JP2013252530A - Bend straightening method of electric cobalt plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bend straightening method of an electric cobalt plate that can efficiently perform straightening of bending.SOLUTION: In two or more electric cobalt plates A obtained by electrowinning, those with small bending are disposed to the highest rung and the lowest rung, are piled in a direction in which bending becomes convex up, and annealed. Straightening of bending can be efficiently performed by annealing. Because the electric cobalt plate A with small bending is disposed to the highest rung, straightening of bending can be sufficiently performed only by its own weight. Because the electric cobalt plate A with small bending is disposed to the lowest rung, influence to the electric cobalt plate A in an upper rung decreases. Because it is piled to a direction that becomes convex up, collapse can be prevented and straightening of bending can be performed by its own weight.

Description

  The present invention relates to a method for correcting the bending of an electric cobalt plate. The electrocobalt plate obtained by electrowinning is cut by a cutting machine into rectangular pieces. The present invention relates to a technique for correcting the bending so that the electric cobalt plate is not broken when it is cut by a cutting machine.

  In hydrometallurgical recovery of nickel and cobalt, chlorine leaching is performed using nickel matte or MS (mixed sulfide of nickel and cobalt) as raw material, and nickel and cobalt in the raw material are leached into an aqueous solution. Done. Then, electrolytic nickel and electrolytic cobalt are obtained by electrolytic collection using a leachate from which nickel or cobalt has been leached (for example, Patent Document 1).

  Electrolytic cobalt is obtained as an electrocobalt plate having a length and width of about 1m x about 0.8m, a thickness of 10 to 12mm, and a weight of 80 to 90kg. Such an electric cobalt plate is made into a product by, for example, cutting it into rectangular pieces of 25 mm square for easy handling. The electric cobalt plate is cut by a cutting machine. This cutting machine cuts an electric cobalt plate vertically and horizontally by pressing with a shear to make small pieces of a predetermined size (for example, Patent Document 2).

  By the way, the electrocobalt plate obtained by electrowinning has a property that the flatness is worse than that of the electronickel plate and the center of the electrocobalt plate is bent so as to be convex. This is because in cobalt electrowinning, cobalt oxyhydroxide (CoOOH), which is a nonconductor, is easily generated on the anode surface, and the current density distribution on the anode side becomes uneven. Along with this, the cathode side on which cobalt is deposited is also affected, and the current density distribution on the cathode side becomes non-uniform as the electric cobalt plate is bent. On the other hand, in nickel electrowinning, no oxyhydroxide is generated on the anode side, so the current density distribution on the cathode side is relatively uniform and the electric nickel plate is less bent. Thus, the flatness of the electric cobalt plate is generally worse than that of the electric nickel plate.

  There is a problem that an electric cobalt plate having a large bend is broken when it is cut by a cutting machine. If the electric cobalt plate is cracked, the cutting process must be interrupted to remove the debris, thus deteriorating the production efficiency.

  In particular, when the current density of electrowinning is increased in order to increase the production amount, the above problem becomes remarkable. When the current density of electrolytic collection is increased, the amount of electrodeposition per unit time can be increased and the electric cobalt plate can be made thicker, and the production amount can be increased accordingly. However, the flatness tends to deteriorate as the electric cobalt plate becomes thicker.

In order to solve the above problem, it is necessary to correct the bend before inserting the electric cobalt plate having a large bend into the cutting machine. As the method, a method of correcting the bending by pressing the electric cobalt plate with a press machine is conceivable.
However, since electric cobalt is hard (Vickers hardness: about 200 to 250 HV) and brittle, it may be cracked when pressed with a press. In particular, an electrocobalt plate obtained by electrowinning has a property that the structure is denser and harder and more easily cracked than a cast metal cobalt product obtained by melting and solidifying. Therefore, the method of correcting the bending of the electric cobalt plate with a press is not efficient.

Japanese Patent Laid-Open No. 11-236630 JP 2009-196039 A

  In view of the above circumstances, an object of the present invention is to provide a method for correcting the bending of an electric cobalt plate that can efficiently correct the bending.

In the method of correcting the bending of the electric cobalt plate according to the first aspect of the present invention, when annealing the electric cobalt plate obtained by electrowinning, a plurality of the electric cobalt plates are arranged in the uppermost and lowermost stages, of which the bending is small. , It is characterized by being stacked in a direction in which the bend is convex upward.
The method for correcting the bending of the electric cobalt plate according to the second invention is the method according to the first invention, wherein the furnace temperature is held at 800 to 1200 ° C. for 10 to 15 hours and then cooled to 200 ° C. or lower to baked the electric cobalt plate. It is characterized by blunting.
The bending correction method for the electric cobalt plate according to the third aspect of the present invention is that, in the first or second aspect, the time required for annealing the electric cobalt plate is substantially the same as the time for obtaining the electric cobalt plate in electrolytic collection. Features.

According to the first invention, the bending can be efficiently corrected by annealing the electric cobalt plate. In addition, since the electric cobalt plate with a small bend is arranged at the uppermost stage, the bend can be sufficiently corrected only by its own weight. In addition, since the electric cobalt plate having a small bend is arranged at the lowermost stage, the influence on the electric cobalt plate at the upper stage of the bend of the electric cobalt plate is reduced. Furthermore, since the electric cobalt plates are stacked in such a direction that the bend is convex upward, the collapse of the load can be prevented and the bend can be corrected by its own weight.
According to the second invention, if the furnace temperature is lower than 800 ° C., annealing becomes insufficient, and if the furnace temperature can exceed 1200 ° C., excessive energy is consumed for the correction of bending, so the furnace temperature is set to 800 ° C. If it is set to -1200 degreeC, the bending of an electric cobalt board can fully be corrected, and excessive energy consumption can be prevented. Moreover, if the annealing furnace is opened at a temperature higher than 200 ° C, the bricks on the furnace wall may be damaged. Therefore, if the furnace is cooled to 200 ° C or lower, the bricks on the furnace wall can be prevented from being damaged.
According to the third invention, the operation cycle of annealing and electrowinning can be synchronized, so that the electric cobalt plate does not stay, there is no play period of the annealing furnace, and the operation can be performed efficiently.

It is explanatory drawing of an annealing furnace. It is a manufacturing-process figure of an electric cobalt.

Next, an embodiment of the present invention will be described with reference to the drawings.
First, the production process of electrolytic cobalt will be described with reference to FIG.
An electrolytic cobalt plate is obtained by electrowinning. Generally, electrowinning is performed as a process of hydrometallurgy. For example, in wet smelting to recover nickel and cobalt, chlorine leaching is performed using nickel matte or MS (Mix Sulfide: mixed sulfide of nickel and cobalt) as a raw material, and nickel and cobalt in the raw material are leached into an aqueous solution. . The leachate is separated into a nickel chloride solution and a cobalt chloride solution by solvent extraction. An electrolytic cobalt plate is obtained by electrolytically collecting the obtained cobalt chloride solution as an electrolytic solution. In addition, although there exist a sulfuric acid bath and a chloride bath as a kind of electrolyte solution used for electrowinning, electrowinning in a chloride bath is adopted in the above-mentioned wet smelting.

  The size of the obtained electrocobalt plate varies depending on the conditions of electrolytic collection, and is not particularly limited. For example, the length and width are about 1 m × about 0.8 m, the thickness is 10 to 12 mm, and the weight is 80 to 90 kg. In addition, the electric cobalt plate has a property that the flatness is worse than that of the electric nickel plate and the center of the electric cobalt plate is bent. And an electric cobalt board with big bending may be cracked when cut | disconnecting to a small piece at a post process. For example, when the electric cobalt plate is placed on a horizontal surface, if the height of the highest portion of the electric cobalt plate from the horizontal surface is so large that it exceeds 40 mm, it may break when cutting with a cutting machine. Get higher. For this reason, the insertion port of the cutting machine has a slit shape with a height of 40 mm so that an electric cobalt plate having a larger bend cannot be inserted into the cutting machine. However, the electrocobalt plate with a large bend cannot be inserted into the cutting machine, and the work is stagnant.

  Then, the thing with a big curvature among the electric cobalt plates obtained by electrowinning corrects the curvature. For this reason, the electric cobalt plate is classified into one having a large bend and one having a small bend. For example, when an electric cobalt plate is placed on a horizontal plane, the electric cobalt plate whose height from the horizontal plane of the highest portion of the electric cobalt plate exceeds 40 mm is regarded as a large electric cobalt plate, and those having a height of 40 mm or less are bent. Select a specific standard, such as a small electric cobalt plate. For this standard, an optimum value is determined in consideration of various conditions such as the properties of the electric cobalt plate and the performance of the cutting machine.

  An electric cobalt plate with a small bend is inserted directly into a cutting machine and cut into small pieces. On the other hand, an electric cobalt plate having a large bend is annealed to correct the bend, and then inserted into a cutting machine and cut into small pieces. The process of correcting the bending of the electric cobalt plate is an application location of the present invention.

  The electric cobalt plate is made into a product by cutting into rectangular pieces of 25 mm square, for example, in order to facilitate handling. A cutting machine that cuts an electric cobalt plate cuts the electric cobalt plate vertically and horizontally by pressing with a shear to make small pieces of a predetermined size.

Next, a method for correcting the bending of an electric cobalt plate according to an embodiment of the present invention will be described.
As shown in FIG. 1, the bending is corrected by charging the electric cobalt plate A into the annealing furnace 1 and annealing. Although the annealing furnace 1 used for annealing is not particularly limited, for example, an electric furnace that generates heat by energizing a carbon rod 11 provided in the furnace can be used. Further, it is preferable to have a thermometer 12 for measuring the temperature in the furnace and to control the temperature in the furnace, and it is preferable to provide a vacuum exhaust port 13 and a gas introduction port 14 to adjust the furnace atmosphere.

  A plurality of electric cobalt plates A are stacked and charged in the annealing furnace 1. The number of the electric cobalt plates A to be stacked is determined by the size of the annealing furnace 1 and is not particularly limited, but is, for example, several to a dozen.

  The electric cobalt plate A is stacked in a direction in which the curve is convex upward. By stacking in this way, the edge portion is grounded and stabilized, so that load collapse can be prevented. In addition, the electric cobalt plate A tends to bend greatly in the vicinity of the edge, but the bending can be corrected by its own weight by grounding the edge portion.

  Further, among the electric cobalt plates A to be stacked, those having relatively small bends are arranged at the uppermost stage and the lowermost stage. The uppermost electric cobalt plate A does not have another electric cobalt plate A on it, so that the pressing force does not work from above, and it is necessary to correct the bending only by its own weight. If the electric cobalt plate A having a small bend is arranged at the uppermost point, the bend can be sufficiently corrected only by its own weight. Further, when the electric cobalt plate A having a large bend is arranged at the bottom, the upper electric cobalt plate A is pushed up by the bend, and the shape of the upper electric cobalt plate A is affected. If the electric cobalt plate A with a small bend is arranged at the lowest stage in this respect, the influence on the upper electric cobalt plate A is reduced.

  The atmosphere in the annealing furnace 1 is adjusted by first connecting a vacuum pump or the like to the vacuum exhaust port 13 to evacuate the inside of the annealing furnace 1 and then introducing nitrogen gas having an oxygen concentration of 100 ppm or less from the gas inlet 14 to the annealing furnace. It is preferable to enclose in 1. In this way, oxidation of the surface of the electric cobalt plate A can be prevented. If the oxygen concentration exceeds 100 ppm, a thin oxide layer is formed on the surface of the electric cobalt plate A and the color becomes dark, resulting in poor appearance.

  The annealing condition is preferably that the furnace temperature is first raised to 800 to 1200 ° C., held at that temperature for 10 to 15 hours, and then cooled to 200 ° C. or lower. When the furnace temperature is lower than 800 ° C., the annealing is insufficient and the bending correction of the electric cobalt plate A is insufficient. Also, if the furnace temperature can exceed 1200 ° C, excessive energy is consumed to correct the bending. Therefore, if the furnace temperature is set to 800 to 1200 ° C., the bending of the electric cobalt plate A can be sufficiently corrected, and excessive energy consumption can be prevented. Moreover, if the annealing is finished at a temperature higher than 200 ° C. and the annealing furnace 1 is opened, the bricks on the furnace wall may be damaged. If the furnace is cooled to 200 ° C or less, the bricks on the furnace wall can be prevented from being damaged.

  In addition, it is preferable that the time required for annealing the electric cobalt plate A is substantially the same as the time required for obtaining the electric cobalt plate by electrowinning while satisfying the above conditions. In this way, since the annealing and electrowinning operation cycles can be synchronized, the electric cobalt plate A does not stay in the annealing process, and there is no play period of the annealing furnace 1, so that it can be operated efficiently. For example, when the time for obtaining the electric cobalt plate by electrowinning is 7 days, the temperature in the furnace, the holding time, the temperature at which the annealing furnace 1 is opened are adjusted, and the annealing of the electric cobalt plate A is set to about 7 days. Thus, the time required for annealing can be matched with the time required for electrowinning by adjusting the annealing conditions.

If the electric cobalt plate A is annealed as described above, the bending can be efficiently corrected because the electric cobalt plate A is not cracked as in the case where the bending is corrected by pressing with a press. And it can prevent that the electric cobalt plate A is broken when it is cut into small pieces with a cutting machine.
In addition, even if annealing is performed, the correction of bending may be insufficient, but since the electric cobalt plate A after annealing is softened, it is cut without being broken even if it is cut with a cutting machine as it is. be able to.

  In addition, it is possible to anneal all the electrocobalt plates obtained by electrowinning in addition to annealing the electrocobalt plate having a large bend and the small bend as described above, and annealing only the large bend. . However, it is preferable to select them because the energy required for annealing can be reduced and the labor of workers can be reduced.

Next, examples will be described.
(Example)
As in the above-described embodiment, nine electrocobalt plates were stacked in a direction in which the curve is convex upward and charged into the annealing furnace. Next, the furnace atmosphere was nitrogen gas with an oxygen concentration of 100 ppm or less. Next, the furnace temperature was raised to 1100 ° C. and held for 15 hours, and then the furnace was cooled. Then, after confirming that the temperature in the furnace was cooled to 30 ° C. after 156 hours from the start of temperature increase, the electric cobalt plate was taken out from the annealing furnace.
The electric cobalt plate taken out from the annealing furnace was loaded into a cutting machine and cut into small pieces. As a result, no electric cobalt plate was broken by the cutting machine.

(Comparative example)
Nine electric cobalt plates were stacked in a direction in which the bends protrude downward, and charged into the annealing furnace. The other conditions were the same as in the example, and the electric cobalt plate was annealed.
As a result, the bending of the electric cobalt plate was not sufficiently corrected. For this reason, bending was corrected with a press machine, but in the process, two electric cobalt plates broke.

  As described above, it was found that the bending is easily corrected by stacking the electric cobalt plates in a direction in which the bending is convex upward.

A Electric cobalt plate 1 Annealing furnace 11 Carbon rod 12 Thermometer 13 Vacuum exhaust port 14 Gas inlet

Claims (3)

In annealing the electric cobalt plate obtained by electrowinning,
A method for correcting the bending of an electric cobalt plate, wherein a plurality of the electric cobalt plates are arranged in an uppermost stage and a lowermost stage, and the electric cobalt plates are stacked in a direction in which the bending is convex upward. The method for correcting the bending of an electric cobalt plate according to claim 1, wherein the electric cobalt plate is annealed by holding the furnace temperature at 800-1200 ° C for 10-15 hours and then cooling to 200 ° C or less. . The method for correcting the bending of an electric cobalt plate according to claim 1 or 2, wherein the time required for annealing the electric cobalt plate is substantially the same as the time required for obtaining the electric cobalt plate by electrowinning.

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