What year did Thomas Edison invent cement?

Answer 1

Thomas Edison DID NOT invent cement! From Rutgers University's "Edison Papers" collection we learn the following: "While attempting to develop his ore milling process to concentrate low-grade iron ore, Edison found that he could sell the waste sand to cement manufacturers. In 1899, he decided to investigate how he might transfer his rock-crushing technology to the production of Portland cement. During the next few years, Edison made other improvements in cement manufacture, the most important of which was a long rotary kiln that he licensed to other manufacturers, as well as using at the automated plant he built in Stewartsville, New Jersey. The kiln helped lead to overproduction in the industry and the Edison cement plant was never very profitable. Edison Portland cement was used extensively for buildings, roads, dams, and other structures, including Yankee Stadium. Edison also designed a system for building inexpensive cement houses that he planned to license to other manufacturers. Only a few of these were ever built." http://edison.rutgers.edu/cement.htm