Vertical Shaft Kilns (VSK) vs. Rotary Kilns

There are two main types of kilns to produce cement: the Vertical Shaft Kiln and the Rotary Kiln. The Vertical Shaft Kiln or VSK is probably the first type of kiln that was used and it can be traced back to the 5th century A.C. in Greece, when they were used for limestone calcining (Reiter, AC, 11/1997, p. 23). In the 20th century, they have been largely replaced by rotary kilns, which were implemented for the first time in 1880. However, in several countries such as China and India, many of these kilns are still operating (4000 units in China in 2005) and even, some companies still offer this technology for sale.

However, the Chinese government expects to close all mechanized shaft kilns by 2020 and that only 10% of the optimized vertical kilns keep operating. (Karstensen, UNIDO, 2006, p. 13)

SIME Ingenieros offers only rotary kilns with preheater tower, with or without calciner.

If you are deciding between a Rotary Kiln and a VSK, we expect that the following comparative chart may help you to make a decision. All information was extracted from the report made by Kåre Helge Karstensen for the United Nations Industrial Development Organization “UNIDO”: