Gold Plating Solution Recovery: A Method for Recovering and Extracting Gold Plating Waste Liquid

With the continuous development of technology, the application of metal plating in various industries is becoming increasingly widespread. However, during the process of metal plating, a large amount of waste liquid is generated, which contains valuable metal components such as gold. In order to reduce waste and protect the environment, it is particularly important to recycle the metal components in these waste liquids. This article will introduce a method for recovering and refining metals from gold plating baths.

1、 Composition and properties of gold plating solution

The gold plating solution mainly consists of gold salts, complexing agents, stabilizers, buffering agents, etc. Among them, gold salt is the main component of gold plating, which usually exists in the form of Chloroauric acid (HAuCl4). Other components have the function of adjusting the properties of the gold plating solution and optimizing the gold plating process. In the process of recycling and refining, we need to separate gold from the plating solution.

2、 Recovery and extraction method of gold plating solution

Below, we will introduce a simple and effective method for recovering and refining gold plating solution: chemical precipitation method. 1. Preparation: Firstly, it is necessary to collect the waste gold plating solution and remove impurities through methods such as filtration or precipitation. 2. Acidity regulation: As the gold plating solution is usually acidic, in order to improve the gold recovery rate, we need to adjust the pH of the waste liquid to neutral or slightly alkaline. This can be achieved by adding alkaline substances, such as sodium hydroxide (NaOH) or ammonia (NH3 · H2O). 3. Chemical precipitation: add reducing agent, such as Sodium thiosulfate (Na2S2O3) or Sodium nitrite (NaNO2), into the waste liquid. These reducing agents can reduce gold ions to metals, thereby causing them to precipitate. After adding an appropriate amount of reducing agent, the gold ions in the waste liquid will gradually be reduced into metal particles and exist in the form of precipitation. 4. Sediment separation: Separation of sediment from liquid through methods such as sedimentation, centrifugation, or filtration. Dry the separated precipitate to obtain a solid containing gold. 5. Metal extraction: Melt the solid containing gold and separate it from other metals through high-temperature treatment. During the melting process, a certain amount of flux can be added to reduce the melting point and improve the melting efficiency. After the metal is melted, the density difference between gold and other metals can be used for separation. Cool and solidify the melted metal to obtain a metal ingot. 6. Refining: Further refining of the extracted metal ingots to improve the purity of gold. The commonly used refining methods include fire method, wet method, etc. Fire refining is the process of separating gold from other impurity metals through high-temperature treatment; Wet refining improves the purity of gold through methods such as solvent extraction and electrolysis. 7. Metal products: The refined gold can be used to make various metal products, such as electronic products, jewelry, etc. In addition, other metals extracted can also be used in production processes in other industries.

3、 Advantages of recycling and refining gold plating solution

Resource saving: Recycling and utilizing the metal components in waste gold plating solution reduces the demand for new resources, which is conducive to the sustainable utilization of resources.

Environmental protection: The recycling and treatment of waste gold plating solution can reduce the discharge of harmful substances and reduce environmental pollution.

Improving economic benefits: Recycling valuable metals such as gold from waste gold plating solution can improve the economic benefits of the enterprise.

This article introduces a method for recovering and refining metals from gold plating baths - chemical precipitation method. By adjusting the acidity and alkalinity, adding reducing agents, separating precipitates, metal extraction, refining, and other steps, gold can be effectively extracted from waste gold plating solution. This method is simple and effective, which not only saves resources but also benefits environmental protection, and is worth promoting and applying in practical production.

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