Iron filing in tea is becoming a major issue at present as the Food Safety and Standards Authority of India (FSSAI) had fixed stringent norms of maximum allowed level of iron filings in tea at 150 mg/kg. The global export market is also very much concerned about the presence of iron filing in tea. Hence it is a burning issue as well as a challenge to remove the iron filing quantitatively from tea at the source itself, i.e. in the online manufacturing process.

The iron filing generally comes to tea during the manufacturing process. The CTC cutter used for CTC tea manufacturing process is to be periodically sharpened (known as teething) which becomes the primary source of iron filing. Moreover, normal wear and tear of the other parts of the machineries used also are sources of iron filing.

The conventional removal process of iron filing in the factory is the use of a magnet and manually taking out the adhered iron particles from the magnet. It is a troublesome exercise as well as involves manpower. This method is not always satisfactory as the conventional Ferro magnets are not that powerful to remove adhered iron particle from made tea. Moreover, it is a tedious job to clean the once used magnet manually. Taking all these into consideration, an attachment to the on line manufacturing process has been conceptualized using special type of new generation rare earth magnets where the magnet never comes into direct contact of the iron filings but can quantitatively remove the Ferro magnetic particles including iron, cobalt and nickel and the alloys of these metals.

This attachment can conveniently be used in any online manufacturing tea factory at any point between the dryer mouth and the sorting point. The attachment can also be used in other food processing industries as well.

Concept and functioning of the attachment:
The processed material with probable iron filing contamination is fed to a tray which can be a conveyor belt. The material moves continuously forward over the surface of a fixed drum which experiences an asymmetrically rotating strong magnetic field. The Ferro magnetic particles (iron filing, cobalt, nickel and the alloys of these metals) are continuously pulled and thrown to the opposite direction of the material movement at the same time allowing the free movement of the iron filing free material in forward direction to another tray or conveyor.