Method for removing surface coating of waste tire cord steel wire

Abstract

The invention provides a method for removing a surface coating of a waste tire cord steel wire, and belongs to the technical field of high-value recycling of the waste tire cord steel wire. According to the method, separation of copper and zinc in coating components is achieved through a sodium benzoate / auxiliary leaching agent system in the first step, zinc precipitation treatment is conducted on first filtrate to obtain zinc hydroxide, a zinc oxide product can be further prepared, high commercial value is achieved, and cyclic utilization of the zinc element in tires is achieved; and 2, carrying out copper deposition treatment on the third filtrate to obtain a byproduct basic cupric carbonate. Through the two successive steps, the waste tire cord steel wire and the surface coating component are effectively separated, echelon separation of zinc and copper valuable elements in the coating component and high-value utilization of the cord steel wire are achieved, and the method has good application prospects and social and ecological benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of high-value recycling and cyclic utilization of waste tire cord steel wires, and in particular relates to a method for removing surface coatings of waste tire cord steel wires. Background Art

[0002] With the rapid development of the global automotive industry, hundreds of millions of waste tires are generated every year. Due to the three-dimensional cross-linked network structure of tires, they are difficult to be biodegraded in the natural state. Improperly treated waste tires not only waste resources, but also pose a safety hazard of causing fire, which harms the ecological environment and human life and health.

[0003] Pyrolysis is a process of thermally decomposing the rubber components in waste tires in an inert or oxygen-deficient atmosphere through a high-temperature environment. Compared with other recycling and treatment methods, waste tire pyrolysis has two main advantages: first, it can achieve the "full use" of waste tires, and can obtain gas, liquid, and solid three-phase products, which has great potential in subsequent high-value applications; second, the entire process of pyrolysis realizes the fully closed cycle treatment of waste tires, which is an environmentally friendly treatment method.

[0004] As a solid product of waste tire recycling, the high-value recycling of waste tire cord wire is of great significance. In the production process of cord wire, in order to improve the bonding strength between the cord wire and rubber, a layer of brass (copper-zinc alloy) needs to be plated on the surface of the cord wire. Since the waste tire cord wire needs to be re-smelted during the recycling process, the introduction of elements such as copper, zinc and sulfur in the cord wire will damage the smelting equipment and affect the forging performance of the steel. Therefore, removing the coating of waste tire cord wire is of great significance.

[0005] CN100369820C adopts a multi-step process to recycle waste tire steel wire. First, the surface brass coating is removed by electrochemical or chemical methods, and then acid dissolution is used to prepare a ferrous salt solution, which is further filtered to remove impurities, and finally dried and calcined to prepare high-purity iron oxide. However, this recovery process has long and cumbersome operation steps, and a high concentration of strong acid is used in the leaching process, and a high calcination temperature is used in the calcination process, which not only increases the cost and energy consumption of subsequent treatment, but also causes serious corrosion to the processing equipment, making the entire process of recycling waste tire cord steel wire economically uneconomical and difficult to mass produce. CN103436899B uses a strong alkaline mixed solution of ammonia water, sodium nitrite, and deionized water to remove the surface coating of waste tire steel cord under heating and oxygenation conditions. However, sodium nitrite is not only expensive, but also chemically toxic, and unstable in itself. It is prone to explosion under certain conditions, which increases the instability and danger of the recycling process. In addition, oxygen needs to be introduced during the recycling process, which also increases the danger of the recycling process, resulting in low economic benefits of the process and making it unsuitable for large-scale industrial production. CN109161692A uses 95% sulfuric acid and sodium thiosulfate solution to remove copper plating from waste plastics under stirring conditions. However, the temperature of the entire leaching process is relatively high, and the use of high-concentration sulfuric acid not only increases the energy consumption and cost of the treatment process, but also causes more serious corrosion to the equipment. At the same time, there are certain safety hazards, which are not suitable for large-scale de-plating production. Therefore, there is an urgent need for a method that can efficiently remove the surface plating of waste tire cord steel wires. Summary of the invention

[0006] The present invention provides a method for removing the surface coating of waste tire cord steel wires. The method enables the waste tire cord steel wires to be effectively separated from the surface coating components, realizes the stepwise separation of zinc and copper valuable elements in the coating components and the high-value utilization of the cord steel wires, and has good application prospects, social and ecological benefits.

[0007] In order to achieve the above object, the present invention provides a method for removing the surface coating of waste tire cord steel wire, comprising the following steps:

[0008] Heat treating waste tire cord steel wires to obtain cord steel wires without rubber adhesion;

[0009] Leaching the waste tire cord steel wire under the conditions of sodium benzoate and an auxiliary leaching agent, filtering and washing to obtain a first filtrate and a first filter residue;

[0010] Adding sodium hydroxide solution to the first filtrate for zinc precipitation treatment, and obtaining zinc hydroxide and a second filtrate through solid-liquid separation, wherein the second filtrate is circulated for leaching of waste tire cord steel wires;

[0011] The first filter residue is leached with an ammonia / ammonium salt system, and after filtering and washing, the cord steel wire after the coating is removed and the third filtrate are obtained. A water-soluble carbonate is added to the third filtrate for copper precipitation treatment, and basic copper carbonate is separated. The mother liquor is continuously circulated for leaching of the waste tire cord steel wire.

[0012] It can be understood that the scheme of the present invention separates the metal coating components of the waste tire cord steel wire from the stainless steel base material by leaching the waste tire cord steel wire in a solution system of sodium benzoate and an auxiliary leaching agent (hydrogen peroxide, potassium permanganate or sodium hypochlorite), and the zinc component in the coating is converted into soluble zinc benzoate, and the copper component in the coating is converted into insoluble copper benzoate, thereby completing the removal of the surface coating of the cord steel wire in the first step of the leaching process; in addition, in order to further separate the insoluble copper benzoate, the first filter residue is treated with an ammonia water / ammonium salt system, and under the action of the ammonia water / ammonium salt solution system, the insoluble copper benzoate is further converted into a soluble copper ammonia complex, thereby achieving the effect of separating and collecting the copper component. The ammonia water / ammonium salt solution system has a selective leaching effect and also has a protective effect on the stainless steel base material. Through the above two-step process, the effective separation of waste tire cord steel wire and surface coating components and the high-value utilization of the cord steel wire are achieved, as well as the cascade separation of zinc and copper valuable elements in the coating components and the recycling of the leaching filtrate are achieved.

[0013] Preferably, the concentration of the sodium benzoate aqueous solution is 2 to 5 mol / L, preferably 2 to 3 mol / L. It is understandable that a high sodium benzoate concentration in the system can achieve a better leaching effect, but a high amount of sodium benzoate can also result in insufficient utilization of the sodium benzoate in the solution and waste of resources.

[0014] Preferably, the auxiliary leaching agent is selected from at least one of hydrogen peroxide, potassium permanganate and sodium hypochlorite;

[0015] The concentration of the auxiliary leaching agent is 1 to 5 mol / L, preferably 1 to 2 mol / L.

[0016] Preferably, the liquid-solid ratio of the sodium benzoate and auxiliary leaching agent system to the waste tire cord steel wire is 4:1 to 10:1, preferably 5:1 to 10:1. It is understandable that selecting an excessively large liquid-solid ratio during the leaching process has a better treatment effect, but will increase the post-processing and recycling costs;

[0017] The leaching reaction temperature is 20-80°C, preferably 35-65°C; the leaching time is 30-120 minutes.

[0018] Preferably, the method further comprises the step of calcining the obtained zinc hydroxide at high temperature to obtain zinc oxide;

[0019] The calcination temperature is 400-800°C, the calcination time is 0.5-1h, and the purity of the obtained zinc oxide reaches 95%.

[0020] Preferably, the ammonia / ammonium salt system is selected from at least one of aqueous ammonia, ammonium chloride and ammonium sulfate;

[0021] The concentration of ammonia water is 5% to 15%, and the concentration of ammonium chloride and ammonium sulfate is 1 to 5 mol / L. It is understood that the concentrations of ammonia water, ammonium chloride and ammonium sulfate in the system should be maintained at moderate concentrations, the main function of which is to convert insoluble copper benzoate into soluble copper ammine complex.

[0022] Preferably, the liquid-solid ratio of the ammonia / ammonium salt system to the first filter residue is 5: 1 to 10: 1. It is understood that the main function of the second step leaching process is to separate copper benzoate, so the liquid-solid ratio of the leaching process should be maintained within a suitable range.

[0023] The leaching temperature is 30-60°C, and the leaching time is 30-60 minutes.

[0024] Preferably, the waste tire cord steel wire is derived from at least one of waste full-steel tires and waste semi-steel tires.

[0025] Preferably, the temperature for heat treatment of waste tire cord steel wire is 400-450° C., and the treatment time is 15-60 min.

[0026] Preferably, the water-soluble carbonate is selected from at least one of sodium carbonate and sodium bicarbonate, and its concentration is 50-80 g / L.

[0027] Preferably, the removal efficiency of the surface coating of the waste tire cord steel wire under the dual action of sodium benzoate and auxiliary leaching agent and ammonia / ammonium salt solution is greater than 95%.

[0028] Compared with the prior art, the advantages and positive effects of the present invention are:

[0029] 1. The present invention realizes the separation of copper and zinc in the coating components through the sodium benzoate / auxiliary leaching agent system in the first step, and the first filtrate is subjected to zinc precipitation treatment to obtain zinc hydroxide, which can further produce zinc oxide products, which have high commercial value and also realize the recycling of zinc elements in tires; the second step is to obtain the byproduct basic copper carbonate by copper precipitation treatment of the third filtrate. Through the above two-step process, the waste tire cord steel wire and the surface coating components can be effectively separated, realizing the tiered separation of zinc and copper valuable elements in the coating components and the high-value utilization of the cord steel wire.

[0030] 2. The process provided by the present invention is simple to operate, has low comprehensive processing costs, saves costs, and is suitable for application and promotion in industrial production. At the same time, the present invention realizes the environmental protection treatment and resource conversion of waste tire cord steel wire, and has good application prospects, social and ecological benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic flow chart of a method for removing surface coatings from waste tire cord steel wires provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment provides a method for removing the surface coating of waste tire cord steel wire, such as Figure 1 As shown, the following steps are included:

[0035] The waste tire cord steel wire (the copper content in the coating is 0.233% and the zinc content is 0.195%) was heat treated at a temperature of 400°C for a treatment time of 20 minutes to obtain a cord steel wire without rubber adhesion.

[0036] The waste tire cord steel wire is placed in a sodium benzoate-hydrogen peroxide solution system for leaching reaction, wherein the sodium benzoate concentration is 3 mol / L, the hydrogen peroxide concentration is 1.5 mol / L, and the liquid-solid ratio of the leaching system is 10:1; the reaction temperature of the entire leaching process is 55°C, the reaction time is 60 min, and the stirring rate is 600 rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the first filtrate and the first filter residue.

[0037] Sodium hydroxide solution is added to the first filtrate for zinc precipitation treatment, and crude zinc hydroxide and a second filtrate are obtained through solid-liquid separation. The second filtrate is mainly composed of sodium benzoate, which is recycled for the leaching process of waste tire cord steel wire.

[0038] The first filter residue is leached with a 5% ammonia solution, and the liquid-solid ratio of the leaching system is 5:1; the reaction temperature of the leaching process is 35°C, the reaction time is 30 minutes, and the stirring rate is 400rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the steel cord wire after the coating is removed and the third filtrate. Sodium carbonate is continued to be added to the third filtrate for copper precipitation treatment, and basic copper carbonate crude product is obtained through solid-liquid separation, and the mother liquor is continuously circulated for the leaching process of the waste tire cord steel wire.

[0039] It is calculated that the purity of the steel cord wire after removing the coating is greater than 98%; during the entire leaching process, zinc is recovered in the form of zinc hydroxide, with a recovery rate of 93.2%; copper is recovered in the form of basic copper carbonate, with a recovery rate of 93.6%.

[0040] Example 2

[0041] This embodiment provides a method for removing the surface coating of waste tire cord steel wire, comprising the following steps:

[0042] The waste tire cord steel wire (the copper content in the coating is 0.187%, and the zinc content is 0.155%) is heat treated at a temperature of 450°C for a treatment time of 15 minutes to obtain a cord steel wire without rubber adhesion.

[0043] The waste tire cord steel wire is placed in a sodium benzoate-sodium hypochlorite solution system for leaching reaction, wherein the sodium benzoate concentration is 2 mol / L, the sodium hypochlorite concentration is 1 mol / L, and the liquid-solid ratio of the leaching system is 7:1; the reaction temperature of the entire leaching process is 40°C, the reaction time is 60 min, and the stirring rate is 800 rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the first filtrate and the first filter residue.

[0044] Sodium hydroxide solution is added to the first filtrate for zinc precipitation treatment, and crude zinc hydroxide and a second filtrate are obtained through solid-liquid separation. The second filtrate is mainly composed of sodium benzoate, which is recycled for the leaching process of waste tire cord steel wire.

[0045] The first filter residue is leached with 5% ammonia water and 1 mol / L ammonium sulfate solution, and the liquid-solid ratio of the leaching system is 7:1; the reaction temperature of the leaching process is 30°C, the reaction time is 30 minutes, and the stirring rate is 400rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the cord steel wire after the coating is removed and the third filtrate. Sodium bicarbonate is continued to be added to the third filtrate for copper precipitation treatment, and basic copper carbonate crude product is obtained through solid-liquid separation, and the mother liquor is continuously circulated for the leaching process of the waste tire cord steel wire.

[0046] It is calculated that the purity of the steel cord after removing the coating is greater than 95%; during the entire leaching process, zinc is recovered in the form of zinc hydroxide, with a recovery rate of 89.9%; copper is recovered in the form of basic copper carbonate, with a recovery rate of 90.6%.

[0047] Example 3

[0048] This embodiment provides a method for removing the surface coating of waste tire cord steel wire, comprising the following steps:

[0049] The waste tire cord steel wire (the copper content in the coating is 0.225%, and the zinc content is 0.192%) was heat treated at a temperature of 420°C for a treatment time of 15 minutes to obtain a cord steel wire without rubber adhesion.

[0050] The waste tire cord steel wire is placed in a sodium benzoate-hydrogen peroxide solution system for leaching reaction, wherein the sodium benzoate concentration is 2.5 mol / L, the hydrogen peroxide concentration is 1 mol / L, and the liquid-solid ratio of the leaching system is 7:1; the reaction temperature of the entire leaching process is 50°C, the reaction time is 90 minutes, and the stirring rate is 800 rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the first filtrate and the first filter residue.

[0051] Sodium hydroxide solution is added to the first filtrate for zinc precipitation treatment, and crude zinc hydroxide and a second filtrate are obtained through solid-liquid separation. The second filtrate is mainly composed of sodium benzoate, which is recycled for the leaching process of waste tire cord steel wire.

[0052] The first filter residue is leached with a 15% ammonia solution, and the liquid-solid ratio of the leaching system is 5:1; the reaction temperature of the leaching process is 45°C, the reaction time is 30 minutes, and the stirring rate is 600rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the cord steel wire after the coating is removed and the third filtrate. Sodium bicarbonate is continued to be added to the third filtrate for copper precipitation treatment, and basic copper carbonate crude product is obtained through solid-liquid separation, and the mother liquor is continuously circulated for the leaching process of the waste tire cord steel wire.

[0053] It is calculated that the purity of the steel cord wire after removing the coating is greater than 98%; during the entire leaching process, zinc is recovered in the form of zinc hydroxide, with a recovery rate of 92.1%; copper is recovered in the form of basic copper carbonate, with a recovery rate of 94.5%.

[0054] Example 4

[0055] This embodiment provides a method for removing the surface coating of waste tire cord steel wire, comprising the following steps:

[0056] The waste tire cord steel wire (the copper content in the coating is 0.195%, and the zinc content is 0.144%) is heat treated at a temperature of 450°C for a treatment time of 15 minutes to obtain a cord steel wire without rubber adhesion.

[0057] The waste tire cord steel wire is placed in a sodium benzoate-hydrogen peroxide solution system for leaching reaction, wherein the sodium benzoate concentration is 3 mol / L, the hydrogen peroxide concentration is 1.5 mol / L, and the liquid-solid ratio of the leaching system is 10:1; the reaction temperature of the entire leaching process is 50°C, the reaction time is 120 min, and the stirring rate is 600 rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the first filtrate and the first filter residue.

[0058] Sodium hydroxide solution is added to the first filtrate for zinc precipitation treatment, and crude zinc hydroxide and a second filtrate are obtained through solid-liquid separation. The second filtrate is mainly composed of sodium benzoate, which is recycled for the leaching process of waste tire cord steel wire.

[0059] The first filter residue is leached with a 5% ammonia solution, and the liquid-solid ratio of the leaching system is 5:1; the reaction temperature of the leaching process is 40°C, the reaction time is 60 minutes, and the stirring rate is 600rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the steel cord wire after the coating is removed and the third filtrate. Sodium carbonate is continued to be added to the third filtrate for copper precipitation treatment, and basic copper carbonate crude product is obtained through solid-liquid separation, and the mother liquor is continuously circulated for the leaching process of the waste tire cord steel wire.

[0060] It is calculated that the purity of the steel cord after removing the coating is greater than 98%; during the entire leaching process, zinc is recovered in the form of zinc hydroxide, with a recovery rate of 93.6%; copper is recovered in the form of basic copper carbonate, with a recovery rate of 94.1%.

[0061] Example 5

[0062] This embodiment provides a method for removing the surface coating of waste tire cord steel wire, comprising the following steps:

[0063] The waste tire cord steel wire (the copper content in the coating is 0.221%, and the zinc content is 0.194%) is heat treated at a temperature of 400°C for a treatment time of 30 minutes to obtain a cord steel wire without rubber adhesion.

[0064] The waste tire cord steel wire is placed in a sodium benzoate-potassium permanganate solution system for leaching reaction, wherein the sodium benzoate concentration is 2 mol / L, the potassium permanganate concentration is 2 mol / L, and the liquid-solid ratio of the leaching system is 5:1; the reaction temperature of the entire leaching process is 45°C, the reaction time is 60 min, and the stirring rate is 600 rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the first filtrate and the first filter residue.

[0065] Sodium hydroxide solution is added to the first filtrate for zinc precipitation treatment, and crude zinc hydroxide and a second filtrate are obtained through solid-liquid separation. The second filtrate is mainly composed of sodium benzoate, which is recycled for the leaching process of waste tire cord steel wire.

[0066] The first filter residue is leached with 5% ammonia water and 2 mol / L ammonium chloride solution, and the liquid-solid ratio of the leaching system is 7:1; the reaction temperature of the leaching process is 40°C, the reaction time is 30 minutes, and the stirring rate is 600rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the cord steel wire after the coating is removed and the third filtrate. Sodium carbonate is continued to be added to the third filtrate for copper precipitation treatment, and basic copper carbonate crude product is obtained through solid-liquid separation, and the mother liquor is continuously circulated for the leaching process of the waste tire cord steel wire.

[0067] It is calculated that the purity of the steel cord wire after removing the coating is greater than 96%; during the entire leaching process, zinc is recovered in the form of zinc hydroxide, with a recovery rate of 90.4%; copper is recovered in the form of basic copper carbonate, with a recovery rate of 91.1%.

[0068] Example 6

[0069] This embodiment provides a method for removing the surface coating of waste tire cord steel wire, comprising the following steps:

[0070] Waste tire cord steel wire (copper content in the coating is 0.216%, zinc content is 0.199%) was heat treated at a temperature of 400°C for 30 minutes to obtain a cord steel wire without rubber adhesion.

[0071] The waste tire cord steel wire is placed in a sodium benzoate-sodium hypochlorite solution system for leaching reaction, wherein the sodium benzoate concentration is 2 mol / L, the sodium hypochlorite concentration is 2 mol / L, and the liquid-solid ratio of the leaching system is 9:1; the reaction temperature of the entire leaching process is 65°C, the reaction time is 60 min, and the stirring rate is 600 rpm / min. After the leaching reaction is completed, the reacted material is washed and filtered to obtain the first filtrate and the first filter residue.

[0072] Sodium hydroxide solution is added to the first filtrate for zinc precipitation treatment, and crude zinc hydroxide and a second filtrate are obtained through solid-liquid separation. The second filtrate is mainly composed of sodium benzoate, which is recycled for the leaching process of waste tire cord steel wire.

[0073] The first filter residue was leached with 3.5 mol / L ammonium chloride solution, and the liquid-solid ratio of the leaching system was 10:1; the reaction temperature of the leaching process was 50°C, the reaction time was 30 min, and the stirring rate was 600 rpm / min. After the leaching reaction was completed, the reacted material was washed and filtered to obtain the cord steel wire after the coating was removed and the third filtrate. Sodium carbonate was continued to be added to the third filtrate for copper precipitation treatment, and basic copper carbonate crude product was obtained through solid-liquid separation, and the mother liquor was continuously circulated for the leaching process of the waste tire cord steel wire.

[0074] It is calculated that the purity of the steel cord after removing the coating is greater than 98%; during the entire leaching process, zinc is recovered in the form of zinc hydroxide, with a recovery rate of 92.7%; copper is recovered in the form of basic copper carbonate, with a recovery rate of 93.9%.

[0075] Comparative Example 1

[0076] The preparation method is the same as that in Example 1, except that the concentration of sodium benzoate in the sodium benzoate-hydrogen peroxide system is 1 mol / L. After two-step leaching process, the purity of the cord steel wire after removing the coating can reach up to 85%. During the entire leaching process, zinc is recovered in the form of zinc hydroxide, and the recovery rate can reach up to 81.2%; copper is recovered in the form of basic copper carbonate, and the recovery rate can reach up to 83.0%.

[0077] Comparative Example 2

[0078] The preparation method is the same as that of Example 3, except that the liquid-to-solid ratio in the sodium benzoate-hydrogen peroxide system leaching process is 3:1. After two-step leaching process, the purity of the cord steel wire after removing the coating can reach up to 93%. During the entire leaching process, zinc is recovered in the form of zinc hydroxide, and the recovery rate can reach up to 83.9%; copper is recovered in the form of basic copper carbonate, and the recovery rate can reach up to 91.3%.

Claims

1. A method for removing the surface coating of waste tire cord steel wire, characterized in that: The steps include: Heat treating waste tire cord steel wires to obtain cord steel wires without rubber adhesion; Leaching the waste tire cord steel wire in a sodium benzoate-auxiliary leaching agent system, filtering and washing to obtain a first filtrate and a first filter residue; Adding sodium hydroxide solution to the first filtrate for zinc precipitation treatment, and obtaining zinc hydroxide and a second filtrate through solid-liquid separation, wherein the second filtrate is circulated for leaching of waste tire cord steel wires; The first filter residue is leached with an ammonia / ammonium salt system, and after filtering and washing, the cord steel wire after the coating is removed and the third filtrate are obtained. A water-soluble carbonate is added to the third filtrate for copper precipitation treatment, and basic copper carbonate is separated. The mother liquor is continuously circulated for leaching of the waste tire cord steel wire.

2. The method for removing the surface coating of waste tire cord steel wire according to claim 1, characterized in that: The concentration of the sodium benzoate aqueous solution is 2 to 5 mol / L.

3. The method for removing the surface coating of waste tire cord steel wire according to claim 1, characterized in that: The auxiliary leaching agent is selected from at least one of hydrogen peroxide, potassium permanganate and sodium hypochlorite; The concentration of the auxiliary leaching agent is 1-5 mol / L.

4. The method for removing the surface coating of waste tire cord steel wire according to claim 2 or 3, characterized in that: The liquid-to-solid ratio of the sodium benzoate and auxiliary leaching agent system to the waste tire cord steel wire is 4:1 to 10:1; The leaching reaction temperature is 20-80°C, and the leaching time is 30-120 minutes.

5. The method for removing the surface coating of waste tire cord steel wire according to claim 1, characterized in that: The ammonia / ammonium salt system is selected from at least one of aqueous ammonia, ammonium chloride and ammonium sulfate; The concentration of ammonia water is 5% to 15%, and the concentration of ammonium chloride and ammonium sulfate is 1 to 5 mol / L.

6. The method for removing the surface coating of waste tire cord steel wire according to claim 5, characterized in that: The liquid-to-solid ratio of the ammonia / ammonium salt system to the first filter residue is 5:1 to 10:1; The leaching temperature is 30-60°C, and the leaching time is 30-60 minutes.

7. The method for removing the surface coating of waste tire cord steel wire according to claim 1, characterized in that: The waste tire cord steel wire comes from at least one of waste full-steel tires and waste semi-steel tires.

8. The method for removing the surface coating of waste tire cord steel wire according to claim 7, characterized in that: The temperature for heat treatment of waste tire cord steel wire is 400-450°C, and the treatment time is 15-60 minutes.

9. The method for removing the surface coating of waste tire cord steel wire according to claim 1, characterized in that: The water-soluble carbonate is selected from at least one of sodium carbonate and sodium bicarbonate, and its concentration is 50-80 g / L.

10. The method for removing the surface coating of waste tire cord steel wire according to any one of claims 1 to 9, characterized in that: Under the dual action of sodium benzoate, auxiliary leaching agent and ammonia / ammonium salt solution, the removal efficiency of the surface coating of the waste tire cord steel wire is greater than 95%.

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