An example can be found referring to the metal blasting process, performed grind, clean and polish metal and/or steel surfaces before painting. This process involves the use of silica sand because, due to its abrasive behaviour, it removes easily rust, past varnishes and other foreign substances. Blasting, however, involves the dispersion of dust particles into the environment, which, if inhaled, can severely harm the health of the operators. For this reason, it is advisable to provide an adequate aspiration and abatement system that, through the following steps, can protect the working environment:
- aspiration = dust is sucked directly to the source through the use of suction hoods;
- pre-abatement = coarse particles captured in the previous phase are pre-treated by cyclones – multicyclones separators;
- filtration = fine and ultrafine powders are treated tusing of special filters.