polished under the following conditions) Cathode size 1070 × 1050 × 3mm Number of cathodes 25 sheets Distance between poles 105mm (distance between anode and center) Current density 220A / m ² Liquid temperature 60 ° C Electrolysis time 22Hr Battery size 3000 × 1250 × 1360mm Polishing conditions Manual polishing with emery paper # 80, 120, 180 Turn finish

[0011]

[Table 1]

Here, the measuring method of the surface roughness of the mother board is described in J.
Based on IS B 0601 (Surface Roughness), Surf Test 201 (Stylus type roughness measuring machine: Stroke the surface in a certain direction with a needle to expand the vertical movement of the needle) (Mitutoyo Co., Ltd.) ), Ra (center line average roughness) was measured in the direction perpendicular to the polishing direction. Ra (center line average roughness) means that a portion of the measurement length l is extracted from the roughness curve in the direction of the center line,
When the roughness curve is represented by y = f (x) with the center line of the extracted portion as the X-axis and the direction of longitudinal magnification as the Y-axis, the value obtained by the following equation is represented by a micrometer (μm). Say.

[0013]

[Equation 1]

As shown in FIG. 1, the seed plate, the peeling force and the measuring method are such that the upper part of the mother plate and the upper part of the seed plate are opened, and only the spring is attached to the opened part of the seed plate and the mother plate is removed. The maximum load at which the seed plate was peeled from the mother plate by pulling in the direction perpendicular to the plate was defined as the peeling force of the seed plate. Further, the seed plate peeling force shown in Table 1 represents the maximum value and the minimum value of the peeling force obtained by several times.

For comparison, a copper electrolysis seed plate was produced under the same electrolysis conditions as in the examples by using a stainless steel base plate which was left unpolished or was polished under the following polishing conditions. The peeling force of the seed plate was measured, and the results are shown in Table 1.

Manual polishing using emery paper (stainless steel 316L, cold rolling plate used) # 240, 320, 400 finishes Sandblast polishing (stainless steel 316L, cold rolling plate used) Silica stone (Ube Industries) Made) ・ Unpolished plate Hot rolled plate ・ No. 1 finish Cold rolled plate, 2B finish

In Table 1, No. 1-3 and No. 4-
By comparing with No. 9, it is understood that when the surface roughness Ra of the stainless steel base plate is 0.5 to 1.53 μm, it is possible to produce a copper electrolysis seed plate having good electrodeposition, releasability and corrosion resistance. .. That is, the surface roughness Ra of the stainless steel mother plate is 0.5 μm.
When it is less than (No. 4 to 6, 9), a natural peeling phenomenon appears, and when it exceeds 1.63 μm (No. 7, 8), the peeling force of the seed plate is more than 20 kgf, which is difficult to peel off. It was in a state.

[0018]

Industrial Applicability Therefore, the stainless steel base plate for copper electrolysis according to the present invention ensures the durability of the base plate, and provides a good seed plate appearance and a good seed plate / peeling force. It plays.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus for measuring the peeling force of a seed plate.

[Explanation of symbols]

 1 Mother board 2 Seed board 3 Spring bakari

Claims (1)

[Claims] 1. The surface has a center line average roughness (Ra) of 0.5.
A stainless steel base plate for copper electrolysis, which is a flat plate made of stainless steel having a surface roughness of ˜1.53 μm.