JPH086150B2 - Method for separating and recovering valuable metals from manganese nodules or cobalt crusts - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for recovering valuable metals such as copper, nickel and cobalt from deep sea bottom manganese nodules or cobalt crusts.

[Conventional technology]

Manganese nodules and cobalt crusts from Cu, Ni, Co
Various methods for separating and recovering valuable metals have been tried. For example, the following methods are known as methods for recovering these from manganese nodules, but they have not yet been industrialized.

For example, (1) A method of performing wet reduction leaching with CO gas in the presence of copper ions to remove Mn as MnCO ₃ and recover Cu, Ni, and Co.

(2) A method of leaching Cu, Ni, and Co with 30% sulfuric acid under a high pressure of 245 ° C and a high pressure of 35 atm.

(3) After reducing by reacting with HCl gas at 500 ℃, water or HC
l Solution leaching method.

(4) Preheated and reduced in the presence of coke and CO gas at 625 to 1000 ° C, and at 1425 ° C Cu, Ni, Co are made into Fe alloy,
Mn and Fe are oxidized and removed as slag. Next, gypsum and coke were added to change Cu, Ni, and Co to sulfide matte, and 110
Method of leaching with 5% H ₂ SO ₄ at ℃.

(5) After leaching with a sulfurous acid solution, Fe and Mn are added to (NH ₄ ) ₂ CO ₃
It is a method of separating and recovering each metal by conventional solvent extraction or hydrometallurgy of electrolysis.

And so on.

[Problems to be solved by the invention]

The method (1) is called Kennecott Cuprion Process, and the reaction at room temperature and pressure has little effect on the environment, but the yield of Co is extremely low.

Moreover, since harmful carbon monoxide is used, there is a problem in terms of environmental hygiene and the cost is high.

Further, the high temperature / high pressure / sulfuric acid leaching method (2) not only makes it difficult to recycle sulfuric acid, but also poses a problem of corrosion resistance of the reaction vessel.

Further, although it can be said that most valuable metal components can be leached by the leaching method of (3) HCl gas reduction under high temperature-water or HCl, it is difficult to recover HCl (2)
Similar to the above method, there is a problem in the corrosion resistance of the reaction vessel.

In the dry smelting / sulfuric acid leaching method of (4), Mn recovery and disposal can be selected according to market conditions, and existing Ni smelting equipment can be used, but a problem that enormous energy is required to heat and dry the raw material There is.

The sulfurous acid leaching method of (5) has an advantage that it can be carried out at room temperature and atmospheric pressure, but when Mn is precipitated, separated and removed from the filtrate,
There is a problem that Co coprecipitates and the recovery rate of Co is as low as 70%.

References: Tadahito Mizoda, Yujiro Fujii, Yoshimi Kono Proceedings of the Spring Meeting of the Japan Mining Association P347〜348 1985 Thus, the conventional method has high reaction conditions such as high temperature and high pressure and high energy consumption. And, a particularly common drawback is that Co yields are low at 50 to 70%.

An object of the present invention is to solve all of the problems of the conventional methods, to provide a method of recovering valuable metals in a high yield at a low cost without causing environmental pollution.

[Specific means for solving problems]

The present invention uses a sulfurous acid solution to produce valuable components, particularly Co, Cu, Ni.
Is a method that can be recovered with a yield of 90% or more.

First, the crushed raw ore has a H ₂ SO ₃ concentration of 0.01 mol under normal temperature and pressure.
/ Stir in the above sulfite solution.

In the present invention, the sulfurous acid solution having a H ₂ SO ₃ concentration of 0.01 mol / or more is used, and the ground ore is stirred in this for at least 1 minute or more. The weight ratio of sulfite water and raw ore varies depending on the content of valuable components, but MO ₂ + H ₂ SO ₃ → M ²⁺ + SO ₄ ^2-
＋ H ₂ O (M: metal ion) equivalent amount of H ₂ SO ₃
If The ratio between the liquid amount of the sulfite water and the weight of the raw ore is not particularly limited as long as it can be mechanically stirred. The temperature can be room temperature and the pressure can be normal pressure, and it is not necessary to give special consideration to the reaction device or the like.

The filtrate, which has been leached with a sulfite solution, and subjected to solid-liquid separation by centrifugation, field press, etc., contains valuable components such as Co, Ni, Cu and Fe, Mn metal ions.

Air is blown into the obtained filtrate to completely oxidize Fe ²⁺ to Fe ^3+, and the precipitate of acidic Fe (OH) ₃ is purified and separated by filtration.

The reason for precipitating in the oxidized acidic region is that valuable components such as Co, Ni, Cu co-precipitate in the precipitation of Fe (OH) ₃ on the alkaline side.
This is because it is impossible to improve the recovery rate.

Therefore, Fe ²⁺ must be oxidized to Fe ³⁺ to form a precipitate on the acidic side.

Oxidation can be performed by sucking a gas containing oxygen into O ₂ , O ₃ , and air.

Ammonium carbonate is then added to the iron-free filtrate. This causes Mn to precipitate as MnCO ₃ , causing Cu, Ni, and C
This is because o is an ammine complex.

To further stabilize the ammine complex of Cu, Ni and Co, in particular to stabilize the ammine complex of Co,
Ammonium salts such as ammonium sulfite and ammonium sulfate are added, or ammonium water is added.

Add the above additives and stir in an oxidizing atmosphere to remove MnCO ₃
Is generated, precipitated, and left to stand, and most of the Mn content is separated by filtration.

The reason for stirring in an oxidizing atmosphere is that by oxidizing [Co (NH ₄ ) ₆ ] ²⁺ , which is an amine complex of Co, a more stable [C
This is to make o (NH ₄ ) ₆ ] ³⁺ .

When the stability constant is [Co (NH ₄ ) ₆ ] ³⁺ , logK = 133, [C
In case of o (NH ₄ ) ₆ ] ²⁺ , logK = 25.8, and in the case of divalent, the stability is low and it is easily decomposed during the operation. It is better to oxidize it to [Co (NH ₄ ) ₆ ] ³⁺ .

In addition, when the redox potential was examined for the oxidation of [Co (NH ₄ ) ₆ ] ²⁺ to [Co (NH ₄ ) ₆ ] ³⁺ , [Co (NH ₄ ) ₆ ] ³⁺ + e ⁻ = [Co ( NH ₄ ) ₆ ] ²⁺ E ₀ = 0.06V, which shows that the oxidation-reduction potential of [Co (NH ₄ ) ₆ ] ³⁺ is extremely low.

Since oxidation can be easily carried out at about this potential, air blowing, shaking in the air, or strong stirring is sufficient. Further reasons stand in this operation, since very slow reaction of MnCO ₃ from Mn, sufficient MnCO ₃
This is to allow precipitation ripening.

 It is also possible to heat to accelerate the formation of precipitate.

By doing so, Co, Cu, and Mi are not included in 9
It can be recovered in a solution with a recovery rate of 0% or more.

When Mn is not separated and recovered, a method of simultaneously separating Fe and Mn can be considered.

In this method, after leaching the raw ore with a sulfite solution, Co, Cu, Ni, Fe, Mn dissolved in the leaching solution and the leaching residue are separated by filtration, and the filtrate is oxidized by air to convert Fe ²⁺ to Fe ³⁺ . Then, add valuable components to the solution with ammonia water, ammonium carbonate, etc.
This is a method in which the Mn content is converted to MnCO ₃ for precipitation, and at the same time, the pH is raised to precipitate and separate the precipitation of Fe (OH) _{3 and} the precipitation of MnCO ₃ .

Further, a method of collectively separating the sulfurous acid solution leaching residue, Fe and Mn from the valuable component, that is, Fe ²⁺ contained in the solution containing the valuable component without removing the sulfite liquid leaching residue is set to Fe ^3+, and then
When Mn is generated in MnCO ₃ , pH is raised and Fe (OH) ₃ is precipitated at the same time to separate the valuable component from the valuable component.
Co19.3%, Cu9.8% and Ni5.8% remain, but valuable components can be recovered in the solution.

Since the raw ore grades of Mn and Fe are high, Mn and a trace amount of Fe, which are about the same as Cu and Ni, remain in the precious liquids of Co, Cu and Ni by any of the above methods.

As a method for further separating these, MnCO
It is also possible to add a coprecipitating agent that is expected to have a coprecipitation effect with ₃ .

The coprecipitant in this case is CaCl ₂ .

To separate Fe, Mn and valuable components, (NH ₄ ) ₂ CO ₃ and CaCl ₂ are added in an amount corresponding to the next reaction, and the mixture is precipitated and aged for 1 hour or more, and separated by filtration.

Mn ²⁺ ＋ CaCl ₂ ＋2 (NH ₄ ) ₂ CO ₃ → MnCO ₃ ↑ ＋ CaCO ₃ ↓ ＋ 2NH ₄ Cl ＋ 2NH ₄ ⁺ Fe, Mn co-precipitate CaCO ₃ efficiently and the concentration of Fe and Mn in the noble liquid Remarkably lower.

As described above, there is a method of separating Fe and Mn at the same time, but it is not suitable when each of Fe and Mn is to be effectively utilized individually.

〔Example〕

1g of manganese nodule with the chemical composition shown in Table 1
Add 100 ml of H ₂ SO ₃ 0.2 mol / sulfite water at 25 ℃
The valuable component was leached by shaking for time.

After leaching, solid-liquid separation was performed with a centrifuge. In the filtrate
Cu, Ni, Co, Mn, Fe ions are present. 26.7% of Fe contained in the original ore remained in the residue.

Next, air was blown into the filtrate at 500 ml / min for 2.5 hours for oxidation. ₃ ml of Na ₂ CO ₃ with a concentration of 0.5 mol / in the air-oxidized filtrate
Was added and the pH was adjusted to 4.04 and air oxidation was carried out for 1 hour.

This caused Fe to precipitate as Fe (OH) ₃ . This Fe
The solution containing the (OH) ₃ precipitate was centrifuged to separate the hydroxylated precipitate.

Add 5 g of (NH ₄ ) ₂ CO ₃ to the iron-free filtrate, and add 28% N
15 ml of H ₄ OH was added.

Further, ₅ gr of (NH ₄ ) ₂ SO ₄ was added to the filtrate, and 100 r.p.m1.
Shake for 5 hours.

After shaking, the solution was allowed to stand for 2 days to precipitate and separate Mn.
In the final filtrate, the recovery rates of Cu, Ni and Co were 94.0% and 94.
It was 2% and 94.4%.

 The results are summarized in Table 2.

(Effect of the invention) Room temperature by sulphite leaching, the facility is simple because it can be leached under normal pressure, there is no problem of environmental pollution, not only extremely advantageous in practice, valuable metals, especially Co, Ni, Cu, etc. 90
It can be separated and recovered with a high yield of at least%, and in a state in which Mn and Fe are little present.

Claims (1)

[Claims] 1. When separating a valuable component from a manganese nodule or cobalt crust raw ore, the valuable component is eluted from a manganese nodule or cobalt crust raw ore in a sulfurous acid solution having a H ₂ SO ₃ concentration of 0.01 mol / or more. The semen solution residue and the eluate are separated by filtration, and then the eluate is blown with an oxidizing gas to oxidize Fe ²⁺ to Fe ³⁺ to precipitate Fe (OH) ₃ hydroxide in the acidic region, Iron carbonate was separated, ammonium carbonate was added to the filtrate from which iron was removed, and further ammonium salt or aqueous ammonia was added,
After air oxidation, the mixture was left to stand, manganese was separated as MnCO ₃ precipitate, and valuable components such as copper, nickel, and cobalt were left in the filtrate for hydrometallurgy. A method of separating and recovering metals.