Gold leaching agent for waste circuit board and method for selectively and preferentially leaching gold

Abstract

The invention relates to a gold leaching agent for a waste circuit board and a method for selectively and preferentially leaching gold. The gold leaching agent comprises carbonized sodium cyanurate, alkaline thiourea, alkaline polymeric iron, alkali, carbonate, an anionic surfactant and water. The mass ratio of the carbonized sodium cyanurate to the alkaline thiourea to the alkaline polymeric iron to the alkali to the carbonate to the anionic surfactant to the water is (0.01-5): (0.01-5): (0.1-1): (0.1-1): (0.1-1): (0.01-5): (50-100); wherein the anionic surfactant is sodium m-nitro-p-toluenesulfonate and / or sodium nitrobenzene sulfonate; by means of the gold leaching agent, gold on the waste circuit board can be effectively leached out, and the leaching rate and the reaction efficiency are both high.

Description

Technical Field

[0001] The present invention relates to the technical field of waste circuit board recycling, and more specifically, to a gold leaching agent for waste circuit boards and a method for selective preferential gold leaching. Background Art

[0002] In my country, the disposal of waste circuit boards is mostly at the stage of rough recycling and reuse. At present, the methods of recycling waste circuit boards are mainly divided into mechanical treatment recycling, pyrolysis treatment technology, chemical recycling, biological recycling, etc. The structure of circuit boards is very complex, and its recycling is a difficult and tedious process. Therefore, the above methods are not completely isolated and need to be combined to optimize the recycling effect.

[0003] Compared with other recycling technologies, mechanical crushing-physical sorting technology mainly realizes the separation of metal and non-metal in waste circuit board substrates. It crushes waste circuit boards into a certain particle size by impact crushing, shear crushing and extrusion crushing, and then separates the components according to the physical property differences of each component of the crushed particles (such as density, electromagnetic, shape, etc.) through gravity sorting, magnetic sorting, eddy current sorting, shape sorting, optical sorting and other sorting technologies, so as to achieve the purpose of recycling metal and non-metal powders. The separated metal part is a multi-metal powder with copper as the main component, which has a low organic content and can be refined using existing smelting technology. Non-metallic powder is a resin material that can be used in the construction industry, etc.

[0004] However, since the gold on the circuit board is an electroplated layer, the crushing process easily forms ultrafine powder, resulting in a large amount of gold entering the resin powder during the physical sorting process and cannot be recovered. Therefore, it is urgent to break the inherent thinking of first extracting copper and then enriching gold in the traditional wet treatment process of waste circuit boards, and extract gold first before crushing-sorting to achieve efficient recovery of gold in waste circuit boards. Summary of the invention

[0005] Based on the above technical problems existing in the prior art, one of the purposes of the present invention is to provide a gold removal agent for waste circuit boards, which can achieve rapid and selective gold removal of waste circuit boards and improve the priority and efficient recovery of gold in waste circuit boards.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A gold leaching agent for waste circuit boards, comprising carbonized sodium cyanurate, alkaline thiourea, alkaline polymerized iron, alkali, carbonate, anionic surfactant and water; the mass ratio of carbonized sodium cyanurate, alkaline thiourea, alkaline polymerized iron, alkali, carbonate, anionic surfactant and water is 0.01-5: 0.01-5: 0.1-1: 0.1-1: 0.1-1: 0.01-5: 50-100;

[0008] Wherein, the anionic surfactant is sodium m-nitro-p-toluenesulfonate and / or sodium nitrobenzenesulfonate.

[0009] In some embodiments, the base is at least one of sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium oxide, lithium oxide, and potassium oxide.

[0010] In some embodiments, the carbonate salt comprises sodium carbonate.

[0011] In some embodiments, the sodium nitrobenzene sulfonate is sodium 3-nitrobenzene sulfonate and / or sodium p-nitrobenzene sulfonate.

[0012] The second object of the present invention is to provide a method for selectively and preferentially immersing gold in waste circuit boards, the method comprising the following steps:

[0013] The waste circuit board is placed in a gold leaching agent, heated to perform a gold stripping reaction, and a gold stripping liquid and a gold stripping substrate are obtained;

[0014] The gold leaching agent is the gold leaching agent for waste circuit board substrates described in any of the above embodiments.

[0015] In some embodiments, the temperature of the gold removal reaction is 50-90° C.; and / or the gold removal time is 1-10 min.

[0016] In some embodiments, the method further comprises the following steps:

[0017] The waste circuit board substrate is placed in the gold leaching agent, heated and subjected to gold removal reaction under ultrasonic-assisted conditions to obtain a gold removal liquid and a gold removal substrate.

[0018] In some embodiments, the ultrasonic power is 500-900W.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] In the gold leaching agent of the present invention, carbonized sodium cyanurate and alkaline thiourea react with gold to form a complex reaction; alkaline polymerized iron (polyferric sulfate) maintains the weak oxidizing property of the leaching system; alkali and carbonate maintain the balanced pH of the leaching system; and sodium m-nitro-p-toluenesulfonate and / or sodium nitrobenzenesulfonate can act as a surfactant to reduce the surface tension of the metal surface, making it easier for water or other solutions to penetrate into the micropores on the surface of the waste circuit board, accelerating the dissolution and removal of corrosion products. In addition, its molecule contains an oxidizing group - "NO", which enables it to oxidize the metal into ions, and at the same time will not corrode the substrate due to its strong oxidizing property, so that it can effectively remove the coating on the surface of the waste circuit board without damaging the substrate, while protecting the substrate from further corrosion. Therefore, when the gold leaching agent of the present application is used, the effect produced by the synergistic effect between the components is completely different from that of the existing gold leaching agent, and the gold removal efficiency and effect are better.

[0021] The method of the present invention can selectively and efficiently leach gold from waste circuit boards, thereby realizing gold recovery with a high recovery rate, and the gold removal process is environmentally friendly. DETAILED DESCRIPTION

[0022] Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the connotation of the present invention, so the present invention is not limited to the specific implementation disclosed below.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0024] Example 1

[0025] A gold leaching agent for waste circuit boards and a method for selective preferential gold leaching, comprising the following steps:

[0026] The waste circuit board is placed in a selective gold leaching agent and heated to 90°C to obtain a gold stripping solution and a gold stripping substrate; wherein the selective gold leaching agent is carbonized sodium cyanurate, alkaline thiourea, alkaline polymerized iron, sodium hydroxide, carbonate, sodium m-nitrotoluenesulfonate, sodium 3-nitrobenzenesulfonate and water in a mass ratio of 1:0.1:0.1:0.1:0.1:0.5:0.5:100, and the gold stripping time is 2 minutes; under this condition, the Au leaching rate is 95.18%.

[0027] Example 2

[0028] The waste circuit board is placed in a selective gold leaching agent and heated to 90°C to obtain a gold depletion liquid and a gold depletion substrate; wherein the selective gold leaching agent is carbonized sodium cyanurate, alkaline thiourea, alkaline polymerized iron, sodium hydroxide, carbonate, sodium m-nitrotoluenesulfonate and water in a mass ratio of 1:0.1:0.1:0.1:0.1:1:100, and the gold depletion time is 2 minutes; under this condition, the Au leaching rate is 96.72%.

[0029] Example 3

[0030] The waste circuit board is placed in a selective gold leaching agent and heated to 90°C to obtain a gold stripping solution and a gold stripping substrate; wherein the selective gold leaching agent is alkaline thiourea, alkaline polymer iron, sodium hydroxide, carbonate, sodium m-nitrotoluenesulfonate and water in a mass ratio of 1:0.1:0.1:0.1:1:100, and the gold stripping time is 5 minutes; under this condition, the Au leaching rate is 86.43%.

[0031] Example 4

[0032] The waste circuit board is placed in a selective gold leaching agent and heated to 90°C to obtain a gold stripping solution and a gold stripping substrate; wherein the selective gold leaching agent is thiosulfate, alkaline polymer iron, sodium hydroxide, carbonate, sodium m-nitrotoluenesulfonate and water in a mass ratio of 1:0.1:0.1:0.1:1:100, and the gold stripping time is 5 minutes; under this condition, the Au leaching rate is 67.97%.

[0033] Example 5

[0034] The waste circuit board is placed in a selective gold leaching agent and heated to 90°C for a gold removal reaction to obtain a gold removal liquid and a gold removal substrate; wherein the selective gold leaching agent is carbonized sodium cyanurate, alkaline thiourea, alkaline polymerized iron, sodium hydroxide, carbonate, sodium m-nitrotoluenesulfonate, sodium 3-nitrobenzenesulfonate and water in a mass ratio of 1:0.1:0.1:0.1:0.1:0.5:0.5:100, and the gold removal time is 10 minutes; under this condition, the Au leaching rate is 98.91%.

[0035] Example 6

[0036] The waste circuit board is placed in a selective gold leaching agent and heated to 90°C, and the gold removal reaction is carried out under ultrasonic-assisted conditions with an ultrasonic power of 500W to obtain a gold removal liquid and a gold removal substrate; wherein the selective gold leaching agent is carbonized sodium cyanurate, alkaline thiourea, alkaline polymerized iron, sodium hydroxide, carbonate, sodium m-nitrotoluenesulfonate, sodium 3-nitrobenzenesulfonate and water in a mass ratio of 1:0.1:0.1:0.1:0.1:0.5:0.5:100, and the gold removal time is 1 min; under this condition, the Au leaching rate is 99.21%.

[0037] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0038] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A gold leaching agent for waste circuit boards, characterized in that: It comprises carbonized sodium cyanurate, alkaline thiourea, alkaline polymerized iron, alkali, carbonate, anionic surfactant and water; the mass ratio of carbonized sodium cyanurate, alkaline thiourea, alkaline polymerized iron, alkali, carbonate, anionic surfactant and water is 0.01-5:0.01-5:0.1-1:0.1-1:0.1-1:0.01-5:50-100; Wherein, the anionic surfactant is sodium m-nitro-p-toluenesulfonate and / or sodium nitrobenzenesulfonate.

2. The gold leaching agent and the selective preferential gold leaching method for waste circuit boards according to claim 1, characterized in that: The alkali is at least one of sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium oxide, lithium oxide, and potassium oxide.

3. The gold leaching agent for waste circuit boards according to claim 1, characterized in that: The carbonate includes sodium carbonate.

4. The gold leaching agent for waste circuit boards according to claim 1, characterized in that: The sodium nitrobenzene sulfonate is sodium 3-nitrobenzene sulfonate and / or sodium p-nitrobenzene sulfonate.

5. A method for selective preferential gold immersion of waste circuit boards, characterized in that: The following steps are involved: The waste circuit board is placed in a gold leaching agent, heated to perform a gold stripping reaction, and a gold stripping liquid and a gold stripping substrate are obtained; The gold leaching agent is the gold leaching agent for waste circuit boards according to any one of claims 1 to 4.

6. The method for selective preferential gold immersion of waste circuit boards according to claim 5, characterized in that: The temperature of the gold removal reaction is 50-90° C.; and / or the gold removal time is 1-10 min.

7. The method for selective preferential gold immersion of waste circuit boards according to claim 5, characterized in that: The following steps are involved: The waste circuit board is placed in the gold leaching agent, heated and subjected to gold stripping reaction under ultrasonic-assisted conditions to obtain gold stripping liquid and gold stripping substrate.

8. The method for selective preferential gold immersion of waste circuit boards according to claim 7, characterized in that: The ultrasonic power is 500-900W.