JPS59232285A - Electrolytic refining method of nickel - Google Patents

Abstract

PURPOSE:To deposit spherical metallic Ni having high quality in the stage of refining electrically Ni by covering the cathode to be deposited thereon with pure Ni with a non-conductive material to form partially exposed parts and regulating the pH and temp. of an electrolyte at specific values. CONSTITUTION:Electrolysis is performed by using a Watts bath as an electrolytic bath and a plate of Ni matte or crude metallic Ni as an anode to deposit electrolytically pure Ni on a cathode. The cathode plate in this case is formed by covering a rectangular strip-shaped conductive metal 1 with a non-conductive material 2 to form exposed parts 3 at a specified interval at the plural points in the longitudinal direction thereof. Electrolytic refining is performed by setting the pH of the Watts bath at 3.0-4.0 and the temp. thereof at >=50 deg.C, by which the nearly spherical pure Ni without having the gas holes existing therein owing to the hydrogen generated in the exposed parts 3 is deposited.

Description

[Detailed Description of the Invention] More specifically, various shapes of electrodepositing mother plates are used as the cathode, a nickel sulfide plate (hereinafter referred to as nickel matte), one of the crude metal nickel plates is used as the anode, and an aqueous solution of nickel sulfate and an aqueous solution of nickel chloride are used. A mixed bath (hereinafter referred to as Watt bath) is used as an electrolyte to produce metallic nickel that has a nearly spherical shape with almost no holes (hereinafter referred to as gas holes) created by gas generation on the surface. This paper relates to the electric refining method.

In electrolytic refining of nickel, as is well known, hydrogen gas is generated from the cathode side. This generation of hydrogen gas is remarkable when the pH of the electrolytic solution is low or when the cathode current density is high.

In the method of the present invention, the effective area of the cathode is small in order to obtain an electrodeposit having a nearly spherical shape. Therefore, in order to improve productivity,
Since it is necessary to increase the cathode current density (hereinafter abbreviated as D.K A/dm) as much as possible, the generation of gas holes due to hydrogen gas generation is particularly significant, which not only lowers the commercial value but also reduces current efficiency and power consumption. There was also a big problem in terms of units.

Therefore, in order to suppress this hydrogen gas generation, the initial D.
Electrolysis is carried out by suppressing K (electrode conductive part base) to 2Q A/am or less, and when the surface area of the electrodeposit becomes large, 2 to 3
The current is made stronger in each stage, and the final stage is D.

A method of increasing K 100 A/am or more was used. During this time, the pH of the electrolytic solution was maintained at 2.6 to 3.0 to suppress the sliding voltage and prevent the electrolysis power from becoming high.

However, this method has the disadvantage that productivity is significantly lower than that of the usual electrolytic method for collecting flat nickel.

An object of the present invention is to provide an electrolytic method that eliminates the above-mentioned drawbacks and obtains an electrodeposit having a smooth surface and a nearly spherical shape without gas holes, with productivity equivalent to that of conventional electrolytic methods.

In order to achieve this objective, the present inventors conducted extensive research on the conditions for electrolytic refining of nickel in a Watts bath, and found that by regulating the pH and temperature of the Watts bath, gas holes on the surface of the electrodeposit could be suppressed and production could be achieved. The present invention has been achieved by discovering that the properties of the present invention can be improved.

That is, in the method of the present invention, one of a nickel matte plate and a coarse metal nickel plate is used as an anode, a strip-shaped conductive metal is coated with a non-conductive material, and the conductive metal is exposed at intervals along the longitudinal edges of the anode. The mother plate for metal electrodeposition formed with the part is 1!3 poles, the Watt bath is an electrolyte, the temperature of the electrolyte is 30C or more, preferably 60C or more, I)B is 3.0 to 17-, preferably 3 ．． From left to right, electrolytic refining is performed with the temperature set to 0. .

According to this method, initially, l at K 110 A/dm
Metallic nickel in a desired shape can be efficiently obtained with a total life (about g days) at about Ig time and K at 1100vd or more.

In the method of the present invention, the temperature of the electrolytic solution is set to 50C or more, preferably 600C or more, because if it is lower than this, nickel hydroxide will precipitate on the cathode, especially in the early stage of electrolysis, causing gas holes and reducing current efficiency. Because it does.

This temperature is preferably about 70C or higher than OtsuOC.

In addition, the pH of the electrolyte should be 3.0 to 3.0, preferably 3.3.
The reason why the range is 1.0 to 1.0 is that if it is lower than this, hydrogen gas will be generated significantly as described above, and gas holes will be generated on the surface of the electrodeposited material.

In addition, at low pH, nickel hydroxide can be deposited on the electrode conductive part, and when the pH is higher than this, the cathode electrodeposit will contain nickel hydroxide, and the sliding voltage will also increase. .

Although the shape of the cathode used in the method of the present invention is not specified, when obtaining a spherical cathode, for example, those shown in FIGS. 1 and 3 are used. In the figure, / is a strip-shaped conductive metal, 2 is a non-conductive coating material that covers the surface of the conductive metal, and 3 is a conductive metal from a non-conductive covering material formed at intervals on the longitudinal edge of the conductive metal. The exposed part is the metal nickel electrodeposited part. Reference numeral 7 denotes a hanging hand for hanging the conductive metal on the bus bar.

FIG. 2 shows the state of electrodeposition.

According to the method of the present invention, as shown in the examples, there are almost no gas holes on the surface of the product, and metallic nickel having a desired shape with a smooth surface and uniform size can be efficiently obtained.

Examples will be described below.

Example Vertical //, 5' horizontal // 6 depth iso for each column, gox ioo x 10" at both ends of a vinyl chloride electrolytic cell with a capacity of a
(Thickness) 7 anodes each, width 2, in the middle of the anode.
Using 5US3/2 as the strip-shaped conductive metal shown in Figure 1 with a length of 3 am/QQu and a vinyl chloride plate as the non-conductive covering material, the exposed part 3 (area per 1 conductive part is A set of three rectangular strips with λ
,0,So/3! r XCI Ak, 0, Ma'
l0-0.4 2 COO,002% (IuO,00θ'71Feθ,
0θ/Each gjl is filled with an electrolytic solution with a predetermined pH value, the amount of liquid supplied is /ampere, adjusted to 50ml per 7 hours, maintained at the predetermined temperature with a water bath, and D K ′f for the initial 7g hours.
i:lIOA/dm %DK for the next 6 days/20
Electrolysis was carried out for 1J6m-lifeg days.

In addition, there are 7 cathode conductive parts (N output parts) for each 7 strips,
The average size of the spherical metallic nickel electrodeposited on this electrodeposited material was about 1 nmφ, but this electrolytic operation was repeated several times under the same conditions, and each electrodeposited material was randomly selected from the electrodeposited material. , 20 samples were taken, and gas holes on the surface of the electrodeposit were measured using calipers. The results are shown in the table below as average values per unit.

Table notes: *marks indicate comparative examples.

As is clear from the table, there were no large gas holes at all according to the method of the present invention, and almost no gas holes were observed under suitable conditions A6 and Arashi g.

In addition, gas holes of the magnitude of Experiment 1a s and q do not reduce the commercial value of the product and pose no practical problem.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of the first embodiment, FIG. 2 is a side view showing the electrodeposition state, and FIG. 3 is a partial perspective view of the λth embodiment. /...Strip-shaped conductive metal, λ...Electric non-conductive coating material, 3...Exposed part, Hiroshi...Handle. Applicant Sumitomo Metal Mining Co., Ltd. Agent Katsunari Nakamura Figure 1 Figure 2

Claims (1)

[Claims] (1) A base plate for metal electrodeposition, in which a nickel matte or coarse nickel is used as an anode, the surface of a conductive metal strip is coated with a non-conductive material, and exposed parts of the conductive metal are formed at intervals along the edges in the longitudinal direction. In the method of producing metallic nickel having a nearly spherical shape by electrolyzing a Watts bath, which is a mixed bath of a nickel sulfate aqueous solution and a nickel chloride aqueous solution, as a cathode and as an electrolyte, the pH of the electrolyte is 3.0 to 3.0 degrees, the temperature is 0. 300 or more.