[en] An in situ bag method was used to study, in natural soil conditions, the U solubilization from rocks and minerals and also the U fixation and preconcentration by soil constituents. By this means, interesting data are obtained. U solubilization depends not only upon the rock and mineral nature but also upon the humus type, induced by the nature of the vegetation and its associated microbial activity. Clays and non-transformed plant materials (cellulose, lignin) are not appropriate sinks for U, but ferric oxyhydroxides or microbial metabolites and microbial constituents appear as very efficient sinks that occur in preconcentration processes in soils. The in situ fixed amounts of U are lower than those obtained in laboratory experiments, but probably more realistic. Finally, this experimental method seems of great interest to study the U (but also other metals) behaviour in natural conditions. 16 refs.; 8 tabs

[en] The company has been dormant since May 1981 when the assets it was administering for the federal government of Canada, the stockpile of uranium concentrates, were transferred to Eldorado Nuclear Limited. Uranium Canada Limited was charged, together with five Canadian uranium producers, under the Combines Investigation Act with conspiring to prevent or lessen competition in Canada of the production, purchase, sale or supply of uranium and other uranium substances. The Supreme Court of Ontario and the Court of Appeal of Ontario declared the corporation immune from prosecution under the act

No abstract available

[en] Two major types of leaching performed in UCIL for uranium processing are acidic atmospheric leaching and alkali pressurized autoclave leaching. The selection of leaching is based on the characteristic of the ore. Tummalapalle unit operates based on pressurized alkali leaching whereas Jaduguda and Turamdih units are operating based on acidic atmospheric leaching. Drum filters are used for filtration in the Jaduguda unit. Ion exchange is used for increasing Uranium concentration. IX is a reversible interchange of one kind of ion present in an insoluble solid with another of like charge present in a solution surrounding the solid with the reaction being used especially for the separation of solute of importance. It is one of the major processes of Jaduguda and Turamdih unit. UCIL's Tummalapalle uranium extraction unit has adopted pressurized alkali leaching in autoclaves. Leaching is the process where solute becoming detached or extracted from its carrier substance through a solvent at standard operating condition. A series of unit operations and unit processes are involved in extraction of uranium from ore i.e. crushing, grinding, dewatering, filtration, leaching, clarification, precipitation, drying, etc. Advanced separation techniques are used in the entire process of extraction of uranium from ore and to convert it into desired product; sodium diuranate/uranium concentrate. In addition to this, UCIL and BARC did a series of R&D / trials in terms of separation science and technology on a lab scale and pilot scale to stabilize the process i.e. nanofiltration, centrifuge, ultrafiltration, ion exchange, candle filtration, re-dissolution, etc

[en] Method for concentrating a substance containing uranium and calcium in solution, whereby the solution is passed through a first separation system containing at least one semi-permeable membrane capable of concentrating the uranium, in order to concentrate it and allow through a significant portion of the solution to provide a current of uranium concentrate and a uranium-free current containing cations, anions and impurities of low molecular weight

[en] Within the framework of its activities in nuclear raw materials the International Atomic Energy Agency has convened a series of meetings to discuss various aspects of uranium ore processing technology, recovery of uranium from non-conventional resources and development of projects for the production of uranium concentrates including economic aspects. As part of this continuing effort to discuss and document important aspects of uranium production the IAEA convened a Technical Committee Meeting on Technical, Economic and Environmental Aspects of In-Situ Leaching. Although the use of this technique is limited by geological and economic constraints, it has a significant potential to produce uranium at competitive prices. This is especially important in the current uranium market which is mainly characterised by large inventories, excess production capability and low prices. This situation is not expected to last indefinitely but it is unlikely to change drastically in the next ten years or so. This Technical Committee Meeting was held in Vienna from 3 to 6 November 1987 with the attendance of 24 participants from 12 countries. Eight papers were presented. Technical sessions covered in-situ mining research, environmental and licensing aspects and restoration of leached orebodies; the technological status of in-situ leaching, the current status and future prospects of in-situ leaching of uranium in Member States, general aspects of planning and implementation of in-situ projects and the economics of in-situ leaching. Refs, figs and tabs

No abstract available

[en] Uranium Canada, Ltd., as agent on behalf of the federal government for dispositions from the joint and Government of Canada general stockpiles of uranium concentrates, concluded negotiations with Spanish and Japanese utilities re price and delivery adjustments in existing contracts. Most of the general stockpile remains committed to the domestic market. (E.C.B.)

[en] An investigation is reported of several damaged 17H 55-gal drums, from which natural uranium concentrate was spilled as a result of a truck accident. Spillage occurred when the drums were deformed such that the lids separated from the drums. It was concluded that this deformation was produced by quasi-static crush loading when the truck rolled over and the side of the truck impacted the ground. Laboratory tests that simulated this quasi-static crush loading were conducted on standard drums and on modified drums. It was found that an opening between the drum and lid was created only when the top of the damaged drum was lower than the tops of adjacent drum. In standard 17H drums, an opening was created typically at a crush of about 4 in and a force of about 15,000 lb. A cylindrical skirt, small enough to fit into the drum and attached to the bottom of the drum lid, prevented separation of lid and drum even at a crush of 7.5 in and a force of 15,000 lb. Drum integrity could also be significantly improved by placing a neoprene bag into the drum before placing the contents into the drum. The drum crush characteristic measured in the experiments were used as input to a nonlinear spring-mass analysis that was used to model the drum response in the accident. It was found that the predicted drum damage corresponded to the damage caused when the side of the truck impacted the gound at a velocity of about 15 fps. If the top drum restraint beams had been used it is likely that the drums would still have been crushed but would have been contained within the trailer after the trailer rolled over. 29 figures, 2 tables

No abstract available