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135 YEARS AGO - 1882

Patent Specification

A long tradition of sustainability: First patent for a recycling process

The traditional process for separating precious metals from their ore that was in
use in the mid-1800s was beset with serious ventilation problems. When the silver
was separated, sulfurous acid was released that also formed a thick white fog
on the chimneys of Degussa’s refineries in Frankfurt. Sinking onto the surrounding
streets, this bothered the neighbors, leading to continuous complaints.
To remedy this situation, Heinrich Roessler, Degussa’s technical director, developed
a “Method to eliminate sulfurous acid from foundry smoke and factory gases
using copper sulfate and atmospheric air.” This method, for which a patent was
applied on December 17, 1882, involved a recycling process, namely extensive
recovery of the sulfuric acid. Other European refineries were quick to adopt this
clean method. At Evonik there is a long tradition of sustainability, which is now a
central pillar of the corporate strategy.