Status of the organized recycling of cadmium-bearing secondary raw materials

Abstract

The main methods being used in metallurgy to systematically recycle cadmium-bearing secondary raw materials are examined. Hydrometallurgical methods which use sequestering reagents that can be regenerated are the most promising technologies from the standpoint of suitability for industrial use, environmental safety, and the selectivity with which cadmium is extracted. Keywords: cadmium-bearing secondary raw materials, regenerable sequestering reagents.Alkaline nickel-cadmium power sources are widely used in different areas of the economy (from mine lamps to the pulling accumulators of electric locomotives and submarines). Their favorable combination of technical-economic and electrical characteristics has made them one of the main chemical sources of electric current.Nickel-cadmium power supplies account for about 10% of all chemical current sources in use [1]. Their volume of use and recycling in Russia cannot be estimated because there is no legal framework that regulates recycling of the hazardous wastes. Having such laws would make it possible to control the collection and recycling of storage batteries that have exhausted their service life.Spent nickel-cadmium current sources are complex multicomponent raw materials: the phase composition and dimensions of the batteries vary widely and depend on the battery's specific function. The battery may contain different additives that improve its service properties, and the quantity and composition of these additives also vary. As a result, it is necessary to use unconventional multistage methods to recycle used batteries [2].The organized recycling of alkaline nickel-cadmium batteries has become important for environmental, economic, and technological reasons. The selective recovery of metals from such a multicomponent resource -a resource which is characterized by a wide range of compositions -is a challenging problem that requires new research. The recycling of wastes of this type is particularly important in the case of nickel-cadmium batteries because of the simultaneous presence of substantial quantities of valuable nickel and highly toxic cadmium. Any recycling technology that is developed should therefore be designed so as to fully recover these metals in the finished product, thus preventing the formation of gaseous emissions and keeping these metals out of waste water.Consequently, the following requirements must be met by a technology used to recycle nickel-cadmium batteries:• it must be environmentally clean and safe;• a high percentage of the valuable components should be recovered;• the equipment used should be as simple as possible; and • the technology should yield high-quality products suitable for the production of new storage batteries. Existing pyrometallurgical methods essentially involve the sublimation of cadmium oxide at high temperatures. There are three main pyrometallurgical methods of recycling nickel-cadmium batteries: 1) sublimation of cadmium oxide in an open furnace followed by its condensation in the form of a powder [3,4];

Determination of recovered Cadmium and Nickel from spent alkaline batteries using acidic solutions and AAS measurements

“…Recycling that constitutes the most generally acceptable environmentally friendly method of managing these wastes must be taken seriously, to minimize environmental toxicity, for economic gains and a reduction in dependence on foreign resources or on virgin materials for productions in the industry as well as for the sustainability of the natural resources [3]. Any recycling technology that is developed should therefore be designed so as to fully recover these metals in the finished product, thus preventing the formation of gaseous emissions and keeping these metals out of waste water [4]. Hydrometallurgical routes are commonly found more economical and efficient than pyrometallurgical ones.…”