MAXIMISING THE RECOVERY OF USEFUL METAL
FROM ORES: THE CHALLENGE
Metal By-Products Recovery Conference, Brussels - 12 November 2015
Dr Chris Broadbent BSc, PhD, CEng, CEnv, MAE
Director: Wardell Armstrong International Ltd
Coordinator: FAME Project
Contents
• Resource V Reserve
• Polymetallic Processes
• Case Studies
– Au / Sb from sulphides
– Zn / Pb from Fluorspar
– In from Sn ore
• Conclusions
Resource V Reserve
DEFINITIONS
JORC
MINERAL RESOURCES:
Potentially valuable and for which
reasonable prospects exist for eventual
economic extraction.
MINERAL RESERVES:
Valuable and legally, economically and
technically feasible to extract
Resource / Reserve Implication
If there is no proven processing route there
can never be a Reserve quoted and without a
semi-known route it is difficult to justify some
resource categories.
The Challenge (1)
TO DEVELOP TRULY
POLYMETALLIC PROCESSES
HISTORICALLY VERY FEW –
PERHAPS THE ONLY 20TH CENTURY
PYRO-METALLURGICAL PROCESS
THAT WAS A POLYMETALLIC
PROCESS WAS THE IMPERIAL
SMELTING PROCESS
The Challenge (2)
SUSTAINABLE METAL PRODUCTION REQUIRES
EFFECTIVE
AND
OPTIMISED
RESOURCE
UTILISATION – RECOVERY OF ALL VALUABLE
COMPONENTS
i.e. RECOVERY OF METAL BY-PRODUCTS
The Challenge (3)
•
ARE THERE EXISTING PROCESSING OPTIONS?
•
DO WE ALWAYS KNOW WHAT IS PRESENT – do we
know what we are missing?
•
IS THERE ACCESS TO FINANCE TO DEVELOP NEW
TECHOLOGIES?
Case Study 1
RECOVERY OF GOLD AND ANTIMONY FROM SULPHIDE
ORES (1)
PROBLEM:
LACK OF PRODUCTION CAPACITY FOR ANTIMONY
OR ANTIMONY OXIDE PRODUCTION
ALL FACILITIES OLD AND CAN’T HANDLE ORES
CONTAINING GOLD (i.e. GOLD NOT RECOVERED)
Case Study 1
GOLD / ANTIMONY (2)
FUNDAMENTAL RESEARCH NEEDED FOR THE ROASTING
ASPECTS OF A PROPOSED “NEW” PROCESS FLOW SCHEME
CONCERNS:
NO FACILITY IN EUROPE IDENTIFIED TO UNDERTAKE PILOT SCALE
ROASTING TESTS
PROCESS FLOW DIAGRAM:
Sb concentrate
Roasting
Fume Sb (+As / Zn)
controlled
quenching to precipitate various oxides
smelting Sb2O3
refining
to pure Sb
Case Study 1
GOLD / ANTIMONY (3)
KEY STEPS:
CONTROL OF QUENCHING TO
PRECIPITATE METAL OXIDES
ROASTING
No European Facility – therefore work
undertaken at Hazen, Colorado
Pb / Zn / As / Sb
Case Study 1
GOLD / ANTIMONY (4)
CALCINE:
CONTAINS GOLD SUBJECT TO CIL PROCESSING
FOR RECOVERY
No Au Plant to produce Gold from sulphidic ores
Client raised finance to construct facility in Oman
•Product Sb
•Recover Au
•Phase II
build Au Roaster – Recovery plant for Refractory gold
ores.
Case Study 2
REMOVAL AND
RECOVERY OF ZINC AND
LEAD FROM FLUORSPAR
ORES (1)
Case Study 2
REMOVAL AND RECOVERY OF ZINC AND LEAD FROM
FLUORSPAR ORES (2)
Case Study 2
REMOVAL AND RECOVERY OF ZINC AND LEAD FROM
FLUORSPAR ORES (3)
CHALLENGE
- FOR ACID GRADE FLUORSPAR
IMPURITY LEVELS NEED TO BE VERY
LOW
- OVERALL ≥97% CaF2
- But ppm levels Pb, Zn As
Case Study 2
REMOVAL AND RECOVERY OF ZINC AND LEAD FROM
FLUORSPAR ORES (4)
NEED HIGHLY EFFICIENT FLOTATION (OR OTHER SEPARATION
TECHNIQUES).
R&D NEEDED –
NEW REAGENTS?
NEW TECHNIQUES?
Case Study 3
RECOVERY OF BY-PRODUCTS FROM Sn ORES (1)
There are extensive tin (and tungsten) resources within
the EC (e.g. UK, Spain, Saxony) and elsewhere (e.g.
Syrymbet Kazakhstan) that are not exploited because
their relatively low tin content prohibits economic
production using current technology
Case Study 3
RECOVERY OF BY-PRODUCTS FROM Sn ORES (2)
Current Smelting
Technology - Needs
Cassiterite
concentrate
containing 60%+ Sn
Case Study 3
RECOVERY OF BY-PRODUCTS FROM Sn ORES (3)
• Many Sn Resources contain Indium + Tantulum, gallium,
germanium, scandium and niobium.
BUT - Minor Metals can not be included in Reserve (and / or
Resource) Statements.
• New Processing technologies – Extractive Metallurgy are
required to recover tin economically as well as the associated
by-products.
• Development of hydro or pyro-metallurgical routes designed to
maximise metal(s) recovery, recycled secondary material and
minimise environmental footprint
Case Study 3
RECOVERY OF BY-PRODUCTS FROM Sn ORES (4)
Mineral Processing
-
Extractive Metallurgy -
R&I Programmes such as FAME can
help
Pyrometallurgy – R&I needed
Hydrometallurgy – R&I needed
Development of these technologies can lead to:
• Utilisation of more European ores; and
• Increase to Resource / Reserves Base
Conclusions
•
•
•
•
•
•
•
Reserve for many By-product metals are often understated
Under International classification schemes such as JORC this is always
going to be the case unless there are proven recovery methods
Sustainable mining requires utilisation of all valuable components in an
ore
Truly poly-metallic Processing technologies are not common
Need to Develop new technologies both mineral processing
(beneficiation) a well as extractive (e.g. smelting) technologies to
recover multi-element components
General lack of experimental facilities in Europe
H2020 is addressing some of the technology issues
[email protected]
www.wardell-armstrong.com
www.fame-project.eu