JPH10152730A - Method for removing positive metal in base metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove base metals from a base metal-contg. metallic solution by utilizing oxygen generated by bringing an oxygen-contg. compound of alkaline metals or the like into reaction with chlorine. SOLUTION: In this method, the oxide, carbonate or hydroxide of alkaline metals or alkaline earth metals more stable in the shape of chloride is used as an oxygen source. By introducing gaseous chlorine into a base metal solution contg. positive metals in the presence of the oxygen source, the oxygen source is chlorinated, the positive metals contained in the metallic solution are oxidized by oxygen having high activity generated at this time, and this oxide is transferred to slag and is removed, where the base metals denote the metals except for gold, silver, copper and platinum group elements, and the positive metals concretely denote Ni-Co allays, iron contg. Cr or the like. Since active oxygen is utilized in this way, the efficiency of the oxidation reaction of the metals is high. Moreover, since the oxide of the positive metals forms stable slag with the by-produced chloride, there is no fear of causing the clogging of a flue or the like by volatilization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for efficiently and easily removing a positive metal contained in a base metal. INDUSTRIAL APPLICABILITY The present invention is suitable as a method for removing iron from a battery waste material such as a nickel-cobalt alloy.

[0002]

2. Description of the Related Art Nickel-cobalt alloys are used as hydrogen storage materials in nickel-hydrogen batteries (Ni-MH batteries) and the like. MH batteries (collectively referred to as battery waste) contain a significant proportion of nickel and cobalt. For this reason, in order to effectively utilize resources and protect the environment, it is required to efficiently recover and reuse nickel and cobalt from these wastes.

[0003] In this case, the waste battery material contains a large amount of iron, and it is necessary to remove iron efficiently in order to recover and reuse nickel and cobalt. As a conventionally known deironing method, (a) a chlorine gas is blown into a nickel-cobalt alloy solution to chlorinate the impurity iron,
(2) a method in which chloride is added instead of chlorine gas to chlorinate iron. (C) Nickel
There is known a method of blowing oxygen gas into a cobalt alloy melt to preferentially oxidize iron to form slag.

[0004]

However, the method of chlorinating iron to volatilize and remove iron has a problem that if the iron content is large, a large amount of iron chloride is generated and adheres to the flue to block it. In addition, those in which chlorine gas is blown into the melt have a low reaction efficiency, and those using chloride have a problem in that the reaction efficiency is also low because the added chloride is volatilized. The method of blowing oxygen gas does not have such a problem, but when the oxidation proceeds and the iron concentration in the melt decreases, the oxidation of cobalt and nickel proceeds,
These recovery rates decrease. The present invention has solved the above-mentioned problems in the conventional treatment method, and has as its object to provide a method for efficiently removing a base metal from a base metal-containing metal.

[0005]

According to the present invention, instead of directly introducing oxygen gas into a metal melt to oxidize iron, chlorides utilize oxides and carbonates, which are more stable, as an oxygen source.
By introducing chlorine gas into the metal melt in the presence of this oxygen source, the oxygen source is changed into chloride, and the highly active oxygen generated at this time efficiently oxidizes the positive metal in the melt to form slag. And can be removed from the metal melt.

That is, the present invention relates to (1) chlorine gas in a base metal melt containing a positive metal in the presence of an oxygen source selected from oxides, carbonates or hydroxides of alkali metals or alkaline earth metals. Oxidation characterized by oxidizing the positive metal in the melt by oxygen generated when the oxygen source is chlorinated by introducing oxygen, transferring the metal oxide to slag and removing it from the metal melt. This is a method for removing the conductive metal.

[0007] The removal method of the present invention includes the following aspects. (2) a removal method in which a base metal containing a positive metal is melted together with a flux, an oxygen-containing gas is introduced into the base metal to promote oxidation of the positive metal, and then an oxygen source is added to introduce a chlorine gas; A removal method in which the base metal containing the positive metal is nickel, cobalt or an alloy thereof containing iron,
(4) a method of removing battery waste material in which the base metal containing a positive metal is an iron-containing nickel-cobalt alloy; (5) an oxygen source comprising:
Calcium oxide, sodium oxide, calcium carbonate,
A method for removing one or two compounds selected from sodium carbonate and sodium hydroxide.

[0008]

[Detailed Description] The removal method of the present invention will be specifically described below. In the following description,% is% by weight unless otherwise indicated.

[0009] The removal method of the present invention uses an oxide, carbonate or hydroxide in which chloride is more stable as an oxygen source, and in the presence of this oxygen source, applies chlorine gas to a base metal solution containing a positive metal. A method of chlorinating the oxygen source by introducing the same, oxidizing a positive metal contained in the metal melt by highly active oxygen generated at this time, transferring the metal oxide to slag, and removing the metal oxide from the metal melt. It is.

In the removing method of the present invention, the base metal is gold,
It is a metal element excluding silver, copper, and platinum group elements, and includes an alloy composed of two or more metal elements. The positive metal refers to a metal which has a higher ionization tendency and is more easily oxidized than a base metal containing the positive metal. Specifically, for example, a nickel-cobalt alloy containing iron, such as battery waste, and iron containing chromium, may be mentioned. The thing used as an oxygen source in the above-mentioned removal method is an oxide, carbonate or hydroxide in which chloride is more stable. For this, an oxide, carbonate or hydroxide of an alkali metal or alkaline earth metal can be used. Specifically, one or two selected from calcium oxide, sodium oxide, calcium carbonate, sodium carbonate or sodium hydroxide
Certain compounds are suitable.

Hereinafter, the removal method will be described for each processing step. (I) A base metal to be melted is heated and melted to form a metal melt. Note that pretreatment is preferably performed as appropriate depending on the material. For example, when treating battery waste, etc., part of the outer can is opened or cut so that the hydrogen gas generated from the hydrogen storage alloy built into the battery during heating escapes to the outside of the can. It is preferable to perform heating in an atmosphere of an inert gas such as nitrogen so as not to cause the generation of the gas.

(II) Addition of Oxygen Source The above oxygen source is added during or after the base metal is melted. Examples of suitable oxygen sources include calcium oxide (CaO)
, Sodium oxide (Na ₂ O), sodium hydroxide (NaOH),
Examples include calcium carbonate (CaCO ₃ ) and sodium carbonate (Na ₂ CO ₃ ). These may be used alone or as a mixture of two or more. Since calcium oxide has a high melting point, it is preferable to use it together with an appropriate flux, for example, calcium chloride. The amount of the oxygen source to be used is slightly larger than the equivalent to the positive metal so that the positive metal to be removed does not remain unoxidized. In addition, it is not preferable to use a large amount exceeding the equivalent because oxidation of the base metal proceeds after most of the positive metal is oxidized and slag loss increases.

(III) Introduction of Chlorine Gas A chlorine gas is introduced into a base metal melt in the presence of the oxygen source. The introduction of chlorine gas may be performed by blowing chlorine gas into a closed heating furnace or the like in which the base metal melt is stored, but it is preferable to blow chlorine gas into the melt to increase the reaction efficiency. The introduction of chlorine gas chlorinates the above oxides and the like, thereby releasing active oxygen, and the oxygen oxidizes the positive metal in the base metal to form slag.

For example, when lime (CaO) is added to a nickel-cobalt alloy melting bath and chlorine gas is blown, as shown in the following equation, lime becomes calcium chloride and iron is oxidized by the generated oxygen. You. When sodium oxide is used, iron is similarly slagged. CaO + Fe + Cl ₂ −− → CaCl ₂ + FeO Na ₂ O + Fe + Cl ₂ −− → 2NaCl + FeO

[0015] The amount of chlorine gas introduced is preferably slightly larger than the equivalent to the oxidizing source so that the oxidizing source is sufficiently chlorinated. If the amount is slightly excessive, part of the iron will be chlorinated as the unreacted oxygen source decreases in the latter half of the chlorination reaction, and iron chloride will be generated and volatilized. Do not cause obstacles such as. When the introduction amount of chlorine gas is small, the oxidation of the positive metal becomes insufficient. Further, if the amount is more than the equivalent, the amount of chlorination of the base metal is increased together with the chlorination of the oxidation source, which is not preferable.

In the treatment method of the present invention, the positive metal is oxidized using active oxygen generated by chlorination of the oxygen source, so that the efficiency of the oxidation reaction is extremely high. In addition, since the oxide of the positive metal forms a stable slag together with the by-product chloride, there is no risk of causing a trouble such as obstruction of the flue due to volatilization, and the separation from the metal melt is easy.

(IV) Two-Step Treatment Prior to the introduction of chlorine gas, a flux is added to the melt, and oxygen gas or air is introduced to perform rough oxidation.
Thereafter, the above treatment with chlorine gas may be performed in the presence of an oxygen source. The method of introducing oxygen gas or air is not limited. The amount to be introduced may be determined according to the type of base metal and positive metal to be treated and their contents.

The flux may be any as long as it absorbs the generated iron oxide, and preferably contains a halide of an alkali metal or an alkaline earth metal such as calcium chloride, or silica or alumina. In particular, when iron is slagged and removed, silica (SiO ₂ ) -alumina (A
A three-component flux consisting of l ₂ O ₃ ) -lime (CaO) is preferred. This flux is inexpensive and has good specific gravity and viscosity in terms of separability from iron, and good separation of metal and slag. In addition, since an alumina component is contained, corrosion and erosion of an alumina container are prevented, so that there is an advantage that the container can be used safely.

It is preferable that the proportions of the respective components of the above-mentioned flak be such that the silica content is 55 to 70%, the lime content is 2 to 10%, and the alumina content is 20% or more. 55% silica
If the ratio is lower than the above, the effect of separating iron is reduced. In particular, when the silica content is about 10%, the amount of iron remaining in the melt increases.
Further, when the silica content exceeds 70%, the alumina content and the lime content relatively decrease, and when the lime content is less than 2%, the effect of separating iron decreases. On the other hand, if the lime content exceeds 15%, the silica content and the alumina content are relatively reduced, and the iron separation effect is reduced. Therefore, the lime content is appropriately 5%.
When the alumina content is about 10%, the effect of separating iron is still low. Therefore, the alumina content is preferably 20% or more. On the other hand, when the alumina content is about 85%, the silica content or the lime content relatively falls below a predetermined ratio, and the iron separation effect is undesirably reduced.

The amount of the flux added is generally 20 to 35 parts by weight, preferably 25 to 30 parts by weight, per 100 parts by weight of the base metal.
Parts by weight are appropriate. If the added amount of the flux is less than the above range, the effect of separating the metal is not sufficient, and if the added amount exceeds the above range, the waste of the processing cost increases.

[0021]

Hereinafter, examples of the present invention and comparative examples will be described. In addition, these are illustrations and do not limit the scope of the invention.

Example 1 Nickel hydrogen battery waste material (Fe: 25.5%, Ni: 34.5%, Co: 3.3
%) 100 kg and quick lime 30 kg (1 for iron in waste material)
(2 equivalents) and 10 kg of calcium chloride were added, and the mixture was charged into a melting furnace, heated to 1400 to 1600 ° C. in a nitrogen gas atmosphere, melted, and then blown with chlorine gas (introduced chlorine gas amount: 12.273 Nm ^3). And 1.2 times equivalent to the iron content in the waste material), and the slag was treated. After cooling, 93.5 kg of slag and 38 kg of metal were recovered. The volatilization loss was 8.5 kg. The components (amount ratio) of the recovered slag and metal are as shown in Table 1. The recovery rate of nickel is as high as 98.5% and the recovery rate of cobalt is as high as 87.5%. .5
%, And the iron removal rate was 96.3%.

Example 2 Heating was carried out in the same manner as in Example 1 except that 62.8 kg of sodium carbonate (1.3 equivalent to iron in waste material) was used as an oxygen source instead of quicklime without using calcium chloride as a flux. Melted and chlorinated to blow slag
(Introduced chlorine gas amount: 12.273Nm ³ , 1.
2 equivalents). After cooling, 87.3 kg of slag and 37.5 kg of metal
Was recovered. The loss on volatilization was 38 kg. The components (amount ratio) of the recovered slag and metal are as shown in Table 1. The recovery rate of nickel is 98.6%, and the recovery rate of cobalt is 85.2%.
The amount of recovered metal was as low as 1.5%, and the iron removal rate was 97.8%.

Example 3 20 kg of flux (CaCl ₂ ) was added to 100 kg of the same battery waste material as used in Examples 1 and 2, and the mixture was charged into a melting furnace and heated to 1400 to 1600 ° C. in a nitrogen gas atmosphere. After melting, air is blown into the melt (oxygen amount of introduced air: 4.091 Nm ³ ,
0.8 times equivalent of iron in waste material) to produce slag. The components of the slag and the melt are shown in Table 1. After blowing air, 5.8 kg of quicklime (1.2 equivalents to iron in the melt) was added, and chlorine gas was blown into the melt in the same manner as in Examples 1 and 2 (introduced chlorine gas amount: 2.295 Nm). ³ , 1.2 times equivalent to iron in the melt). After cooling, 13.7 kg of slag and 36.5 kg of metal were recovered. The loss on volatilization was 1.5 kg. The components (amount ratio) of the recovered slag and metal are as shown in Table 1. The recovery rate of nickel is as high as 97.1% and the recovery rate of cobalt is as high as 88.5%. .1
% And less than 99% of iron was removed. As shown in this embodiment, by performing the first-stage treatment by blowing oxygen or air and the subsequent second-stage treatment of introducing chlorine gas in the presence of an oxygen source, iron contained in the battery waste material is reduced. It can be almost completely removed.

Example 4 Chromium-containing iron-based alloy (Fe: 96%, Cr: 2.5%, C: 1.0%) 10
After adding 80 kg of quicklime to 00 kg, the mixture was charged into a melting furnace, heated to 1500 to 1700 ° C. in a nitrogen gas atmosphere and melted, and then chlorine gas was blown into the melt (introduced chlorine gas amount: 19.386 Nm ³ ,
A slag-forming treatment was performed with 1.2 times equivalent to the chromium content in the alloy. After cooling, 110 kg of slag and 945 kg of metal were recovered. The loss on volatilization was 25 kg. The components (amount ratio) of the recovered slag and metal are as shown in Table 1. The recovery rate of iron is 99.6%, and the residual amount of chromium contained in the recovered iron is extremely low at 0.1%. And the chromium removal rate was 96%.

[0026]

[Table 1]

[0027]

As described above, according to the removal method of the present invention, the efficiency of the oxidation reaction is higher than that of the conventional treatment method, and the positive metal in the base metal can be slagged and removed with high removal efficiency. . In addition, the oxide of the positive metal forms a stable slag together with the by-produced chloride, so that there is no possibility of causing an obstruction such as obstruction of the flue by volatilization.

Claims (5)

[Claims] A chlorine gas is introduced into a base metal melt containing a positive metal in the presence of an oxygen source selected from oxides, carbonates or hydroxides of alkali metals or alkaline earth metals. A method for removing an oxidizable metal, comprising oxidizing a positive metal in a melt by oxygen generated when chlorinating an oxygen source, transferring the metal oxide to a slag, and removing the oxidized metal from the metal melt. 2. The method according to claim 1, wherein a base metal containing a positive metal is melted together with the flux, an oxygen-containing gas is introduced into the base metal to promote oxidation of the positive metal, and then an oxygen source is added to introduce a chlorine gas. The removal method described. 3. The method according to claim 1, wherein the base metal containing a positive metal is nickel, cobalt, or an alloy thereof containing iron. 4. The removal method according to claim 3, wherein the base metal containing a positive metal is a battery waste material composed of an iron-containing nickel-cobalt alloy. 5. The removal method according to claim 1, wherein the oxygen source is one or two compounds selected from calcium oxide, sodium oxide, calcium carbonate, sodium carbonate and sodium hydroxide. .