In this paper, through the structural modification of N-phenyl formohydroxamic acid (NPFHA), an isomer of benzohydroxamic acid (BHA), we designed and synthesized a series of N-phenyl hydroxamic acids (NPHA), including N-phenyl acetohydroxamic (NPHA-2), N-phenyl butyrohydroxamic acid (NPHA-4), N-phenyl hexanohydroxamic acid (NPHA-6) and N-phenyl octanohydroxamic acid (NPHA-8), and first introduced them as flotation collectors for selectively separating cassiterite from quartz and feldspar. Micro-flotation tests indicated that with increase of non-polar carbon chain length, the collecting ability to cassiterite improved dramatically. More to the point, compared to BHA, NPHA-6 and NPHA-8 possessed superior flotation performances to cassiterite and enabled the separation of cassiterite and quartz/feldspar over a wide pH range, with no application of frother or activator, providing a new insight into the development of cassiterite collector. Zeta potential experiments indicated that NPHA-8 chemisorbed onto cassiterite surfaces, with no significant adsorption to quartz or feldspar detected. DFT calculations, FT-IR and XPS analyses further demonstrated that NPHA-8 chemisorbed on cassiterite surfaces by forming C–O–Sn and N-O–Sn bonds, accompanied by proposing two interaction geometries, first with the same Sn atom of cassiterite surface, leading to a five-membered chelating ring, second with two different Sn atoms, resulting in constituting an irregular complex.

本文通过苯并异羟肟酸（BHA）异构体N-苯基甲酸异羟肟酸（NPHA）的结构修饰，设计合成了一系列N-苯基异羟肟酸（NPHA），其中包括N-苯基乙酰氧肟酸（NPHA）。 -2），N-苯基丁氧异羟肟酸（NPHA-4），N-苯基六异羟肟酸（NPHA-6）和N-苯基辛基异羟肟酸（NPHA-8），首先将它们作为浮选捕集剂引入，用于选择性地从石英中分离锡石。和长石。微浮选试验表明，随着非极性碳链长度的增加，锡石的收集能力显着提高。更重要的是，与BHA相比，NPHA-6和NPHA-8具有优于锡石的浮选性能，并能够在宽的pH范围内分离锡石和石英/长石，无需使用起泡剂或活化剂，为锡石收集器的发展提供了新的见解。Zeta电位实验表明NPHA-8化学吸附在锡石表面上，未检测到对石英或长石的明显吸附。DFT计算，FT-IR和XPS分析进一步证明，NPHA-8通过形成C–O–Sn和NO–Sn键化学吸附在锡石表面上，并提出了两种相互作用的几何结构，首先是锡石表面具有相同的Sn原子，从而导致一个五元螯合环，第二个具有两个不同的Sn原子，从而构成不规则的络合物。没有发现对石英或长石有明显的吸附。DFT计算，FT-IR和XPS分析进一步证明，NPHA-8通过形成C–O–Sn和NO–Sn键化学吸附在锡石表面上，并提出了两种相互作用的几何结构，首先是锡石表面具有相同的Sn原子，从而导致一个五元螯合环，第二个具有两个不同的Sn原子，从而构成不规则的络合物。没有发现对石英或长石有明显的吸附。DFT计算，FT-IR和XPS分析进一步证明，NPHA-8通过形成C–O–Sn和NO–Sn键化学吸附在锡石表面上，并提出了两种相互作用的几何结构，首先是锡石表面具有相同的Sn原子，从而导致一个五元螯合环，第二个具有两个不同的Sn原子，从而构成不规则的络合物。