[en] Deposit formation during pressure leaching of ores, uranium ores in particular, can be suppressed by adding calcium sulfate powder to the neutral suspension of the ground ore particles in the recycled solution. Calcium sulfate particles constitute crystallization nuclei, eliminating oversaturation of the solution by this salt caused by temperature increase during the pressure leaching. Thus, a larger part of the oversaturation is eliminated by interaction with the nuclei, a minor part only being then engaged in interactions with the walls of the equipment. The amount of CaSO₄ added is 0.1 to 1 kg per m³ suspension. Leached pulp after neutralization with calcium hydroxide can be employed with advantage as the source of CaSO₄; the amount added is 2 to 20 litres of recycled neutralized pulp per m³ of fresh suspension. Addition of solid CaSO₄ directly to the ore prior to grinding is also convenient. (P.A.)

[en] The contaminated mine waters are acted upon with the leachate from sludge plant wastes in an amount of 1.5x10^-4 to 3.10^-4 l to one litre of mine water. One litre of leachate from sludge wastes contains 75 to 150 g of barium chloride. The method is intended for the decontamination of mine waters and for processing sludge plant wastes containing barium chloride and do not contain nitrites and cyanides. Following chloride-oxidation roasting it is possible to process wastes containing nitrites and cyanides. (M.D.)

[en] In the past, environmental monitoring of the facilities was done in accordance with the 'Directive for environmental monitoring of nuclear installations' of the GDR. In order to promote the process of establishing a harmonized German procedure of environmental monitoring, the former system is presented and is discussed from the viewpoint of the German 'Guideline for environmental monitoring of nuclear installations. (orig./DG)

[en] Ground and thickened ash obtained by fluidized-bed combustion of uranium coal is used to act upon residual pulp in a ratio of 0.2 - 0.8 tonne of ash to 1 tonne of low-leachable ore. The ratio depends on the concentration of free sulphuric acid, the density of residual pulp and the neutralization capacity of the ash. In the liquid phase which contains uranium leached from the ash, the content of free sulphuric acid is reduced to 5 - 20 kg/m³. (J.B.) 1 tab

[en] The pulp remaining after the leaching of ore that is difficult to leach, of aluminosilicate type in particular, is mixed in a stirred reactor with a ground and concentrated carbonate-type medium-leachible ore. The mixing ratio is determined by the neutralization capacity of the latter. The mixed pulp is additionally leached until the free H₂SO₄ content in the liquid phase decreases to 50-250 kg/m³. After this treatment, the acid can be additionally neutralized to the required concentration of 5-20 kg/m³ liquid phase by some conventional procedure. (P.A.)

[en] Papers published in 1975 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in vitro and in vivo, the biochemical, pharmacological and toxic effects, the mechanisms of protection of radioprotective agents and the trends in this field of research are described. (author)

[en] Papers published in 1978 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in in-vivo and model systems, the biochemical, pharmacological and toxic effects, and modes of action of radioprotective agents are described and the trends in this field of research appreciated. (author)

[en] Papers published in 1976 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in vitro and in vivo, the biochemical, pharmacological and toxic effects, the mechanisms of protection of radioprotective agents and the trends in this field of research are described. (author)

[en] It is suggested that dust from the production of ferroalloys of manganese, particularly ferrosilicomanganese and ferromanganese, can be conveniently used for oxidation during the acid leaching of non-ferrous ores, particularly uranium ores. This dust contains 30 to 40% oxides of manganese, about one-half of this is MnO₂. Iron in the dust is present in the trivalent form, and the dust is pefectly dry. The conventional grinding of oxidants for the ore processing is eliminated, the dust being available in particle size below 0.2 mm. The dust is added in amounts of 5 to 100 kg per ton of the ore, and the suspension is typically heated at 115 degC for 3.5 hr. (P.A.)

[en] Uranium ore pulp is introduced repeatedly, at least twice in succession, in the leaching process. Following each passage through the process, the liquid phase is partitioned as a separate fraction. For leaching the individual fractions, a different type of leaching medium, or different conditions of using the original leaching solution are applied. In fractionated leaching, the subsequent processing is simplified and very specific procedures and simpler separation methods can be used for the individual fractions. The resulting product shows significantly higher purity. (E.J