Review of silver recovery techniques from radiographic effluent and X-ray film waste

This paper highlights the techniques for silver recovery from radiographic waste; effluent and X-ray films. The decline in silver natural resource has increased the cost of sourcing for pure silver. The ecological problems caused by the disposal of radiographic waste is a huge motivation for increased recovery, regeneration and recycling process. The negative impact of pure silver on human and the environment is low but its soluble salt and emission from its recovery process pose a great risk to the ecosystem. Pyro-metallurgical processes of silver recovery requires heat >950°C which also destroys the polymer substrate. Hydrometallurgical processes such as electrolysis, metallic replacement, chemical precipitation and adsorption, are often used and provides high purity and efficiency. A proposed research work for silver recovery based on chemical precipitation using oxalic acid has been presented.