Regarding waste printed circuit boards (WPCBs) as a secondary resource for recycling precious metals such as gold has become a worldwide consensus to conserve mineral resources, sustainably utilize resources, and prevent pollution. The dissolving of gold is the most important part for gold recycling because this process determines the maximum gold recovery efficiency. However, aqua regia and cyanide are dominantly used in the abovementioned process, causing serious environmental contamination and human health damage. This paper reports an environmentally friendly technology combining electrolysis and the chlorination process to extract gold from WPCBs. A response surface methodology called central composite design was employed to optimize the parameters. The results showed that the response surface quadratic model was significant (p-value = 0.0107), and the interaction of current density and time (p-value = 0.0335) and the interaction of temperature and time (p-value = 0.0034) were recognized as significant model terms. The leaching rate of gold reached 98.96% under the optimal conditions of 1.4 mol/L sodium chloride concentration, 643.54 A/m² current density, 40 °C, and 3 h. In this reaction system, the electrolyte was only composed of NaCl which was used as the chlorinating agent, and the electron was used as an oxidizing agent for potential controlling. Compared with the traditional approaches, the present strategy shows the major advantage of using fewer, nontoxic, and noncorrosive chemicals, which contributes to cleaner production and environmental protection.

中文翻译：

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从废印刷电路板中分离金的环保技术：悬浮电解和氯化工艺的结合

关于废印刷电路板（WPCB）作为回收黄金等贵金属的辅助资源，已成为保护矿产资源，可持续利用资源和防止污染的全球共识。金的溶解是金回收中最重要的部分，因为此过程决定了最大的金回收效率。然而，在上述方法中主要使用王水和氰化物，导致严重的环境污染和对人类健康的损害。本文报道了一种结合电解和氯化工艺从WPCB中提取金的环保技术。采用了称为中央复合设计的响应面方法来优化参数。结果表明，响应面二次模型具有显着性（p值= 0.0107），电流密度和时间的相互作用（p值= 0.0335）和温度和时间的相互作用（p值= 0.0034）被认为是重要的模型项。在1.4 mol / L氯化钠浓度，643.54 A / m ²电流密度，40°C和3 h的最佳条件下，金的浸出率达到98.96％。在该反应系统中，电解质仅由用作氯化剂的NaCl组成，并且将电子用作控制电位的氧化剂。与传统方法相比，本策略显示出使用更少，无毒且无腐蚀性的化学药品的主要优势，这有助于清洁生产和环境保护。