Recycling and back integration Concept The Recycling concept is the heart of our „Verbund“ system and fundamental for key processes and products within SF-Chem. Starting with salt and sulfur the two essential raw materials for all further activities are produced: chlorine and sulfur trioxide. The various chlorination and sulfonation reagents deriving from these starting materials are key compounds in the course of our Fine Chemicals and Custom Manufacturing activities. The gaseous by-products (HCl and SO2) formed during the various chlorination processes under captive use of our raw materials, are collected, separated and purified in a separate plant and fed back to the „Verbund“ system again.