Uranium and Thorium Resources in Chile Prospection and

Transcripción

Uranium and Thorium Resources in Chile
Prospection and Recovery Experiences
Congreso Minero Mundial
Interregional CYTED-UNECE-IAEA UNFC Workshop
Colegio de Ingenieros de Chile
Santiago, Chile
Comisión
Chilena
de
Energía
Nuclear
Pedro A. Orrego Alfaro
M. Sc. – Metallurgical Engineer
9 – 12 Julio – 2013
TABLE OF CONTENTS

Introduction

Uranium exploration in Chile

Legal status of uranium in Chile

Future activities required

Uranium metallurgy

Conclusions
Comisión Chilena de Energía Nuclear
2
NUCLEAR FUEL CYCLE, DEVELOPMENT IN CHILE
3
GEOLOGY & MINING SECTION
MAIN OBJECTIVES
 To establish, increase and maintain of currently geological
estimation of the potential Atomic Natural Materials and
Interested
Nuclear
Materials
in
the
country,
to
the
governmental considerations into national policies, also,
requirement of public and private companies.
 To develop and investigate technologies for the concentration
and purification of Atomic Natural Materials and Interested
Nuclear Materials and/or solutions that contain them.
4
GEOLOGICAL
AREA
5
MOST COMMON MINERAL OCURRENCES IN CHILE
MOST COMMON MINERAL OCURRENCES IN CHILE
7
METHODOLOGY PROSPECTING OF URANIUM ORES IN CHILE
8
RESOURCES, HYSTORICAL REVIEW
9
10
11
MAIN METALLOGENIC PROVINCES IN NORTH
OF CHILE
1.
Superficial deposits area, Upper Cenozoic
2.
Metasomatic and vein related deposits
areas, Upper Cretaceous
3.
Hydrothermal - magmatic deposits area,
Upper Cenozoic
12
GEOLOGICAL FAVORABILITY FOR URANIUM
Applying basic geological parameters
for major uranium deposits models
worldwide to national geology.
13
MAIN PROSPECTS KNOWN IN CHILE
Salar Grande, I Region
Cerro Carmen, III Region
Phosphate rocks at Bahía Inglesa, III Region
Productora, III Region
Cerro Castillo, IX Region
14
SALAR GRANDE
•
Pull-apart basin, salt flat, formed by tectonic accomodation
structures related to Atacama fault system in Pleistocene
•
Previosly explored by ESSEX minerals in 1977-1981
•
Lens
shaped
and
erratic
mineralization
of
carnotite
and
schroeckingerite from 200 up to 1,000 ppm of U 3 O 8 in blue halite
•
3 Structural dominions
– Dextral N-S faults dipping 80 – 70 °E
– NW-SE transpressive dextral lineations (Salar Grande fault
system, with extensional T type faults associated)
– E-W Normal faults, dipping 50 – 60 °N
•
10
radiometric
anomalous
zones,
related
to
these
fault
intersections
15
CHILEAN PHOSPHORITES
 They occur in marine sediments
of the continental shelf off the
coast between 23°and 31°LS.
 Sediments
unconformably
basement.
to
overly
Paleozoic
 From north to south, the main
manifestations are Mejillones,
Bahia Inglesa, Bahia Salado and
Tongoy.
AR
survey
 Phosphate rocks, phosphorites
and vein deposits with apatite,
all of them from low to medium
quality grade in P 2 O 5.
16
CERRO CARMEN
•
Located 20 km NW of Diego de Almagro city in III Region, north of
Chile.
•
Chargeability anomaly associated.
•
Disseminated davidite-mineralized bodies, in a 400×2.000m zone at
surface.
•
Skarn deposit with uranium (U) and Rare Earth Elements (REE)
associated, hosted in intermediate to basic volcanic rocks.
 Other elements also present, like Th, Ti, Fe, Y and Sc.
•
In a structural trend NW with emplacements of monzonitic and
aplitic intrusive rocks from upper Cretaceous age with K
metasomatism and mineralization of U and REE.
 In the contact of volcanic rocks from La Negra Formation
(Pliensbachian to upper Jurassic), with Sierra Aspera Pluton
(Neocomian).
17
PROSPECTO PRODUCTORA
 12 Km SW of Vallenar city in III region.
 Ryolites (hauterivian-barremian)
in
contact
with
middle
Cretaceous
intrusive unit.
 Hydrothermal
alteration
zone
of
3x0.7km, trending N10W.
 Development of regional and contact
methamorphism
and
potassic
metasomatism,
enhancement
of
perthitic structures.
(Aragon Resources Limited).
18
•
Mineralized dikes, after
hydrothermal
alteration
they add chlorite and Fe +3
to the system, and also P is
released from apatite
•
Fixation of uranium as
torbenite and austenite in
Prospecto Productora
19
RESULTS FOR THE EXPLORATION OF URANIUM
7% of the Chilean continental territory has been explored.
The main results are:
 1,200 radio-metric and geochemical anomalies.
 80 occurrences of Uranium and Thorium.
 70 Sectors of interest.
 10 Uranium Prospects of Thorium and Rare-earth metals.
 In 4 prospects, preliminary geological studies have been conducted.
20
IDENTIFIED CONVENTIONAL RESOURCES
(Reasonably Assured and Inferred Resources)
Source: Uranium 2011: Resources, Production and Demand. (Red book)
21
UNDISCOVERED CONVENTIONAL RESOURCES
(Prognosticated and Speculative Resources)
22
UNCONVENTIONAL RESOURCES AND OTHER MATERIALS
23
URANIUM RESOURCES, CHILE (TONNES U)
24
FUTURE ACTIVITIES REQUIRED
 Training and formation of new human resources.
 Update uranium exploration techniques and equipment.
 Focus of exploration on first priority areas and development of projects in
“Project Portfolio” [Uranium geological research projects needed to improve
understanding of deposits models detected, define new models and advance in
determining the country's uranium potential.].
Source: Investigación Geológica del Potencial de Uranio, Chile, Avance-2001. Cartera de Proyectos.
25
LEGAL SITUATION OF URANIUM IN CHILE
 Law 18,097 enacted on January 21, 1982
Article 3 rd : “…… They are concessible, and for them any interested party
may be constitute a mining concession, all substances metallic and
nonmetallic minerals, and in general, all fossil substances, in whatever
form they are naturally present……”, “…… No mining concession
susceptible liquid or gaseous hydrocarbons, lithium,……”
 Law 18,248 enacted on September 26, 1983, “CODIGO DE MINERIA”
Article 10 nth : “The State has, at regular price and market arrangements,
the right first choice purchase of mining products originated in mines
developed in the country in which the thorium and uranium have
significant presence…...” “……the producer must notify their production
to Chilean Nuclear Energy Commission so that it can exercise that right by
the State, and will point out the quantity, quality and other
characteristics of the product, its market price and the manner, timing
and place of delivery ......”
26
METALLURGICAL
AREA
27
28
METHODOLOGY FOR OBTAINING URANIUM CONCENTRATES
Crushing
Milling
Leaching (H2SO4, Fe3+, MnO2, NaHCO3 – Na2CO3)
(UO2)
(UO22+)
Acid (Ganga Silica)
Basic (Ganga calcareous)
PLS
Solvent Extraction
Ionic Exchange
(NH4)2 U2 O7
(NH4)4 UO2 (CO3)3
UO4 * 2H2O
Precipitation
Yellow - Cake
[U3O8] > 75 %
29
AMONIUM DIURANATE - ADU
NH4OH
(UO2(SO4)3)4-
Precipitation
(NH4)2U2O7
2 UO 2 (SO 4 ) 3−4 + 6 NH 4 OH → (NH 4 ) 2 U 2 O 7 + 2 (NH 4 ) 2 SO 4 + 3 H 2 O + 4 SO 4
30
−2
AMONIUM URANIL CARBONATE - AUC
(NH 4 ) 2 U 2 O 7 + 6 HNO3 → 2 UO 2 (NO3 ) 2 + 2 NH 4 NO 3 + 3 H 2 O
UO 2 (NO3 ) 2 + 3 (NH 4 ) 2 CO 3 → (NH 4 ) 4 UO 2 (CO 3 ) 3 + 2 NH 4 NO 3
UO 2 (NO3 ) 2 + 3 H 2 O + 6 (NH 3 ) + 3 CO 2 → (NH 4 ) 4 UO 2 (CO 3 )3 + 2 NH 4 NO3
31
BI-HIDRATED URANIUM PEROXIDE
(NH 4 ) 2 U 2 O 7 + 6 HNO3 → 2 UO 2 (NO3 ) 2 + 2 NH 4 NO 3 + 3 H 2 O
UO 2 (NO3 ) 2 + H 2O 2 + 2 H 2O → UO 4 × 2H 2O (S ) + 2 HNO3
75% U3O8
32
URANIUM DIOXIDE
(NH 4 ) 2 U 2 O 7 + T 0 → 2 UO 3 + 2 NH 3 + H 2 O
UO 3 + H 2 + N 2 → UO 2 + H 2 O
33
URANIUM TETRAFLUORIDE
UF6 + 2 H 2 O → UO 2 F2 + 4HF
UO 2 F2 + 2SnCl 2 + 4HF → UF4 + SnCl 2 F2 + 2H 2 O
UF4 + 2Mg → U 0 + 2MgF2
34
TREATMENT OF A RADIOACTIVE MINERAL, PROSPECTO PRODUCTORA.
• The ore sample, has an average of
0.1011% U 3 O 8 , coming from Productora,
located in near to of Vallenar city, III
Region.
• Ore corresponds to Davidita (Fe 2+ , TR, U,
Ca, Na, Zr, Th) (Ti 4+ , Fe 3+ , U, V 3+ , Cr 3+ ) 3 (O,
OH) 7 ), ilmenite weakly magnetic, further,
secondary minerals idiomorphic to
powdery
types
torbernite
((Cu(UO 2 ) 2 Si 2 O 5 ) 3 x5H 2 O) and autunite
(Ca(UO 2 ) 2 (PO 4 ) 2 x10-12(H 2 O)).
• The ore, after being crushed and
conditioning, was leached with sulfuric
solutions in “pad”.
• The obtained results can be summarized
in the recovery of 89% of the uranium
and an acid consumptions of around 32
kgH 2 SO 4 /tonnes and 26 kg H 2 SO 4 /kg U 3 O 8
R in the leaching stage.
35
• Feed solutions to the SX showed a content of 1.8 g/L U 3 O 8 and pH 1,
which are contacted with the organic phase in three stages arranged
in series, it was obtained refining concentrations lower than 0.01
g/L.
• Feeds loaded organic phase stripping stage generating U 3 O 8 rich
electrolyte of 20 g/L.
36
• Rich electrolyte from SX is precipitated using NH 4 OH to pH 7.5,
obtaining yellow-cake or ADU
"Yellow Cake" obtained by treatment of
ore from the Prospecto Productora.
37
ASOCIATION Cu – U – Mo : PROJECT CCHEN - CODELCO
 The objetive of this project was recover uranium and molybdenum in its
commercial forms, from hydrometallurgical processes. In consideration
of CODELCO, the business opportunity is interesting, since the potential
contribution of this project allows a reduction of the net cost of copper
production of the Division.
 The proposed processes by Chilean Nuclear Energy Commission,
involves directly co-extract Mo and U from RT’s aqueous solutions
employing hydrometallurgical techniques.
 In response to low concentrations of these elements in aqueous
solutions, the process proposed uses ion exchange techniques to
concentrate these elements, after that, them are separated by solvent
extraction and precipitating.
 The Mo and U recovered was precipitate obtained Yellow Cake and
Calcium Molybdate.
 The results demonstrate that it is technically feasible to recover
molybdenum and uranium from RT‘s acid solutions.
 The efficiencies of the used processes, are possible to improve.
38
FLOW – SHETT PROPOSED TO DEVELOP IN RTD
PLS Copper SX
Effluent Copper
SX
IX
Mo - U
H2SO4
HCl
Resin
Regeneration
CaCl2 * 2H2O
Elution
U
Solvent
Extraction
U
NH4OH
NaCl
Elution
Mo
Precipitation
U
Precipitation
Mo
Yellow - Cake
Calcium Molibdate
39
ASOCIATION Cu – U – Mo : PROJECT CCHEN - CODELCO
PRODUCTS OBTAINED IN PHASE I
(NH4)2 U2 O7
82% U3O8
(NH4)2 U2 O7
CaMoO4
67% MoO3
CaMoO4
PRODUCTS OBTAINED IN PHASE II
40
CONCLUSIONS
• 7% of the Chilean continental territory has been prospected.
• The 93% of the country has not yet been prospected for uranium and
thorium.
• The future prospecting project in the country should be focused on
priority areas and to the development of activities included in the
project portfolio, corresponding to 179 projects.
• Chile has declared a total of 3,728.8 tonnes of uranium as “RAR + SAR I”.
• Two kinds of uranium concentrates were obtained: ammonium diuranate
and ammonium uranyl carbonate, commercial quality and nuclear purity.
• At laboratory level, processes to obtain UO 2 and UF 4 were developed.
• Metallic uranium was obtained by magnesiotermia process.
41
Gracias……………..
Gracias...
Identificación de Prospectos y Propuestas de Recuperación de Uranio y Tierras Raras en Chile
41
Pedro A. Orrego Alfaro
M. Sc. – Metallurgical Engineer
Geology and Mining Section
Nuclear Materials Department
Chilean Nuclear Energy Commission
Amunátegui N°95
Santiago, Chile
(562) 24702801
P.O.: 8340701
Email: [email protected]
www.cchen.gob.cl

Uranium and Thorium Resources in Chile Prospection and

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