Abstract. In the present paper, we have studied the intensification of the desorption process of the complex anions of uranium U(VI), from ion exchange resins under the action of the ultrasonic field. The dynamics of uranium desorption from the anionic resins Purolite A600U/3472 and PM 611 was analyzed, both in standard conditions and with ultrasounds. The use of ultrasounds leads to the substantial growth of desorption kinetics and of the uranium recovery degree. The tests for stability of the resin grains size, mechanical resistance and the capacity of loading with uranium, after the repeated action of the ultrasounds field, emphasized the physical-chemical stability of resins used in the experiment (loading capacity of untreated resin 30.36 mgU/g resin and treated in continuous ultrasonic field 30.85 mgU/g resin).

Abstract. There are thousands of historical mine tailings and metallurgical residues present on inactive metal mining sites which have been abandoned. However, the potential release of dissolved metals, acidity, or suspended particulates from mine-waste dumps can be a serious and long-lasting problem. A variety of environmental impacts may occur at this abandoned mine sites and leading the list is acid generation, which is one of the main problems from metal mining. The objective of the present study was to characterize and evaluate the Romanian historical tailing of Sasar-Red Valley, near Baia Mare. This involved physical and chemical characterization of the materials and its acid generating potential. Sasar tailing impoundment contains 8.5 million m 3 of tailings and occupies an area of 32.5 hectares. Tailings samples were collected from different depths in three sampling points, and characterized by grain size, chemical elements concentration, elements distribution of elements in depth, paste pH, acid-base account and net acid generation tests. Acid base accounting (ABA) tests in conjunction with net acid generation (NAG) tests classified the samples into the category of 'potentially acid generating'. This paper presents a synthesis of works performed in the Improve Resource Efficiency and Minimize Environmental Footprint (REMinE) project.

There are thousands of historical mine tailings and metallurgical residues present on inactive metal mining sites which have been abandoned. However, the potential release of dissolved metals, acidity, or suspended particulates from mine-waste dumps can be a serious and long-lasting problem. A variety of environmental impacts may occur at this abandoned mine sites and leading the list is acid generation, which is one of the main problems from metal mining. The objective of the present study was to characterize and evaluate the Romanian historical tailing of Sasar-Red Valley, near Baia Mare. This involved physical and chemical characterization of the materials and its acid generating potential. Sasar tailing impoundment contains 8.5 million m3 of tailings and occupies an area of 32.5 hectares. Tailings samples were collected from different depths in three sampling points, and characterized by grain size, chemical elements concentration, elements distribution of elements in depth, paste pH, acid-base account and net acid generation tests. Acid base accounting (ABA) tests in conjunction with net acid generation (NAG) tests classified the samples into the category of ‘potentially acid generating’. This paper presents a synthesis of works performed in the Improve Resource Efficiency and Minimize Environmental Footprint (REMinE) project.

In the present paper, we have studied the intensification of the desorption process of the complex anions of uranium U(VI), from ion exchange resins under the action of the ultrasonic field. The dynamics of uranium desorption from the anionic resins Purolite A600U/3472 and PM 611 was analyzed, both in standard conditions and with ultrasounds. The use of ultrasounds leads to the substantial growth of desorption kinetics and of the uranium recovery degree. The tests for stability of the resin grains size, mechanical resistance and the capacity of loading with uranium, after the repeated action of the ultrasounds field, emphasized the physical-chemical stability of resins used in the experiment (loading capacity of untreated resin 30.36 mgU/g resin and treated in continuous ultrasonic field 30.85 mgU/g resin).