JPH086149B2 - Method for separating and recovering metals from manganese nodules or cobalt crusts - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for separating and recovering valuable metals such as Cu, Ni and Co from manganese nodules or cobalt crusts produced from the deep sea floor.

[Conventional technology]

From manganese nodules and cobalt crusts to Cu, Ni,
Various methods for separating and recovering valuable metals such as Co 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 254 ° C. and a high pressure of 35 atm.

(3) After reducing by applying HCl gas at 500 ° C, water or
Method of leaching with HCl solution.

(4) Preheat reduction is performed in the presence of coke and CO gas at 625 to 1000 ° C, and Cu, Ni, and Co are converted to Fe alloy, and Mn and Fe are oxidized and removed as slag at 1425 ° C. Next, add gypsum and coke to change Cu, Ni, Co to sulfide matte,
A method of leaching at 110 ° C. and 5% H ₂ SO ₄ .

And so on.

[Problems to be solved by the invention]

The method (1) is called the Kennecott Cuprion Process, and the reaction at room temperature and pressure has little effect on the environment, but the Co yield is 5
% Is extremely low.

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.

As described above, the conventional methods have severe reaction conditions such as high temperature, high pressure, and high energy consumption, and a particularly common drawback is that Co yields are low at 50 to 60%. .

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.

[Means for solving problems]

That is, the present invention, the manganese nodule or cobalt crust ore is ground and stirred in sulfite water to overseparate the leachate, calcium chloride is added to the leachate to precipitate gypsum, and then the It is a method of separating and recovering a metal from manganese nodules or cobalt crusts, which comprises adding an alkali to a liquid and sufficiently stirring to precipitate and separate contained metals as hydroxides.

Manganese nodules and cobalt crusts contain a large amount of MnO ₂ , which is used for reducing and leaching other valuable metals together with sulfurous acid water. Can be leached. Then gypsum is formed with calcium chloride, which is overseparated,
Furthermore, the alkali metal overseparates the valuable metal in the form of a metal hydroxide. In this case, when calcium hydroxide is used as the alkali source, the liquid containing the metal hydroxide becomes a calcium chloride solution, which is advantageous in that it can be reused for the production of gypsum in the previous step.

In the present invention, sulfite water having a H ₂ SO ₃ concentration of 0.2% by weight or more is usually used, and the crushed raw ore is stirred in this for at least 1 minute or more. The weight ratio of sulfite water and raw ore is
Normally, MO ₂ + H ₂ SO ₃ →
_{^{M 2+ + ▲ SO 2- 4 ▼}} + H 2 commensurate with the O of the reaction may be any equivalent or more of an H ₂ SO _3, also the ratio between the liquid volume and the ore weight of sulfur water particularly as long mechanical stirring There is no contract. Temperature is room temperature,
The pressure can also be atmospheric pressure, and it is not necessary to give special consideration to the reactor or the like.

The method of the present invention is configured as described above, and is composed of three steps of reduction leaching with sulphurous acid water, production and separation of gypsum with calcium chloride, and production and separation of metal hydroxide with alkali. Is as follows:

_{(1) MO 2 + H 2} SO 3 → M 2+ + ▲ SO 2- 4 ▼ + H 2 O (2) CaCl 2 + MSO 4 → CaSO 4 + M 2+ + 2Cl - (3) Ca (OH) 2 + MCl 2 → M ^{_{(OH) 2 + Ca 2+ +}} 2Cl - Note if excess SO ₃ ^2-is Zantsu is Yotsute the addition of blowing suck oxidant air, thereby promoting the formation of gypsum as SO ₄ ^2- Good. Therefore, the second stage Ca
Oxidizing porridge powder (CaOCl ₂ , Ca (ClO) instead of Cl _{2
2 · CaCl 2 · 2H 2 O} , can be used CaOCl ₂ · H ₂ O).

〔Example〕

100 g of the raw material obtained by pulverizing the dried cobalt crust to 100 μm or less was put into 200 ml of sulfite water having a H ₂ SO ₃ concentration of 2% by weight and stirred at room temperature for 10 minutes. Over 45g of leaching residue and leaching noble liquid were separated. The leachate contains 96.1% Mn, 98.4% Co, and Ni.
Showed high leaching rates of 96.2% and Cu87.4%.

Calcium chloride (50 gr) was added to the leached precious liquid to obtain 56 g of gypsum precipitate.

Calcium hydroxide was added to the liquid after separating the gypsum to adjust the pH to 11, and the metal hydroxide was precipitated. This was excessively collected to obtain 57 gr of metal hydroxide.

The recovery rate of valuable metals is Mn: 92.1%, Co: 93.3
%, Ni: 92.1%, Cu: 90.7%, and all were high yields of 90% or more.

The grades of raw materials are shown in Table 1 and the recovery results are shown in Table 2.

Table 1 Grade of raw material cobalt crust (Wt%) Mn Co Ni Cu Fe 13.9 0.30 0.30 0.068 8.30 [Effect of the invention] According to the present invention, since it can be leached at room temperature under atmospheric pressure by sulphite water leaching, equipment is simple and there is no problem of environmental pollution,
Not only is it extremely advantageous in practice, but valuable metals, especially Co,
Ni, Cu, etc. can be separated and recovered in a very high yield of 96% or more.

Also, all the by-products produced during the treatment process are harmless. In other words, the sulfite leaching residue can be landfilled, dumped in the ocean, etc., so that the treatment is easy. The gypsum produced in the second stage can be used for various purposes as is well known. Further, by using calcium hydroxide as an alkali source, calcium chloride generated in the liquid can be reused, which is economically advantageous. Furthermore, since the raw materials used in the present invention, such as aqueous solution of sulfite and calcium hydroxide, are inexpensive, they can be carried out at low cost, and the effect of the present invention is extremely large.

Claims (2)

[Claims] 1. A manganese nodule or cobalt crust raw ore is ground and stirred in sulfite water to overseparate the leachate, and calcium chloride or salasi powder is added to the leachate to precipitate gypsum, which is overseparated. After that, an alkali is added to the liquid, and the mixture is sufficiently stirred to precipitate the contained metals as hydroxides for separation and to separate and recover the metals from manganese nodules or cobalt crusts. 2. The method according to claim 1, wherein calcium hydroxide is used as an alkali, and calcium chloride in a liquid obtained by separating a metal hydroxide is used for forming a gypsum precipitate.