uranium and thorium resources in chile prospection … · uranium and thorium resources in chile...

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


GEOLOGICAL AREA

5 Comisión Chilena de Energía Nuclear

MOST COMMON MINERAL OCURRENCES IN CHILE


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MOST COMMON MINERAL OCURRENCES IN CHILE



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


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 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.


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).


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.

18 Comisión Chilena de Energía Nuclear (Aragon Resources Limited).

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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)


Source: Uranium 2011: Resources, Production and Demand. (Red book)

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UNDISCOVERED CONVENTIONAL RESOURCES (Prognosticated and Speculative Resources)



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UNCONVENTIONAL RESOURCES AND OTHER MATERIALS



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URANIUM RESOURCES, CHILE (TONNES U)



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


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


Crushing

Milling

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AMONIUM DIURANATE - ADU

24242472244

4342 SO4OH3SO)(NH2OU)(NHOHNH6)(SOUO2 −− +++→+


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

Comisión Chilena de Energía Nuclear 75% U3O8


URANIUM DIOXIDE

OHNH2UO2TOU)(NH 2330

7224 ++→+

OHUONHUO 22223 +→++

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URANIUM TETRAFLUORIDE


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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• 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.


"Yellow Cake" obtained by treatment of ore from the Prospecto Productora.


• Rich electrolyte from SX is precipitated using NH4OH to pH 7.5, obtaining yellow-cake or ADU


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


(NH4)2 U2 O7 CaMoO4

PRODUCTS OBTAINED IN PHASE II


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

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