A world increase in demand for antioxidants is being reflected in orders for the Sandvik Supercooling process plant for the production of antioxidant pastilles. Antioxidants are used as stabilisers in the plastics and tyre industry. Without them a tyre would harden, drastically shortening its operational life and reducing its elasticity properties. The supercooling process incorporates the Rotoform SC, used to produce antioxidant pastilles, and has designed, developed, supplied and installed more than 50 plants worldwide. Recently it supplied a third plant to National Organic Chemical Industries Ltd, India’s largest manufacturer of rubber chemicals and one plant to KUMHO Korea which is now the third Sandvik installation in their production of antioxidants. The automatically operated plant consists of heating and cooling skid, precrystallizer skid, Rotoform, steel belt cooler and intelligent programmable logic control system offering a complete package for continuous operation that requires only the occasional operator intervention. Key to the production of the antioxidant pastilles is the supercooling process using also the Rotoform SC, which is specially developed for this purpose. This process overcomes the problem of the melt remaining liquid even when cooled below its melting point, known as a subcooling melt. It solidifies these difficult subcooling melts by introducing a homogeneous suspension of crystal nuclei into the melt. This enables the slurry to crystallize quickly on the water-cooled steel belt of the Rotoform. Monitoring and control of the entire continuous process is carried out at every stage routed via the central process control unit, which ensures the settings remain constant.
