Uranium and Thorium Resources in Chile
Prospection and Recovery Experiences
Pedro A. Orrego Alfaro M. Sc. – Metallurgical Engineer
9 – 12 Julio – 2013
Comisión Chilena de Energía Nuclear
Congreso Minero Mundial Interregional CYTED-UNECE-IAEA UNFC Workshop Colegio de Ingenieros de Chile Santiago, Chile
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Introduction
Uranium exploration in Chile
Legal status of uranium in Chile
Future activities required
Uranium metallurgy
Conclusions
TABLE OF CONTENTS
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NUCLEAR FUEL CYCLE, DEVELOPMENT IN CHILE
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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.
GEOLOGY & MINING SECTION
MAIN OBJECTIVES
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GEOLOGICAL AREA
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MOST COMMON MINERAL OCURRENCES IN CHILE
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MOST COMMON MINERAL OCURRENCES IN CHILE
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METHODOLOGY PROSPECTING OF URANIUM ORES IN CHILE
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RESOURCES, HYSTORICAL REVIEW
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1. Superficial deposits area, Upper Cenozoic
2. Metasomatic and vein related deposits areas, Upper Cretaceous
3. Hydrothermal - magmatic deposits area, Upper Cenozoic
MAIN METALLOGENIC PROVINCES IN NORTH OF CHILE
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GEOLOGICAL FAVORABILITY FOR URANIUM
Applying basic geological parameters
for major uranium deposits models
worldwide to national geology.
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Salar Grande, I Region
Cerro Carmen, III Region
MAIN PROSPECTS KNOWN IN CHILE
Phosphate rocks at Bahía Inglesa, III Region
Productora, III Region
Cerro Castillo, IX Region
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SALAR GRANDE
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• 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 U3O8 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
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CHILEAN PHOSPHORITES
AR survey
They occur in marine sediments of the continental shelf off the coast between 23°and 31°LS.
Sediments overly unconformably to Paleozoic basement.
From north to south, the main manifestations are Mejillones, Bahia Inglesa, Bahia Salado and Tongoy.
Phosphate rocks, phosphorites and vein deposits with apatite, all of them from low to medium quality grade in P2O5.
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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).
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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.
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• 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
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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.
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IDENTIFIED CONVENTIONAL RESOURCES (Reasonably Assured and Inferred Resources)
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Source: Uranium 2011: Resources, Production and Demand. (Red book)
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UNDISCOVERED CONVENTIONAL RESOURCES (Prognosticated and Speculative Resources)
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Source: Uranium 2011: Resources, Production and Demand. (Red book)
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UNCONVENTIONAL RESOURCES AND OTHER MATERIALS
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Source: Uranium 2011: Resources, Production and Demand. (Red book)
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URANIUM RESOURCES, CHILE (TONNES U)
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Source: Uranium 2011: Resources, Production and Demand. (Red book)
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.].
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Source: Investigación Geológica del Potencial de Uranio, Chile, Avance-2001. Cartera de Proyectos.
FUTURE ACTIVITIES REQUIRED
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LEGAL SITUATION OF URANIUM IN CHILE
Law 18,097 enacted on January 21, 1982 Article 3rd: “…… 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 10nth: “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 ......”
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METALLURGICAL AREA
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Leaching (H2SO4, Fe3+, MnO2, NaHCO3 – Na2CO3)
(UO2) (UO22+)
Acid (Ganga Silica) Basic (Ganga calcareous)
PLS
Ionic Exchange Solvent Extraction
Precipitation Yellow - Cake
(NH4)2 U2 O7
(NH4)4 UO2 (CO3)3
UO4 * 2H2O [U3O8] > 75 %
METHODOLOGY FOR OBTAINING URANIUM CONCENTRATES
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Crushing
Milling
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AMONIUM DIURANATE - ADU
24242472244
4342 SO4OH3SO)(NH2OU)(NHOHNH6)(SOUO2 −− +++→+
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Precipitation
(UO2(SO4)3)4-
NH4OH
(NH4)2U2O7
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AMONIUM URANIL CARBONATE - AUC
3433244324232 NONH2)(COUO)(NHCO)(NH3)(NOUO +→+
3433244232232 NONH2)(COUO)(NHCO3)(NH6OH3)(NOUO +→+++
OH3NONH2)(NOUO2HNO6OU)(NH 23423237224 ++→+
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OH3NONH2)(NOUO2HNO6OU)(NH 23423237224 ++→+
( ) 3S24222232 HNO2O2HUOOH2OH)(NOUO +×→++
BI-HIDRATED URANIUM PEROXIDE
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URANIUM DIOXIDE
OHNH2UO2TOU)(NH 2330
7224 ++→+
OHUONHUO 22223 +→++
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URANIUM TETRAFLUORIDE
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4HFFUOOH2UF 2226 +→+
O2HFSnClUF4HF2SnClFUO 2224222 ++→++
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4 2MgFUMg2UF +→+
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• The ore sample, has an average of 0.1011% U3O8, coming from Productora, located in near to of Vallenar city, III Region.
• Ore corresponds to Davidita (Fe2+, TR, U, Ca, Na, Zr, Th) (Ti4+, Fe3+, U, V3+, Cr3+)3 (O, OH)7), ilmenite weakly magnetic, further, secondary minerals idiomorphic to powdery types torbernite ((Cu(UO2)2Si2O5)3x5H2O) and autunite (Ca(UO2)2 (PO4)2x10-12(H2O)).
• 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 kgH2SO4/tonnes and 26 kg H2SO4/kg U3O8
R in the leaching stage. Comisión Chilena de Energía Nuclear
TREATMENT OF A RADIOACTIVE MINERAL, PROSPECTO PRODUCTORA.
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TREATMENT OF A RADIOACTIVE MINERAL, PROSPECTO PRODUCTORA.
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• Feed solutions to the SX showed a content of 1.8 g/L U3O8 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 U3O8 rich electrolyte of 20 g/L.
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"Yellow Cake" obtained by treatment of ore from the Prospecto Productora.
TREATMENT OF A RADIOACTIVE MINERAL, PROSPECTO PRODUCTORA.
• Rich electrolyte from SX is precipitated using NH4OH to pH 7.5, obtaining yellow-cake or ADU
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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.
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FLOW – SHETT PROPOSED TO DEVELOP IN RTD
IX Mo - U
Resin Regeneration
Solvent Extraction
U
Precipitation Mo
Elution Mo
Elution U
Precipitation U
Effluent Copper SX
H2SO4
Yellow - Cake
NH4OH NaCl
CaCl2 * 2H2O
Calcium Molibdate
PLS Copper SX
HCl
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ASOCIATION Cu – U – Mo : PROJECT CCHEN - CODELCO
CaMoO4 67% MoO3 (NH4)2 U2 O7 82% U3O8
PRODUCTS OBTAINED IN PHASE I
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(NH4)2 U2 O7 CaMoO4
PRODUCTS OBTAINED IN PHASE II
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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 UO2 and UF4 were developed.
• Metallic uranium was obtained by magnesiotermia process.
Gracias……………..
Identificación de Prospectos y Propuestas de Recuperación de Uranio y Tierras Raras en Chile 41
Gracias...
Pedro A. Orrego Alfaro M. Sc. – Metal lurgical Engineer Geology and Mining Sect ion Nuclear Materials Department Chi lean Nuclear Energy Commission Amunátegui N°95 Santiago, Chi le (562) 24702801 P.O.: 8340701 Email : [email protected] www.cchen.gob.cl