JPS6350328A - Production of nickel carbonate - Google Patents

Abstract

PURPOSE:To produce high-purity NiCO3 used for Ni-Zn plating at a low cost by dissolving powdery Ni granule into a soln. contg. NH3 and carbonic acid and adding powdery Zn granule to the part of the soln. to remove impurities and thereafter pyrolytically decomposing it. CONSTITUTION:Ammonium carbonate complex of Ni [Ni(NH3)6CO3] is produced by adding 1mol powdery Ni granule to a dissolving tank 10 housed with a soln. contg. >=6mol NH3 and >=1mol carbonic acid and adding H2O2 and heating the mixture at room temp. -80 deg.C to batchwise dissolve it. Then after allowing this soln. to stand for 1-2hr, the one batch content of the upper part is transferred to an ion exchange tank 12, 0.05-1.0mol powdery metallic zinc granule is added, and impurities such as Co are deposited by performing ion exchange at normal temp. -60 deg.C and thereafter removed in a filtering stage 3A. Then pure Ni(NH3)6CO3 liquid is transferred to a pyrolytic installation 4 via a storage tank 14 and is heated at 85-100 deg.C to pyrolytically-decompose it, and the obtained NiCO3 contg. Zn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing high purity nickel carbonate for Ni--Zn plating.

[Prior Art] Ni-Zn plating is widely used in plated steel sheets for automobiles and home appliances due to its excellent corrosion resistance.

It is said that the plating composition is preferably about Zn:Ni-87:13.

The Ni for this plating is usually nickel carbonate (NiC
O3) is used, but impurities such as Co, Fe+Cu+Pb+Cd, etc. are required to be absent or in very small amounts in order not to impair the plating properties.

Conventional methods for producing high-purity nickel carbonate generally involve the first
It is based on the process shown in Figure 0. That is, Ni matte (Ni
Air, water, and if necessary sulfur are added to Snea (2 to 73% Ni) for pressure extraction 50, followed by filtration 51.
The residue was removed to obtain crude NiSO4, which was purified in step 5.
2 and remove impurities to obtain a pure N15Oa liquid, then add soda ash Na2COi and perform a carbonation reaction 53,
Filter and wash with water 54, use the Na2SO4 wastewater as a raw material for fertilizer, etc., and then dry the cake 55,
Nickel carbonate NiCO3 is obtained.

[Problem that the invention seeks to solve]

However, the conventional method described above requires a reaction at high temperature and high pressure, and the sulfur and soda ash are disposable, making the product nickel carbonate extremely expensive.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a manufacturing method for obtaining extremely inexpensive and highly pure nickel carbonate for Ni--Zn plating.

Another object is to provide a manufacturing method that is rational as a manufacturing process and requires simple manufacturing equipment.

Means for Solving Problem C] The present invention for solving the above problems consists of dissolving Ni powder in a solution containing ammonia and carbonic acid to form an ammonium carbonate complex salt of nickel (Ni(N)). lz)b
cOi) is generated, then it is allowed to settle, and only the upper solution part is transferred to another container, metal zinc powder is added to this, impurities such as Co are precipitated and separated, and the liquid from which the impurities have been separated is obtained. It is characterized by obtaining Zn-containing nickel carbonate through thermal decomposition.

[For production]

The method of the present invention is basically a normal temperature and normal pressure method, ammonia can be reused, and the raw material Ni powder is inexpensive, making it an inexpensive packaging method overall.

On the other hand, as described above, nickel carbonate for plating, which is the object of the present invention, is extremely susceptible to contamination with impurities from the viewpoint of plating properties. However, when Zn powder is added according to the present invention, since Zn has a strong ionization tendency, for example, dissolved Co(NH3)6CO3 undergoes ion exchange with Zn and Co precipitates. Cu
Impurities such as , Fe, Pb, and Cd are precipitated, and the final product has a high purity with a content of each impurity of 5 PPFI or less.

By the way, the present invention is fortunately applicable to Ni for Zn Ni plating.
Since the purpose is to produce CO3, there is no problem in adding Zn as an impurity separating agent. This point is the novel idea of the present inventors, and is the greatest feature of the present invention.

On the other hand, when Ni powder is dissolved in an ammonium carbonate solution, it has become clear that the higher the Ni powder slurry is, the easier it is for Ni to dissolve, as will be described later. Moreover, in this case, if Ni is to be dissolved continuously and transferred to the F-seal ion exchange process, a solution with a high seismic intensity and a high slurry concentration must be continuously transferred to the ion exchange process. Therefore, troubles such as clogging of the transfer line are likely to occur. Further, in order to transfer only the dissolved Ni content to the ion exchange process, the automatic control system becomes complicated and equipment costs increase.

Therefore, according to the present invention, by using the punch method, it is possible to reduce Ni loss in a solution with a high Ni concentration, and to perform a smooth transfer operation to the next ion exchange step.

[Specific examples of the invention]

The present invention will be explained in more detail below.

Figures 1 and 2 are schematic process diagrams of the method of the present invention.
3. :>, ,; and for an aqueous solution in which Co2 is present,
Xi powder (m-element nickel) for use in powder metallurgy and catalysts, etc.) is added, and NH:+dissolution 1 is performed. This dissolution may be carried out by bubbling air or oxygen, but preferably by adding hydrogen peroxide intermittently or continuously. This dissolution reaction is expressed by equation (1).

Ni + -02+ 6NH, + Co□→N1(NH
z) bcO3... (1) In this reaction, since the Ni powder originally contains the impurity described in 1, this impurity dissolves in the form of Co (NHI, CO3, etc.), (11
As is clear from the formula, 6 mol or more of ammonia and 1 mol or more of carbonic acid (CO2) are required for 1 mol of N j powder. The melting temperature is preferably about room temperature to 80'C. When the temperature exceeds 80℃, Ni (N11.), CO
, there is a risk of thermal decomposition of .

The dissolution is performed, for example, in the dissolution tank 10 for 20 hours while stirring using the stirrer 11. After dissolving, for example, about 1
After settling for ~2 hours, the upper hatch was transferred to the next empty ion exchange tank 12. One batch taken out is charged into the υf tank from the recovery liquid tank 13. If necessary, 218-2 may be performed prior to this transfer.

In any case, Zn powder is added to 6 cOz of crude N1 (NH3) after dissolution, and ion exchange 3 is performed based on (2) 2, followed by filtration 3A of the slurry liquid.

N1(NH3)6cO3+ Co(NHa)i, cOz
+ -...+ Zn In this ion exchange, each impurity is reliably precipitated because Zn has a large tendency to ionize. Then, if the slurry liquid is filtered, N1(NH3)6
A mixed solution of CO3 and Zn(NH)6coz is obtained.

The ion exchange temperature is preferably room temperature to 60°C, and 60°C
If it exceeds, Zn will be dissolved preferentially and ion exchange will not be carried out sufficiently.

As mentioned above, the amount of Zn added to Ni is approximately
:N1 = 87 : Since the aim is a weight ratio of 13, a maximum of 6.1 mol can be added per 1 mol of Ni, but considering the loss due to precipitated Ni, 0.0
The amount is preferably 5 to 1.0 mol, most preferably about 0.1 mol.

In actual equipment, Zn is added at a rate of 1 to 50 g/N.

Thereafter, the N1(NH+) 6cO+ pure solution obtained in this way was heated at 85 to 100°C, usually about 93 to 94°C (
3) Perform thermal decomposition of 2.

Ni (NH3) 6CO3+ Zn (NHi) b
cOz =NiCoff ↓+ZnC0z↓
(3) In this thermal decomposition reaction, a continuous distillation column with trays may be used, and steam may be directly blown from the bottom of the column. However, since nickel carbonate is sticky, It is preferable to use a batch system using a single tank which does not clog the filtrate, and therefore it is suitable to charge the filtrate stored in the filtrate storage tank 14 once. The ammonia evaporated in this distillation/pyrolysis step 4 is recovered by the NH recovery equipment 5 and reused.

The obtained Zn-containing nickel carbonate slurry is filtered and washed with water 6, and then dehydrated and dried to obtain a product.

Incidentally, in the above example, Ni powder was used, but Ni particles may be used as long as the dissolution time is longer.

In this sense, it is referred to as "Ni powder" in the present invention.

The same applies to Zn. It is desired that the Ni powder has a purity of 98% or more, most preferably 99% or more.

On the other hand, the solubility of Ni depends on various conditions.

In other words, as shown in Figure 3, as the dissolution time increases, N
i QM degree increases, NH3 = 9 mol/e(
Since the ammonia concentration is almost saturated at 153 g/N), the ammonia concentration is preferably 150 g/It to 200 g/A.

Further, as shown in FIG. 4, the higher the melting temperature, the better the solubility, but even if the temperature exceeds 45 degrees, the solubility does not change much, so a temperature of about 40 to 60 degrees Celsius is preferable.

As shown in Figure 5, the higher the rotation speed of the rotating blade, the higher the solubility, but considering the limits of the rotating motor,
00rp is desirable. As shown in FIG. 6, the Ni powder slurry concentration is preferably high, preferably 8 to 12 mol/ff. Furthermore, as shown in FIG. 7, N i ? When the Q degree is high, Ni loss is small and Zn is easily dissolved.

As shown in Figure 8, it is preferable to use hydrogen peroxide rather than air, and it is better to use a large amount of hydrogen peroxide.However, when adding hydrogen peroxide to a given area, as shown in C, 7 ml is added every hour. Total 14mj in time! A dispensing or continuous addition method is preferable because it is convenient to add. The amount of hydrogen peroxide added is preferably 0.8 mol/1 or more in molar ratio to Ni.

On the other hand, in order to reduce the Ni loss and the undissolved amount of Zn, the amount of Zn added is 20 to 3, as shown in Figure 9.
5 g/l is preferred.

〔Example〕

Next, examples will be shown.

Under the process shown in Figure 2, first Ni? 8 solutions were carried out in a hatched manner.

As the Ni powder, one manufactured by Kanto Kagaku Orensha was used, and liquid 1 containing 102 g/β of NJ and 44 g of CO2 was used! ! 116g was added to. After dissolving, Zn powder with a purity of 99% or more was added at a ratio of 33 g/β, and
Ion exchange was performed while stirring at 30° C. for 1 hour.

In the dissolution process, the dissolution characteristics as shown in Figure 3 are observed, and the dissolution characteristics are approximately 5.
The saturation concentration was 58 g/l at 0 hours.

In addition, after ion exchange, the obtained N1C (h product is the first
As shown in the table, it was of high purity. On the other hand, as shown in the same table, those without ion exchange had extremely poor purity.

Table 1 [Effects of the Invention] As described above, according to the present invention, highly pure and inexpensive nickel carbonate for Zn-Ni can be obtained through an economical process. Further, Ni can be efficiently dissolved using simple equipment.

[Brief explanation of drawings]

FIG. 1 is an illustrative process diagram of the method of the present invention, FIG. 2 is a schematic diagram of an experimental apparatus, FIGS. 3 to 9 are diagrams of dissolution characteristics of Ni or Zn, and FIG. 10 is a process diagram of the conventional method. Fig. 1 Fig. 4 Fig. 5 Raneko Ginmon (H) Fig. 6 Fig. 7 Figure 9 Zn ?# Addition (g/N+ Figure 10 No. iCO3

Claims (2)

[Claims] (1) Ni powder is dissolved in a solution containing ammonia and carbonic acid in a batch manner to produce ammonium carbonate complex salt of nickel (Ni(NH_3)_6CO_3), and then,
After this is allowed to settle, only the upper solution portion is transferred to another container, metal zinc powder is added thereto, impurities such as Co are precipitated and separated, and the liquid from which the impurities have been separated is thermally decomposed to produce Zn-containing carbonate. A method for producing high-purity nickel carbonate for Ni/Zn plating, characterized by obtaining nickel. (2) A method for producing high-purity nickel carbonate for Ni/Zn plating according to claim 1, in which pyrolysis is carried out for each batch in a single distillation facility without trays.