阅读说明：本技术 一种Fe-PGMs合金电解回收铂族金属的方法 (Method for electrolyzing and recycling platinum group metals from Fe-PGMs (Fe-PGMs) alloy ) 是由 张深根 丁云集 温泉 于 2019-10-23 设计创作，主要内容包括：本发明涉及铂族金属循环利用技术领域,提供了一种Fe-PGMs合金电解回收铂族金属的方法,该方法以Fe-PGMs合金为阳极,惰性电极为阴极；向经除氧的水中加入硫酸亚铁,加入稳定剂、表面活性剂、Fe<Sup>2+</Sup>络合剂和恒电导剂得到电解液；采用恒压电解得到富含PGMs阳极泥和阴极纯铁。本发明实现了PGMs与Fe基体绿色高效分离；不消耗酸、不产生酸性废水,解决了现有的Fe-PGMs合金碎化酸解法环境负担重的技术难题；工艺简单,成本低,易于产业化。(The invention relates to the technical field of platinum group metal recycling, and provides a method for recovering platinum group metals by electrolyzing Fe-PGMs (platinum group metals), which takes Fe-PGMs as an anode and an inert electrode as a cathode; adding ferrous sulfate, stabilizer, surfactant and Fe into deoxygenated water 2+ Complexing agent and constant electric conduction agent to obtain electrolyte; obtaining anode mud rich in PGMs and cathode pure iron by constant-voltage electrolysis. The invention realizes green and efficient separation of PGMs and Fe matrix; acid is not consumed, acid waste water is not generated, and the technical problem of heavy environmental burden of the conventional Fe-PGMs alloy fragmentation acidolysis method is solved; simple process, low cost and easy industrialization.)

1. A method for the electrolytic recovery of platinum group metals from Fe-PGMs alloys, said method comprising:

s1, taking Fe-PGMs alloy as an anode and taking an inert electrode as a cathode;

s2, adding ferrous sulfate into the deoxidized water, adding a stabilizer, a surfactant and Fe²⁺Complexing agent and constant electric conduction agent to obtain electrolyte;

and S3, obtaining anode mud rich in PGMs and cathode pure iron by constant-voltage electrolysis.

2. The method for the electrolytic recovery of platinum group metals from Fe-PGMs alloys according to claim 1 wherein in step S1, said anode is a Fe-PGMs alloy anode plate obtained by trapping PGMs in secondary resources with iron, said anode plate having a thickness of 3.0-20.0 mm; the inert electrode is titanium or graphite.

3. The method for the electrolytic recovery of platinum group metals from Fe-PGMs alloys according to claim 1 wherein in step S2, the oxygen content of said deoxygenated water is not higher than 1.5 mg/L; dissolving ferrous sulfate in the deoxygenated water, Fe²⁺Adjusting the pH to 3.0-4.5 by using sulfuric acid with the concentration of 30-120 g/L;

the addition amount of the stabilizer is 0.1-1.0 g/L;

the addition amount of the surfactant is 0.5-2.5 g/L;

said Fe²⁺The addition amount of the complexing agent is 20-100 g/L;

the addition amount of the constant-conductivity agent is 10-60 g/L;

the prepared electrolyte covers the insulating agent for insulating air.

4. The method for the electrolytic recovery of platinum group metals from Fe-PGMs as claimed in claim 3, wherein the stabilizer is one or more of bovine gelatin and bone gelatin.

5. The method for the electrolytic recovery of platinum group metals from Fe-PGMs as claimed in claim 3, wherein said surfactant is one or more of sodium dodecyl sulfate and sodium alkyl benzene sulfonate.

6. The method for the electrolytic recovery of platinum group metals from Fe-PGMs alloys as claimed in claim 3, wherein said Fe is²⁺The complexing agent is one or more of ethylenediamine tetraacetic acid and sodium citrate.

7. The method for the electrolytic recovery of platinum group metals from Fe-PGMs as claimed in claim 3, wherein said constant conductivity agent is added in an amount of one or more of potassium sulfate and sodium sulfate.

8. The method for the electrolytic recovery of platinum group metals from Fe-PGMs alloys as claimed in claim 3, wherein said insulating agent is edible oil.

9. The method for the electrolytic recovery of platinum group metals from Fe-PGMs alloys as claimed in any one of claims 1 to 8, wherein the constant voltage electrolysis is performed at an electrolysis voltage of 0.50 to 0.80V and an electrolysis temperature of 25 to 95 ℃ in step S3.

10. The method for the electrolytic recovery of platinum group metals from Fe-PGMs alloys as claimed in any of claims 1 to 8 wherein in step S3 said anode slime is enriched with PGMs and said cathode pure iron can be recovered for use in an iron capture process.

Technical Field

The invention relates to the technical field of platinum group metal recycling, in particular to a method for recovering platinum group metals by electrolyzing Fe-PGMs (Fe-PGMs).

Background

Platinum group metals have excellent physical and chemical properties such as high melting point, corrosion resistance, catalytic activity, etc., which makes them indispensable metal materials in many industrial fields. Global PGMs resources are scarce and very unevenly distributed. China is seriously poor in PGMs mineral resources, but the industrial demand is large. Moreover, because PGMs have strong biological activity, a large amount of toxic and harmful substances can be mixed in the catalyst in the using process, and serious influence is caused on the ecological environment. In recent years, the consumption of PGMs is large, the updating is fast, the growth of waste containing the PGMs is fast, the grade of the PGMs in the waste is far higher than that of associated ores, the recovery cost is low, and the environmental burden is relatively small. Therefore, the research and development of the green recovery technology of the PGMs secondary resources are urgently needed. Since Fe is a green metal, iron capture is the most industrially valuable green recovery process for PGMs.

Fe is trapped to obtain Fe-PGMs alloy, and PGMs are required to be further separated and extracted. The separation and extraction of PGMs from Fe-PGMs alloys typically employs a fragmentation-acidolysis process. The invention patent of China 'precious metal fragmentation and dissolution method' (application No. CN90104468.7) discloses the procedures of mixing, melting and fragmenting a material containing precious metals by using a base metal fragmentation agent at 700-1200 ℃, then carrying out acidolysis by using a hydrochloric acid solution, carrying out aqueous solution chlorination and dissolution on leaching residues (precious metal powder), and the like. The weight ratio of the material containing noble metal to the aluminum-zinc base alloy composite crushing agent is 1: 5-10. The fragmentation acidolysis method has the disadvantages of high acid consumption, high acid wastewater and heavy environmental burden, and is difficult to meet the environmental protection requirement.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a method for electrolyzing and recovering platinum group metals from Fe-PGMs, which can realize green and efficient separation and extraction of PGMs and a matrix, can separate and extract PGMs by electrolyzing Fe-PGMs to avoid fragmentation and acidolysis, directly uses Fe-PGMs as a sacrificial anode, electrolyzes and migrates Fe in the Fe-PGMs to a cathode to obtain cathode iron, and deposits the PGMs as insoluble substances to obtain anode mud. The method does not consume acid and generate acid wastewater, and solves the technical problem of heavy environmental burden of the conventional Fe-PGMs alloy fragmentation acidolysis method.

The technical principle of the invention is as follows:

(1) according to the standard electrode potential of the substance (see table 1), the standard potentials of Pt, Pd, Rh and the oxygen evolution reaction potential of water are all greater than the standard potential of Fe, so that the anode undergoes only the Fe electrodissolution reaction, i.e.: fe_(s)-2e^-＝Fe²⁺ _(aq)And the PGMs are settled in a simple substance state to form anode mud, so that the separation of the iron matrix and the PGMs is realized.

TABLE 1 Standard electrode potentials

Inert material is used as cathode and sulfuric acid is used asIron solution is used as electrolyte, and Fe is increased²⁺Activity and pH, inhibiting hydrogen evolution reaction and realizing ferroelectrolysis.

(2) Preparing electrolyte by adopting deoxygenated water with oxygen content not higher than 1.5mg/L, adding ferrous sulfate and the like to prevent Fe²⁺Is oxidized into Fe³⁺(ii) a The prepared electrolyte is covered with an isolating agent (edible oil) to isolate air, so that the electrolyte is prevented from oxygenation, and Fe is avoided²⁺Is oxidized.

(3) Addition of Fe²⁺The complexing agent can improve Fe²⁺Potential for oxidation to occur and avoidance of Fe²⁺→Fe³⁺And (4) carrying out secondary reaction.

(4) The added stabilizer ionizes OH in acidic solution^-And the colloid root with positive electricity is adsorbed on the surface of the cathode to form a cationic membrane, so that the cathode polarization is increased, the growth speed of iron grains is slowed down, the grains are refined, and the surface smoothness of the cathode is improved; the surfactant is added, so that the wettability of the electrolyte on the surface of the cathode can be improved, the interface resistance is reduced, and the deposition quality is improved.

(5) Adding potassium sulfate or sodium sulfate as constant-conductivity agent, since Na⁺、K⁺The migration rate is high, the conductivity of the electrolyte is increased, and the current is stabilized.

The invention is realized by the following technical scheme:

a method for the electrolytic recovery of platinum group metals from Fe-PGMs alloys, said method comprising:

s1, taking Fe-PGMs alloy as an anode and taking an inert electrode as a cathode;

s2, adding ferrous sulfate into the deoxidized water, adding a stabilizer, a surfactant and Fe²⁺Complexing agent and constant electric conduction agent to obtain electrolyte;

and S3, obtaining anode mud rich in PGMs and cathode pure iron by constant-voltage electrolysis.

Further, in step S1, the anode is an Fe-PGMs alloy anode plate obtained by trapping PGMs in the secondary resource with iron, and the thickness of the anode plate is 3.0-20.0 mm; the inert electrode is titanium or graphite.

Further, in step S2, the oxygen content in the deoxygenated water is notHigher than 1.5 mg/L; dissolving ferrous sulfate in the deoxygenated water, Fe²⁺Adjusting the pH to 3.0-4.5 by using sulfuric acid with the concentration of 30-120 g/L;

the addition amount of the stabilizer is 0.1-1.0 g/L;

the addition amount of the surfactant is 0.5-2.5 g/L;

said Fe²⁺The addition amount of the complexing agent is 20-100 g/L;

the addition amount of the constant-conductivity agent is 10-60 g/L;

the prepared electrolyte covers the insulating agent for insulating air.

Further, the stabilizer is one or more of bovine gelatin and bone gelatin.

Further, the surfactant is any one or more of sodium dodecyl sulfate and sodium alkyl benzene sulfonate.

Further, said Fe²⁺One or more of complexing agent ethylene diamine tetraacetic acid and sodium citrate.

Further, the addition amount of the constant conductivity agent is any one or more than one of potassium sulfate and sodium sulfate.

Further, the isolating agent is edible oil.

Further, in step S3, the constant voltage electrolysis is performed at an electrolysis voltage of 0.50-0.80V and an electrolysis temperature of 25-95 ℃.

Further, in step S3, the anode slime is enriched with PGMs and the cathode pure iron can be recovered for use in the iron capture process.

The invention has the beneficial effects that:

(1) the method is characterized in that iron is electrolytically transferred to a cathode to obtain cathode iron, and PGMs are deposited as insoluble substances to obtain anode mud, so that the separation and extraction of PGMs from Fe-PGMs alloy are realized, and no acid is consumed and no acidic wastewater is generated.

(2) The stable electrolysis of Fe is realized by adopting constant voltage electrolysis of 0.50-0.80V, the electrolytic migration of PGMs is avoided, the effective separation of Fe and PGMs is realized, and the cathode pure iron can be reused in the iron trapping process.

(3) With low oxygen contentPreparing electrolyte with 1.5mg/L of deoxygenated water, covering edible oil on the surface of the prepared electrolyte to isolate air and avoid oxygenation, thereby preventing Fe²⁺Is oxidized into Fe³⁺。

(4) One or more complexing agents of ethylene diamine tetraacetic acid and sodium citrate are added to improve Fe²⁺Potential for oxidation to occur and avoidance of Fe²⁺→Fe³⁺And (4) side reaction.

(5) Adding one or more stabilizers selected from ox gelatin and bone gelatin, and ionizing to obtain OH in acidic solution^-And the colloid root with positive electricity increases cathode polarization, slows down the growth speed of iron crystal grains, refines the crystal grains and improves the surface smoothness of the cathode.

(6) Any one or more than one surfactant of sodium dodecyl sulfate and sodium alkyl benzene sulfonate is added, so that the wettability of the electrolyte on the surface of the cathode is improved, the interface resistance is reduced, and the deposition quality is improved.

(7) Any one or more than one constant conductivity agent of potassium sulfate and sodium sulfate is added, so that the conductivity of the electrolyte is increased, and the current is stabilized.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described in detail. It should be noted that technical features or combinations of technical features described in the following embodiments should not be considered as being isolated, and they may be combined with each other to achieve a better technical effect.

Without loss of generality, the invention is further illustrated by the following examples.