Invotec Group to recover metals from crab shells

European PCB manufacturer Invotec Group will be participating in the Sustainable Treatment Of Waste Using Recycled Chitosans (STOWURC) project, which has been set up under the auspices of the UK’s Technology Strategy Board. Tim Tatton, Invotec Group’s managing director, said the project “promises to offer not only environmental but also commercial benefits”.

The UK’s seafood industry generates large volumes of shellfish waste, including the shells of crabs and other crustaceans. These shells are typically expensive to dispose of but are also a source of materials known as chitosans, which are known to have the capacity to absorb metals. The two-year STOWURC project is designed to develop the use of these waste products to recover metals from the effluent generated in PCB and related manufacturing processes.

A key aspect of the project will be to change the crab shells into useable materials, which will involve their mechanical and chemical conversion into a granular form with optimised absorption capabilities. The materials will then be evaluated over a range of operating conditions to determine how well they can absorb copper. Once saturated with copper, it will be desorbed into a solution from which it can be recovered as a metal by electroplating. 

The overall aim is to use the materials produced from the crab shells in a similar manner to ion exchange resins, so that once the metal has been desorbed, the chitosan materials can be re-used. The influence of absorption, desorption and plating conditions will be studied in order to optimise the overall process efficiency. Ultimately, the project partners are aiming to develop regenerable chitosan-based materials and to define accompanying processes for a range of metals.

The project consortium represents the whole requisite supply chain, from crab-shell suppliers to PCB fabricators. In addition to their own desires to develop and exploit the new technology, the partners have also identified international interest in using chitosan-based materials from PCB manufacturers and there are also potentially much larger applications in other sectors, including surface engineering and metal finishing.

Invotec Group joins fellow partners Kynance Cornish Crab, Chestech, Env-Aqua Solutions, C-Tech Innovation, the Surface Engineering Association and the Institute of Circuit Technology on the project.