Japanese scientists invent ecological cement

In June 2003, Japanese scientists invented a method for producing cement using municipal waste ash and sewage sludge as raw materials. This technology can turn waste into treasure and protect the environment, so its products are called "ecological cement."
The technology was jointly invented by the Japanese Government's New Energy and Industrial Technology Comprehensive Development Agency and Pacific Cement Corporation. The process is not much different from the firing process of ordinary cement: Ash, sewer sludge mixed with natural limestone after incineration of municipal waste is mixed in the rotary kiln, and then the solid after firing is crushed together with the plaster.
The difference is that the firing temperature of this cement is 1350 °C, slightly lower than that of ordinary cement 1500 °C. Since garbage contains 5% to 10% of chlorine in the ashes, the solidification rate of the fired cement is faster after adding water. If coagulation retarder is added, it can be used like ordinary cement.