Method for recycling hydrogen fuel cell of new energy vehicle

Abstract

Disclosed is a method for recycling a hydrogen fuel cell of a new energy vehicle, including the following steps of: (1) discharging and disassembling a hydrogen fuel cell in turn to obtain a hydrogen supply system, an air supply system, a cooling system and a galvanic pile; (2) disassembling the galvanic pile into a catalyst and carbon cloth, and ashing to obtain ash; (3) adding an auxiliary agent into the ash, mixing, introducing inert gas, heating, introducing oxidizing gas, and absorbing tail gas by using an ammonium salt solution; and (4) adding a reducing agent into the ammonium salt solution absorbing the tail gas in step (3) to react, filtering, taking and cleaning a filter residue to obtain Pt.

Claims

1. A method for recycling a hydrogen fuel cell, comprising: (1) discharging and disassembling a hydrogen fuel cell to obtain a hydrogen supply system, an air supply system, a cooling system and a galvanic pile; (2) disassembling the galvanic pile into a catalyst and carbon cloth, and ashing to obtain ash; (3) adding an auxiliary agent into the ash, mixing, introducing inert gas, heating, introducing oxidizing gas, and absorbing tail gas by using an ammonium salt solution; and (4) adding a reducing agent into the ammonium salt solution absorbing the tail gas in step (3) to react, filtering, taking and cleaning a filter residue to obtain Pt; wherein in step (3), the auxiliary agent is one of NaF, CaF.sub.2, KCl, NaCl, or CaCl.sub.2.

2. The method of claim 1, wherein in step (2), the ashing is carried out at a temperature of 400° C. to 600° C., and lasts for 30 minutes to 60 minutes.

3. The method of claim 1, wherein in step (3), the oxidizing gas is one of chlorine gas or bromine gas.

4. The method of claim 1, wherein in step (3), the oxidizing gas is one of nitrogen, helium or argon.

5. The method of claim 1, wherein in step (3), the heating is carried out at a rate of 2° C..Math.min.sup.−1 to 6° C..Math.min.sup.−1 and a temperature of 1,000° C. to 1,200° C.

6. The method of claim 1, wherein in step (4), the reducing agent is one of sodium thiosulfate, sodium borohydride or hydrazine.

7. The method of claim 1, wherein in step (4), the ammonium salt solution is one of ammonium chloride solution or ammonium bromide solution.

8. The method of claim 1, wherein in step (4), a further purification process of Pt after preparing Pt is as follows: adding a leachate into Pt, heating, washing, filtering, taking a filtrate, adding a reducing agent for reaction, filtering, taking and cleaning a filter residue to obtain pure Pt, wherein a mass ratio of Pt to the leachate is 1:(10 to 20).

9. The method of claim 8, wherein the leachate is aqua regia, and the aqua regia has a mass concentration of 50% to 100%.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a flowchart of a hydrogen fuel cell recycling process according to Embodiment 1 of the present invention.

DETAILED DESCRIPTION

(2) In order to make the technical solutions of the present invention clearer to those skilled in the art, the following embodiments are listed for explanation. It should be noted that the following embodiments do not limit the scope of protection claimed by the present invention.

(3) Unless otherwise specified, the raw materials, reagents or devices used in the following embodiments can be obtained from conventional commercial sources or by existing known methods.

Embodiment 1

(4) A method for recycling a hydrogen fuel cell of a new energy vehicle included the following specific steps of:

(5) (1) discharging a hydrogen fuel cell until a hydrogen fuel in a hydrogen storage tank was completely exhausted, and disassembling the hydrogen fuel cell to obtain a hydrogen supply system, an air supply system, a cooling system, an electric control system and a galvanic pile;

(6) (2) further disassembling the hydrogen supply system to obtain a hydrogen ejector, a high-pressure hydrogen sealing valve, a reducing valve, a hydrogen tank, a hydrogen circulating pump, an inverter, a hydrogen concentration sensor, a hydrogen temperature sensor, a hydrogenation control unit, a hydrogen pressure sensor, and a hydrogen pipeline; further disassembling the air supply system to obtain an air compressor, a muffler, an air valve module, and an air pipeline; and further disassembling the cooling system to obtain a water pump, a radiator, a deionization device, and a thermostat (three-way valve);

(7) (3) further disassembling the galvanic pile to obtain metal fasteners such as a screw stem, alloy bipolar plates and a plastic shell for direct recycling, directly discarding graphite bipolar plates, further disassembling membrane electrodes to directly recover proton exchange membranes as polymers, placing the obtained catalyst and carbon cloth in a ceramic crucible, and ashing the ceramic crucible in a muffle furnace at 400° C. for 30 minutes to obtain ash;

(8) (4) placing the ash in mortar, adding NaF according to a weight ratio of 1:1, grinding the mixture evenly, pouring the mixture into a corundum porcelain boat and then placing the boat in a middle heating zone of a tube furnace, introducing nitrogen at a flow rate of 1 mL.Math.min.sup.−1, absorbing the tail gas with 30 mL of ammonium chloride solution with a concentration of 1 mol.Math.L.sup.−1, introducing nitrogen for 5 minutes, then raising the temperature to 1,000° C. at a heating rate of 2° C..Math.min.sup.−1, switching to another gas channel to introduce the chlorine gas for 20 minutes, then switching back to the nitrogen again, turning off the heating system, cooling to room temperature, and turning off the chlorine gas;

(9) (5) adding the ammonium chloride solution absorbing the tail gas into sodium thiosulfate solution with a mass concentration of 40% according to a volume ratio of 1:0.1, filtering, cleaning, and taking a filter residue to obtain crude Pt; and

(10) (6) adding aqua regia with a mass concentration of 50% into the crude Pt according to a mass ratio of 1:10, heating the mixture to slight boiling for 5 minutes, rinsing the cup wall with 5 mL of deionized water, filtering, taking and adding the filtrate into sodium thiosulfate solution with a mass concentration of 40% according to a volume ratio of 1:0.1, filtering, cleaning, and take a filter residue which was pure Pt.

Embodiment 2

(11) A method for recycling a hydrogen fuel cell of a new energy vehicle included the following specific steps of:

(12) (1) discharging a hydrogen fuel cell until a hydrogen fuel in a hydrogen storage tank was completely exhausted, and disassembling the hydrogen fuel cell to obtain a hydrogen supply system, an air supply system, a cooling system, an electric control system and a galvanic pile;

(13) (2) further disassembling the hydrogen supply system to obtain a hydrogen ejector, a high-pressure hydrogen sealing valve, a reducing valve, a hydrogen tank, a hydrogen circulating pump, an inverter, a hydrogen concentration sensor, a hydrogen temperature sensor, a hydrogenation control unit, a hydrogen pressure sensor, and a hydrogen pipeline; further disassembling the air supply system to obtain an air compressor, a muffler, an air valve module, and an air pipeline; and further disassembling the cooling system to obtain a water pump, a radiator, a deionization device, and a thermostat (three-way valve);

(14) (3) further disassembling the galvanic pile to obtain metal fasteners such as a screw stem, alloy bipolar plates and a plastic shell for direct recycling, directly discarding graphite bipolar plates, further disassembling membrane electrodes to directly recover proton exchange membranes as polymers, placing the obtained catalyst and carbon cloth in a ceramic crucible, and ashing the ceramic crucible in a muffle furnace at 500° C. for 45 minutes to obtain ash;

(15) (4) placing the ash in mortar, adding KCl according to a weight ratio of 1:3, grinding the mixture evenly, pouring the mixture into a corundum porcelain boat and then placing the boat in a middle heating zone of a tube furnace, introducing nitrogen at a flow rate of 15 mL.Math.min.sup.−1, absorbing the tail gas with 35 mL of ammonium chloride solution with a concentration of 3 mol.Math.L.sup.-1, introducing nitrogen for 10 minutes, then raising the temperature to 1,100° C. at a heating rate of 4° C..Math.min.sup.−1, introducing chlorine gas for 40 minutes, then switching back to the nitrogen again, turning off the heating system, cooling to room temperature, and turning off the chlorine gas;

(16) (5) adding the ammonium chloride solution absorbing the tail gas into sodium borohydride with a mass concentration of 60% according to a volume ratio of 1:0.2, filtering, cleaning, and taking a filter residue to obtain crude Pt; and

(17) (6) adding aqua regia with a mass concentration of 75% into the crude Pt according to a mass ratio of 1:15, heating the mixture to slight boiling for 7 minutes, rinsing the cup wall with 7 mL of deionized water, filtering, taking and adding the filtrate into sodium borohydride with a mass concentration of 40% according to a volume ratio of 1:0.1, filtering, cleaning, and take a filter residue which was pure Pt.

Embodiment 3

(18) A method for recycling a hydrogen fuel cell of a new energy vehicle included the following specific steps of:

(19) (1) discharging a hydrogen fuel cell until a hydrogen fuel in a hydrogen storage tank was completely exhausted, and disassembling the hydrogen fuel cell to obtain a hydrogen supply system, an air supply system, a cooling system, an electric control system and a galvanic pile;

(20) (2) further disassembling the hydrogen supply system to obtain a hydrogen ejector, a high-pressure hydrogen sealing valve, a reducing valve, a hydrogen tank, a hydrogen circulating pump, an inverter, a hydrogen concentration sensor, a hydrogen temperature sensor, a hydrogenation control unit, a hydrogen pressure sensor, and a hydrogen pipeline; further disassembling the air supply system to obtain an air compressor, a muffler, an air valve module, and an air pipeline; and further disassembling the cooling system to obtain a water pump, a radiator, a deionization device, and a thermostat (three-way valve);

(21) (3) further disassembling the galvanic pile to obtain metal fasteners such as a screw stem, alloy bipolar plates and a plastic shell for direct recycling, directly discarding graphite bipolar plates, further disassembling membrane electrodes to directly recover proton exchange membranes as polymers, placing the obtained catalyst and carbon cloth in a ceramic crucible, and ashing the ceramic crucible in a muffle furnace at 600° C. for 60 minutes to obtain ash;

(22) (4) placing the ash in mortar, adding NaCl according to a weight ratio of 1:5, grinding the mixture evenly, pouring the mixture into a corundum porcelain boat and then placing the boat in a middle heating zone of a tube furnace, introducing nitrogen at a flow rate of 30 mL.Math.min.sup.−1, absorbing the tail gas with 40 mL of ammonium chloride solution with a concentration of 5 mol.Math.L.sup.−1, introducing nitrogen for 15 minutes, then raising the temperature to 1,200° C. at a heating rate of 6° C..Math.min.sup.−1, introducing chlorine gas for 60 minutes, then switching back to the nitrogen again, turning off the heating system, cooling to room temperature, and turning off the chlorine gas;

(23) (5) adding the ammonium chloride solution absorbing the tail gas into hydrazine with a mass concentration of 100% according to a volume ratio of 1:0.3, filtering, cleaning, and taking a filter residue to obtain crude Pt; and

(24) (6) adding aqua regia with a mass concentration 100% into the crude Pt according to a mass ratio of 1:20, heating the mixture to slight boiling for 10 minutes, rinsing the cup wall with 10 mL of deionized water, filtering, taking and adding the filtrate into hydrazine with a mass concentration of 100% according to a volume ratio of 1:0.3, filtering, cleaning, and take a filter residue which was pure Pt.

Comparative Example 1 (CN104745836A)

(25) A platinum recycling refining process included the following process steps of:

(26) a. carbonizing a platinum-containing material for 1.5 hours to 2.5 hours at 750° C. to 850° C.;

(27) b. cooling to a room temperature and then adding aqua regia to dissolve the material at a temperature control between 65° C. and 75° C. until the material was completely dissolved;

(28) c. adding ammonium chloride and precipitating for 0.5 hour to 1.5 hours, and after precipitating, filtering and washing ammonium chloroplatinate;

(29) d. adding sodium hydroxide till dissolving in 20 minutes to 40 minutes to form a dissolution solution;

(30) e. heating the dissolution solution obtained in the step d to 45° C. to 55° C. and then adding hydrazine hydrate for reducing, and reacting for 0.5 hour to 1.5 hours to finish platinum recycling; and

(31) f. drying the reduced platinum powder.

(32) Recycling efficiency:

(33) TABLE-US-00001 TABLE 1 Recycling status and cost of Embodiment 2 Recycling Recycling Crude Process Recycling rate amount product cost object (%) (per ton of battery) purity (%) (RMB) Pt 99.7 60.56 g  99.9 231 Cu 98.6 82.62 kg 99.6  36 Fe 98.7 636.5 kg 98.7  23 Zn 99.5  1.2 kg 99.5 103 Al 99.8 160.9 kg 99.8  41 Plastic 99.5  67.0 kg 99.2  37

(34) TABLE-US-00002 TABLE 2 Recycling status and cost of Embodiment 3 Recycling Recycling Crude Process Recycling rate amount product cost object (%) (per ton of battery) purity (%) (RMB) Pt 99.3 58.36 g  99.8 246 Cu 98.5 81.99 kg 99.4  42 Fe 98.6 631.7 kg 98.5  29 Zn 99.2  1.13 kg 99.3 125 Al 99.5 159.6 kg 99.5  44 Plastic 99.3  65.8 kg 99.1  39

(35) TABLE-US-00003 TABLE 2 Recycling status and cost of Comparative Example 1 Recycling Recycling Crude Process Recycling rate amount product cost object (%) (per ton of battery) purity (%) (RMB) Pt 96.7 57.56 g  99.8 588 Cu 97.6 76.62 kg 99.1  43 Fe 95.7 616.5 kg 98.2  35 Zn 96.5   1.1 kg 99.3 121 Al 97.8 155.9 kg 98.8  57 Plastic 96.5  65.0 kg 97.2  42

(36) It can be seen from Tables 1 to 3 that, in each ton of hydrogen fuel cell, the recycling rate of Pt in Embodiment 2 of the present invention is 99.7% , and the purity of the Pt crude product is 99.9%; the recycling rate of Cu is 98.6%, and the purity of the Cu crude product is 99.6%; the recycling rate of Fe is 98.7%, and the purity of the Fe crude product is 98.7%; the recycling rate of Zn is 99.5%, and the purity of the Zn crude product is 99.5%; the recycling rate of Al is 99.8%, and the purity of the Al crude product is 99.8%; and the recycling rate of plastic is 99.5%, and the purity of the Pt crude product is 99.2%. In each ton of hydrogen fuel cell, the recycling rate of Pt in Embodiment 3 of the present invention is 99.3% , and the purity of the Pt crude product is 99.8%; the recycling rate of Cu is 98.5%, and the purity of the Cu crude product is 99.4%; the recycling rate of Fe is 98.6%, and the purity of the Fe crude product is 98.5%; the recycling rate of Zn is 99.2%, and the purity of the Zn crude product is 99.3%; the recycling rate of Al is 99.5%, and the purity of the Al crude product is 99.5%; and the recycling rate of plastic is 99.3%, and the purity of the Pt crude product is 99.1%.In the Comparative Example 2, the recycling rate of Pt is 96.7%, the recycling rate of Cu is 97.6%, the recycling rate of Fe is 95.7%, the recycling rate of Zn is 96.5%, the recycling rate of Al is 97.8%, and the recycling rate of plastic is 96.5%, respectively. The recycling rates of all components are lower than those in Embodiments 2 and 3, and the process cost of recycling Pt is much higher than that in Embodiment 2. From this, it can be seen that by using the method for recycling of the present invention, the process for obtaining pure platinum is simple, low in cost, and industrially recoverable.

(37) FIG. 1 is a flowchart of a waste hydrogen fuel cell recycling process according to Embodiment 1 of the present invention. It can be seen from FIG. 1 that the entire recycling process is simple and efficient. The recycling range includes materials with a specific gravity of more than 99% and can obtain crude products with higher purity. The difficulty in the whole process is the method for recycling platinum. The ashing treatment can directly increase the purity of platinum to more than 98%. After two steps of high temperature chlorination and reduction, the platinum can be purified, and the purity can reach 99.9%.

(38) The method for recycling the hydrogen fuel cell of the new energy vehicle provided by the present invention has been introduced in detail above, and the principle and implementation of the present invention have been illustrated with specific embodiments. The explanation of the above embodiments is only used to help understand the method and the core idea of the present invention, including the best mode, and also enables any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be pointed out that for those of ordinary skills in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention is defined by the claims, and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the literal expression of the claims, or if they include equivalent structural elements that are not materially different from the literal expression of the claims, these other embodiments should