JPH02172829A - Production of nickel carbonate or nickel oxide - Google Patents

Abstract

PURPOSE:To produce high purity nickel carbonate for plating at low cost by allowing NaOH solution to absorb CO2 to produce Na2CO3 solution and neutralizing this solution with refined NiSO4. CONSTITUTION:The NaOH solution is allowed to absorb CO2 gas in an absorption tower packed with packing to produce Na2CO3. Refined NiSO4 is added to produce NiCO3, which is then filtered, washed with water and dried to obtain high purity NiCO3. Further, high purity NiO can be obtained by decomposing the NiCO3 by heat.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing high-purity nickel carbonate or nickel oxide for plating and the like.

[Conventional technology]

Nickel or its alloy plating is often used to improve the corrosion resistance of steel plates.

The Ni source for this plating is usually nickel carbonate (N
i COv ) is used, but in order not to inhibit plating properties, Co, Fe, Cu, and Pb are used.

No or very small amount of impurities such as Cd and C1
It is required that the content of such substances is low.

Conventional methods for producing high-purity nickel carbonate generally involve
It is based on the process shown in the figure. That is, Ni matte (Nis
2 to 73%Ni), air, water, and if necessary, sulfur are added to extract under pressure 50 (, then filtration 51).
The residue was removed to obtain crude NiSO4, which was purified in step 5.
2 and remove impurities to obtain a N15O<pure liquid, then add industrial soda ash Nazc Off, perform a carbonation reaction 53, filter and wash with water 54, and NazS
The O4 wastewater is used as a raw material for fertilizer, and the cake is then dried to obtain nickel carbonate NjCOz.

[Problem to be solved by the invention]

However, as shown in Table 1, the industrial soda ash used in the above conventional method has extremely poor purity, making it impossible to obtain the desired high-purity nickel carbonate.

Table 1 (unit: ppm) Therefore, the main object of the present invention is to provide a method for producing high-purity nickel carbonate or nickel oxide at low cost.

[Means to solve the problem]

The method for producing nickel carbonate to solve the above problems is as follows:
By absorbing CO2 gas into NaOH aqueous solution, Na 2
The method is characterized in that a solution of CO is obtained and purified ZnSOs is added thereto to neutralize it to obtain nickel carbonate.

Further, in the method for producing nickel oxide of the present invention, COt gas is absorbed into an NaOH aqueous solution to obtain a Na□COj solution, which is neutralized by adding purified N t S Os to obtain nickel carbonate. It is characterized by obtaining nickel oxide by thermally decomposing nickel carbonate.

[Effect]

In the present invention, without using industrial soda ash, NaO
Since Na 2 COy is obtained by absorbing CO2 gas into an H aqueous solution, NaOH as a starting material is obtained by the mercury method or diaphragm method, and has extremely high purity, so the obtained Na 2 COs is also highly pure. Become. Moreover, N
Since aOH is inexpensive, the resulting zinc carbonate is also inexpensive.

[Specific structure of the invention]

The present invention will be explained in more detail below.

FIG. 1 is a schematic diagram of the method of the present invention.

1 is an absorption tower, and the inside thereof is filled with a filler 2. CO and gas are blown from the bottom, and Na from the top.
The OH aqueous solution is sprayed and in the process of falling comes into contact with CO2 gas to form NaC0z, which is extracted from the lower part and led to the neutralization tank 3.

Purified N i S O4 is added to this neutralization tank 3, and (
1) The neutralization reaction of the formula occurs and the aqueous solution of nickel carbonate is changed.

Na2COi+N15O*→N1COz +Na25O
The N i CO3 thus obtained is taken out as crystals by a crystal separator 4 such as a filter using washing water. Next, it is dried in a dryer 5 to obtain high purity N i CO3.
Available as crystals.

By the way, in the present invention, the above-mentioned purified NIS Oa refers to one having a purity shown in Table 2.

Table 2 (unit: ppm) In the present invention, when obtaining nickel oxide from the nickel carbonate obtained above, it is thermally decomposed in a thermal decomposition means 6 such as an annular furnace at a temperature higher than the thermal decomposition temperature of nickel carbonate. It is preferable that the CO2 gas produced by this thermal decomposition is returned to the absorption tower 1 via the return line 7 for circulation use, since the amount of supplementary CO2 gas passing through the supply line 8 is small.

〔Example〕

Next, an uninvented example will be shown.

Z, COI was produced in the laboratory at room temperature.

First, 10g of NaOH was made into a 5% aqueous solution, and the pH was adjusted to 13.7.
An aqueous NaOH solution was obtained. This was brought into contact with cO gas in a countercurrent manner in an absorption tower to obtain an aqueous solution of Na and CO5 with a pH of 10.3.

To this, 40.0 g//(7) of Ni SO4 solution with purity shown in Table 2 above and N1 content of 100 g//(7) was added for neutralization and crystallization. The end point pH at that time was 8.
It was 4.

After that, dehydration, washing, and drying are performed to reduce the N i COi end point to 9
I got g. The purity of both Co1Cu and Pb was 1 ppm or less, and the C/min was 10 ppm or less.

Next, heat this 9g of N i COs crystals to 600'C.
.

After thermal decomposition in an annular furnace for 1 hour, 5 g of NiO crystals were obtained. Its purity is shown in Table 3.

Table 3 (unit: ppm) [Comparative example] Using industrial soda ash having the purity (unit: ppm) shown in Table 1, nickel carbonate was obtained by the reaction of equation 11, which was dehydrated, washed and dried. When crystals of N r COy were obtained, the purity (unit: ppm) was as shown in Table 4.

Table 4 (Unit: ppm) [Effects of the Invention] As described above, according to the present invention, high purity nickel carbonate or nickel oxide can be produced through simple steps and at low cost.

[Brief explanation of the drawing]

FIG. 1 is an exemplary flow sheet of the present invention, and FIG. 2 is a flow sheet of a conventional method for producing nickel carbonate. l ... Absorption tower 2.3 ... Neutralization tank 4 ... Crystal separator 5 ... Dryer 6 ・
... Pyrolysis means patent applicant Sumitomo Metal Industries Co., Ltd. Taenaka Mining Co., Ltd. Agent Patent attorney Yoshihisa Nagai NtCO:s Procedural amendment (spontaneous) 1゜Indication of case 1988 Patent Application No. 328592 2゜Name of the invention Process for producing nickel carbonate or nickel oxide 3゜Relationship with the case of the person making the amendment

Claims (2)

[Claims] (1) By absorbing CO_2 gas into NaOH aqueous solution,
A method for producing nickel carbonate, which comprises obtaining a _2CO_3 solution and neutralizing it by adding purified NiSO_4 to obtain nickel carbonate. (2) By absorbing CO_2 gas into NaOH aqueous solution,
A method for producing nickel oxide, which comprises obtaining a _2CO_3 solution, neutralizing it by adding purified NiSO_4 to obtain nickel carbonate, and then thermally decomposing the nickel carbonate to obtain nickel oxide.