JPS62151222A - Leveling method for lead alloy plate - Google Patents

Abstract

PURPOSE:To easily level a deformed lead alloy plate having high hardness with a mechanical treatment by heating the lead alloy plate to a limit temp. and pressurizing the plate under the limit pressure. CONSTITUTION:The plate is made of a lead-calcium alloy or lead-calcium multi- element alloy and since said plate is deformed by curing on aging, the plate is heated to 70-300 deg.C in the stage of leveling. The leveling effect is not enough if the heating temp. is <=70 deg.C and there is an energy loss if >=300 deg.C. The pressu rizing is executed by a press and the pressurizing force is specified to 0.1-10kg/cm<2>. The leveling effect is not enough if the pressure is <=0.1kg/cm<2>. An excessively large installation is required and is uneconomical if the pressure is >=10kg/cm<2>. The pressing time is satisfactory with <=5min. The plate after leveling is not easily deformed again and is stable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for straightening a lead-based alloy electrode plate. More specifically, the method for correcting deformation, especially warping and bending, of lead-based alloy electrode plates used as electrode plates in fields such as the electrochemical industry, battery industry, and hydrometallurgical smelting industry for the purpose of electrowinning of metals. Regarding.

Conventionally, as insoluble electrode materials, lead-based materials, such as pure lead, lead-antimony alloys, lead-silver alloys, etc., have been widely used as a result of comprehensive consideration of their workability, durability, economic efficiency, etc. It's here.

In recent years, it has been used as a material for battery grids.
Lead-calcium based alloys such as those disclosed in Japanese Patent Laid-open No. 59-59891 and Japanese Patent Laid-Open No. 60-106988 have come to be used favorably as electrode plate materials for industrial electrolysis. Lead-calcium-silver alloys, lead-calcium-tin alloys, etc., such as those disclosed, have come into use. Since these lead-calcium alloys have excellent corrosion resistance and electrochemical properties, they are expected to become the mainstream lead-based electrode materials in the future.

However, since these are usually lead alloys containing about 0.01 to 2.0 inches of calcium, they have the following drawbacks. In other words, the solubility of calcium in ships at room temperature is said to be about 0.01%, and in the case of alloys containing excess calcium as described above, calcium is
It becomes a compound represented by the formula b3Ca, which gradually precipitates in the ship, and the hardness of the alloy increases over time. As described above, lead-calcium alloys exhibit age-hardening phenomena, so when this alloy is used as an insoluble anode for electrowinning of metals, for example, the electrode plate may become warped or otherwise deformed after a certain period of use. Because it hardens and becomes a highly hard deformed electrode plate, it has been impossible to correct the deformation by simple cold working.

Deformation of the electrode plate as described above occurs when the alloy is stored for a long period of time after being cast and processed into an electrode plate, or when it is suspended in an electrolytic bath and energized and used for actual electrolytic operation. This phenomenon inevitably occurs due to short-circuits, etc. that occur during this period. However, since the deformation usually occurs in a much shorter time than the life of the electrode plate, it is common to correct the deformation and reuse the electrode plate. However, when a lead-calcium alloy plate is used, the age hardening phenomenon described above causes the plate to become a highly hard deformed body, making it impossible to straighten it by simple cold working. , had to be corrected by a type of manual forging.

For this reason, a great deal of effort was required to straighten the plates, and the straightening effect was insufficient. Therefore, a method was developed to effectively straighten such highly hard deformed plates with simple operations. By doing so, not only can the cost of straightening electrode plates be significantly reduced, but defective plates can be straightened easily and quickly, so electrolysis can always be carried out in the best possible condition, and current efficiency is improved, contributing to the development of industry. It can be said that there is a large contribution to be made. The present invention provides a correction method that precisely meets such needs.

The present inventor has proposed that when shaping a deformed electrode plate by machining it with a press or the like, the electrode plate can be preheated separately or the electrode plate can be shaped by using a press die plate as a direct heat source. By raising the temperature of the electrode plate and holding it in a heated and pressurized state for a certain period of time, even highly hard deformed electrode plates such as age-hardened lead-calcium alloys can be easily and easily deformed. The present invention has been achieved by discovering that straightening can be achieved to a sufficiently satisfactory degree. In carrying out the method of the present invention, the heating temperature of the electrode plate that should normally be employed is 70°C to 300°C.

If the temperature is lower than 70°C, the straightening effect will be insufficient, and if the temperature is higher than 300°C, energy will be wasted. Furthermore, if the temperature is too high, the electrode plate will become semi-molten, causing various problems. It has been empirically determined that the suitable temperature range for implementation is 100<0>C to 200<0>C.

The processing is most conveniently carried out by the pressing method, in which case the pressure that can be employed is 0. IKs'/ffl~10
Kg/crl, preferably 015Kf/CI? L~10
9/cI? It is L. Desired correction can be easily achieved by applying pressure within the above-mentioned range at the same time as heating. A pressure lower than 0,1Kp/cIIl will not provide a sufficient straightening effect, and applying a pressure higher than 10Kp/cIIl will be uneconomical because it will apply an unnecessarily high pressure and require excessive equipment. It is.

Even if such a high pressure is applied, the effect does not increase proportionally, so it is not economical compared to the effect. The pressing time should be selected appropriately depending on the alloy composition, but usually 5 minutes or less is sufficient.

Further, as is obvious in principle, it is naturally possible to employ pressing and processing methods other than the pressing method. For example, using a roller leveler or the like, the alloy electrode plate can be heated and pressurized to the above-mentioned temperature and pressure range, and the deformed electrode plate can be mechanically straightened.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 Using a deformed and hardened lead-calcium alloy electrode plate as a test piece, it was heated to a temperature of 170°C and a pressure of 5% using a press that can directly heat the press die. /c+y! .

Heat and pressure treatment was performed according to the method of the present invention under conditions of a pressing time of 5 minutes. The length of the test piece is 750 m8% and the width is 745 m.
It was deformed and age-hardened as shown in Figure 1, with an average thickness of 8 mm.

The warpage of the electrode plate before correction, indicated by A in FIG. 1, was 11 mm, but by the heating and pressure processing described above, it was possible to correct the warp to a flat state where no warp could be measured.

This straightening was stable and did not easily deform even if the electrode plate was subsequently immersed in an electrolytic solution and used. The plates tested were conventional insoluble anode plates made of a lead alloy containing about 0.85% calcium and about 0.60% silver.

Example 2 A lead-calcium alloy electrode plate made of the same material and having the same dimensions as those used in Example 1 was used as a sample piece, and using the same press die, a temperature of 130°C and a pressure of 2Ks+/cri- were used.
An attempt was made to correct the deformed electrode plate by heating and pressurizing the deformed and hardened electrode plate under conditions of a pressing time of 5 minutes. In Figure 1, the warpage of the electrode plate before straightening, which corresponds to OA, was 12 degrees, but due to the above heating and pressure treatment, there was no problem in practical use.
Warps up to mm could be easily corrected. The electrode plate after correction is
As in the case of Example 1, it was stable and did not easily deform again.

Comparative Example A lead-calcium alloy electrode plate made of the same material and having the same dimensions as those used in Example 1 or 2 was used as a sample piece, and the electrode plate was heated at room temperature (25°C) using the same press die. An attempt was made to correct the deformation and hardening of the hardened electrode plate by performing pressure treatment under the conditions of a pressure of 2Ks+/d and a press time of 5 minutes. I was only able to correct it until I had 8 balls.

As shown in the examples above, the method of the present invention can be applied to lead-calcium alloy electrode plates that have conventionally required a great deal of manual labor and have not produced sufficient effects. It has become possible to easily correct the deformation of the material by simple mechanical processing to the extent that there is no problem in practical use.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the cross-sectional shape and dimensions of a deformed electrode plate used in a test to demonstrate the effectiveness of the method of the present invention taken along its longitudinal direction, and the measurement positions of warpage. A in the figure indicates the magnitude of warpage.

Claims (7)

[Claims] (1) A method for straightening a lead-based alloy electrode plate, which comprises heating the electrode plate to a temperature in the range of 70° C. to 300° C. and pressurizing the electrode plate. (2) The method according to claim 1, wherein the heating temperature is in the range of 100°C to 200°C. (3) The lead-based alloy electrode plate according to claim 1 or 2, wherein the lead-based alloy electrode plate is a lead-calcium-based alloy or a lead-calcium-based multi-element alloy electrode plate containing a small amount of calcium. Method. (4) The method according to claim 3, wherein the electrode plate is either a lead-calcium-silver alloy electrode plate or a lead-calcium-tin alloy electrode plate. (5) The method according to claim 1 or 2, wherein the pressurizing process is performed by a press method. (6) The press pressure used in the above press method is 0.1 kg.
6. The method according to claim 5, wherein the pressure is in the range of /cm^2 to 10 kg/cm^2. (7) The method according to claim 1 or 2, wherein the pressure processing is performed by a roller leveler method.