398 KANSAS CITY REVIEW OF SCIENCE. 



"IRON SPONGE" FOR GAS PURIFICATION— A NEW INDUSTRY. 



Iron sponge is a term quite unfamiliar to the average reader, although the 

 manufacture of that article is now one of established industries of this city, and it 

 is shipped from this point to almost every state and territory in the Union. 



For the benefit of the uninitiated in the manufacture of gas we will explain 

 the nature of the new product and its uses. 



Coal gas, after being washed and condensed, remains heavily charged with 

 impurities in the form of sulphuretted hydrogen, ammonia and carbonic acid, 

 which must be extracted before the gas is fit for consumption, otherwise the odors 

 emitted by the gas while burning would be unbearable. 



To remove these impurities lime has— until within the last three years — been 

 universally employed, being considered the cheapest and most effective absorb- 

 ent, although its use entailed many disadvantages. As it could be used but once 

 the rapid accumulation of " spent lime" with its accompanying odors — familiar 

 to all persons living near gas works — necessitated hauling the same outside the 

 city limits, in many places being an expense of no little importance. 



Various experiments were made by those interested in the manufacture of 

 gas to find an absorbent equaling lime without its disadvantages, and success was 

 finally attained some three years ago. 



Iron sponge— the term given the successful rival to lime — is obtained by 

 treating oxides of iron in contact with carbon at a suitable heat with complete 

 isolation from the atmosphere, and its peculiar spongy texture is caused by the 

 loss of the volatile matter which, separating from the ore, leaves minute cells and 

 spaces throughout its entire mass, rendering it extremely sensitive to chemical 

 action. 



After being used and becoming thoroughly saturated with impurities, it is 

 exposed to the atmosphere for two or three days, which thoroughly revivifies it, 

 and it is again ready for use ; the same material being used over and over again 

 for the period of from one to three years, depending upon the condition of the 

 works, character of the coal used, etc. 



The advantages claimed for iron sponge over lime are : greater economy, 

 saving of labor, odors, etc., and it would seem not without reason, for since its 

 introduction into the gas works of this city it has been adopted in Philadelphia, 

 Cincinnati, Chicago, St. Louis, Kansas City, Sacramento, and scores of other 

 works of less importance, throughout the country. — American Manufacturer. 



