JPH0982371A - Valuable material recovering method from waste nickel-hydrogen secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently recover a valuable material such as nickel, cobalt and rare earth metal even when impurity such as copper and iron is mixed in from a waste nickel.hydrogen secondary battery by a small quantity of industrial chemical to be used without practically causing a problem of corrosion of a device. SOLUTION: A used nickel.hydrogen secondary battery is crushed, cracked and sieved, and is separated into a coarse grain part containing plastic, iron, foaming nickel or the like and a fine grain part containing a nickel hydroxide and hydrogen storage alloy. After plastic and paper are removed from the coarse grain part after being sieved by magnetic separation, an organic substance such as remaining carbon is completely removed by combustion, and iron is removed by pulverization and sieving, and foaming nickel is recovered. Nickel and cobalt are melted from the fine grain part after being sieved by a sulfuric acid solution containing alkaline metal such as sodium and potassium, and rare earth metal such as cerium and lanthanum is separated as a deposit of sulfuric acid double salt with alkaline metal, and the rare earth metal is recovered. A sulfuric acid solution of cobalt is electrolyzed by adjusting pH of a cathode part to 4 or more, and nickel and cobalt are recovered as metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a used nickel
The present invention relates to a method of recovering nickel, cobalt and rare earth elements from a hydrogen secondary battery (waste nickel / hydrogen secondary battery).

[0002]

2. Description of the Related Art As a method of recovering valuable nickel, cobalt, and rare earth elements from a waste nickel-hydrogen secondary battery, as shown in JP-A-6-340930, valuable materials such as rare earth and nickel are dissolved with a mineral acid. However, a method has been proposed in which rare earth is separated and recovered as a fluoride, and nickel is recovered as a hydroxide precipitate from the liquid from which the rare earth is removed. However, waste nickel-hydrogen secondary batteries often contain miscellaneous impurities such as copper and iron, and these impurities form complex ions with fluorine when fluorine is present in the solution, making it difficult to separate them from rare earths. become.

Further, the fluorine in the liquid is highly corrosive, so that an apparatus having specially improved corrosion resistance is required. Furthermore, since it is difficult to repeatedly reuse the mineral acid used to dissolve valuable substances such as rare earth and nickel and the alkali used to neutralize the liquid, all of these chemicals are discarded in the wastewater treatment process. It is considered that there is a difficulty in mass processing from the viewpoint of economy and resource saving.

[0004]

The object of the present invention is applicable to the recovery of nickel, cobalt, and rare earth elements from waste nickel-hydrogen secondary waste batteries even when impurities such as copper and iron are mixed, The objective is to recover nickel, cobalt, and rare earth elements with a small amount of chemicals and less problems of equipment corrosion.

[0005]

The present invention is directed to crushing, crushing and sieving a used nickel-hydrogen secondary battery, and a coarse particle portion containing plastics, iron, foamed nickel and the like and nickel hydroxide. And fine particles containing hydrogen-absorbing alloy, and from the coarse particles, plastics and paper are removed by magnetic selection, organic substances such as carbon are removed by combustion, iron is removed by crushing and sieving, and nickel foam is used. Collect. On the other hand, nickel and cobalt are dissolved from the fine grain portion with a sulfuric acid solution containing an alkali metal such as sodium and potassium, and the rare earth element is recovered as a sulfate double salt precipitate.

The sulfuric acid solution of nickel and cobalt is electrolyzed to recover nickel and cobalt as metals. The electrolytic solution (electrolytic tail solution) after recovering nickel and cobalt as metals can be used again for dissolving the waste nickel-hydrogen secondary battery. When the electrolytic tail solution is used to dissolve a waste nickel-hydrogen secondary battery, it is replenished with an equivalent amount of sulfuric acid and alkali metal that produces a sulfuric acid double salt of rare earth and alkali metal. When copper or cadmium is mixed in the solution of nickel or cobalt, alkali sulfide (sodium sulfide,
Copper and cadmium were removed by adding potassium sulfide, ammonium sulfide) or hydrogen sulfide to the solution, and when iron was mixed, an oxidizing agent such as potassium permanganate was added to oxidize it to trivalent iron. After that, it is removed by adjusting the pH to 4 or more.

[0007]

EXAMPLES The present invention will be specifically described below based on examples.

Example 1 A nickel-hydrogen secondary battery was sheared by a shear crusher (Alpine).
A. G. Rotoplex Cut made in Germany
toning Mill), 960 rpm, 200
V, 3.7 kW, and discharge diameter 12 mmΦ (1/2 ") were used for dry crushing. Next, a crusher (Attract)
Ion Machine) was used for wet crushing under the condition of 4 blades and 5 stages, and then classified with a 28 mesh sieve. The coarse particle part (+28 mesh) on the sieve is 2,000-
After magnetically screening with a magnetic force of 3,000 Gauss to remove non-magnetized substances such as plastics and paper, a small amount of plastics and paper were burned and removed.

The residue after combustion was 925 rpm, 100 V, using a vibration mill (T-100 type manufactured by Kawasaki Heavy Industries, Ltd.).
By pulverizing under a condition of 0.8 KW and classifying with a sieve of 24 mesh, metallic iron and nickel foam were separated, and nickel foam was concentrated and recovered in a fine particle portion of -24 mesh. On the other hand, a crusher (Attraction Machine)
-28mesh obtained by wet crushing and classification with ne)
Valuable materials such as nickel / hydrogen and nickel hydroxide, which are the active materials of the battery, are concentrated in the fine-grained portion. In Table 1,
The above-mentioned treatment was carried out on four kinds of waste nickel-hydrogen secondary batteries (A to D), and the analysis results of the fine grained parts obtained are shown.

[0010]

[Table 1]

No. 1 in Table 1 100 g of A was added to a sulfuric acid concentration of 3.
When dissolved in 1 liter of a liquid adjusted to 5 mol / l and a sodium concentration of 1.0 mol / l at 80 ° C. for 6 hours,
Nickel and cobalt were 100% dissolved, but cerium,
Lanthanum and neodymium were hardly dissolved. When the remaining dissolution residue was subjected to X-ray diffraction analysis, it was confirmed that these rare earth elements were sulfuric acid double salts with poorly soluble sodium. Caustic soda was added to the sulfuric acid solution of nickel and cobalt to adjust the pH to 5, and diaphragm electrolysis was performed to obtain nickel and cobalt metals.

Example 2 No. 1 in Table 1 obtained in Example 1 When 10 g of A, a sulfuric acid concentration of 1.0 mol / l and a sodium concentration of 1.5 mol / l were dissolved in 1 liter of liquid at 80 ° C. for 6 hours, nickel was dissolved by 83% and cobalt was dissolved by 92%.
Cerium, lanthanum and neodymium were hardly dissolved. Caustic soda was added to the solution of nickel and cobalt to adjust the pH to 5, and then diaphragm electrolysis was performed to obtain nickel and cobalt metals. When the residue was dissolved again at 80 ° C. for 6 hours with an electrolytic tail solution after electrolysis, all nickel and cobalt were dissolved. Cerium, lanthanum, and neodymium were hardly dissolved in the redissolved solution in the electrolytic tail solution.

Example 3 No. 1 in Table 1 obtained in Example 1 B 100 g, sulfuric acid concentration 3.5 mol / l, sodium concentration 1.0 mol / l
When dissolved in 1 liter of the liquid prepared in Step 6, at 80 ° C. for 6 hours, nickel, cobalt and copper were dissolved 100%, but cerium, lanthanum and neodymium were hardly dissolved. Sodium sulfide (10 g) was added to the solution, and the temperature was 30 ° C
After standing for a while and filtering, 100% of copper was removed. Nickel was lost as 5% and cobalt was lost as 7%. After removing the copper, caustic soda was added to the nickel and cobalt solution to adjust the pH to 5, and then diaphragm electrolysis was performed to obtain nickel and cobalt metals. Further, by washing the precipitate generated by adding sodium sulfide with an electrolytic tail solution, all nickel and cobalt precipitated together with copper could be dissolved and recovered.

Example 4 No. 1 in Table 1 obtained in Example 1 C 100 g, sulfuric acid concentration 3.5 mol / l, sodium concentration 1.0 mol / l
When 1 liter of the liquid prepared in Example 1 was dissolved at 80 ° C. for 6 hours, 100% of nickel, cobalt and iron were dissolved, but cerium, lanthanum and neodymium were hardly dissolved. 10 g of potassium permanganate was added to the solution, caustic soda was added to adjust the pH to 4, and the generated precipitate was filtered. 98% of iron was removed as a precipitate. 4% of nickel and 1% of cobalt were lost as precipitates. Caustic soda was added to the nickel-cobalt solution from which iron was removed to adjust the pH to 5, and diaphragm electrolysis was performed to obtain nickel and cobalt metals.

Example 5 No. 1 in Table 1 obtained in Example 1 100 g of D, sulfuric acid concentration 3.5 mol / l, sodium concentration 1.0 mol / l
When dissolved in 1 liter of the liquid prepared in Step 6, at 80 ° C. for 6 hours, nickel, cobalt and copper were dissolved 100%, but cerium, lanthanum and neodymium were hardly dissolved. To this solution, add 10 g of sodium sulfide,
When left at 6 ° C. for 6 hours and filtered, 100% of copper was removed. Nickel was lost as 5% and cobalt was lost as 7%. After removing the copper, caustic soda was added to the nickel and cobalt solution to adjust the pH to 5, and then diaphragm electrolysis was performed to obtain nickel and cobalt metals. Further, by washing the precipitate generated by adding sodium sulfide with an electrolytic tail solution, all the nickel and cobalt precipitated together with copper could be dissolved and recovered.

[0016]

As described above, according to the method of the present invention, there are few problems of equipment corrosion, a small amount of industrial chemicals is used, and impurities such as copper and iron are removed from a spent nickel-hydrogen secondary battery. Even if mixed, nickel, cobalt,
Valuable materials such as rare earth can be collected.

Claims (5)

[Claims] 1. A crushed, crushed, and sieved used nickel-hydrogen secondary battery, and a coarse-grained portion containing plastics, iron, nickel foam, etc. and a fine-grained portion containing nickel hydroxide and a hydrogen storage alloy. After removing the plastics and paper from the coarse particles after sieving by magnetic separation, the organic substances such as carbon remaining after combustion are completely removed, and iron is removed by crushing and sieving to foam. Nickel and cobalt are dissolved with a sulfuric acid solution containing an alkali metal such as sodium and potassium from the step of recovering nickel and fine particles after sieving, and rare earths such as cerium and lanthanum are precipitated as a sulfate double salt with an alkali metal. Process of separating rare earths as rare earth, sulfuric acid solution of nickel and cobalt, pH of cathode part
And a value of 4 or more for electrolysis, and a step of recovering nickel and cobalt as metals, a method for recovering valuable materials from a waste nickel-hydrogen secondary battery. 2. A valuable material recovery from a waste nickel-hydrogen secondary battery according to claim 1, wherein an electrolytic solution after electrolytic recovery of nickel and cobalt is used as a solution for dissolving nickel and cobalt. Method. 3. Following the step of recovering the rare earth, an alkali sulfide or hydrogen sulfide is added to a solution of nickel and cobalt to remove copper and cadmium in the solution as sulfides. Alternatively, the method for recovering valuable materials from the waste nickel-hydrogen secondary battery according to claim 2. 4. After the step of recovering the rare earth, an oxidizing agent such as potassium permanganate is added to a solution of nickel and cobalt to oxidize the iron dissolved in the solution to trivalent, and then the pH is adjusted to 4 Alternatively, the value of 5 is adjusted to remove iron in the solution as a hydroxide precipitate, and the valuable material recovery method from the spent nickel-hydrogen secondary battery according to claim 1 or claim 2. 5. Subsequent to the step of recovering the rare earth, alkali sulfide or hydrogen sulfide is added to a solution of nickel and cobalt to remove copper and cadmium in the solution as sulfides, and then the solution of permanganese is removed. Characterized by adding an oxidizing agent such as potassium acid to oxidize the iron dissolved in the solution to trivalent, and then adjusting the pH to 4 or 5 to remove the iron in the solution as a hydroxide precipitate. Claim 1
Alternatively, the method for recovering valuable materials from the waste nickel-hydrogen secondary battery according to claim 2.