SULFURIC ACID. 31 



With this indeed ended the hardest struggle which met us in the 

 attempt to introduce the new sulfuric acid process into technical 

 industry. It was, however, by no means the last contest. When the 

 process came to be put in operation on a larger scale, new difficulties in 

 purifying the gases appeared, whose cause was almost as problematical 

 and unforeseen as those which have been already described. 



When the pyrites-burners were used to their full capacity, fumes 

 were formed which seemed to mock every effort at absorption. Their 

 cause was finally found to be the presence of unconsumed sulfur in 

 small quantities. Like the quickly cooled sulfuric acid fume, this 

 sulfur proved exceedingly difficult to remove. But how could this 

 unburned sulfur be detrimental, when in the contact-apparatus it would 

 burn to sulfur dioxid and sulfur trioxid ? The explanation rests in the 

 fact that this sulfur fume again contains traces of arsenic. This also 

 it was unconditionally necessary to remove. 



A radical means for this was finally found in thoroughly mixing the 

 gases while still hot, so that the combustion of the last trace of sulfur 

 was ensured. This mixing was accomplished by the injection of steam, 

 which was found to have other and not less important advantages. It 

 especially served to dilute the concentrated sulfuric acid in the gases, 

 so that they were no longer condensed in the preliminary cooling con- 

 ductors, and hence the evolution of arsin was avoided; when finally 

 condensed in the chief cooling apparatus which was made of lead, 

 they were so much diluted that they ceased to corrode the metal. 

 Furthermore the formation of hard dust-scale in the various conductors 

 was prevented, and danger of these becoming stopped up was avoided. 



* * * * 



In closing this lecture I may be permitted to place before you what 

 a development the sulfuric acid manufacture has enjoyed in our works 

 alone, since the introduction of this contact-process. The annual pro- 

 duction of sulfuric acid anhydrid has been: 



In 1888 18,500 tons. 



In 1894 39,000 tons. 



In 1899 89,600 tons. 



In 1900 116,000 tons. 



For the accomplishment of such a work the powers of a single 

 individual were naturally far too limited. It required the powerful 

 assistance of an establishment like the Badische Anilin- und Soda- 

 Fabrik, the keen and far-seeing direction of a Heinrich Brunck, the 

 experience of a Gustav Jacobsen, and the intelligent help of distin- 

 guished engineers, to bring to a successful completion such results as 

 those I have endeavored to describe in this lecture, and which stand as 

 an honor to the industrial progress of our fatherland. 



