KR20100108746A - A method for nickel and precious metals recovery from nickel matte using an atmospheric direct leaching process - Google Patents

Abstract

PURPOSE: A method for collecting valuable metal from nickel matte using an atmospheric direct leaching process is provided to collect Ni, Co(Cobalt), and Cu from nickel matte without a pressure vessel by an atmospheric pressure direct leaching method. CONSTITUTION: A method for collecting valuable metal from nickel matte using an atmospheric direct leaching process comprises following steps. A nickel matte is pulverized(S100). First leaching solution is put into a reaction bath under atmospheric pressure, temperature is maintained at 80~85°C, and the pulverized nickel matte and oxygen are put into a reactor(S200). The first leaching solution is divided into the leached residue and leachate(S300). The second leaching solution is put into the reactor and is maintained at 90~95°C, and the leached residue and oxygen are put into the reactor(S400). The second leaching solution is divided into the final leached residue and the final leachate(S500).

Description

A method for nickel and precious metals recovery from nickel matte using an atmospheric direct leaching process

The present invention provides a method of leaching at atmospheric pressure conditions for recovering nickel and valuable metals from a nickel matte in the form of sulfide, and more specifically, atmospheric direct leaching method using oxygen and sulfuric acid under atmospheric pressure conditions. As a leaching process, the present invention relates to a wet smelting method for recovering nickel contained in a matt without the use of highly corrosive hydrochloric acid or a pressure vessel for high temperature and high pressure.

Nickel (Ni) is a metal resistant to oxidation and corrosion and is used for corrosion resistant alloys and electroplating. Nickel may be obtained by leaching (NiFe) ₉ S ₈ (pentlandite), Ni ₃ S ₂ (heazlewoodite), NiS (millerite), or the like. As a method for recovering nickel from the nickel matte, hydrochloric acid, ammonia, chlorine gas, or sulfuric acid is used.

Nickel matte atmospheric leaching method using hydrochloric acid is an expensive facility made of corrosion resistant materials due to environmental problems due to hydrogen sulfide (H2S) gas from the leaching process and chlorine (Cl2) gas from the electrolytic smelting process. There is a disadvantage that requires.

Nickel matte pressurized leaching method using ammonia requires complex pollution reduction facilities such as ammonia gas scrubber due to environmental problems of ammonia gas generated in the leaching process, and precious metals contained in nickel matte Since it is dissolved in the leaching solution together with nickel, a difficult process, which requires a high treatment cost, is required to recover the dissolved precious metals again.

Nickel matte atmospheric leaching method using chlorine (Cl 2) gas has the advantage that the reaction proceeds at room temperature, but there is a problem of using a toxic gas and chlorine (Cl 2) gas generated during electrowinning (electrowinning). In addition, since SO4 ions and Cl ions coexist, the solvent extraction process, which is a post-treatment process, is complicated.

The nickel matte pressure leaching method using sulfuric acid is advantageous in recovering precious metals concentrated in undissolved residues after leaching reactions, and leaching reactions such as nickel and copper easily occur, whereas Expensive pressure vessels with corrosion resistant materials are required due to temperature and pressure. In addition, there is a problem of the release of hydrogen sulfide (H 2 S) gas that can be generated during the leaching reaction.

In the method for recovering nickel and valuable metals according to an embodiment of the present invention, a grinding step of pulverizing the nickel mat, putting the first leaching solution in the reaction tank under normal pressure and maintaining a temperature of 80 ℃ or more and 85 ℃ or less, the reaction tank Into the reactor, the first leaching step of introducing the pulverized nickel mat into the reactor, the first separation step of separating the first leaching solution into the leaching residue and leaching filtrate, the second leaching solution under normal pressure to the reaction tank The second leaching step and the second leaching solution to put the leaching residue in the reactor, and the second leaching solution is separated into the final leaching residue and the final leaching filtrate to keep the temperature at 90 ℃ or more and 95 ℃ or less A second separation step may be included.

In the grinding step, the nickel mat may be pulverized to have an average particle size of 5 ~ 8㎛. In addition, the grinding step, the first grinding step of grinding the nickel mat to an average particle size of 55 ~ 60㎛ and the second grinding the nickel mat through the first grinding step further to make an average particle size of 5 ~ 8㎛ It may comprise a grinding step. In the second grinding step, the maximum particle size of the further crushed nickel mat may be 15㎛ or less.

In the first leaching step, the first leaching solution may include a nickel electrolytic solution having a sulfuric acid concentration of 40 ~ 60g / L and the final leaching filtrate. In addition, the first leaching solution is the volume ratio of the nickel electrolytic solution and the final leaching filtrate. 4: 1 may be mixed. In addition, in the first leaching step, the redox potential may be 380mV or more and 480mV or less by continuously adding oxygen.

In the second leaching step, the second leaching solution may include an iron precipitate (goethite) with iron of 40% or more and 50% or less and a nickel electrolytic solution having a concentration of 40-60 g / L sulfuric acid.

In addition, in the second leaching step, the redox potential may be 380mV or more and 480mV or less by continuously adding oxygen.

The final leaching filtrate may be used as the first leaching solution in the first leaching step, and may further comprise a smelting step of smelting the final leaching residue. In addition, in the first leaching step, the pulverized nickel mat may be continuously added to the reactor.

The present invention has a sulfide form of a nickel matte (matte) has an average particle size of 5 ~ 8um, the particle size of Max. It is pulverized into powder form with size less than 15um and leached. Atmospheric direct leaching process that uses only oxygen and sulfuric acid at atmospheric pressure is separated into 1st and 2nd stages to operate efficiently and made of materials resistant to corrosion. Leaching Ni in 99% (Min.), Co in 99.5% (Min.), Cu in 99.5% (Min.) In nickel matt without using expensive equipment such as expensive equipment or autoclave Recovered by filtrate.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

1 is a process chart showing a method for recovering nickel and valuable metals in a nickel mat according to an embodiment of the present invention.

Referring to Figure 1, the method for recovering nickel and valuable metals according to an embodiment of the present invention is a grinding step (S100), a first leaching step (S200), a first separation step (S300), a second leaching step ( S400), the second separation step S500 and the smelting step S600.

The grinding step S100 is a step of grinding the nickel mat raw material prior to the first leaching step S200. Nickel mat raw materials are granules and include nickel (Ni), cobalt (Co), copper (Cu), iron (Fe) and the like.

The grinding step S100 may include a first grinding step and a second grinding step. In the first grinding step, the nickel mat raw material is pulverized with a dry grinder to make an average particle size of 55 ~ 60㎛ or less, in the second grinding step it is wet pulverized to make an average particle size of 5 ~ 8㎛ or less. It is difficult to produce the average particle size of less than 4um by wet grinding, if the average particle size exceeds 8㎛ the dissolution rate of nickel (Ni) in the first leaching step (S200) is less than 95%. In this case, there is a problem that the final recovery of nickel is lower than 99%.

On the other hand, the maximum particle size of the nickel mat further ground in the second milling step is 15 µm or less.

The first leaching step (S200) is a step in which the first leaching solution is put in a reaction tank under atmospheric pressure, the temperature is maintained at 80 ° C. or higher and 85 ° C. or lower, and the crushed nickel mat and oxygen are introduced into the reaction tank.

The first leaching solution is a solution in which the nickel electrolytic solution and the final leaching filtrate are mixed. The nickel electrolytic solution is generated in the nickel electrolysis process and transferred to the first leaching step S200, and the final leaching filtrate is separated in the second separation step S500 and transferred to the first leaching step S200. The sulfuric acid concentration of the nickel electrolytic solution and the final leaching filtrate is 40-60 g / L, respectively, and the two solutions are mixed at a volume ratio of 4: 1.

The first leaching solution is introduced into the reactor and the temperature is maintained at 80 ° C or higher and 85 ° C or lower. If the temperature is lower than 80 ° C., the reaction rate is slowed, resulting in a final recovery of nickel lower than 99%. On the other hand, when the temperature is higher than 85 ° C., the sulfur (S) aggregates on the surface of the nickel mat particles, thereby increasing the particles. In this case, the final recovery of nickel is lower than 99%.

Oxygen-reduction potential (ORP) is maintained at 380 mV or more, preferably 380 mV or more and 480 mV or less by continuously introducing oxygen into the reactor. When the ORP is lower than 380 mV, hydrogen sulfide (H 2 S) gas is generated as shown in Chemical Formula 1, which is harmful to the environment. Furthermore, the use of pollution prevention equipment to solve this problem is less economical.

Ni3S2 + 3H2SO4 → 3NiSO4 + H2 + 2H2S

On the other hand, the introduced oxygen is pure oxygen.

Nickel mat is pulverized in the crushing step (S100), it is continuously added to the reactor and leached for 16 hours.

Formula 2 represents an individual reaction occurring in the first leaching step (S200). Schemes 1 and 2 show that nickel is leached and hydrogen ions react with oxygen to produce water. Schemes 3 and 5 show that the leaching of nickel is accelerated by catalysis of ferric sulfate in the final leaching filtrate. Indicates. Meanwhile, the ferrous sulfate produced at this time is reacted with sulfuric acid and oxygen again by Scheme 4 to form ferric sulfate.

Scheme 1: Ni3S2 + H2SO4 + 1 / 2O2 → NiSO4 + 2NiS + H2O

Scheme 2: NiS + H2SO4 + 1 / 2O2 → NiSO4 + S + H2O

Scheme 3: NiS + Fe2 (SO4) 3 → NiSO4 + 2FeSO4 + S

Scheme 4: 2FeSO4 + H2SO4 + 1 / 2O2 → Fe2 (SO4) 3 + H2O

Scheme 5: Ni3S2 + 3Fe2 (SO4) 3 → 3NiSO4 + 6FeSO4 + 2S

The first separation step (S300) is a step of separating the first leaching solution by filtering the leaching residue and the leaching filtrate. That is, the first leaching solution present at the bottom of the settling tank is filtered through a filter to separate the leaching residue and the leaching filtrate. The leaching filtrate is reloaded into the settling tank.

Meanwhile, the leaching filtrate remaining in the settling tank is sent to a separate iron (Fe) removal process. The sulfuric acid concentration of this leaching filtrate is 1 g / L or less because most of the sulfuric acid is consumed in the first leaching step (S200). Since the sulfuric acid concentration in the leaching filtrate is so low, less soda ash, a neutralizing agent, may be used in the iron removal process.

The second leaching step (S400) is a step of putting the second leaching solution in the reaction vessel under normal pressure to maintain the temperature at 90 ℃ or more and 95 ℃ or less, and injecting oxygen and leaching residue in the reaction tank.

The second leaching solution is a mixture of iron precipitate (goethite) with iron (Fe) of 40-50% and a nickel electrolytic solution with a concentration of 40-60 g / L sulfuric acid. The second leaching solution is added to the reactor and the temperature is maintained at 90 ° C or more and 95 ° C or less. If the temperature is lower than 90 ℃ it is difficult to obtain the final nickel dissolution rate of more than 99%, and if the temperature is higher than 95 ℃ it consumes too much energy, so economical.

Similarly to the first leaching step (S200), in the second leaching step (S400) ORP is maintained at 380mV or more, preferably 380mV or more and 480mV or less.

The leaching residue is from the first separation step (S300), is continuously added to the reactor and leached for 16 hours.

The second separation step S500 is similar to the first separation step S300. That is, the second separation step S500 is a step of filtering the second leach solution into a filter to separate the final leach residue and the final leach filtrate. The final leaching filtrate is reloaded into the settling tank.

Meanwhile, the final leaching filtrate remaining in the settling tank is sent to the first leaching step and reused as the first leaching solution.

Smelting step (S600) is a step of smelting the final leaching residue in the melting furnace. By going through the smelting step (S600), it is possible to recover the valuable metal concentrated in the final leaching residue.

Experimental Example

A nickel mat raw material containing 67.14% nickel (Ni), 0.76% cobalt (Co), 2.86% copper (Cu), 3.92% iron (Fe), and 25% sulfur (S) was used. Nickel (Ni), cobalt (Co), copper (Cu) and iron (Fe) were quantitatively analyzed by atomic absorption spectrophotometer (F-AAS), and sulfur (S) was analyzed by infrared spectroscopy using a CS analyzer. . X-ray diffraction analysis of the nickel mat raw material showed that the main component was Ni3S2 (heazlewoodite).

Experimental Example 1

In the grinding step, 1 kg of the nickel mat raw material was pulverized with a dry pulverizer to make an average particle size of 60 mu m, and then further pulverized with a wet pulverizer to obtain a powder having an average particle size of 4.6 mu m and a maximum particle diameter of 14.3 mu m.

In the first leaching step, 20L of a leaching solution having a sulfuric acid concentration of 55 g / L and a final leaching filtrate mixed at a volume ratio of 4: 1 was placed in a 30L reactor and kept at 80 ° C, and oxygen was added to the reactor. 1 kg of nickel matte powder was continuously added while maintaining a redox potential (ORP) at 380 mV or more, and leached for 16 hours.

In the first separation step, the leach solution was filtered to separate the leach residue and the leach filtrate.

In the second leaching step, 45 g of iron goethite and 45 L of nickel electrolytic solution having a sulfuric acid concentration of 55 g / L generated in the iron removal process were placed in a 6 L reactor and the temperature was maintained at 90 to 95 ° C. Oxygen was added to the reactor, and 200 g of the leaching residue was continuously added while leaching for 16 hours while maintaining the redox potential at 380 mV or more.

Experimental Example 2

Except that the temperature was maintained at 85 ℃ in the first leaching step was carried out in the same manner as in Experiment 1.

Experimental Example 3

The nickel mat was wet pulverized in the first leaching step, and was tested in the same manner as in Experiment 1 except that the average particle size became 5.7 μm.

Experimental Example 4

The nickel mat was wet pulverized in the first leaching step, and the experiment was performed in the same manner as in Experimental Example 1 except that the average particle size became 7.6 μm.

Comparative Example 1

Experiment was carried out in the same manner as in Experiment 1, except that the temperature was maintained at 70 ℃ in the first leaching step.

Comparative Example 2

The experiment was carried out in the same manner as in Experiment 1, except that the temperature was maintained at 95 ° C. in the first leaching step.

Comparative Example 3

The nickel mat was wet pulverized in the first leaching step, and was tested in the same manner as in Experimental Example 1, except that the average particle size was 8.3 μm.

Comparative Example 4

Except that the temperature was maintained at 85 ~ 90 ℃ in the second leaching step was carried out in the same manner as in Experiment 2.

The results of the experiment as described above are shown in Table 1 below.

Average particle size
(Μm) First leaching stage reactor temperature
(℃) Second leaching stage reactor temperature
(℃) Recovery rate (%) Nickel (Ni) Cobalt (Co) Copper (Cu) Experimental Example 1 4.6 80 90-95 99.4 99.7 99.9 Experimental Example 2 4.6 85 90-95 99.3 99.6 99.8 Experimental Example 3 5.7 80 90-95 99.4 99.5 99.7 Experimental Example 4 7.6 80 90-95 99.4 99.8 99.8 Comparative Example 1 4.6 70 90-95 97.5 98.9 99.8 Comparative Example 2 4.6 95 90-95 97.3 98.8 99.2 Comparative Example 3 8.3 80 90-95 97.7 99.1 99.3 Comparative Example 4 4.6 85 85-90 97.8 99.0 99.1

Experimental Example 1 Experimental result of ~ 4

As a result of analyzing the final leaching residue and leaching filtrate produced in Experimental Example 1 it was possible to recover 99.4% of nickel (Ni), 99.7% of cobalt (Co), 99.9% of copper (Cu) in the nickel mat.

As a result of analyzing the final leaching residue and the leaching filtrate produced in Experiment 2, it was possible to recover 99.3% of nickel (Ni), 99.6% of cobalt (Co), 99.8% of copper (Cu) in the nickel mat.

As a result of analyzing the final leaching residue and the leaching filtrate produced in Experiment 3, it was possible to recover 99.4% of nickel (Ni), 99.5% of cobalt (Co), and 99.7% of copper (Cu) in the nickel mat.

As a result of analyzing the final leaching residue and the leaching filtrate produced in Experimental Example 4 it was possible to recover 99.4% of nickel (Ni), 99.8% of cobalt (Co), 99.8% of copper (Cu) in the nickel mat.

Comparative Example 1 Experimental result of ~ 4

As a result of analyzing the final leaching residue and the leaching filtrate produced in Comparative Example 1, it was possible to recover 97.5% of nickel (Ni), 98.9% of cobalt (Co), and 99.8% of copper (Cu) in the nickel mat.

As a result of analyzing the final leaching residue and the leaching filtrate produced in Comparative Example 2, it was possible to recover 97.3% of nickel (Ni), 98.8% of cobalt (Co), 99.2% of copper (Cu) in the nickel mat.

As a result of analyzing the final leaching residue and leaching filtrate produced in Comparative Example 3, it was possible to recover 97.7% of nickel (Ni), 99.1% of cobalt (Co), and 99.3% of copper (Cu) in the nickel mat.

As a result of analyzing the final leaching residue and leaching filtrate produced in Comparative Example 4, 97.8% of nickel (Ni), 99.0% of cobalt (Co), and 99.1% of copper (Cu) in the nickel mat were recovered.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it is within the scope of the present invention.

1 is a process chart showing a method for recovering nickel and valuable metals in a nickel mat according to an embodiment of the present invention.

Claims (12)

Grinding step of crushing nickel mat, A first leaching step of putting the first leaching solution in a reaction tank at atmospheric pressure to maintain the temperature at 80 ° C. or higher and 85 ° C. or lower, injecting oxygen into the reaction tank, and adding the crushed nickel mat to the reaction tank; A first separation step of separating the first leaching solution into a leaching residue and a leaching filtrate, A second leaching step of putting a second leaching solution in a reaction vessel under normal pressure, maintaining a temperature of 90 ° C. or higher and 95 ° C. or lower, injecting oxygen into the reaction tank, and introducing the leaching residue into the reaction tank; A second separation step of separating the second leach solution into a final leach residue and a final leach filtrate Method for recovering nickel and valuable metals comprising a. In claim 1, In the grinding step, A method for recovering nickel and valuable metals by grinding the nickel mat to an average particle size of 5 ~ 8㎛. In claim 1, The grinding step, A first grinding step of grinding the nickel mat to obtain an average particle size of 55 to 60 µm and And a second grinding step of further grinding the nickel mat having passed through the first grinding step to obtain an average particle size of 5 to 8 µm. 4. The method of claim 3, In the second milling step, The method for recovering nickel and valuable metals having a maximum particle diameter of the further pulverized nickel mat is 15㎛ or less. The method according to any one of claims 1 to 3, In the first leaching step, The first leaching solution is a method for recovering nickel and valuable metals comprising a nickel electrolytic solution having a sulfuric acid concentration of 40 ~ 60g / L and the final leaching filtrate. In claim 5, The first leaching solution has a volume ratio of the nickel electrolytic solution and the final leaching filtrate. Recovery of nickel and valuable metals mixed at 4: 1. The method according to any one of claims 1 to 3, In the first leaching step, A method for recovering nickel and valuable metals having a redox potential of 380 mV or more and 480 mV or less by continuously introducing oxygen. The method according to any one of claims 1 to 3, In the second leaching step, The second leaching solution is a method for recovering nickel and valuable metals including iron precipitate (goethite) of iron 40% or more and 50% or less and a nickel electrolytic solution having a sulfuric acid concentration of 40 ~ 60g / L. The method according to any one of claims 1 to 3, In the second leaching step, A method for recovering nickel and valuable metals having a redox potential of 380 mV or more and 480 mV or less by continuously introducing oxygen. The method according to any one of claims 1 to 3, Recovering nickel and valuable metals using the final leaching filtrate as the first leaching solution in the first leaching step. The method according to any one of claims 1 to 3, And smelting the final leach residue to recover nickel and valuable metals. The method according to any one of claims 1 to 3, In the first leaching step, A method for recovering nickel and valuable metals in which the crushed nickel mat is continuously introduced into the reactor.

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