NKK has developed the world's first technology using granulated blast furnace slag as a material for covering and insulating colloidal sediment accumulated on the seabed. The company recently delivered the slag for that use to the Ministry of Land, Infrastructure and Transport. The 54,000 metric tons of blast furnace slag was shipped from NKK's Fukuyama Works and laid gently over the seabed in the vicinity of the shore on the Japan Sea. The slag was laid over a 40,000 square m area (10 acres), with a thickness of more than 15 cm (6 inches) using a global positioning system.This technology was developed to maintain a habitable environment near the seabed by reducing the generation of orthophosphates and nitrogen oxides in the sea. Granulated blast furnace slag is laid on the seabed so that it can cover the colloidal sediment or sludge. This method also helps prevent the generation of hydrogen sulfide by keeping the condition of the seabed slightly alkaline with a pH level of 8.5. Moreover, since granulated blast furnace slag contains silicates that are essential nutrients for plants growing in water, the propagation of diatoms is enhanced and red tides are prevented.
展开▼
