KOREA INSTITUTE OF GEOSCIENCE AND MINERAL RESOURCES

All of the CSA(4CaO·3Al 2 O 3 ·SO 3 ) cement, a special construction material for civil engineering are imported from other countries such as Japan and China due to a lack of bauxite, which does not exist in Korea. Therefore, Green Cement Technology is developed in order to replace CSA cement with Green Cement which utilizes low-quality limestone, power plant's bottom ash, and bauxite residues, a by-product of aluminum manufacturing. Early strength-low shrinkage clinker can be calcinated at a low temperature and has 4CaO·3Al 2 O 3 ·SO 3 base on portland cement, so it boasts its high performance with low shrinkage, a reduced crack, a wider application such as backfill in exhausted mine.

Low Carbon-High Functionality Green Cement was developed based on the technology of early strength-low shrinkage clinker using low-quality limestone and power plant's bottom ash as a main material. The problem of high contents of impurity such as SiO 2 and Fe 2 O 3 in low-quality limestone and power plant's bottom ash can also be solved by manufacturing and material combination method that secures quality safety.

For the demonstration of the Green Cement technology, pilot plant(2 tons/per day) was constructed within Danyang plant of Hanil Cement Co., Ltd. and simulated the optimal condition such as pre-heater‘s temperature, pressure, material balance, and calcination temperature balance. The pilot plant was equipped with a channel that protects volatile material from being accumulated at the bottom of pre-heater, improving manufacturing process.

The manufacturing temperature of early strength-low shrinkage clinker can be manufactured at 1300 ℃ (570kcal/kg_Clinker), a 150 ℃ lower than that of the existing clinker, 1450 ℃ (720kcal/kg_Clinker), saving 20% of the energy consumption. Low Carbon-High Functionality Green Cement can reduce about 2% of the CO 2 amount, which can be translated into 100,000 tons of the CO 2 reduction a year when producing 5 million tons of cements.