New Malonamide Polyethoxylated Surfactant for Eco-friendly Ion Foam Flotation Process

本工作旨在开发一种利用离子泡沫浮选过程萃取和分离稀土元素和/或铂族金属的新表面活性剂体系。为此，本文研究了一种新型丙二酰胺聚氧乙烯化表面活性剂的合成与表征。合成路线主要有两条：(1)聚乙氧基羧酸表面活性剂AKYPO LS-O90与N(1)，N(3)-双(2-羟乙基)丙二酰胺的酯化反应；(2)丙二酰胺分子与聚乙氧基醇表面活性剂BrijO10(或BrijS10)的烷基化反应。对反应物进行了排序和接收，并从纯度、pKa和胶束表面电荷等方面对表面活性剂进行了表征。正在考虑更多的合成路线，以减少反应物成本和合成步骤。为了通过SANS和NR分析对浮选效率和微观结构进行表征，设计了专用柱(和浮选器)，并对其进行了排序和接收。用模型表面活性剂体系论证了采用新型色谱柱进行SANS泡沫分离实验的技术可行性。作为初步实验，在J-PARC，MLF进行了丙二酰胺标准体系的NR测量，并论证了分析液-气界面的可行性。最后，这些初步分析允许编辑并在同行评议期刊上提交两篇文章。

This work aims to develop a new surfactant system for the extraction and separation of rare earth elements and/or platinum group metals using the ion foam flotation process. For this purpose, synthesis and characterisation of a new malonamide polyethoxylated surfactant is consider. For the synthesis, two main routes are planned: (i) esterification between the polyethoxylated carboxylic acid surfactant AKYPO LS-O90 and the N(1), N(3)-Bis(2-hydroxyethyl)malonamide, and (ii) alkylation between malonamide molecule and the polyethoxylated alcohol surfactant BrijO10 (or Brij S10). Reactants have been ordered and received, and the characterisation of surfactants were performed in term of purity, pKa and micelle surface charge. Additional synthesis routes are being consider in order to reduce reactant cost and synthesis steps. For the characterisation of the process in term of flotation efficiency and microstructure through SANS and NR analyses, dedicated columns (and flowmter) were designed, ordered and received. Technical feasibility of SANS experiments on foam with the new column has been demonstrated with a model surfactant system. NR measurement on malonamide standard systems has been performed at J-PARC, MLF, as a preliminary experiment and had demonstrated the feasibility of analysing liquid-air interfaces. Finally, these preliminary analyses allowed redacting and submitting two articles in peer reviewed journal.