As a professional extraction equipment manufacturer, we are well-versed in using extraction technology to efficiently recover gold and silver from electronic waste. Taking the treatment of printed circuit board (PCB) waste as an example, our process flow is as follows:

First, the pretreatment stage is crucial. We finely pulverize the waste and then calcine it at high temperature to completely remove organic matter, laying the foundation for subsequent steps.

Next comes the dissolution stage. We use aqua regia to dissolve the metal components, producing a solution containing various metal ions, including Au³⁺, Ag⁺, and Cu²⁺, preparing for subsequent separation.

To separate the silver, we first add NaCl to convert Ag⁺ into an AgCl precipitate. Subsequently, sodium thiosulfate dissolves the AgCl, forming a stable [Ag(S₂O₃)₂]³⁻ complex. This is where our extraction equipment comes into play, efficiently extracting the silver complex with trioctylamine, followed by stripping with nitric acid, ultimately yielding a pure AgNO₃ solution. To separate the gold, we use DBC extractant to perform a three-stage countercurrent extraction of the Au³⁺ in the remaining solution to ensure optimal extraction results. Subsequently, stripping with water and reduction of the stripping solution with oxalic acid yields high-purity gold.

Our process achieves gold and silver recovery rates exceeding 99%, and platinum group metals (such as Pd and Pt) can also be further recovered through ion exchange or extraction. We are committed to providing customers with efficient and reliable extraction equipment and solutions, helping to recycle electronic waste and achieve both economic and environmental benefits.