The extraction of Nd(III), Gd(III), and Er(III), which represent light, middle, and heavy lanthanides, respectively, from chloride solutions has been carried out by using N,N-di(2-ethylhexyl)-diglycolamic acid (HDEHDGA, HA) diluted in kerosene as the organic phase. The results from the slope analysis method indicate that the extraction of Ln(III) with HDEHDGA is mainly governed by the cation-exchange reaction mechanisms in the low pH region (pH 1.2–2.7). The obtained data reveal that the extracted species in the organic phase might be LnA₃∙HA_(1~2), which consist of a core of 1:3 LnA₃ complex and one additional neutral HA molecule for light Ln(III) or two for heavy Ln(III) associated with the core in the outer coordination sphere. The dependency on the temperatures indicates that the extraction of Ln(III) with HDEHDGA is exothermic and is mainly driven by the exothermic enthalpies crossing the whole Ln(III) series. The extraction of the whole Ln(III) series (except for Pm(III)) and Th(IV) has also been evaluated. HDEHDGA provides remarkable extraction capability with considerable separation factors (SF) for adjacent light Ln(III) pairs (SF_Ce/La = 6.8, SF_Pr/Ce = 3.3, SF_Nd/Pr = 2.5, and SF_Sm/Nd = 3.5), but relatively poor selectivity for the adjacent heavy Ln(III) pairs. It also presents very good selectivity/extractability for Th(IV) over the light Ln(III) ions (SF_Th/La = 1362 and SF_Th/Ce = 200). These properties make HDEHDGA a promising extractant for separating Th(IV) from light Ln(III) ions and for separating light Ln(III) ions from each other, which coexist significantly in some Rare Earth (RE) minerals, especially monazite and bastnaesite.

Nd（III），Gd（III）和Er（III）分别从氯化物溶液中萃取出来，分别代表轻，中和重镧系元素，方法是使用N，N-二（2-乙基己基）在煤油中稀释的二甘氨酸（HDEHDGA，HA）作为有机相。斜率分析法的结果表明，HDEHDGA提取Ln（III）主要受低pH区域（pH 1.2-2.7）中阳离子交换反应机理的控制。获得的数据表明，有机相中提取的物种可能是LnA ₃ ∙HA _（ 1〜2 _），其核心为1：3 LnA ₃配体和一个轻链Ln（III）的中性HA分子或两个重链Ln（III）的中性HA分子，它们与外部配位域的核心相关。对温度的依赖性表明，用HDEHDGA提取Ln（III）是放热的，并且主要由跨整个Ln（III）系列的放热焓驱动。还评估了整个Ln（III）系列（Pm（III）除外）和Th（IV）的提取。HDEHDGA具有出色的提取能力，并具有用于相邻轻Ln（III）对的相当大的分离因子（SF）（SF _{Ce / La}  = 6.8，SF _{Pr / Ce}  = 3.3，SF _{Nd / Pr}  = 2.5和SF _{Sm / Nd} = 3.5），但对相邻的重Ln（III）对的选择性相对较差。对于轻质Ln（III）离子（SF _{Th / La}  = 1362和SF _{Th / Ce}  = 200），Th（IV）的选择性/可萃取性也非常好。这些特性使HDEHDGA成为一种从轻Ln（III）离子中分离Th（IV）并彼此分离轻Ln（III）离子的有前途的萃取剂，它们显着共存于某些稀土（RE）矿物中，尤其是独居石和玄武岩。