XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1209
deal with industrial hygiene problems caused by the ele-
vated natural radioactivity of monazite.
This paper discusses outcomes from metallurgical test
work on rare earth-bearing mineral sands ores originating
from Africa (ore-1) and Australia (ore-2). Specifically, this
paper discusses the influence of both the minerals’ char-
acteristics on the resultant process routes. In addition, the
circuit development strategy considered risks associated
with dry processing of radioactive monazite and therefore
targeted a pathway to produce mixed rare earth mineral
concentrates using wet processing techniques only.
MINERAL, CHEMICAL, AND
METALLURGICAL CHARACTERIZATION
Overview
Characterization is an essential activity for the understand-
ing of the fundamental features of the ore. It highlights the
physical, chemical and interrelation of the mineral com-
ponents of an ore and represents a vital tool in assessing
potential beneficiation techniques that may be used to effi-
ciently separate valuable from non-valuable components.
Ore characterization is also comparatively a low cost
and short duration component of a typical total project
development but can quickly outline suitable beneficiation
techniques worth evaluating thereby providing opportuni-
ties to improve project outcomes by focusing studies on
methods that might have a better chance of being success-
ful. It can also identify technical difficulties and assist in
the establishment of realistic targets at an early stage of the
project.
In this paper, the methods used to determine the
chemical composition of an ore include x-ray florescence
(XRF), and inductively coupled plasma mass spectrometry
(ICP-MS). Techniques for determining the mineralogical
composition are optical microscopy and quantitative elec-
tron microscopy (QEMSCAN).
Particle size distribution analyses and density profile
analyses by float-sink methods were also used to character-
ize the ore and provide further insight into the requirement
for feed classification and the amenability to separation by
gravity separation.
Elemental Composition
The elemental composition of each ore sample was analyzed
using standard fusion and XRF techniques. The results of
the analysis are shown in Table 2. The data generally indi-
cate a comparable composition with dominant SiO2 at
81.5% for ore-1 and 82.2% for ore-2. Results also indicate
similar CeO2 grade of 0.031% and 0.026%, thereby sug-
gesting similar monazite content. Differences in the ratio of
Titania and Zirconia-bearing minerals are evident though,
overall, grades are low in comparison to SiO2.
Particle Size Distribution
The particle size distribution of each sample is shown in
Figure 1. Both samples show comparable proportion of fines
at 16.8% and 15.2% by mass of less than 45μm particles.
Table 1. Classification of rare earth elements
Light REE Heavy REE
Element Name Symbol Atomic Number Element Name Symbol Atomic Number
Scandium Sc 21 Yttrium Y 39
Lanthanum La 57 Gadolinium Gd 64
Cerium Ce 58 Terbium Tb 65
Praesidium Pr 59 Dysprosium Dy 66
Neodymium Nd 60 Holmium Ho 67
Promethium Pm 61 Erbium Er 68
Samarium Sm 62 Thulium Tm 69
Europium Eu 63 Ytterbium Yb 70
Lutetium Lu 71
Table 2. Ore sample chemical composition
Description TiO2 Fe2O3 SiO2 Al2O3 ZrO2 P2O5 U Th CeO2
Unit %%%%%%ppm ppm %
Detection limit 0.01 0.01 0.01 0.01 0.01 0.001 10 10 0.002
Ore-1 3.04 5.32 81.5 5.31 0.28 0.059 10 115 0.031
Ore-2 1.81 5.11 82.2 6.25 0.50 0.085 23 61 0.026
deal with industrial hygiene problems caused by the ele-
vated natural radioactivity of monazite.
This paper discusses outcomes from metallurgical test
work on rare earth-bearing mineral sands ores originating
from Africa (ore-1) and Australia (ore-2). Specifically, this
paper discusses the influence of both the minerals’ char-
acteristics on the resultant process routes. In addition, the
circuit development strategy considered risks associated
with dry processing of radioactive monazite and therefore
targeted a pathway to produce mixed rare earth mineral
concentrates using wet processing techniques only.
MINERAL, CHEMICAL, AND
METALLURGICAL CHARACTERIZATION
Overview
Characterization is an essential activity for the understand-
ing of the fundamental features of the ore. It highlights the
physical, chemical and interrelation of the mineral com-
ponents of an ore and represents a vital tool in assessing
potential beneficiation techniques that may be used to effi-
ciently separate valuable from non-valuable components.
Ore characterization is also comparatively a low cost
and short duration component of a typical total project
development but can quickly outline suitable beneficiation
techniques worth evaluating thereby providing opportuni-
ties to improve project outcomes by focusing studies on
methods that might have a better chance of being success-
ful. It can also identify technical difficulties and assist in
the establishment of realistic targets at an early stage of the
project.
In this paper, the methods used to determine the
chemical composition of an ore include x-ray florescence
(XRF), and inductively coupled plasma mass spectrometry
(ICP-MS). Techniques for determining the mineralogical
composition are optical microscopy and quantitative elec-
tron microscopy (QEMSCAN).
Particle size distribution analyses and density profile
analyses by float-sink methods were also used to character-
ize the ore and provide further insight into the requirement
for feed classification and the amenability to separation by
gravity separation.
Elemental Composition
The elemental composition of each ore sample was analyzed
using standard fusion and XRF techniques. The results of
the analysis are shown in Table 2. The data generally indi-
cate a comparable composition with dominant SiO2 at
81.5% for ore-1 and 82.2% for ore-2. Results also indicate
similar CeO2 grade of 0.031% and 0.026%, thereby sug-
gesting similar monazite content. Differences in the ratio of
Titania and Zirconia-bearing minerals are evident though,
overall, grades are low in comparison to SiO2.
Particle Size Distribution
The particle size distribution of each sample is shown in
Figure 1. Both samples show comparable proportion of fines
at 16.8% and 15.2% by mass of less than 45μm particles.
Table 1. Classification of rare earth elements
Light REE Heavy REE
Element Name Symbol Atomic Number Element Name Symbol Atomic Number
Scandium Sc 21 Yttrium Y 39
Lanthanum La 57 Gadolinium Gd 64
Cerium Ce 58 Terbium Tb 65
Praesidium Pr 59 Dysprosium Dy 66
Neodymium Nd 60 Holmium Ho 67
Promethium Pm 61 Erbium Er 68
Samarium Sm 62 Thulium Tm 69
Europium Eu 63 Ytterbium Yb 70
Lutetium Lu 71
Table 2. Ore sample chemical composition
Description TiO2 Fe2O3 SiO2 Al2O3 ZrO2 P2O5 U Th CeO2
Unit %%%%%%ppm ppm %
Detection limit 0.01 0.01 0.01 0.01 0.01 0.001 10 10 0.002
Ore-1 3.04 5.32 81.5 5.31 0.28 0.059 10 115 0.031
Ore-2 1.81 5.11 82.2 6.25 0.50 0.085 23 61 0.026