JPH07243080A - Method for removing fe and p in copper containing metal of platinum group recovered after absorption of metal of platinum group from used catalyst of automobile - Google Patents

Abstract

PURPOSE:To remove Fe and P in copper contg. a metal of the platinum group and to minimize the loss of the metal of the platinum group by adding a flux to the copper, melting them by heating and then feeding copper oxide or oxidizing gas before the electrolysis when the metal of the platinum group is recovered by electrolyzing the copper. CONSTITUTION:The used catalyst of an automobile with an alumina or cordierite substrate and copper are melted, a metal of the platinum group in the used catalyst is flocculated and absorbed in the metal copper and this copper contg. the metal of the platinum group is electrolyzed. Copper is recovered as electrolytic copper and the metal of the platinum group is concd., separated and recovered as electrolytic slime. In this method, CaO, SiO2 or Na2CO3 as a flux is added to the copper contg. the metal of the platinum group, they are melted by heating and copper oxide or one or more kinds of oxidizing gases selected from among air, oxygen-enriched air and oxygen are fed to remove Fe and P in the copper contg. the metal of the platinum group before the electrolysis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spent spent catalyst (hereinafter referred to as a spent catalyst) comprising a honeycomb-like or bead-like substrate such as alumina or cordierite having a platinum group metal (hereinafter referred to as PGM) for purifying automobile exhaust gas. From ASC) to PG
Removal of F from copper containing platinum group metal in the step of recovering M
e, the P removal method.

[0002]

2. Description of the Related Art As a method for recovering PGM from ASC,
Copper is used as an absorber of PGM, ASC is reduced and dissolved in an electric furnace or the like, PGM is absorbed in Cu, and this Cu is electrolyzed as an anode.
There is a method of recovering M as electrolytic slime.

However, when Fe and P coexist in the Cu anode, Fe and P are eluted during electrolysis, and PG
Of M, the problem that Rh elution occurs has become apparent.
Since this eluted Rh does not enter the electrolytic slime, many steps, labor and time are required for its recovery, leading to an increase in cost. Further, in the recovery of Rh, Fe and P eluted in the electrolytic solution exhibit almost the same behavior as that of Rh, and deteriorate the quality of the recovered Rh precipitate.

As described above, in the method of recovering PGM from ASC using Cu as an absorbent, Fe and P coexisting in ASC enter copper together with PGM in the reduction dissolution step. It is desirable that Fe and P in this copper be removed before electrolysis. It can be said that a normal copper deFe method can be applied to the removal of Fe in this copper, but there are many unclear points in deFe from copper containing a high PGM content and P, resulting in a loss of PGM. Minimized Fe-free and P-free methods are required.

[0005]

In order to prevent the elution of Rh during the electrolysis of PGM-containing copper as described above, the present invention properly selects a flux and an oxidizing agent to remove Fe from PGM-containing copper. , P removal with a minimum PGM loss.

[0006]

In order to solve the above-mentioned problems, the present invention is to melt an automobile waste catalyst having alumina or cordierite as a base material together with copper to convert the platinum group metal in the automobile waste catalyst into copper metal. Aggregation, after absorption, by electrolyzing the platinum group metal-containing copper, copper as electrolytic copper, in the method of concentrating and separating platinum group metal as electrolytic slime, before the electrolysis, to platinum group metal-containing copper One of CaO, SiO ₂ , and Na ₂ CO ₃ is added as a flux to heat and melt, and at least one oxidizing gas of copper oxide, air, oxygen-enriched air, or oxygen is supplied to supply platinum group metals. Removal of Fe and P from platinum group metal-containing copper recovered by absorbing platinum group metal from an automobile waste catalyst, characterized by removing Fe and P in the metal-containing copper
On the way.

The basic reactions of Fe removal and P removal from copper containing a platinum group metal are considered as follows.

Cu ₂ O + Fe = 2Cu + FeO (1) 5Cu ₂ O + 2P = 10Cu + P ₂ O ₅ (2)

The Cu ₂ O is produced by the following equation.

2Cu + 1 / 2O ₂ = Cu ₂ O (3)

The basic principle of Fe removal and P removal is that PGM-containing copper is Cu.
Must be saturated with ₂ O. Therefore, first, the amount of oxygen required for Fe removal and P removal was grasped using copper oxide as an oxidant.

[0012] In consideration of cost and handleability, the produced slag-based slag is a Fe-O-based or Ca-Fe-based slag whose main component is iron oxide produced by removing Fe.
The O type, the Si-Fe-O type, and the Na-Fe-O type were examined. The minimum requirement for performing Fe removal and P removal by minimizing the loss of PGM is good separation of the produced slag and metal.
Some physical properties such as specific gravity and surface tension influence, but first, the following compositions were examined with reference to the phase diagram.

Fe-O system (oxidation and removal of iron by charging Cu ₂ O) All iron in PGM-containing copper metal is oxidized to Fe ₂ O ₃ Ca-Fe-O system (charge of Cu ₂ O and CaO) slag-removal) target slag composition of iron by _{(mol%) CaO: Fe 2 O 3} : FeO = 23: 75: 2 Si-FeO system (Cu ₂ O and slag of iron by charging of SiO ₂ and removing) the target slag composition _{(mol%) SiO 2: Fe 2 O} 3: FeO = 32: 7: 61 Na-FeO system (Cu ₂ O and Na ₂ CO ₃ slag and removal of iron by charging) _{-1 Na 2 O · Fe 2 O} 3 iron product removal PGM-containing copper in metal (l) was oxidized until all _{Fe 2 O 3, Na 2 O} · by Fe ₂ O ₃ and equivalents of Na ₂ CO ₃
Fe ₂ O ₃ (l) is produced. Reaction formula: Fe ₂ O ₃ + Na ₂ CO ₃ = Na ₂ O.Fe _{2
O 3 (l) + CO 2} -2 3Na 2 O · Fe 2 O 3 iron product removal PGM-containing copper in metal (l) All was oxidized to _{Fe 2 O 3, Fe 2 O} 3 to 3 equivalents of Na 3N by ₂ CO ₃
a ₂ O · Fe ₂ O ₃ (l) is produced. Reaction formula: Fe ₂ O ₃ + 3Na ₂ CO ₃ = 3Na ₂ O · F
e ₂ O ₃ (l) + 3CO ₂

After charging the alumina Tamman tubes (T-5) in the proportions shown in Table 1 for each of the above-mentioned systems, the temperature was raised to 1250 ° C. and 1300 ° C. in a small electric furnace for testing and 4 hr. Immediately after holding, it was taken out of the furnace and cooled to the atmosphere.

[0015]

[Table 1]

The experimental results will be described below. PGM
Since it was found that the slag loss of slag was caused by the copper metal suspended in the slag, first, in order to grasp the situation of the suspension loss, the slag / metal separation property of the sample after cooling was qualitatively determined in four stages. evaluated. Further Fe in metal
Was analyzed. The results are shown in Tables 2 and 3. Fe% in the table is% by weight.

[0017]

[Table 2]

[0018]

[Table 3]

As is clear from Tables 2 and 3, Si--F
The e-O-based slag has very good separability at both 1250 ° C and 1300 ° C, and the Fe removal is progressing. Na-Fe-O
Regarding the system slag, the one with a large amount of Na ₂ CO ₃ charged exhibited good separability. As for the Ca-Fe-O system, the result that the temperature is as high as 1300 ° C. can be said to be good.

As mentioned above, the slag of Experiment No.-2 is 1
Although it showed good separability in the experiment at 300 ° C, it did not reach the separability of the slag of the experiment number. Therefore, an experiment was conducted to see if the separability is improved when the amount of Na ₂ CO ₃ charged further increases.

-3 All Fe in the PGM-containing copper is Fe ₂
Until O ₃ is oxidized, Fe ₂ O ₃ to 5 equivalents of Na ₂ CO
_{By 3} , the Fe ₂ O ₃ is dissolved. All -4 PGM iron-containing copper oxide to Fe ₂ O _3, the Na ₂ CO ₃ in 7 equivalents relative to Fe ₂ O _3,
This Fe ₂ O ₃ is dissolved. The -5 all PGM iron-containing copper oxide to _{Fe 2 O 3, Fe 2 O} 3 to 10 equivalents of Na ₂ CO _3,
This Fe ₂ O ₃ is dissolved.

An experiment was carried out on each of the above slag systems in the same manner as the above-mentioned experiment except that the experimental conditions and method were 1300 ° C. The amount of each charge is shown in Table 4.

[0023]

[Table 4]

As the results of the experiment, the slag / metal separation property of the sample after cooling was evaluated in four stages as in the above experiment, and Fe in the metal was analyzed. This is shown in Table 5.

[0025]

[Table 5]

That is, in each case, the slag was separated into two layers, but the separability from the metal was good, and Fe was also removed well.

[0027]

As apparent from the above experiment, SiO ₂ , Na ₂ CO ₃ and CaO can be used as the flux.
Among these, more preferable are SiO ₂ , Na ₂ CO ₃
Is.

When SiO ₂ is used as the flux, Fe in PGM-containing copper is oxidized to obtain SiO ₂ : Fe.
_{The condition that 2} O ₃ : FeO = 32: 7: 61 (molar ratio) was selected in the preliminary experiment, but in reality, Fe ₂ O ₃ and F
Since it is difficult to identify the ratio of eO, the amount of SiO ₂ added may be determined with respect to the amount of Fe in PGM-containing copper so as to produce the following ferrite slag.

2FeO + SiO ₂ = 2FeO · SiO ₂ (4)

[0030] Next, the amount of Na ₂ CO ₃ in the case of adding a Na ₂ CO ₃ as fluxes, PGM
Fe in the contained copper is oxidized to Fe ₂ O ₃ to obtain 3Na ₂ O.
It is preferable to select the addition amount so that Fe ₂ O ₃ is produced. Further, the amount of addition of Na ₂ CO ₃ may be larger than this, but since the amount of Na ₂ CO ₃ is relatively expensive, the above amount is most preferable.

When CaO is added as a flux, P removal in the form of 3CaO.P ₂ O ₅ is expected together with Fe removal. Therefore, Fe in PGM-containing copper is oxidized to
In addition to the amount of CaO: Fe ₂ O ₃ : FeO = 23: 75: 2 (molar ratio), CaO: P ₂ O ₅ = 3: 1 (molar ratio)
The amount of CaO added is preferably such that Note that Ca
O: Fe ₂ O ₃ : FeO = 23: 75: 2 is defined as
This is to make the slag a melting region at a temperature as low as possible.

As the oxidizing agent, copper oxide (Cu ₂ O) can be used as shown in the above experiment, but more practically, oxidizing gas such as oxygen, oxygen-enriched air, or air can be used. . When an oxidizing gas is used, the O ₂ content has almost no effect on the reaction, but there is a problem that the melt is cooled by the heat of removing N ₂ , so the O ₂ content is high. Better.

[0033]

【Example】

Example 1 200.33 g of PGM-containing copper containing 3.7% by weight of Fe and 0.8% by weight of P was charged into an alumina crucible, and 13
After holding at 00 ° C for 30 minutes to make the solution uniform, Fe
Is oxidized to become FeO, and 39.2 g of silica is added and pure oxygen is added at about 500 cc / min so that it reacts with silica to form the ferrite slag 2FeO.SiO _2.
After de-Feing and de-Ping while blowing, the amount of blowing reaches the amount required for de-Feing, and after 5-10 minutes settling to sufficiently phase-separate the generated slag and metal, take out from the furnace and cool to the atmosphere. Later, the slag and metal were separated. When weighed the slag and metal, it was 184.38g and 18
It was 15.26 g. Table 6 shows the quantity and quality.

[0034]

[Table 6]

The Cu content in the slag was 7.23% by weight, which was mostly the chemically dissolved copper as Cu ₂ O. The PGM grades in the slag are Pt = 0.
0015% by weight, Pd = 0.0016% by weight, Rh =
It was 0.0003% by weight. Table 7 shows the distribution ratio of each element obtained based on Table 6.

[0036]

[Table 7]

The copper loss to the slag is 0.76% and P
The slag loss of GM is Pt = 0.017%, Pd = 0.0
It was 49% and Rh = 0.031%. When electrolysis was performed using the copper metal from which Fe and P had been removed as an anode, the elution rate of Rh in the electrolytic solution was 1% or less.
Table 8 shows the deFe and deP behavior during the treatment. Sampling was done by syringe and quenched in water.

[0038]

[Table 8]

Example 2 200.33 g of PGM-containing copper containing 3.7% by weight of Fe and 0.8% by weight of P was charged into an alumina crucible, and 13
After holding at 00 ° C for 30 minutes to make the solution uniform, Na was added so as to generate soda slag 3Na ₂ O · Fe ₂ O _3.
2 CO ₃ 207.8g was added, and pure oxygen was about 500cc
Fe / P removal while blowing at a flow rate of / min. After the amount of injection reaches the amount required for Fe removal, settling is performed for 5 to 10 minutes to sufficiently phase-separate the generated slag and metal, and then remove from the furnace. After cooling the atmosphere, the slag and metal were separated. The slag was separated into two layers, and Na-based slag was formed on the Fe-based slag. As for the output,
Fe-based slag 80.31 g, Na-based slag 183.
The amount of Fe-free metal was 1862.59 g. Table 9 shows the quantity and quality.

[0040]

[Table 9]

Table 10 shows the distribution ratio of the elements in this case.

[0042]

[Table 10]

The Cu quality of the slag was 1.51% by weight for the Fe-based slag and 0.20% by weight for the Na-based slag. The PGM grades in the slag are 0.0052 wt% Pt, 0.0020 wt% Pd, and 0.0009 wt% Rh in the Fe-based slag, and 0.0008 wt% Pt and 0.0003 wt% in the Na-based slag.
It was h 0.0001% by weight.

As for the distribution ratio, the copper loss to the slag was 0.07% for the Fe-based slag and 0.0 for the Na-based slag.
2%, and the PGM slag loss at this time was 0.026% Pt, 0.027% Pd, and Rh for Fe-based slag.
0.040%, Pt 0.009 for Na-based slag
%, Pd 0.009%, and Rh 0.010%.

When electrolysis was performed using this copper anode that had been deFe and P removed, the elution rate of Rh in the electrolytic solution was 1% or less.

Table 11 shows the Fe-free and P-free behaviors when the Na-Fe-O slag was used. Sampling was performed with a syringe and quenched in water.

[0047]

[Table 11]

Example 3 The same conditions and methods as in Example 2 were used except that CaO was used as the flux and the oxygen blowing rate was set to 1000 cc / min. The amount of CaO added is the amount required for Fe removal and P removal, and Fe in PGM-containing copper is oxidized to CaO: Fe ₂ O ₃ : FeO = 23: 75:
2 (molar ratio), and P is oxidized to CaO: P ₂ O ₅ =
26.8g which added the amount of CaO which becomes 3: 1 (molar ratio)
Was added.

Table 12 shows the Fe-free and P-free behaviors.

[0050]

[Table 12]

When CaO is used as the flux, the slag formation seems to be worse than that of SiO ₂ or Na ₂ CO ₃ , so the P removal rate tends to be slow in the first half of the reaction.
When O is slagged, CaO reacts with P ₂ O ₅ to remove P
Also progressed sufficiently and finally became less than 0.05% by weight. Regarding Fe removal, it proceeded almost in proportion to the amount of blown oxygen.

The Cu content in the slag was as high as 3.5% by weight, but when the slag was observed, most of the metallic Cu was present. For this reason, the PGM quality in the slag was as high as 0.040% by weight in total PGM.
However, when this Fe-free and P-free copper was used as an anode for electrolysis, the elution rate of Rh into the electrolytic solution was 1% or less.

Example 4 Example 2 except that normal air was used as the oxidizing gas.
Although the PGM-containing copper was treated under the same conditions as described above, it was deFeed and dePed as in the case of using oxygen. That is,
As a result of de-Feing and de-Ping PGM-containing copper containing 3.7 wt% Fe and 0.8 wt% P, Fe grade and P in metal
The quality was 0.05% by weight or less.

However, the temperature of the melt tended to drop, and it was necessary to interrupt the blowing from time to time and wait for the bath temperature to rise before blowing air. However, the oxygen efficiency was not different from that when oxygen was used.

Example 5 Under the same conditions as in Example 2, referring to the phenomenon of Example 4, O
_{When 2} = 50% oxygen-enriched air was used, there was almost no decrease in the temperature of the melt, and F removal was performed in the same manner as in Example 2.
e, P removal could be implemented. That is, the PGM-containing copper containing 3.7 wt% Fe and 0.8 wt% P was deFeed and dePed, and as a result, the Fe grade and P grade in the metal were each 0.0
It became 5% by weight or less.

[0056]

INDUSTRIAL APPLICABILITY According to the present invention, from PGM-containing copper to PGM
Fe and P contained in the PGM-containing copper can be efficiently removed while minimizing the loss of As a result, the PGM absorbed by copper can be efficiently recovered by the existing copper electrolysis while suppressing the elution of Rh.

Claims (1)

[Claims] 1. An automobile waste catalyst containing alumina or cordierite as a base material is melted together with copper, the platinum group metal in the automobile waste catalyst is aggregated and absorbed in the copper metal, and the platinum group metal-containing copper is electrolyzed. In the method of concentrating, separating and recovering copper as electrolytic copper and platinum group metal as electrolytic slime by doing so, any one of CaO, SiO ₂ , and Na ₂ CO ₃ as a flux is added to the platinum group metal-containing copper before the electrolysis. Fe and P in the platinum-group metal-containing copper are removed by adding at least one oxidizing gas selected from copper oxide or air, oxygen-enriched air, and oxygen while adding and melting. Removal of Fe and P from platinum group metal-containing copper recovered by absorbing platinum group metal from used automobile waste catalysts
Method.