On the friability of mussel shells as abrasive

The spread of raft-farming of mussels in river estuaries around the world produces about 1.4 million tons of shell waste which mainly ends up in landfills. In addition, the United Nations and the European Union promote the sustainable development goals (SDG) for sustainable food production, which requires adequate waste management to analyse the life cycle and reuse of goods and materials. This work proposes to use mussels shells by-products created by the canning industry as abrasive in the sandblasting process. One of the main characteristic of abrasive grains is the friability, which determines the behaviour of the abrasive in the sandblasting process. Shells need to be prepared before using in sandblasting, a conditioning that involves cleaning, grinding and sieving of shells. The purpose of this work is to examine the friability of mussel shells from two points of view, the effect of the cleaning process and a comparison with a common abrasive material, the garnet. The characterisation of the friability of mussel shells allows to foresee the behaviour as abrasive and to define the most suitable applications. The obtained results reveal that garnet is four times more friable than shells thanks to shells biocomposite nature. This interesting feature enlarges the life of sand in close cycles and foresees a promising future to the new abrasive.