Analytical Methods for Rare Earth (REE) by AGS

What does “Rare Earth" mean?

The word “rare” here refers something present on the nature in small quantities. Its acronym in English is REE (Rare Earths) and the scarcity is related not to the quantity but to the possibility of extracting them in an economically viable and environmentally sustainable way. That mean that is difficult to find. These are 17 non-ferrous metallic elements, which are found together in nature and have very similar chemical characteristics in the periodic table. These include, for example, lanthanum, neodymium, prometheus, yttrium and scandium. The important thing is that 4 of them have magnetic properties.

Very few are known about them, but outside of China, which concentrates 90% of production, there are only three places in the world where the sustainable extraction of “rare earths” is possible, a set of 17 critical elements in the fight against climate change. One of them is in Uganda, another in Goiás, Brazil, and the other is Chile.

It´s worth highlighting that there is a certain type of clay rich in rare earths as an important reservoir; These specific clays originate from exposure to the weather of common igneous rock with the presence of rare earths. This fact can cause leaching of these rocks and subsequent absorption on the surface of clay-like aluminosilicate minerals (kaolinite, illite and smectite). enriching these with rare earths and making them viable for economic extraction (clays found in Chile).

Although the concentrations of rare earth elements are usually low, compared to the minerals described above, the processing of this type of deposit is less complex, which makes it economically competitive.

What aspects should we take into account for the analysis of REE, either in clays or in complex mineralizations? (Monazite, Lopardite, Xenothymium, Bastnaesite, Euxenite, Allanite etc)

1. Never consider a partial extraction as aqua regia in these determinations since we will only be able to quantify alterations on the surface of the mineral (aqua regia).
2. ALMOST total digestions (four acids) are not recommended since many of the minerals that house the REE are resistant to acids, so the results will be underestimated at the concentration.
3. A total method is always recommended, whether peroxide fusion or metaborate tetraborate fusion.

Minerals with the Presence of REE

The main minerals found in REE are bastnasite, monazite, loparite and lateritic clays; All clays, except laterite, are very resistant to acid digestion, so an aggressive or total method such as fusions is necessary.

Our company has developed its own methods for obtaining total REE, coming from various mineralogy. These AGS methods are carried out by aggressive fusions and quantified with cutting-edge technology, which makes us leaders in the determination of these elements.

AGS, in addition to being a leader in obtaining the total REE present, has developed extraction methodologies to obtain these REE through cation solutions, producing an ion exchange between monovalent ions and lanthanide ions.

These methodologies developed by AGS are quantified through ICP (inductively coupled plasma) Optical & Mass, which are carried out entirely in Chile in our central laboratory.

Our vast experience in total and extractable REE methods places us as an important laboratory in the market with reliable, precise and accurate results as well as response times in accordance with market requirements. These developments are supported directly by our clients located throughout the region of South America.

Alex Caniguante Abdala
Business Development Manager
AGS