Continued multicolumns bioleaching for low grade uranium ore. Pdf a brief note on the heap leaching technologies for the. Uranium processing, preparation of the ore for use in various products. Uranium mining an introduction page 7 1 uranium mining an introduction 1. It is controlled by surface etching, diffusion, and mass transfer within the ore. Uranium is commonly understood as a material storing a huge energy and its only commercial application is as nuclear fuel. While investigating the importance of biogenic fe iii in the bio leaching process a maximum recovery of 84. Introduction, methods, application, copper, microorganisms, and processes. Leaching of uranium, radium and thorium from vertisol soil by ground water article pdf available in journal of radioanalytical and nuclear chemistry 2742.
Leach solutions will be removed from solution using a solvent extraction sx circuit which loads the concentrate uranium onto resin. Bioleaching of uranium pdf united pdf comunication. Request pdf an integrated multiscale approach to heap leaching of uranium ore agglomerates in heap leaching, agglomeration of clay rich ores is commonly used and may prevent plugging phenomena. App032 insitu leach uranium mining in the united states of america. In situ leach works by artificially dissolving minerals occurring naturally in a solid state. Pdf leaching of uranium, radium and thorium from vertisol. Evaluation of agglomerates using the kappes percolation test randall. Bioleaching of lowgrade uranium ore using acidithiobacillus.
Preconcentration by screening, gravity separation and radiometric sorting can. Designing heap leaching for nickel production that. Status of uranium mining in france and remediation issues aiea rls workshop grand junction colorado, us august 2124, 2012. If, at any time, two channels occupy the same grid point, they are merged. Uranium ore reserves an instruction manual, technical reports series no. The first use of cyanide for leaching of gold and silver ores was in england in 1887 by j. Mar 09, 2010 bioleaching of uranium was carried out with turamdih ore sample procured from uranium corporation of india limited, jaduguda. Heap leaching in some cases uranium has been removed from lowgrade ore by heap leaching.
The chemistry of the leaching process revolves around oxidation of the uranium compounds, which is typically achieved using manganese dioxide mno 2, sodium chlorate. The plant was originally designed to treat uranium ores with low limehigh vanadium content from the lukachukai mountains. But, sometimes the occurrence of uranium in sandstone provide an opportunity to recover the metal in an innovative method of extraction called insitu leaching, provided some necessary geological and geotechnical conditions are met. A nominal 50 pounds of 93% h2so4 acid per ton of mineralized material will be applied to the heap via a drip system to leach the contained uranium. Heap leach developments on low grade ores refractory minerals deemed difficult to leach brannerite, tirich coffinite karoo sandstone acid consumption high due to presence of carbonates calcite and dolomite investigating acid ferric leaching improve rate and extent of uranium dissolution increased acid dosages during agglomeration. Nuclear regulatory commission nrc has licensed numerous uranium recovery facilities in the united states, which used a variety of extraction methods. Bioleaching of uranium was carried out with turamdih ore sample procured from uranium corporation of india limited, jaduguda. The worldwide production of uranium in 2015 amounted to 60,496 tonnes. Selective leaching of desired metals often becomes possible through application of electrobioleaching under applied potentials, use of galvanic mechanisms, and in the presence of adapted microorganisms. Building a uranium heap leach project iaea scientific and. Acid leaching is sometimes also referred to as heap leaching because the leaching process can be performed on large heaps of uranium ore that have been collected from mines. The solution collecting in the bottom pit will include copper metal, which is removed by precipitation. Mar 31, 2015 comparison of conventional mill, heap leach, and in situ recovery facilities through the years, the u. Field operations include heap leaching of gold and silver ores in alkali conditions and copper ores employing acid leaching.
Etango uranium project heap leach demonstration program phase 2 november 2015. Uranium, from mine to mill world nuclear association. Heap leaching provides mining operators with a benign. Underhill, in iaea tecdoc720, uranium in situ leaching, proceedings of a technical committee held in vienna, 58 october 1992, september 1993. Recovery uranium from uraniumbearing waste ore using heap. In the mineralization under investigation uranium does not form a definite mineral but it is hosted by apatites. Based on the current understanding of uranium deposits in the commonwealth of virginia, extraction of uranium ore would use openpit mining, or underground mining, or a combination of both. The second step of this research is doing the nickel heap leaching in the micro industry scale by a variety of laterite sample height 0. The progression of metallurgical testwork during heap leach design. While it is possible to directly precipitate uranium from. In some cases, uranium is extracted from lowgrade ore by heap leaching.
Application of united nations framework classification 2009. Heap leaching of gold ore started to gain promenence in the late 1960s when it was applied on a large scale to low grade ores that were uneconomic to procees by conventional tank leach. Etango uranium project heap leach demonstration program. As the chemicals soak in, the uranium leaches into underground pipes that gather the solution. Heap leaching is used extensively for the processing of copper and gold ores. Biogenically generated ferric sulfate has been in vogue for many dump and heap leaching operations, to recover uranium and copper values. Bioleaching is one of several applications within biohydrometallurgy and several methods are used to recover copper, zinc, lead, arsenic, antimony, nickel, molybdenum, gold, silver, and cobalt. Bioleaching circuits can be made more flexible and simpler to merge with existing pyro and hydrometallurgical circuits. This is an early turning point in the microbiological leaching of uranium ores. Heap leaching is an extraction process by which chemicals usually sulfuric acid are used to extract the economic element from ore which has been mined and placed in piles on the surface. An integrated multiscale approach to heap leaching of. However, despite much progress since it was first applied in recent times, the process remains limited by low recoveries and long extraction times.
The opportunities for employing techniques aimed at reducing the capital and operating costs of the overall process such as heap leach and beneficiation. Test results indicate an overall recovery of 90% is achievable. Heap leach mining of uranium and associated risks in laymans terms not unlike insitu leach mining, heap leach mining is a process whereby uranium, copper and other precious metals are extracted from ore with a chemical solution. Heap leaching is generally economically feasible only for oxide ore deposits. Recovery of uranium by heap leaching is less common, with acid heap leaching used in hungary neaiaea, 2000 and and alkaline heap leaching process used in namibia schnell, 2010. Improving process controls at insitu leaching uranium mines natalya bokovoya1, biays bowerman2, michael browne3, colin carroll2, sean dunlop4, a. The goal of the present study was to compare uranium recovery by bioleaching and acid leaching in identical columns under similar process conditions for the same material.
Similar to in situ mining, heap leach mining differs in that it places ore on a liner, then adds the chemicals via drip systems to the. Sampling showed the microorganisms aerobic and anaerobic were present till 1. Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical reactions that absorb specific minerals and reseparate them after their division from other earth materials. A comparison of the uranium recovery from lowgrade ore by. Application of united nations framework classification. Bioleaching is the extraction of metals from their ores through the use of living organisms. Uranium mining constitutes the first step of the nuclear fuel cycle and its used for military and civilian applications. These general terms incorporate a large variety of design possibilitiesthere are as many methods of mining uranium as there are orebody sizes, shapes, and mineral constituents. In industry, bioleaching of uranium is still facing many problems such as site space, high cost of production, and limited industrial facilities. At the same time, the first modern copper heap leach operation may have been the bluebird copper oxide mine in 1968 bartlett, 1998, followed in the early 1970s by a few other small operations in the western united states. Uram conference, vienna 2014 uranium heap leaching.
Uranium mining, processing, and reclamation uranium mining. Further enhancing project knowledge designed, permitted, constructed and successfully commissioned large scale demonstration plant. Heap leaching is a tried and tested mining technique enabling the processing of different kinds of ores which could not otherwise be exploited under viable economic conditions. Typical operations take place for about one to three months per heap and the recovery achieved is at least 60% and may be as high as 85% in some cases. Uranium leaching uranium leaching is more important than copper, although less amount of uranium is obtained than copper. Kasabekov1, karen miller3, scott purvis5, gulnara yeligbayeva6. The bacterial strain that was used in the leaching experiments was isolated from the jaduguda mine water sample. This may be done if the uranium contents is too low for the ore to be economically processed in a uranium mill.
Heap leaching technology open research exeter university of. In situ leach isl mining of uranium june 2009 z most uranium mining in the usa and kazakhstan is now by in situ leach methods, also known as in situ recovery isr. University of pretoria i recovery of uranium from uranium residue by alkaline leaching by bundjoko kweto supervisor. Other important uranium producing countries in excess of 1,000 tons per year are niger, russia, namibia, uzbekistan, china, the. Leaching process was first observed in pumps and pipelines installed in mine pits containing acid water. The primary uranium mineralisation at etango is confined to leucogranites, locally referred to as alaskites. Pressure leaching has been in use since 1890s for recovery of numerous metallic ores with advances in hydrometallurgy. Leaching of uranium from milled ore can be arranged in the following ways. After 146 days of performance, the slag uranium leaching rate was 55. International journal of environmental science and development, vol. Another critical factor was the supply of water for the leaching heaps. Bioleaching has lots of advantages compared with traditional heap leaching. Cement, limestone or fly ash are used for heap leaching gold ores with cyanide, and could be considered for alkaline heap leaching of uranium ores or ammonia leaching. Pdf conventional heap leaching of uranium ore in the western.
Some operations use heap leaching, a process by which companies extract ore, break it into smaller pieces above ground and leach the pile with chemicals to separate the uranium. Generally heap leaching process is employed in copper leaching process but sometimes a combination of heap leaching and in situ leaching processes are used. Mechanism of uranium bioleaching there has been a longstanding debate as to whether the microbially assisted leaching of uranium ore is by direct or indirect mechanism. For many decades, there has been a growing demand for heap leaching due to its environmental benefits. Evaluation of agglomerates using the kappes percolation test. Heap leaching technologycurrent state, innovations, and future directions. The crushed ore is placed on a leaching pad with a liner. Microbial leaching of uranium ore 293 waste materials. This is much cleaner than the traditional heap leaching using cyanide. Status of uranium mining in france and remediation issues.
Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical. Etango uranium project optimisation study november 2015. Application of united nations framework classification 2009 unfc2009 for uranium resources uranium ore processing i. Heap leaching and its application to copper, uranium. Pdf heap leaching is a lowcost technology used in industrial mining to recover precious metals such as gold and uranium, along with several other. The front cover shows a general view of the mining area, and the back cover installations for heap leaching. Purification or separation of uranium in carbonate systems. In addition to conventional uranium milling and in situ recovery isr, which are currently used to extract uranium from ore, some nrclicensed facilities used extraction methods. The cover pictures are of the sierra pintada uranium district in the mendoza province of argentina. In this paper, a continued column bioleaching system has been established for leaching a certain uranium ore which contains. Heap leaching of gold ore started to gain promenence in the late 1960s when it was applied on a large scale to low grade ores that were uneconomic to procees by conventional tank leach methods. Biohydrometallurgy an overview sciencedirect topics.
Modern day heap leaching, which has a relatively low level of energy consumption, is for example. Microbiological leaching has been use as an alternative approach to conventional hydrometallurgical methods of uranium s extraction. The waste materials low grad e black schist consisted of 0. Pdf conventional heap leaching of uranium ore is neither a new. Designing heap leaching for nickel production that environmentally and economically sustain. The mill can be fed with a blend of different ores or the mill can treat various. The individual sheets may merge to form larger composite plutons or alaskite stockworks.
Copper recovery using leachsolvent extractionelectrowinning technology 65 figure 2 and a catalytic amount of lix 63, was introduced in 19657 and in march 1968 the first commercial copper lsxew operation, the bluebird plan of ranchers. A further advantage of ccix over fix is that it is capable of handling unclarified solutions with, in practice, solids contents of up to 12%3. Number of uranium mills and plants producing uranium concentrate in the united states. The uranium ore was st acked in heaps, similar to dump leaching of. When in situ leach isl is used, the ore remains underground and uranium is dissolved by appropriate lixiviants directly from the ore body. Heap leaching heap leaching is being done these days on relatively lowgrade ores for gold, copper and uranium recovery. T his chapter outlines the basic steps involved in mining, processing, and reclamation that might be suitable for uranium ore deposits in the commonwealth of virginia. This process was later on employed for recovering metals from ores containing low quantity of the metal. During 1952 and 1953, the plant at urgeirica started a uranium heap leaching process on a commercial scale. Notes of practical application of ion exchange resins in.
A brief note on the heap leaching technologies for the. Preconcentration by screening, gravity separation and radiometric sorting can potentially reduce the mass flow to the downstream leach and recovery plants. Comparison of conventional mill, heap leach, and in situ. Testing confirms the simple chemistry and efficient leaching nature of the granite host rock and uranium mineralisation. Heap leaching is a lowcost technology used in industrial mining to recover precious metals such as gold and uranium, along with several other highly sought after metals like copper, from their primary resources ores and minerals. The process utilized is known as the acid cure and had been developed for the most part by the aec to increase recovery of vanadium values. The solution sulphatefe 3 solution is sprinkled over the heap which percolates through the ore and collects at the bottom pit. The activity in leaching heaps is lower than that in ore stockpiles, and it can.
The leaching agent alkaline, or sulfuric acid is introduced on the top. Natural bioleaching has been taking place for almost as long as the history of the world, but it is only in the last few decades that we have realized that bioleaching is responsible for acid production in some mining wastes, and that this bacterial activity can be used to liberate some metals. Heap leaching today is applied to crushed ores, and modern heaps are designed to prevent ground contamination using a minimum of double containment, groundwater. Bannerman announced on 8 april 2014 the progression to a heap leach demonstration plant program as an integral step in progress towards the projects detailed engineering and financing phases. The technique of insitu leaching is a relatively unknown method in india, though it is. Operating means that an impoundment is being used for the continued placement of uranium. In the usa 200 tonnes of copper is recovered per day. Dr dr groot a dissertation submitted in partial fulfilment of the requirements for the degree of. Microbial leaching of copper has been widely used in the usa. A joint report by the oecd nuclear energy agency and the international atomic energy agency uranium 2014.
Uranium leaching with sulphuric acid is a complex process governed by chemical dissolution, and the oxidation of uranium. The isl produces clean pls with total suspended solids tss less than 50 ppm. Heap leaching is a wellestablished extractive metallurgical technology enabling the economical processing of various kinds of lowgrade ores, which could not otherwise be exploited. Insitu leaching isl, also called insitu recovery isr or solution mining, is a mining process used to recover minerals such as copper and uranium through boreholes drilled into a deposit, in situ. These are often sheetlike and predominantly occur as beddingparallel bodies which dip at between 15 and 40 degrees to the west. In the leaching of uranium, the bacteria do not directly attack the uranium mineral.
In the case of heap leaching, the uranium ore is mined, placed on a pad in heaps 530 metres high and irrigated with acid or alkaline solution over many weeks, leaching uranium into the resulting pregnant liquor, which is then collected and treated to extract the uoc. Phosphate fertilizers as a proliferationrelevant source. Nuclear regulatory commission nrc has licensed numerous uranium recovery facilities in the united states, which used a variety of extraction methods to glean uranium from ore. Etango uranium project heap leach demonstration program phase 1 july 2015. Kazakhstan, canada, and australia are the top three producers and together account for 70% of world uranium production. Dump heap leaching for copper, uranium lean oresin situ leaching for uranium and copper. Wmc copper uranium division copper ore heap leaching.
Building a uranium heap leach project henry schnell uram 2014 conference vienna, june 2014 ha schnell consulting inc. Heap leach and ionexchange facilities through the years, the u. Uranium mining is the process of extraction of uranium ore from the ground. Ranchers exploration and development corporation later merged with. Studies on uranium recovery from a uranium bearing phosphatic sandstone by a combined heap leaching liquidgel extraction process. Indeed, the metallic properties of uranium appear to be intermediate between those of silver and other true metals. For uranium ore deposits, the choice of mining methods and processing options is very depositspecific and dependent on many variables such as the quality and quantity of the ore, the shape and depth of the ore deposit, site. The leaching of uranium in the bioreactor improved the dissolution rate by reducing the time from 40 days in shake flask as per our earlier studies to 14 days. Microbial leaching of uranium ore hadi hamidian islamic azad university, qaemshahr branch iran 1. In this paper, a continued column bioleaching system has been established for leaching a certain uranium ore which contains high fluoride. Design of the heap leaching reactor in laboratory scale. The study has proven that recovery uranium from uranium bearing waste ore using heap bioleaching is feasible. Presently certain metals from sulfide ores and other ores are. Studies on uranium recovery from a uraniumbearing phosphatic.
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