JPH10218623A - Removal of ammonium salt in nickel sulfate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove ammonium salt in nickel sulfate crystals through simple operations and not via complicated dissolution or neutralization steps by firing nickel sulfate containing ammonium salts while a carrier gas is fed at a specific rate and the nickel sulfate is heated at a specific temperature. SOLUTION: Ammonium salt-containing nickel sulfate is fired by heating at 550-800 deg.C for more than 90 minutes, as the flow rate of the carrier gas as air or nitrogen is kept at >=0.1m/min. In a preferred embodiment, the flow rate of the carrier gas is pref. set to 0.3-1.5m/min. Under the firing conditions, the ammonium salt can be removed whereby high-purity nickel sulfate is obtained for nickel plating with an ammonium content of <=0.05% ammonium. The removed ammonium salt can be recovered in a solid form by cooing the carrier gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing high-purity nickel sulfate, and more particularly to a method for removing ammonium salts from nickel sulfate containing ammonium salts.

[0002]

2. Description of the Related Art Nickel sulfate is used as a raw material for nickel plating, an aluminum color former, a battery material, and a raw material for producing various chemical products. Such nickel sulfate crystals usually contain ammonium salts as impurities in the form of ammonium sulfate and nickel ammonium sulfate.

However, with the recent technological innovation, nickel sulfate used for certain applications has been required to have higher purity. In particular, nickel sulfate used as a raw material for nickel plating is , The content of ammonium salt is required to be 0.05% by weight or less as ammonia. In order to meet such quality requirements, it is necessary to remove ammonium salts from nickel sulfate,
The following method was used.

That is, water is added to nickel sulfate containing an ammonium salt and redissolved to form an aqueous solution containing nickel sulfate and an ammonium salt. Then, sodium hydroxide or sodium carbonate is added to convert nickel to a hydroxide or nickel hydroxide. Solid-liquid separation as carbonate. The nickel hydroxide or carbonate obtained in this manner is washed with water, dissolved in sulfuric acid, and further concentrated and crystallized to obtain nickel sulfate-free crystals.

[0005] However, such a conventional method for removing ammonium salts includes a dissolution-neutralization-dissolution step.
Neutralizing agents such as sodium hydroxide and sodium carbonate are required, complicated operations and complicated facilities are required for solid-liquid separation, and a large amount of water is required for washing nickel hydroxide or carbonate. There was a problem that.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention provides a method for efficiently removing an ammonium salt from nickel sulfate crystals by a simple operation without performing complicated steps such as dissolution and neutralization. It is an object to provide a method of removing well.

[0007]

In order to achieve the above object, the present invention provides a method for removing an ammonium salt in nickel sulfate provided by heating nickel sulfate containing an ammonium salt to a temperature of 550 to 800 ° C. 0.1m
And roasting while supplying at a flow rate of / min or more.

In the method for removing ammonium salts in nickel sulfate according to the present invention, the roasting time is set to 90 minutes or more, and air or nitrogen gas is used as a carrier gas, and the flow rate is set to 0.3 to 3.0. It is preferably 1.5 m / min.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the method according to the present invention, the higher the heating temperature, the faster the reaction for removing ammonium salts. However, when the heating temperature is lower than 550 ° C., the progress of the ammonium salt removal reaction becomes extremely slow, and conversely, when roasting at a temperature higher than 800 ° C., nickel sulfate changes to nickel oxide, so that 550 to 800 ° C. It is necessary to roast at the temperature.

[0010] Maintaining the flow rate of the carrier gas at 0.1 m / min or more is necessary for the progress of the ammonium salt removal reaction. However, in order to efficiently achieve a final ammonia content of 0.05% by weight, the flow rate of the carrier gas is preferably set to 0.3 m / min or more.
Even if the flow rate exceeds 1.5 m / min, the removal rate of the ammonium salt does not change much and the raw material is liable to be scattered. Therefore, the flow rate is preferably 1.5 m / min or less. Air or nitrogen gas is preferable as the carrier gas, but easily available air is sufficient.

Under the above roasting conditions, ammonium salts in nickel sulfate can be removed. In particular, in order to reduce the ammonia content to 0.05% or less as nickel sulfate as a nickel plating raw material, a heating temperature must be set. In general, the roasting time is preferably 90 minutes or more, depending on the flow rate of the carrier gas.

As described above, in the present invention, nickel sulfate can be removed from nickel sulfate by a simple dry method without going through complicated steps such as dissolution and neutralization, and thus without using a neutralizing agent or a large amount of water. Ammonium salts can be removed.
Further, the removed ammonium salt can be recovered as a solid by cooling the carrier gas.

The effects of the above conditions in the method for removing ammonium salts in nickel sulfate according to the present invention will be further described by experiments using nickel ammonium sulfate as a reagent described below. In addition, the content of the ammonium salt was evaluated by the analytical value of ammonia.

Experimental Example 1 As an experimental device, a length of 115 mm, a width of 46 mm,
A magnetic tube having an inner diameter of 60 mm, into which a half-quartz cylindrical boat having a maximum height of 20 mm was inserted, was used. The magnetic tube was externally heated, and the temperature was measured at the center of the magnetic tube. The nickel grade in the nickel ammonium sulfate crystals (hexahydrate) used was 14.4% by weight, and the ammonia grade was 8.
18% by weight.

Into the above quartz boat, 50 g of the above nickel ammonium sulfate reagent was put, and while blowing air at 850 ml / min (corresponding to a flow rate of 0.3 m / min) as a carrier gas, the temperature was set to the set temperature shown in Table 1 for 120 minutes, respectively. Roasted. Thereafter, the roasted product was taken out and cooled, and the results of quantitative analysis of Ni and NH ₃ in the roasted product are shown in Table 1.

[0016]

[Table 1]

From the results in Table 1, it can be seen that the removal of the ammonium salt increases as the heating temperature increases. Even at a heating temperature of 350 ° C.,
Wt% ammonium salts have been removed,
And at 650 ° C., 99.7% by weight or more of ammonium salts were removed.

[0018]Experimental example 2  The same experimental apparatus and nickel ammonium sulfate as in Experimental Example 1
And the heating temperature is kept at 650 ° C (constant).
850 ml / min of air as Agus (flow rate 0.3 m / min)
The roasting time is shown in Table 2 below.
Was changed as follows. Ni grade and NH of the obtained roasted product_Three
Table 2 shows the quality.

[0019]

[Table 2]

From the results shown in Table 2, it can be seen that, when the heating temperature and the flow rate of the carrier gas are constant, the longer the roasting time, the more the removal of ammonium salts in the roasted product. In this test, the ammonia grade in the roasted product was 0.05% by weight in the roasting time of 90 minutes, but the roasting time to obtain the same ammonia grade was the amount of nickel ammonium sulfate, the heating temperature and the carrier gas. It changes according to the flow velocity.

Experimental Example 3 Using the same experimental apparatus and nickel ammonium sulfate as in Experimental Example 1, the heating temperature was maintained at 650 ° C. (constant), and the flow rate of air as a carrier gas was changed as shown in Table 3 below. Roast for 120 minutes. Ni and NH of the obtained roasted product
_Three of the quality shown in Table 3.

[0022]

[Table 3]

From the results in Table 3, it can be seen that as the flow rate of the air used as the carrier gas increases, the removal of ammonium salt is promoted, and the flow rate becomes 850 ml / min or more (at a flow rate of 0.1%).
(3 m / min or more), it can be seen that the ammonium salt is effectively removed.

In each of the above experiments, when the gas discharged from the experimental apparatus was collected and cooled, ammonium sulfate was recovered as a solid.

[0025]

EXAMPLE 1 Example 1 had a length of 115 mm, a width of 46 mm, and a maximum height of 20 mm.
Using a magnetic tube with an inner diameter of 60 mm into which a quartz boat having a half-cylindrical cylindrical shape is inserted, put 50 g of nickel sulfate recovered from the copper electrolytic refining process of copper smelting into a quartz boat in the magnetic tube,
The magnetic tube was externally heated, and the temperature was measured at the center of the magnetic tube. The quality of the nickel sulfate used was nickel: 2.
The content was 1.4% by weight, 0.006% by weight of copper, 0.2% by weight of iron, and 0.21% by weight of ammonia.

In the magnetic tube, 85 is supplied as air as a carrier gas.
5 ml while blowing at 0 ml / min (flow rate 0.3 m / min).
It was roasted at 50 ° C. for 120 minutes. Thereafter, the roasted product was taken out of the magnetic tube and cooled, and a quantitative analysis of the roasted product was performed. As a result, the grade of the obtained roasted product was nickel: 36.3.
% By weight, 0.01% by weight of copper, 0.34% by weight of iron, and 0.005% by weight or less of ammonia.

Example 2 In a quartz boat in the same magnetic tube as in Example 1 above, nickel recovered from the copper electrorefining step: 20.7% by weight, copper:
0.004% by weight, iron: 0.09% by weight, ammonia:
50 g of nickel sulfate containing 0.9% by weight was charged, and 850 ml / min of nitrogen gas was used as a carrier gas (at a flow rate of 0.9%).
(3 m / min) while roasting at 550 ° C. for 90 minutes. As a result of analyzing the obtained roasted product in the same manner as in Example 1, the quality of the roasted product was 36.2% by weight of nickel,
Copper: 0.006% by weight, iron: 0.15% by weight, ammonia: 0.005% by weight or less.

[0028]

According to the present invention, ammonium salt can be directly removed from nickel sulfate containing ammonium salt by a simple dry method, and the removed ammonium salt can be recovered as a solid.

Claims (3)

[Claims] 1. Nickel sulfate containing ammonium salt is heated to a temperature of 550 to 800 ° C., and a carrier gas is heated to 0.1 m.
A method for removing ammonium salts in nickel sulfate, characterized by roasting while supplying at a flow rate of not less than / min. 2. The method for removing ammonium salts in nickel sulfate according to claim 1, wherein the carrier gas is air or nitrogen gas, and the flow rate is 0.3 to 1.5 m / min. . 3. The method for removing ammonium salts in nickel sulfate according to claim 1, wherein the roasting time is 90 minutes or more.