Flotation is a physicochemical process utilizing the difference in surface properties of particles for their separation. One of the common methods to study the surface properties of the particle is by using Inverse gas chromatography (IGC). It can be used to estimate the surface energies, surface energy heterogeneity, work of adhesion, and index of hydrophilicity of a given sample, thus predicting their flotation behavior.

This paper utilizes the IGC method to determine the surface energy heterogeneity of waste printed circuit boards (PCB) rejects, also known as the nonmetal fraction (NMF). The test was performed to observe if any differences exist in the surface energy of NMF particles that might provide preliminary information regarding their response to flotation. The results showed that the distribution of surface energies is narrow and reached a plateau by 10% surface coverage. It suggests that approximately 10% of all the available particle surfaces have relatively higher surface energy compared to other particles that would report to the tailings (remain in water) if subjected to flotation without any reagent and further grinding.

浮选是一种利用颗粒表面性质差异进行分离的物理化学过程。研究颗粒表面性能的常用方法之一是使用反相气相色谱（IGC）。它可用于估计给定样品的表面能，表面能异质性，附着力和亲水性指数，从而预测其浮选行为。

本文利用IGC方法确定废印刷电路板（PCB）废品（也称为非金属级分（NMF））的表面能异质性。进行该测试以观察NMF颗粒的表面能是否存在任何差异，这些差异可能提供有关其对浮选反应的初步信息。结果表明，表面能的分布较窄，表面覆盖率为10％，达到平稳状态。这表明，与其他颗粒相比，所有可用颗粒表面中约有10％的表面能具有相对较高的表面能，如果在没有任何试剂的情况下进行浮选并进一步研磨，这些颗粒会向尾矿（残留在水中）报告。