JP2003277067A - Method for manufacturing nickel sulfide with excellent oxidation resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing nickel sulfide with excellent oxidation resistance. <P>SOLUTION: The method is characterized by making gaseous hydrogen sulfide pass through an aqueous solution containing nickel ions and sulfurating nickel or by a method consisting of adding sodium hydrosulfide to the aqueous solution containing nickel ions, sulfurating nickel and obtaining nickel sulfide. The method is characterized by adding metal powder to the aqueous solution. Also the aqueous solution containing nickel ions preferably comprises nickel sulfate, and the metal powder to be added in the sulfuration reaction is preferably copper powder. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing nickel sulfide having excellent oxidation resistance, and more specifically,
The present invention relates to a method for producing nickel sulfide from nickel sulfide, which has a low oxidation rate of sulfur in the nickel sulfide when nickel is leached with chlorine.

[0002]

2. Description of the Related Art When smelting metals, it is advantageous in terms of costs such as transportation costs that the produced ore can be refined to the final metal at the hill, but the life of mine, location conditions, smelter construction Due to various conditions such as investment in the mine, it is also common to limit production to concentrates and intermediate raw materials at the foot of the mine, and then transport this to a smelter with sufficient conditions to finish it into a final product. .

In the case of nickel as well, an optimum smelting method is selected from the same idea. One of the selected methods,
An aqueous solution of nickel obtained by adding a sulfiding agent such as sodium hydrosulfide (NaHS) to a solution in which nickel ore has been leached with sulfuric acid or the like to form a sulfide, which is used as an intermediate raw material, and leaching the intermediate raw material with chlorine or the like. There is a process of electrowinning to obtain electric nickel.

In this process, most of the impurities contained in the ore can be separated in the sulfurization step, so that a high-purity intermediate raw material can be obtained as compared with the case of finishing in the form of intermediate raw materials such as oxides and hydroxides. There is an advantage that it is easy and the burden of impurity treatment in the refining process can be reduced.

When the intermediate raw material is a sulfide, the nickel grade can be made relatively high, and the sulfur produced in the leaching residue can be easily reused when leaching nickel in a later step. There are many features such as

However, nickel sulfide may oxidize sulfur during leaching with chlorine. When sulfur in sulfide oxidizes, the concentration of SO ₄ ions in the electrolytic solution rises, and when SO ₄ concentration in the electrolytic solution rises excessively, the conductivity of the electrolytic solution decreases and the power cost rises. Becomes

Further, the increase in SO ₄ concentration lowers the current efficiency of chlorine generation at the anode during nickel electrowinning,
Since oxygen is easily generated together with chlorine, deterioration of the electrode is promoted, which contributes to cost increase. Therefore, in order to prevent such a situation, the SO ₄ concentration must be maintained below a certain limit by periodically neutralizing the electrolytic solution or the like and discharging it out of the system. The cost of processing has become a heavy burden.

Therefore, in order to prevent the SO ₄ concentration in the nickel electrolytic solution from rising, that is, in order to reduce the cost, it is preferable to suppress the oxidation of sulfur in the sulfide. The main cause of sulfur oxidation is due to excessive chlorine gas being blown in, but when chlorine is not sufficiently blown in, the amount of nickel remaining without being leached increases, resulting in operational loss. There is an essential problem.

As described above, in order to suppress the oxidation of sulfur, it is necessary to adjust the leaching conditions such as the leaching temperature and the leaching time and the blowing amount of chlorine, but it is difficult to quantitatively control these. , Was a difficulty in operation.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides a form of nickel sulfide having excellent oxidation resistance during the production of the nickel sulfide so that oxidation of sulfur can be suppressed when chlorine leaching a nickel sulfide raw material. To do.

[0011]

In order to solve the above problems, in the first aspect of the present invention, hydrogen sulfide gas is used as the sulfiding agent. The second aspect of the present invention is a method in which sodium hydrosulfide is added as a solid or a liquid sulfidizing agent in which sodium hydrosulfide is dissolved is used, and at the same time, a sulfidation reaction is performed while interposing a metal such as copper.

The method of the present invention is a method for producing nickel sulfide having excellent oxidation resistance, which is characterized in that hydrogen sulfide gas is passed through an aqueous solution containing nickel ions to sulfide nickel. A method for obtaining nickel sulfide by adding sodium hydrosulfide to an aqueous solution containing ions to obtain nickel sulfide is characterized by adding a metal powder to the aqueous solution. The metal powder added during the sulfurization reaction is preferably copper powder.

Further, in the above production method, the aqueous solution containing nickel ions for carrying out the present invention is nickel sulfate.

[0014]

DETAILED DESCRIPTION OF THE INVENTION A method itself for producing a sulfide by a sulfide reaction by simply blowing hydrogen sulfide gas is known. However, the present inventor has found that when the nickel sulfide produced by various sulfiding agents is subjected to chlorine leaching, there is a difference in the oxidation rate of sulfur at the time of leaching the obtained sulfide, depending on the sulfiding agent.

Specifically, when a sulfide produced by simply adding sodium hydrosulfide to an aqueous solution of nickel sulfate is leached with chlorine gas, when 99% of nickel is leached, about 20% of sulfur is simultaneously oxidized. Will be done. On the other hand, 99% if sulfide is produced using hydrogen sulfide gas
It has been found that, even if nickel is leached out, only 5% of sulfur is leached out, and when hydrogen sulfide gas is blown in, the sulfur oxidation rate at the time of chlorine leaching can be made lower than when sodium hydrosulfide is added. .

When the cause was investigated by using X-ray diffraction or the like, when sodium hydrosulfide was added, nickel sulfide was precipitated in the form of Ni ₃ S ₄ or the like. , Ni when blowing hydrogen sulfide gas
It has been found that it precipitates in the form of S.

From this fact, it can be said that the oxidation of nickel sulfide occurs because the sulfur in the sulfide is present in excess compared to nickel. Therefore, it is considered that the use of hydrogen sulfide gas capable of producing a sulfide in the form of NiS is an effective method for obtaining a sulfide in which sulfur is difficult to oxidize.

However, hydrogen sulfide gas is extremely toxic and requires careful handling and storage, and due to such a property, there is a drawback in that the investment amount for equipment is large. In contrast, sodium hydrosulfide is usually solid and can be safely handled. In addition, since it is easier to install than gas, there is an advantage that capital investment can be saved, and switching cannot be done easily.

Therefore, it is considered that the oxidation resistance can be improved if the excess sulfur can be fixed by some other method to bring the ratio of nickel and sulfur close to 1: 1. Here, iron, copper, and the like are known as metals that are highly reactive with sulfur. In particular, in the case of copper, it can be easily removed by electrowinning after leaching, and there is an advantage that no adverse effect is left on the electrowinning process of nickel. In the method of the present invention, the excess sulfur is fixed by adding a metal having a strong affinity with sulfur and easily forming a sulfide during the sulfurization reaction.

[0020]

Example (Comparative Example 1) While maintaining 1 liter of a sulfuric acid solution having a nickel concentration of 5 g / liter at 70 ° C., 5 g of sodium hydrosulfide was added as an anhydrous solution, and the mixture was stirred for sulfide. The amount of sulfur added to nickel is approximately equivalent in molar ratio. After 1 hour, it was filtered and vacuum dried. When the morphology after drying was examined by X-ray diffraction, a peak of Ni ₃ S ₄ was detected along with a peak of nickel sulfide being oxidized to NiSO ₄ .

Next, the sulfided sample was adjusted to a slurry concentration of 225 g / liter, mixed with a leachate prepared so that the copper concentration was 60 g / liter with CuCl ₂ .2H ₂ O, and the redox potential was obtained. Was maintained at 520 mV (Ag-AgCl) while chlorine gas was blown in for 3 hours. At this time, the nickel leaching rate was 98% and the sulfur oxidation rate was 12.9.
%Met.

Example 1 In the same manner as in Comparative Example 1, while maintaining 1 liter of a solution having a nickel concentration of 5 g / liter at 70 ° C., hydrogen sulfide gas was blown therein at a rate of 0.05 liter / min for 1 hour for sulfurization. did. When the sample was observed by X-ray diffraction after the completion, it was found that the peak was mainly NiS or NiS _1.03 . When this sample was subjected to chlorine leaching in the same manner as in Comparative Example 1, the nickel leaching rate was 98%, and the sulfur oxidation rate was 4.6%, which was considerably lower than that in Comparative Example 1.

Example 2 Using the same equipment as in Comparative Example 1, 1 liter of a solution having a nickel concentration of 5 g / liter was used.
While maintaining at 0 ° C, 7 g of sodium hydrosulfide and 2 g of copper powder were added as anhydrous and stirred for 1 hour to form a sulfide. When this sulfide was subjected to X-ray diffraction in the same manner as in Comparative Example 1, it was found to have NiS or NiS _1.03 along with the peak of CuS.
It was confirmed that a sulfide having the same morphology as in Example 1 was produced. When this sample was leached by the same method as in Comparative Example 1, the sulfur leaching rate was 5.7% with respect to the nickel leaching rate of 99%, which is close to that of Example 1, and the oxidation resistance is higher than that of Comparative Example 1. It was confirmed that it was improving. Although a copper sulfate solution was added in place of the copper powder, a peak of Ni ₃ O ₄ was shown by X-ray diffraction, and the form of the sulfide formed was the same as that of Comparative Example 1.

[0024]

According to the present invention, nickel can be leached while suppressing the oxidation of sulfur in nickel sulfide, and the cost in the refining process can be reduced.

Claims (4)

[Claims] 1. A method for producing nickel sulfide excellent in oxidation resistance, which comprises passing hydrogen sulfide gas through an aqueous solution containing nickel ions to sulfide nickel. 2. A method for obtaining nickel sulfide by adding sodium hydrosulfide to an aqueous solution containing nickel ions to obtain nickel sulfide, wherein a metal powder is added to the aqueous solution. An excellent method for producing nickel sulfide. 3. The method for producing nickel sulfide having excellent oxidation resistance according to claim 1, wherein the aqueous solution containing nickel ions is nickel sulfate. 4. The method for producing nickel sulfide having excellent oxidation resistance according to claim 2, wherein the metal powder is copper powder.