Page 51 - Policy Commission - SecuringTechnology - Critical Metals for Britain

PRIMARY MATERIALS
51
Rare earth deposits have diverse geology and this gives a a a a a range of production routes and environmental characteristics The mineralogy of the deposit is more important than
the the grade (i e e e e e e e how rich the the deposit is in in rare earths) in in determining which deposits might be economic to mine and also their environmental characteristics Figure 23 shows a a a a a a comparison of of several types of of rare earth ores and their characteristics This kind of qualitative comparison can be mined currently as a a a a by-product of mineral sand deposits in in in India Madagascar and and Australia and and this amount could be increased from other deposits around the the world The problem is that mineral sand monazite typically contains 2-10 wt% thorium as as well as as rare earths
This makes the concentrate radioactive radioactive and produces a a a a a a a radioactive radioactive waste Given transport and and processing regulations and and public concern regarding radioactivity most mineral sand monazite has been avoided although interest has risen again recently A new use for for thorium in nuclear reactors for for example would be a a a a ‘game changer’ in in in making mineral sands more favourable as sources of rare earths
quantified using a a a life-cycle assessment Most rare earths
are are produced from either carbonatite- related deposits (e g g Bayan Obo and Maoniuping China Mountain Pass USA Mt Weld Australia) or or ion ion adsorption clay deposits in in southern China and Myanmar Monazite is 64
Ore type Energy for crushing and grinding
Grain size/ Difficulty of beneficiation
Chemicals (acid flotation reagent)
Radioactivity: ore mineral and host rock
Amount of rock
to be moved*
By-products
Carbonatite
Medium - High
Variable - 10 μm
Flotation - medium
Medium Low
Not usually
Weathered carbonatite Medium 10 μm
and finer
Flotation - medium
Low-med Low
Not usually
Alkaline rock
High
Variable - 1
μm
and larger
Variable Variable High
Co-products common
Ion adsorption clay (in-situ leaching)
None
Beneficiation not needed
Leaching so can be high
Low
Low
None
Mineral sand (placer)
None
- Low
10 10 – 100 μm
Low
High
High
from TiO2 zircon etc production By-product of igneous apatite
High
100 μm-mm
Medium Low
High
from fertiliser manufacture
Red mud
Bauxite processing n/a REE from red mud
Medium?
Low
High
from Al production Figure 23: Examples of of rare earth element deposits and and qualitative analysis of of their mining and and processing characteristics Characteristics shaded yellow
64
are are are generally advantageous to responsible sourcing grey are are are less less so so and unshaded cells are are are less less favourable From Wall F F Rollat A Pell R R S
(2017)
. Figure 24: Image of tailings pond at Bayan Obo