JPS5967384A - Method for recovering valuable metal from alloy containing rare earth elements - Google Patents

Abstract

PURPOSE:To separate and recover rare earth elements and valuable metals with easy operation, by electrolyzing an electrolyte using an alloy contg. rare earth elements as anode, depositing or separating valuable metals as a residue and recovering the rare earth elements as oxalate from an end liquid of the electroysis. CONSTITUTION:An alloy contg. rare earth elements and contg. >=1 kinds among Ni, Co, Cu, Fe and Zr is used as an anode and a stainless steel plate or the like as cathode, and the alloy is electrolyzed by using an electrolyte contg. of <=15g/l concn. of rare earth elements, <=50g/l Co+Ni+Fe, and adjusted pH to 1.5-4.0. Then Co, Ni, Fe are deposited on the cathode and are thus recovered, and Cu and Zr are separated and recovered as an insoluble residue. Oxalic acid of the amt. equiv. to the amt. of the rare earth elements contained in the end liquid of the electrolysis is added to the liquid and the oxalate precipitate of the rare earth elements formed by the same is separated and calcined in the atm. air, whereby the rare earth elements are recovered as oxide. The aq. soln. after the precipitation and sepn. is recycled as the initial electrolyte.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention contains rare earth elements, and includes C, o, NiXFe,
The present invention relates to a method for separately separating and recovering rare earth elements, CO1N-Fe, and CuXZr from an alloy containing at least one of Cu and Zr.

In recent years, rare earth elements, especially samarium (Sm) and lanthanum (L), have been used as high-performance magnet alloys or hydrogen storage alloys.
a), cerium (Ce), praseodymium (P r )
, neodymium (Nd) etc. and C01NiXFe, Cu.

Alloys with Zr etc. are often used. For example, S
mCo, , M, MCo, (MM means Mitsushi metal, which is a mixture of the above rare earth elements), CeCo
,, Sm, (COlFe, CuXZr'), 7, etc. are still used as alloys for permanent magnets. These are typical hydrogen storage alloys, and the demand for them is increasing year by year.

Because these rare earth elements have high performance, they are often used in small sizes, and the process of cutting, polishing, etc. from a relatively large shape into a smaller shape results in machining waste and polishing powder. A large amount of scrap) is generated. Since these component metals are expensive, it is important to recover these valuable metals, and various methods have been proposed for this purpose. For example, (],) Sm
A method of recovering Sm as a hydroxide by heating and dissolving Co and the alloy in aqua regia, then adding triethanolamine and potassium cyanide to hide the CO, and removing it with ammonia to recover Sm as a hydroxide (% Kaimei 49-36526 (2) Add a slag-forming agent to rare earth-containing scrap and melt it at high temperature by high-frequency melting, arc melting, plasma melting, etc.1. (3) A method of adding calcium to the scrap and heating it in an argon stream to remove carbon and oxygen from the scrap and regenerating it as a rare earth alloy (Japanese Unexamined Patent Publication No. 56-38438) ) etc.

However, method (1) above requires special equipment because it uses aqua regia, uses potassium cyanide, which is undesirable from a sanitary standpoint, and is expensive.8 Methods (2) and (3) above In this case, there is the disadvantage that rare earths cannot be separated from valuable materials such as CO, and there are problems such as making processing difficult, especially when impurities such as abrasives and glass are mixed in the scrap. There was a point.

An object of the present invention is to solve the above-mentioned problems and provide a method for separating and recovering rare earth elements and other valuable substances as oxides or metals by relatively simple operations.

In order to achieve this objective, the present inventors extracted an alloy containing rare earth elements and at least one of cobalt, nickel, iron, copper, and zirconium with an aqueous sulfuric acid solution to extract rare earth elements and other valuables. After dissolving and extracting most of the
We researched methods for separating and recovering each element, and the subject matter was an invention related to a method for separating and recovering copper and zirconium as insoluble residues, cobalt, nickel, and iron as alloys by insoluble electrolysis, and rare earth elements as oxides. This was disclosed in a separate patent application.

The present invention is a further improvement of the above invention, and is intended to simplify the operation by combining the acid extraction step and the electrolysis step of the above invention into a single step.

According to the present invention, the rare earth element-containing alloy is used as an anode,
Using an aqueous solution containing a rare earth element and a predetermined concentration of Co, Fe, etc. as an electrolyte, the alloy is electrolytically dissolved, Zr and Cu are precipitated as undissolved residues, and at the same time Co - is applied to the cathode. The first step is to precipitate the 4-Ni-)-Fe alloy in an amount corresponding to the amount electrolytically dissolved, and the diluted and
The second step consists of adding oxalic acid in an amount equal to or less than the equivalent amount to the element, separating the generated rare earth oxalate precipitate from the aqueous solution, and calcining it in the atmosphere, and the separated aqueous solution is recycled and used as an electrolyte. By this, rare earth elements and Co,
This is a method for efficiently separating and recovering valuable materials such as F'e. An important structural distinction between the present invention and the separate inventions by the present inventors lies in the use of a direct electrolysis method in which a rare earth element-containing alloy powder is directly used as an anode in the present invention.

That is, the first step of the present invention contains a rare earth element, or 77) Go, N1. , p e-, Cu, Z r
A powdered or lumpy alloy containing one or more of The charged material is used as an anode, a metal plate such as stainless steel is used as a cathode, and the rare earth element (hereinafter abbreviated as R) concentration x5y/ is preferably 5 to 15f/1.
XCo -1-Ni -1-Fe concentration 50? /L or less.

Preferable structure 20-50y/l, pl+ 1.5-4
01 Preferably, using an aqueous solution of 2.0 to 3.0 as the electrolyte, electrolysis is performed at a DK = 2 A/dn♂ or less, a tank weight, and a pressure of 5 V or less.

The electrolytic solution is usually continuously supplied to the electrolytic cell, and the overflow liquid from the electrolytic cell is sent to the second step, the R removal step, where solid oxalic acid is added to an aqueous solution of oxalic acid in an amount equal to or less than the amount of R contained in the electrolytic cell. The resulting precipitate is separated using a suitable filter, and then roasted in the atmosphere to recover the rare earth total oxide.

- The aqueous solution is recycled as it is or after adding an appropriate amount of sulfuric acid aqueous solution to the electrolytic cell, and the ZrXCu that settles as an undissolved residue in the πJ1 decomposition tank is allowed to overflow or is allowed to settle in the tank and then recycled as appropriate. Separate and collect.

The electrolyte used in the method of the present invention contains rare earth elements and Co.
, Fe, etc., for example, 50 to 1001i'
The concentration of each metal and p+ (values are within the specified range, i
The -1 of this electrolytic solution can be adjusted to 1' and 1 to adjust the amount of the raw material alloy. Since this alloy is very active, when it is poured into a dilute sulfuric acid solution and stirred, the above-mentioned electrolyte can be obtained in the valley 8. The R8 degree in the electrolyte is 15 degrees or less, preferably 5~□15f
The reason for setting the range of /l is that it is clever to electrolytically dissolve the rare earth element at its solubility limit of 1 and then send it to the next de-R step. This is necessary to efficiently react with the added oxalic acid.

If the oxalic acid added here has poor reactivity with rare earth elements, a sufficient amount of R2 (C,0,) will precipitate during the RI removal process. When it is liquidized, it precipitates in the electrolytic cell and is discharged outside the system as an undissolved residue, resulting in a loss of TFT or 1.

Any of these causes undesirable results, such as mixing with electrodeposit such as -1-Fe and interfering with normal electrolysis.

Next, the concentration of Co -1-Ni and Fe is 50 fl
/ L or less, preferably in the range of 20 to 50 l/L, because if the concentration is less than this, hydrogen gas will be generated during electrolysis and efficient electrolysis will not be carried out. This is because even if the rare earth element concentration is sufficiently high in the R removal process of the final solution, the reactivity with oxalic acid will be impaired. The reason why -1 of the trench electrolyte is regulated to 1.5 to 4.0 is 1.
．． This is because when pll is less than 5, hydrogen generation increases during electrolysis and the current efficiency decreases, and when pll is greater than 4.0, rare earth elements precipitate as oxides.

The present invention will be explained in more detail below.

The method of the present invention applies a so-called direct electrolysis method to electrolytically dissolve rare earth elements and alloys of Co, Fe, etc. using a predetermined electrolytic solution as an electrolytic starting solution, while at the same time applying Co, NiXFe, etc. to the cathode. In this electrolytic process, rare earth elements are not electrodeposited, and Zr is an oxide, and even if Cu is once dissolved, it becomes a metal through a substitution reaction with rare earth elements, etc. However, it is essentially precipitated and separated as a metal.

These Zr and Cu can be reused as raw materials for permanent magnets and the like.

TtCP3 tank rj, I Hl, L ['4 poles t,
1. A small hole is made around an insoluble plate, such as titanium or stainless steel; the screen throat is filled with an alloy having 1, 1 and 3, which is the raw material of the present invention. 111 As the solution progresses, the raw materials are replenished as appropriate into the scale.Meanwhile, the cathode is made of a stainless steel plate, but this stainless steel plate is made of, for example, vinyl chloride.

It is used by placing it in a box made by gluing cloth such as Tetron to a Niru board. The aforementioned lightning liquid is poured into this box. Using the diaphragm type in this way not only prevents insoluble matters and precipitates from being mixed into the cathode deposits, but also prevents the pH of the electrolyte solution from increasing. Advantages such as easy M adjustment can be obtained.

This 'f! 5. C01Ni only dissolved in the solution
,, Fe is deposited on the C01 (substantially all) A cathode, and the electrolysis starting solution and the C01 of the electrolysis final solution overflowing this electrolytic cell are
It is preferable to adjust the concentration of Fe, etc. and β() to be approximately constant.

The final electrolyzed solution is sent to the second step, the R-removal step, where oxalic acid, preferably 10% oxalic acid, is added to precipitate all the rare earth elements that were dissolved in the box or group tank. Preference is given to adding an aqueous solution.

The reason why oxalic acid is added in an amount equal to or less than the total amount of rare earths contained in the aqueous solution is to efficiently obtain rare earth precipitates and separate them using a vacuum filter, etc., as mentioned earlier. This is to prevent contamination of the electrolytic deposits and loss of oxalic acid metal when the mother liquor is returned to the electrolytic cell in the first step.
In addition, the purpose of completely preventing the formation of precipitates such as Co(CzOJ)2 can also be achieved.

Preferably, the precipitate produced here is separated from the mother liquor after aging for about 1 hour or more.

After drying, the precipitate obtained by further heating is heated to about 900
Firing at a temperature of 1. to obtain rare earth oxides.

The metal deposited on the cathode in the electrolytic cell is pulled up and stripped off at appropriate times, and Zr and Cu precipitated in the electrolytic cell are recovered at appropriate intervals.

The metals such as CO and rare earth elements obtained by the method of the present invention are of high quality as seen in the examples, and can be used as they are as raw materials for permanent magnets, hydrogen storage alloys, etc.

According to the method of the present invention, the final solution of the first step is recycled into the electrolyte solution of the first step, so that each metal in the alloy contains Zr.
+ 1 of 1; 1, 711' of Co, Ni, Fo, and rare earth elements, each one separately 100! ! It can be separated and recovered with a yield of B.

Another advantage is that the well-known direct '11 A solution method and the A1 acid metal engineering method's precipitation 11 separation method can be performed in succession, so G) 5 works can be done in the middle. (l2,]
Unnecessary loss of 411 between two f7s can be prevented.

Hereinafter, 11 examples will be explained.

EXAMPLE 213 of the present invention was prepared using an electrolytic cell as shown in the attached drawings.
Perform one step. The size of the electrolytic cell used is t.
1M'l・, ;(, F4 row and height are 350 each
+++m.

3001 and 4001. The anode buttons are 218mm wide and 218mm long (inner dimensions).

A titanium basket 1 having dimensions of 270τ1 and 20ra and a 5-square mesh is used, and as shown in the accompanying drawings, it is wrapped in a bag 2 made of Butron. As a cathode, the width, length and thickness are each 200wm,
Using a stainless steel plate 3 of 300wmm and 3 cages, the stainless steel plate was made of a vinyl chloride plate and Tetoron cloth.
, '380mm and 20cm box 4 for use.

The three anode bags and the two cathode boxes are arranged alternately as shown. Sm 34 by weight in the anode bank
%, 0.065% of block magnet scrap with a diameter of about 10 is charged in each case.

Co 40f/L1 Sm” was added to this electrolytic cell as an electrolyte.
After filling the sulfuric acid acid aqueous solution of /4p'2.2, the liquid is supplied to each cathode box 4 at a rate of 35me/min, and the overflow from the electrolytic cell outlet 5 is drained into the 1O where the stirring device is located.
t beaker (not shown) and this beaker is used as a Sm removal tank. Add 20% oxalic acid aqueous solution to this 8 m tank.
．． The overflow of the Sm removal tank was passed through a filter (Nutche), and then a dilute sulfuric acid aqueous solution was added to the solution to adjust the pH of the aqueous solution to 22, and the solution was ladled. The second step and the circulation step are carried out by circulating the cathode box in the cathode tank. The electrolytic conditions are D
K 1.5 A/dn♂, tank τ(), pressure 4 V,
'T1. The seedling solution was heated to 50°C for 1 hour. Incidentally, the Sm in the final electrolytic solution entering the Sm removal tank was maintained at 10 f'/ or more.

The metal deposited on the cathode by this electrolysis is C099,
0%, Sm O-1"' or less was 630 f, the amount of scrap melted during this period was 1 Kl, and the actual yield of Co from the charged raw material was d, 96. Oy (,. Precipitate C8wm (t-to+
)s] was dried and then heated in a Matsufuru furnace maintained at 900°C.
After firing for half an hour, Sm 85.2%, Co 0.
06%brr+t Us 390? was obtained, and the actual yield of samarium from the raw material was 97.7 y.

Example 2 sm 43. obtained when producing Sm, (Co, Fe, Cu, Zr), 7 by high frequency melting method.
7%, Co 32.9%, Fe 9.15%, Cu
Slag 3 with a composition of 5.13%, Zr 0.97%
．． After coarsely crushing 6 Kq into 2 meshes or less, Example 1
Sm 8.0, Co 30.0 were used as the anode by dividing the titanium basket used in the above into equal parts and making it extremely large.
1Fe ] (3,0 each ?/1 containing l(l 2.
An aqueous solution of 0 is used as an electric wC solution, and DK is 1. Electrolysis was carried out for 24 hours in the same manner as in Example 1 except that the temperature was 0/cW. As a result, the amount of dissolved raw material was 1.5 K9 and C(7s,
4y(,, 600 electrodeposit with Fe 21.0%, smo 1% or less were obtained, and the actual yield of Co-1-Fe from the raw material was 94.6%. On the other hand, the precipitation of Sm compound was After drying, it was fired for 2 hours in a Matsufuru furnace held at 900°C, resulting in 84.5% Sm, Co -1-Fe o,
Sm of 1% or less, 03753 f, was obtained, and the actual yield of Sm from the raw material was 97.1%.

Cu and Zr were hardly dissolved and their respective concentrations in the electrolyte were below o, oO5y7.

Example 3 A lumpy LaNi alloy 3Kf with a diameter of about 10W consisting of 31.5% La and the balance Ni was electrolyzed in the same manner as in Example 1, and Ni and La were recovered.
After 4 hours of operation, the solubility value of the raw material was 1.2 KGI, the purity of H1 was 99.25 (, with an actual yield of 97.2%, and La
The actual yield of LaR5,1% Lit, O, was 946%, which was calculated from the raw materials.

Above, the process of electrolyte solution and recovered rare earth elements has been explained using a circulation method. However, only the electrolytic process or only the rare earth recovery process is circulated to sufficiently dissolve the raw material or rare earth element. You may adopt a method of proceeding to the next step after collection.

Also, electric Wl! The conditions, the amount of oxalic acid added for recovering rare earths, the aging time for precipitation, etc. are preferably adjusted as appropriate depending on the intended use of the recovered metal.

[Brief explanation of drawings]

The accompanying drawings are longitudinal cross-sectional views of exemplary electrolytic cells used in the practice of the present invention. 1... Titanium basket; 2 Tetron anode pack; 3... Cathode plate; 4... Cathode box loss; 5... Overflow 45 ・'rfj, group tank. 1 #Acceptance ir person 2 resident woman T'b j;,? :If!
('I Bukai)・1 agent: -noj, 1+ii A;
'+, t (' 459

Claims (1)

[Claims] Contains rare earth elements, including nickel, cobalt, copper, iron,
An alloy containing at least one type of zirconium is used as an anode, and a rare earth element concentration of 15 f/ is hereinafter referred to as Co-1-Ni.
-4-F050g/ is electrolyzed and dissolved using an electrolytic solution of -1.5 to 40 to precipitate C01Ni and Fe on the cathode, and the first step is to separate the final electrolysis solution from the insoluble residue. ,
Adding less than the current amount of oxalic acid to the rare earth elements contained in the final electrolysis solution [7] Separating the generated rare earth oxalate precipitate from the aqueous solution [7] A method for recovering valuable metals from rare earth element-containing alloys, characterized in that an aqueous solution obtained in two steps is recycled as an electrolyte in the first step.